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Climate Watch 2017
Climate Watch - Issue #23
06 December 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
October started off with the first summer thunderstorms over large parts of the summer rainfall region. Many areas reported 10 mm and more during the first 10 days of the month. Some noticeable... Read more
Climate
Climate Watch - Issue #23
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
06 December 2017Monthly Overview
November started off with good rainfall over the Western Cape and the west coast region. Isolated thundershowers caused rainfall over North-West, Gauteng, Mpumalanga and KZN during the first week. During the second week, the cape region remained dry with isolated showers, but most parts of the summer rainfall region received good rainfall with many parts of Limpopo, Mpumalanga and KZN receiving more than 40 mm.
From the 15th of the month and onward, a large cold front brought cold weather to South Africa, and snow fell over the Eastern Cape and Drakensberg mountains. Good rains were received along the coastal regions stretching from the Western Cape northwards towards KZN with more than 50 mm over the northern Eastern Cape and most parts of KZN.
During the 4th week, the western parts of the Western Cape received good rains while large parts of the summer rainfall region received good rainfall - with more than 50 mm over most of Mpumalanga.
The month ended with good rainfall over the north-eastern Free State and KZN.
Rainfall
Good rainfall - more than 80 mm - fell over large parts of the summer rainfall region, most notably Gauteng, Mpumalanga and KwaZulu-Natal.
Figure 1: Total rainfall estimation in millimetres for 1 to 30 November 2017
Figure 2: Percentage difference - rainfall for 1 to 30 November 2017.
Figure 2 gives perspective for November. Rainfall of well-above the norm for this time of year occurred over large parts of the winter rainfall region while good rain fell over the western parts of the Northern Cape, the southern parts of the Eastern Cape, Gauteng, Mpumalanga, and isolated areas of KZN. The eastern parts of the Northern Cape and the western parts of the Free State all received below normal rainfall.
Figure 3: Cumulative rainfall from 1 june 2017 to 30 November 2017 in millimetres.
This cumulative rainfall map (Figure 3) for 1 June to 30 November highlights those areas that received more than 150 mm during the period: Light green indicates areas receiving between 150 and 200 mm; dark green indicates areas receiving between 200 and 300 mm; and areas that received more than 400 mm, are indicated in blue.
Figure 4: Percentage difference - rainfall for 1 June 2017 to 30 November 2017.
Figure 4 highlights those areas that received below and above-normal rainfall during the last 6 months. Yellow to light brown show areas of concern while isolated areas throughout the country highlighted in green, received above normal rainfall during the last 6 months.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). Possibility of La Nina conditions developing this December. Normal to above-normal rainfall is expected for the summer rainfall region during the 2017/18 rainfall season.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for November 2017 compared to the long-term (20-year) average.
Figure 6: This map is created by calculating the difference between November 2017, and the long-term  (20-year)average for November. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Free State, the northern parts of KZN, the western and eastern parts of Limpopo and the western parts of the Eastern Cape and isolated areas of the Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in November 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape, western & southern Northern Cape. Conditions remain neutral over the summer rainfall region but these conditions should start changing with the first summer rains.
General Discussion
Figure 8: South African dam levels between November 2017 and December 2017
In the current marketing year (April 2017 to May 2018, of produce from 2016-17 growing season), there has been a strong recovery in most commodities, following the droughts of the preceding seasons. The exception is the Western Cape where dry conditions persist.
The maize crop is expected to be the second largest on record - about 14.5 million tons, while soybean sales are expected to increase by 66% to reach 1.2 million tons, the highest ever. South Africa will return to being a net exporter of maize.
In the summer-rainfall areas of the country, some good rains in October and November have ensured the establishment of dry-land cereal crops for the coming season.
The full effects of the current drought in the Western Cape, particularly on grape production, are still unclear while table grapes will possibly be less affected than wine grape production. Table grape output will be reduced in the Berg and Hex River regions, and to an extent in the Oliphant's River area, but grapes growing in the Orange River projects, have been unaffected by the drought and yields are expected to be slightly bigger than last season. Consequently, the effect of the drought on national production levels is expected to be less pronounced than expected, because of these variations between production areas.
The drought has had a huge impact for livestock farmers in the western cape. Herd numbers are being reduced as farmers are battling to feed their animals. This has had a negative impact on farm workers in the area mainly due to job losses. On top of the drought conditions, high feed costs and severe water restrictions, high fire risks will develop. Animals are also more prone to health issues due to stress and poor condition.
For the summer rainfall regions, increased insect activity puts many animals at risk for insect-borne diseases such as lumpy skin, rift valley fever and bluetongue, etc. Farmers who have not vaccinated their animals in time should consult with a veterinarian to discuss control measures. Control of internal and external parasites is also essential to guard against important parasitic diseases and keep animals in good health.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #22
08 November 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
October started off with the first summer thunderstorms over large parts of the summer rainfall region. Many areas reported 10 mm and more during the first 10 days of the month. Some noticeable... Read more
Climate
Climate Watch - Issue #22
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
08 November 2017Monthly Overview
October started off with the first summer thunderstorms over large parts of the summer rainfall region. Many areas reported 10 mm and more during the first 10 days of the month. Some noticeable rainfall totals during the week include Bothaville 40 mm, Boshof 30 mm, Lephalale 32 mm and Mopane 40 mm. A major system moved over the country on the 9th and 10th of October with high rainfall over many areas, mainly the Eastern Cape, with KwaZulu Natal suffering considerable storm damage. Durban harbour was forced to close as a result. Highest rainfall figures include; Ramsgate 95 mm, Durban 108Â mm, Elliot 55 mm, with 30 cm of snow at Tiffindell.
The next 10 days of the month was rather quiet, with many areas receiving a little rain.
Most areas received rain during the final 11 days of the month, while more intense thunderstorms were experienced at Perdekop in Mpumalanga reporting 94 mm, Boksburg 30 mm, Secunda 40 mm, Ulundi 33, and Nylstroom 30 mm. Yet another cold front causing snow over the Drakensberg ended the month off with a cold weekend.
Rainfall
Good rainfall - more than 60 mm - fell over large parts of the summer rainfall region, most notably northern Eastern Cape and southern KZN.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 October 2017
Figure 2: Percentage difference - rainfall for 1 to 31 October 2017.
Figure 2 gives perspective of the rainfall for October. Rainfall of well-above the norm for this time of he year, occurred over large parts of the summer rainfall region. Good rain fell over most parts of the Northern Cape, North West, Gauteng, Limpopo, northern Eastern Cape, southern KZN and isolated areas in Mpumalanga. The eastern Western Cape and western Eastern Cape, northern KZN and eastern Free State received below normal rainfall.
Figure 3: Cumulative rainfall from 1 May 2017 to 31 October 2017 in millimetres.
This cumulative rainfall map (Figure 3) for 1 May to 31 October highlights those areas that received more than 150 mm during the period: Light green indicates areas receiving between 150 and 200 mm; dark green indicates areas receiving between 200 and 300 mm; and areas that received more than 400 mm, are indicated in blue. The map highlights the drought over the winter rainfall region with total rainfall below 200 mm, over most areas for the 6 months so far.
Figure 4: Percentage difference - rainfall for 1 May 2017 to 31 October 2017.
Figure 4 highlights those areas that received below-, and above-normal rainfall during last 6 months. Yellow to light brown show areas of concern. Below-normal areas include the Western, Northern, and western Eastern Cape areas, as well as the eastern Free State and north western KZN. Large areas over southern KZN, north eastern areas of the Eastern Cape, western Free State, Gauteng, Mpumalanga and  Limpopo received above normal rainfall for the last 6 months.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). Normal to above-normal rainfall is expected for the summer rainfall region during the 2017/18 rainfall season.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for July 2017 compared to the long-term (19-year) average.
Figure 6: This map is created by calculating the difference between October 2017, and the long-term (20-year) average for October. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen on the west coast, western Eastern Cape & Western Cape. Higher vegetation activity can be seen over large parts of the summer rainfall region as a result of good early seasonal rainfall.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in October 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape, western & southern Northern Cape. Conditions remain neutral over the summer rainfall region but these conditions should start changing with the first summer rains.
General Discussion
Figure 8: South African dam levels between September 2017 and October 2017
After some rains, drier conditions in October favoured summer crop planting, especially maize. Similarly, after recent periods of beneficial rainfall, drier weather aided harvesting in the eastern maize belt. Rain in the Western Cape was minimal and the situation grows increasingly dire.
During the spring months insect activities increase. Control of flies and other insects as well as internal and external parasite control is important. Animals should be vaccinated for all important diseases in their areas. A veterinarian can be consulted regarding a health programme for the farm.
During the month of October there were reports of changing weather conditions such as rainfall, dry conditions, cold fronts. It is important that farmers follow weather reports and warnings and plan ahead. Severe winds in dry areas can exasperate veld fires. Cold snaps can affect newly born lambs and kids during lambing and kidding seasons.
The avian influenza caused major losses in several provinces, resulting in the culling of thousands of birds as well as causing a shortage of eggs (and subsequent price increase of eggs). The number of reported cases is likely to drop during the warmer months, however biosecurity practices is still very important and any suspected cases must be reported to a State Veterinarian.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #21
05 October 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
The first ten days of September continued with the July/August trend of cold fronts bringing rain to the Western and Eastern Cape, while the rest of South Africa remained dry. Extremely warm temperatures for September... Read more
Climate
Climate Watch - Issue #21
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
05 October 2017Monthly Overview
The first ten days of September continued with the July/August trend of cold fronts bringing rain to the Western and Eastern Cape, while the rest of South Africa remained dry. Extremely warm temperatures for September were recorded over large parts of the northern regions, with temperatures reaching well above 30° C around the 10th of September.
During the second ten days of the month warm temperatures (above 30° C), dominated the northern regions. A strong cut-off low pressure system developed along the southern coastline bringing good rains to the Eastern Cape. As a result of this system, George and Port Elizabeth reported as much as 50 mm and 40 mm respectively on the 15th of September. As the system moved northward along the coast, it generated gale force winds over KZN and many areas reported damage as a result. The first summer thunderstorms were reported on the 17th of September bringing rain to large parts of the summer rainfall region - welcome relief from the high temperatures experienced.
Most areas of South Africa received rain during the last week of September, most notably, the summer rainfall region. Large parts of the eastern Free State and Mpumalanga reported hailstorms between the 24th and 26th of September.
Rainfall
Good rainfall - more than 60 mm - fell over isolated parts of South Africa, most notably just north of Kimberly and along coastal areas around Port Elizabeth. While most areas received rain during September, in many instances it turned out to be less than 20 mm.
Figure 1: Total rainfall estimation in millimetres for 1 to 30 September 2017
Figure 2: Percentage difference - rainfall for 1 to 30 September 2017.
Figure 2 gives perspective of the rainfall in September. Rainfall over large parts of the summer rainfall region proved to be well above the norm for this time of year, especially over parts of the North West and Free State receiving more than 500% of their normal rainfall for the month. Good rain fell over Mpumalanga and Gauteng. The Western and Eastern Cape provinces received below normal rainfall with only some areas around Port Elizabeth receiving good rains.
Figure 3: Cumulative rainfall from 1 April 2017 to 30 September 2017 in millimetres.
This cumulative rainfall map (Figure 3) for 1 April to 30 September highlights those areas that received more than 150 mm during the period: Light green indicates areas receiving between 150 and 200 mm; dark green indicates areas receiving between 200 and 300 mm; and areas that received more than 400 mm, are indicated in blue. The map highlights the drought over the winter rainfall region with total rainfall below 200 mm, over most areas for the 6 months so far.
Figure 4: Percentage difference - rainfall for 1 April 2017 to 30 September 2017.
Figure 4 highlights areas that received below-normal, and above-normal rainfall over the last 6 months with yellow to light brown highlight areas of concern. Isolated areas over KwaZulu-Natal received normal rainfall for this period. Since the six-month period covers the winter rainfall season, it is to be expected that the summer rainfall region will show below-normal rainfall. It is of concern, however, that the winter rainfall region shows below-normal rainfall for the entire winter rainfall season. Early rainfall over the summer rainfall region in September means that large areas show above normal rainfall for this time of year.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). There is a possibility of La Nina conditions developing at the start of the South African summer. Normal to above-normal rainfall is expected for the summer rainfall region during the 2017/18 rainfall season.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for July 2017 compared to the long-term (19-year) average.
Figure 6: This map is created by calculating the difference between September 2017 and the long-term (20 year) average for September. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the west coast, western Eastern Cape & Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in September 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape and western Northern Cape. Conditions remain neutral over the summer rainfall region but these conditions should start changing with the first summer rains.
General Discussion
Figure 8: South African dam levels between September 2017 and October 2017
The first rains of summer fell over the interior of the country with predictions of possible good summer rainfall to follow. This could bode well for the estimated 2.46 million hectares of maize that was reportedly planted - lower than the five-year average and only slightly higher than last season.
However, if rainfall is less than normal, there is a likelihood of South Africa becoming a net importer of maize next season. Even if it is a normal year, yellow maize may still have to be imported. On the other hand, if rainfall is as predicted, we might be a net exporter of maize, causing the prices to be close to export parity levels Meanwhile in the Cape, hope for late rains receded. In fact, recent water-usage tipped into deficit as a change of -0.1% was recorded over the past week in the province's dam levels. For the week prior to this, there was a small rise of 0.4% in the levels. Various measures are being implemented to use crop irrigation water as expediently as possible during the coming summer.This time of the year is marked with sudden changes in weather conditions, cold fronts are still bringing rain and cold winds, along the coast while the northern regions may experience hot weather with thunderstorms and fire risks. Farmers should follow weather reports and warnings and ensure their livestock are well protected for these adverse weather conditions.
Many cases of plant poisoning are reported during the spring months. Farmers should be especially aware of the poisonous plants in their areas at this time of the year. Some plants (or plant parts) are more poisonous at this time of the year. Coming out of the dry season, hungry animals may be quite vulnerable. Farmers must ensure that animals are vaccinated against Pulpy kidney - animals coming out of the dry season may overeat on lush pastures after the rains and risk succumbing to this deadly disease.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #20
07 September 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
Rainfall during August occurred mainly over the Western and Eastern Cape provinces, and KwaZulu-Natal. Rain in these provinces were regularly accompanied by cold fronts as they made landfall over the Western Cape... Read more
Climate
Climate Watch - Issue #20
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
07 September 2017Monthly Overview
Rainfall during August occurred mainly over the Western and Eastern Cape provinces, and KwaZulu-Natal. Rain in these provinces were regularly accompanied by cold fronts as they made landfall over the Western Cape, before moving north eastward bringing rain and snow.
Despite the regular cold fronts, rainfall produced by these systems remained relatively small, not exceeding 10 mm in most instances. Two cold fronts did, however, have a major impact during the month. The first major cold front brought heavy rainfall to the Eastern Cape with Port Elizabeth receiving 52 mm, and Cape St Francis 57 mm, in 24 hours.
The next major cold front that affected large parts of South Africa made landfall on 16 August over the Western Cape. This system cause major snowfalls over the Western Cape, Eastern Cape and Drakensberg mountains causing temperatures to drop to its lowest levels for August across the country. This system brought heavy rain to large parts of the Eastern Cape province and southern KwaZulu-Natal.
Rainfall
While the Western and Eastern Cape did receive rainfall as a result of frontal systems in August, rainfall was well below normal over most areas. The dam levels for the Western Cape currently is on average 32% compared to 58% last year.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 August 2017
Figure 2: Percentage difference - rainfall for 1 to 31 August 2017.
Figure 2 gives perspective of the rainfall in August. The unseasonal rain over parts Limpopo is highlighted with the blue and green. Areas around Durban extending southward received good rains while the majority of South Africa remained dry. The Western Cape remains in a tight grip of the devastating drought with below normal rainfall over most of the Winter Rainfall region resulting in only a small increase in dam levels.
Figure 3: Cumulative rainfall from 1 March 2017 to 31 August 2017 in millimetres.
This cumulative rainfall map (Figure 3) for 1 March to 31 August highlights areas that received more than 150 mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200 mm; dark green colours indicate areas that received between 200 and 300 mm; areas that received more than 400 mm are indicated in blue. This map highlights the drought over the winter rainfall region with total rainfall below 200 mm, over most areas for the 6 months so far.
Figure 4: Percentage difference - rainfall for 1 March 2017 to 31 August 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall, over the last 6 months. Yellow to light brown highlight areas of concern. Isolated areas over KwaZulu-Natal received normal rainfall over this period. Since the 6-month period covers the winter rainfall season, it is to be expected that the summer rainfall region will show below-normal rainfall. It is of concern, however, that the winter rainfall region show below-normal rainfall for the entire winter rainfall season.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). Normal to above-normal rainfall is expected for the summer rainfall region during the 2017/18 rainfall season.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for July 2017 compared to the long-term (19-year) average.
Figure 6: The map is created by calculating the difference between August 2017 and the long-term (20 year) average for August. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the west coast, Eastern & Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in August 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape and western Northern Cape. Conditions remain neutral over the summer rainfall region but these conditions should start changing with the first summer rains.
General Discussion
Figure 8: South African dam levels between August 2017 and September 2017
Forecasting the size of the maize crop becomes more accurate at this late stage of the season. It has been adjusted upwards to 16.4 million tons making it the largest on record and 4.0 million tons could be exported; however, international maize prices are low and exports may end up being lower than expected.
The total summer grain production could be double that of the previous season. Winter grain production, however, is likely to decline by 16% from 2016 - a consequence of the poor winter rains in the Western Cape.
Of most concern in the Western Cape are the water reserves for irrigation during the dry summer period. Improving the irrigation efficiency, through more precise monitoring and other means, has now become very important. The ranking of growers' orchards in terms of returns per cubic meter of irrigation water used (rand/m3) is also being suggested. Those trees which are performing poorly would be removed and the water saved used more efficiently on better performing orchards.
The dry conditions across the country dry conditions across the country increases fire risk and farmers should continue to monitor weather warnings of strong winds and high fire incidents. The dry weather also increases the risk of plant poisoning cases as animals seek greenery. Warnings of cold fronts bring rain and cold winds are also important especially over the lambing and kidding season.
Farmers should consult their local vets regarding vaccines as well as dipping and deworming schedules to follow during the spring months.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #19
07 August 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
The month of July was a quiet month weather wise for South Africa. The month was categorised by dry weather over the interior of the country, with cold fronts bringing rain to the Western and Eastern Cape on a weekly basis... Read more
Climate
Climate Watch - Issue #19
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
07 August 2017Monthly Overview
The month of July was a quiet month weather wise for South Africa. The month was categorised by dry weather over the interior of the country, with cold fronts bringing rain to the Western and Eastern Cape on a weekly basis. However, the rainfall received during July over these areas remained well below normal which is of major concern for the drought stricken Western Cape.
An upper air trough caused unseasonal rainfall over parts of the summer rainfall region during the start of the month. The rest of the month was dominated by dry conditions. While the Cape region got used to regular cold fronts, the only system of note made landfall during the weekend of 15/16 July. This system brought rain to large parts of the Western Cape, but was also responsible for heavy snowfalls over the Western and Eastern Cape as well as Drakensberg mountains causing temperatures to drop to below zero with most areas of the country experiencing its coldest conditions this winter.
On a positive note, conditions are expected to remain neutral over the Pacific Ocean with no El Nino predicted for the 2017/18 summer rainfall season. Normal rainfall is expected for the summer rainfall region with a possibility of higher than normal rainfall over the drought stricken Western Cape.
Rainfall
While the Western and Eastern Cape did receive rainfall as a result of frontal systems in July, the rainfall was well below normal. With dam levels already at record low levels for this time of year, July didn't bring any relief to the drought stricken Western Cape.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 July 2017
Figure 2: Percentage difference - rainfall for 1 to 31 July 2017.
Figure 2 gives perspective of the rainfall for July 2017. The unseasonal rain over parts of the summer rainfall region (Gauteng, Mpumalanga & Limpopo) is highlighted with the blue and green colours. Areas around Durban extending northward also received good rainfall. The majority of South Africa remained dry. The Western Cape remains in a tight grip of the devastating drought with below normal rainfall over most of the Winter Rainfall region resulting in only a small increase in dam levels.
Figure 3: Cumulative rainfall from 1 February 2017 to 31 July 2017 in millimetres.
This cumulative rainfall map (Figure 3) for 1 February to 31 July highlights areas that received more than 150 mm during the last 6 months: Light green colours indicate areas receiving between 150 - 200 mm; dark green colours indicate areas that received between 200 and 300 mm; areas that received more than 400 mm are indicated with the blue colours. This map highlights the devastating drought over the winter rainfall region with total rainfall below 200mm over most areas for the 6 months so far.
Figure 4: Percentage difference - rainfall for 1 February 2017 to 31 July 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (Northern South Africa) received normal to above normal rainfall during the last 6 months while isolated areas, indicated in yellow (southern Free State, Limpopo and Eastern Cape), received below-normal rainfall. Severe drought is highlighted in the brown colours and include the Western Cape and the western parts of the western Northern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). Normal rainfall is expected for the summer rainfall region during the 2017/18 rainfall season, with a possibility of above normal rainfall for the drought stricken Western Cape region.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for July 2017 compared to the long-term (19-year) average.
Figure 6: The map is created by calculating the difference between July 2017 and the long-term (20 year) average for July. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern & Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in July 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape and western Northern Cape. Higher vegetation conditions can be seen over the Free State, north-eastern Northern Cape, and North West.
General Discussion
Figure 8: South African dam levels between July 2017 and August 2017
It was anticipated that the volumes of pome fruit (apples and pears) being exported from the Western Cape would increase by 5% this year because of new orchards coming into production, and despite the dry conditions. However, the drought and heat-wave conditions were more severe than expected and estimates have been adjusted downwards to 6 to 9% less than last season. Pear exports are down by 5% and apples even more.
Unusual weather conditions in the Eastern Cape during June have affected citrus orchards. Exceptionally strong winds caused extremely high evapo-transpiration from the leaves of some Valencia oranges (Midnight variety) to such an extent that leaves fell off, followed by the fruit; it is estimated that ½ million to a million cartons have been lost. Navel oranges were less affected because their root-stock enables a strong flow of sap replacing moisture lost from the leaves.
The month of July saw more cases of avian flu bringing the total to10. Four were reported on commercial farms while the rest were found in wild flocks as well as back yard flocks. Strict movement regulations were put in place. It is suspected that wild migratory birds carried the disease over from Europe and biosecurity is essential to prevent the spread of avian flu. There is no vaccination for avian flu.
Biosecurity is not only necessary to contain the avian flu, but for all animals in general especially breeding animals. A number of venereal diseases as well as Brucellosis is on the rise. These diseases have severe negative impacts for farmers and animals bought should be tested negative for these diseases.
Vaccinations and parasite control should be kept up to date. Many diseases can be prevented by vaccinations and parasites are not always dormant in winter. With the weather warming up, many parasites and vectors will increase in activity and it is important to keep up to date with vaccinations and treatment plans. A vet should be consulted to draw up a health programme.
Weather wise, August is known as a windy month with fluctuating temperatures as we near Spring. Fire warnings should be noted and animals protected from the elements especially during cold fronts that bring rain and snow.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #18
07 July 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
June 2017 started with a cold front making landfall over the Western Cape bringing much needed rain to the drought stricken area. A few days later a second cold front also hit the Western Cape and the resultant storm counted as one of the biggest to hit the Western Cape in... Read more
Climate
Climate Watch - Issue #18
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
07 July 2017Monthly Overview
June 2017 started with a cold front making landfall over the Western Cape bringing much needed rain to the drought stricken area. A few days later a second cold front also hit the Western Cape and the resultant storm counted as one of the biggest to hit the Western Cape in more than 50 years. The storm brought widespread rain, but it was the high seas and gale force winds (75 to 100km/h) that caused most damage. The storm caused snowfalls over the mountain areas in the Western and Eastern Cape and resulted in the coldest day of winter, over the interior of the country. The storm will also be remembered for the role the high winds played in the devastating Knysna and Plettenberg Bay fires.
Unfortunately a number of people lost their lives, and nearly 10 000 people were displaced as a result of the fiery devastation that took almost a week to bring under control. Eventually more than 4 000 people were left homeless as their homes totally destroyed by the fires. Early estimates indicated the total damage to exceed R 4-billion.
The Western Cape continued to receive intermittent rainfall due to the cold fronts.. Towards the end of the month, a cold front caused snowfalls on the Drakensberg mountains resulting in cooler temperatures over the interior of the country.
Rainfall
With winter settling in over South Africa, the only major rainfall fell over the Western Cape with isolated areas receiving more than 100mm. The drought stricken Western Cape needs much more rain before the devastating drought in the area will be broken.
Figure 1: Total rainfall estimation in millimetres for 1 to 30 June 2017
Figure 2: Percentage difference - rainfall for 1 to 30 June 2017.
Figure 2 gives perspective of the rainfall for June 2017. The western parts of the country received most of the rainfall during June. Isolated areas, shown in green, over the western parts of the Western Cape and western Northern Cape received 100% or more of its normal rainfall. The rest received 75% or more as indicated in yellow. While the western parts of the Eastern Cape remained dry, areas in the east and interior of the province received between 75 to 125% of their normal rainfall. The rest of South Africa remained dry with isolated areas that received rain during the month of June.
Figure 3: Cumulative rainfall from 1 January 2017 to 30 June 2017 in millimetres.
This cumulative rainfall map (Figure 3) for 1 January to 30 June highlights areas that received more than 150 mm during the last 6 months: Light green colours indicate areas receiving between 150 - 200 mm; dark green colours indicate areas that received between 200 and 300 mm; areas that received more than 400 mm are indicated with the blue colours. Large parts of the summer rainfall region has received more than 400 mm during the last 6 months.
Figure 4: Percentage difference - rainfall for 1 January 2017 to 30 June 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (Northern South Africa) received normal to above normal rainfall during the last 6 months while isolated areas, indicated in yellow (southern Free State, and Eastern Cape), received below-normal rainfall. Severe drought is highlighted in the brown colours and include the Western Cape and the western parts of the Northern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). Prediction models tend to be less accurate during the autumn months and will become more accurate as we move towards June 2017 (winter).
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for June 2017 compared to the long-term (19-year) average.
Figure 6: The map is created by calculating the difference between June 2017 and the long-term (20 year) average for June. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern & Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in June 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape and western Northern Cape. Higher vegetation conditions can be seen over the Free State, north-eastern Northern Cape, North West and Limpopo provinces.
General Discussion
Figure 8: South African dam levels between 6 February 2017 and 27 February 2017
The current drought affecting the Western Cape could have long-term effects not only on agriculture in the province, but also on the economy of the country as a whole. The two broad factors which could impact on the economy are firstly the fact that the Western Cape is responsible for more agricultural exports than any other province. Fruit, nuts, wine, table grapes and citrus constitute more than 50% of exports. Although some crops such, as tropical and sub-tropical fruit, are grown in other provinces, the production of wine grapes, deciduous fruits, nuts and, to an increasing extent citrus, is centred in the Cape. Secondly, more agricultural workers are employed in the Western Cape than any other province (24.5% of all agricultural employees). The drought is likely to have a major impact on seasonal employment in the fruit industry; lower production will result in fewer seasonal workers being employed. In general, restricted financial margins will affect agriculture employment levels, with consequent socio-economic implications.
The storms and fires in the Western Cape during June had a devastating effect on farmers over and above the crippling drought they are experiencing. Livestock died as a result of the fires and many were displaced, while grazing land, farm fences and infrastructure was destroyed. It is important that animals be identified to help with tracing of displaced animals and farmers should ensure they comply with the law and have animals identified with legal markings. Animals suffering burns need to be assessed over several weeks as the extent of burn wounds is not known immediately and need to be monitored on a daily basis to prevent infection.
Towards the end of June there was an outbreak of Avian Influenza detected on a farm near Villiers in the Free State as well as another farm in Mpumalanga. Sales of live hens were banned and strict regulations were put in place to control the outbreak. It has been reported that wild migrating ducks may have carried the disease over into South Africa. Biosecurity measures are critical to limit movement on a farm and prevent the spread of the disease. Farmers should continue to watch weather reports for adverse weather conditions and fire warnings. During the dry season fires are common and can spread quickly. Cold fronts often bring winds, rain and snow and very young and old animals are especially vulnerable and should have access to shelters and kept warm.
Acknowledgements:
Mr. Dawie Maree, FNB Agribusiness Unit
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #17
08 June 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
April is the month of the year when Autumn really weather sets in over South Africa. With dryer air in circulation over the country, minimum temperatures dropped to the low teens in most parts of the summer rainfall region, with maximum temperatures dropping to the mid twenties... Read more
Climate
Climate Watch - Issue #17
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
08 June 2017Monthly Overview
The month of May started off with rainfall over the Eastern Cape during the first week, while the rest of South Africa remained dry with mild temperatures. During the second week of May the first major cold front of the 2017 winter season made landfall. In comparison, the first cold front in 2016 made landfall in April while in 2014 and 2015 the first cold fronts made landfall only in June.
The first cold front brought rainfall to large parts of the Western Cape before moving inland bringing rainfall over the Free State and moving on to Gauteng where heavy rainfall was experienced throughout the weekend. The cold front was responsible for snowfalls over the high lying regions in the Eastern Cape and Drakensberg.
The third week of May started off with heavy rainfall along the KwaZulu-Natal coastline with many areas reporting up to 200mm. In Richards Bay flooding was reported in areas where more than 350mm was recorded. The rest of South Africa remained dry with cold weather setting in as a result of the snow on the mountains.
The month of May ended with cold and windy conditions as a result of an upper air trough, while parts of the Western Cape received light rainfall.
Rainfall
The coastal regions of KwaZulu-Natal received good rainfall during the month of May 2017 with more than 100mm recorded over most areas, with some areas receiving up to 200mm.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 May 2017
Figure 2: Percentage difference - rainfall for 1 to 31 May 2017.
Figure 2 gives a good perspective of the rainfall for May 2017. Good rainfall fell over the eastern half of South Africa with most areas receiving well above the normal amount of rain for this time of year. The drought hit Western Cape, however, remained dry with below normal rainfall for the month of May.
Figure 3: Cumulative rainfall from 1 December 2016 to 31 May 2017 in millimetres.
The cumulative rainfall map (Figure 3) for 1 December to 31 May highlights areas that received more than 150 mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200 mm; dark green colours indicate areas that received between 200 and 300 mm; areas that received more than 400 mm are indicated with the blue colours. Large parts of the summer rainfall region has received more than 500 mm during the last 6 months.
Figure 4: Percentage difference - rainfall for 1 December 2016 to 31 May 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (Northern South Africa) received normal to above normal rainfall during the last 6 months while isolated areas, indicated in yellow, received below-normal rainfall and include the southern Free State, and the Eastern Cape. Severe drought is highlighted in the brown colours and includes the Western Cape and western Northern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). Prediction models tend to be less accurate during the autumn months and will become more accurate as we move towards June 2017 (winter).
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for May 2017 compared to the long-term (19-year) average.
Figure 6: The map was created by calculating the difference between May 2017 and the long-term (20 year) average for May. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern & Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in May 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western Cape, Eastern Cape and western Northern Cape. Higher vegetation conditions can be seen over the Free State, north-eastern Northern Cape, North West and Limpopo provinces.
General Discussion
Figure 8: South African dam levels between 1 May 2017 and 05 June 2017
Agriculture is the one sector of the economy that has shown expansion over the last six months mainly as a result of the improved rains in 2016-17. While this provides some buoyancy, the situation for many farmers in the Western Cape is dire.
Livestock farmers and irrigation farmers have been amongst the worst affected.
For example, there has been a decline in the volume of wine grapes harvested, in part due to a lack of irrigation water; this is likely to result in an estimated R500 million loss to that industry.
Furthermore, this could also affect the future crop. In the Berg-Riviersonderend water system current restrictions for irrigation farmers vary from 30% to 100% and these restrictions will have a serious impact on the crop yields in 2017-18. It means very little water will be available for the important post-harvest irrigation period during which water is needed to move the fertiliser into the soil in preparation for the next crop.
The Western Cape Department of Agriculture has estimated that R96 million is needed to support farmers in drought affected areas for the next five months.
As we move on into winter, changes in the nutritional value of veld grasses occur. To keep animals in optimum condition throughout the winter, licks can be provided to supplement the shortfalls in nutrients and enhance the nutritional value of the veld. Animals that generally maintain their weights are in a better condition to conceive in the next breeding season.
The change of season can have an impact red-meat prices. The high producer prices and the low grazing value favours slaughtering, and except for demand peaks on special days (e.g. fathers' day), demand may drop especially due to consumers seeking cheaper alternative protein sources. The poultry and pig industry may benefit from this as well as the lower cost of feed.
Farmers are urged to monitor weather warnings for cold fronts and veldfires. Both can have a severe impact especially for farmers unprepared. The drought continues in The Western Cape and farmers there must continue to conserve water in all possible ways.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #16
08 May 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
April is the month of the year when Autumn really weather sets in over South Africa. With dryer air in circulation over the country, minimum temperatures dropped to the low teens in most parts of the summer rainfall region, with maximum temperatures dropping to the mid twenties... Read more
Climate
Climate Watch - Issue #16
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
08 May 2017Monthly Overview
April is the month of the year when Autumn really weather sets in over South Africa. With dryer air in circulation over the country, minimum temperatures dropped to the low teens in most parts of the summer rainfall region, with maximum temperatures dropping to the mid twenties. While the rainfall also decreased significantly over the summer rainfall areas, these areas still received above normal rainfall. In the Western Cape, temperatures remained high while the winter rainfall region received more rain with the change of season. The winter rainfall region is in dire need of good rainfall now as dam levels continued dropping to critical levels.
Most of South Africa experienced good rainfall during the first 10 days of April and the trend continued during the second 10 days of the month, while less rain fell in the northern regions of the country towards the end of April. By the 20th of April, the Western Cape and west coast were hit by a heat wave while in contrast, some areas in the eastern Free State experienced its first frost of the colder season. During the last 10 days of April, rainfall was mainly over the winter rainfall region, with Cape Town experiencing rare thundershowers. While good rainfall fell over many areas in the winter rainfall region, a lot more rain is needed to bring relief from the drought.
Rainfall
Isolated areas in the summer rainfall region received 60mm and more rainfall during April. Although not noticeable in Figure 1, most areas of South Africa received good rainfall for this time of year.
Figure 1: Total rainfall estimation in millimetres for 1 to 30 April 2017
Figure 2: Percentage difference - rainfall for 1 to 30 April 2017.
Figure 2 gives a good perspective of the rainfall for April 2017. Good rainfall fell over most of South Africa while the western and southern areas of the Cape and the Eastern Cape received less rain than normal for this time of year.
Figure 3: Cumulative rainfall from 1 November 2016 to 30 April 2017 in millimetres.
The cumulative rainfall map (Figure 3) for 1 November to 30 April highlights areas that received more than 150 mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200 mm; dark green colours indicate areas that received between 200 and 300 mm; areas that received more than 400 mm are indicated with the blue colours. Large parts of the summer rainfall region has received more than 500 mm during the last 6 months.
Figure 4: Percentage difference - rainfall for 1 November 2016 to 30 April 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (Northern South Africa) received normal to above normal rainfall during the last 6 months while isolated areas, indicated in yellow, received below-normal rainfall and include the southern Free State, KZN and the Eastern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). There is currently no major cooling in the Pacific Ocean which contributes to the neutral conditions. Climate models do indicate a warming in the Pacific Ocean. Although conditions will still remain neutral, prediction models indicate the warming of the ocean to continue to near El Nino levels around January 2018. Prediction models tend to be less accurate during the autumn months and will become more accurate as we move towards June 2017 (winter).
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for April 2017 compared to the long-term (19-year) average.
Figure 6: The map was created by calculating the difference between April 2017 and the long-term (20 year) average for April. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern & Western Cape.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in April 2017.
Drought is a long-term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western & Eastern Cape provinces. Higher vegetation conditions can be seen over the northern and central Free State, as well as over parts of the Northern Cape, North West and Limpopo provinces.
General Discussion
Figure 8: South African dam levels between 6 February 2017 and 27 February 2017
Last month it was noted that the maize crop for the 2016-17 season was expected to be over 70% higher than the production in the disastrous 2015-16 season. The Crop Estimate Committee similarly expects significant increases in production of other crops; sorghum should increase by 99%, dry beans 80%, soybeans 44% and sunflower 23%. A much larger area of groundnuts was planted this season and production could be up to x4 times higher. The increase in plantings of groundnuts and sorghum specifically, indicates a risk mitigation strategy following the severe drought, particularly by small-scale farmers.
Some perennial fruit crops have not recovered fully from the drought. Avocados production is down, but this is being compensated for by good export prices. The high prices are a continuation of the upward trend of the past seven years. European consumers are becoming more familiar with the avocado; what is most attractive to the consumer is the convenience of the newer "ripe-and-ready" avocado product.
April was a good month for many livestock farmers. Demand for all types of meats increased over the Easter weekend. The lower feed prices and good grazing conditions has benefited many farmers. High meat prices, especially for mutton farmers, however may lead to consumer resistance and they may seek cheaper alternatives.
By this time of the year, farmers should have already planned their winter programmes to maintain animal condition and health through the winter months. Small stock farmers that have an autumn lambing season should watch out for cold fronts coming along and build adequate shelters for lambs and goat kids. The condition of animals may begin to drop with the decrease in nutritive value of veld grasses, farmers should watch that animals do not lose too much condition as that will have a negative impact on growth as well as fertility in the long run.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #15
10 April 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
March signifies the change of the season in the southern hemisphere. While meteorological autumn starts on 1 March, astrological autumn starts on 20 March. The only difference between the two is that meteorologists use a fixed... Read more
Climate
Climate Watch - Issue #15
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
10 April 2017Monthly Overview
March signifies the change of the season in the southern hemisphere. While meteorological autumn starts on 1 March, astrological autumn starts on 20 March. The only difference between the two is that meteorologists use a fixed date, while astrological autumn is determined by the earth's orbit around the sun.
While February proved to be the wettest month of the 2016/17 summer rainfall season, the change of season in March brought much dryer conditions to the summer rainfall region but also the first rain to the winter rainfall region and the Western Cape. Isolated thundershowers occurred over large parts of the summer rainfall region during the first 10 days of the month. Flooding was reported in Roodepoort after a cloudburst on 2 March 2017. Rainfall was mainly limited to the Free State and Eastern Cape between 11 March and 20 March 2017. On 15th and 20th of March, the first rainfall was reported for the drought hit Western Cape. The first cold front for 2017 made landfall over the Western Cape on 23 March, bringing more rain to the area. As the cold front moved on, it brought wet and cold weather to large parts of the country. Rainfall during the last 11 days of the month was mainly over the Eastern Cape and KZN.
Rainfall
March 2017 proved to be a dry month with the changing of the seasons. The only noticeable rainfall, more than 80 mm, is seen in the green colours mainly along the north eastern Eastern Cape and KwaZulu-Natal. While there was widespread rain throughout South Africa during the month, it was mainly below 50 mm.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 March 2017
Figure 2: Percentage difference - rainfall for 1 to 31 March 2017.
Figure 2 gives a better perspective of the rainfall for March 2017 compared to figure 1. Good rainfall fell over most of KwaZulu-Natal, while the rest of South Africa received a lot less rainfall than normal. The first rainfall for the Winter season fell in the Western Cape bringing some relief to drought affected areas. A lot of rain is needed before the drought in the area will be broken.
Figure 3: Cumulative rainfall from 1 October 2016 to 31 March 2017 in millimetres.
The cumulative rainfall map (Figure 3) for 1 October to 31 March highlights areas that received more than 150 mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200 mm; dark green colours indicate areas that received between 200 and 300 mm; areas that received more than 400 mm are indicated with the blue colours. Large parts of the summer rainfall region has received more than 500 mm during the last 6 months.
Figure 4: Percentage difference - rainfall for 1 October 2016 to 31 March 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (North eastern South Africa) has received normal to above normal rainfall during the last 6 months. Isolated areas, indicated in yellow, received below-normal rainfall and include the southern Free State, KZN and the Eastern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). There is currently no major cooling in the Pacific Ocean which contributes to the neutral conditions. Climate models do indicate a warming in the Pacific Ocean from February 2017. Although conditions will still remain neutral, prediction models indicate the warming of the ocean to continue to near El Nino levels at the end of August 2017. Prediction models tend to be less accurate during the autumn months and will become more accurate as we move towards May 2017 (winter).
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for March 2017 compared to the long-term (19-year) average.
Figure 6: The map was created by calculating the difference between March 2017 and the long-term (19 year) average for March. Figure 6 is dominated by normal vegetation activity (beige colour) and above-normal vegetation activity (green colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern Cape. Higher vegetation activity (green colours) can be seen over large parts of the summer rainfall region as a result of the good rainfall in February.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in March 2017.
Drought is a long term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the Western & Eastern Cape provinces. Higher vegetation conditions can be seen over the northern and central Free State, as well as over parts of the Northern Cape, North West and Limpopo provinces.
General Discussion
Figure 8: South African dam levels between 6 February 2017 and 27 February 2017
February was the wettest month of the summer rainfall season, ensuring ideal growing conditions for maize. These conditions suit optimal pollination and development of the maturing maize; that is, there were no mid-season droughts which stress the plant and impede development of maize cobs. However, conditions were much drier in March and yields of later-planted maize may be affected.
It is estimated that the national yield will be higher than it has been for several seasons, as shown below.
*The 2017 yields are estimates from the government Crop Estimate Committee, CEC.
Prices for forward contracts maturing in May fell to R 1722 per ton, the lowest in 2 ½ years.
As the days become shorter, grasses start producing seeds and begin storing reserves in their roots before the first frosts. Since the grasses start entering their dormant stages, the nutritional value of the veld will drop as the plants mature and farmers will have to start looking at providing licks and supplements if the grazing does not sustain their animals well. Animals should not lose more than 15 % of their body weight, else they will struggle to regain condition in time to breed and produce.
It must be remembered that licks and supplements are only to complement the veld and make up for the loss in specific nutrients. Consulting with an animal nutritionist for the best products to use is advisable to ensure animals stay in optimum condition through the winter months.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #14
08 March 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
Weather news during February 2017 was dominated by the arrival of Tropical Cyclone Dineo, the first cyclone to make landfall over southern Africa since cyclone Eline in February 2000... Read more
Climate
Climate Watch - Issue #14
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
08 March 2017Monthly Overview
Weather news during February 2017 was dominated by the arrival of Tropical Cyclone Dineo, the first cyclone to make landfall over southern Africa since cyclone Eline in February 2000. The tropical depression was developing in the Mozambique channel while gaining strength during the week of 6 February 2017 and then started moving southwards through the Mozambique channel. It was declared a tropical storm and named Dineo on 14 February 2017, making landfall over Mozambique as a category 1 tropical cyclone on Wednesday evening, February 15.
Seven people died as a direct result of the storm hitting Mozambique, but as it was cut off from the warm Indian ocean, it started losing much of its strength, and by the time its effects reached affect South Africa, it had been downgraded to a tropical depression. Mpumalanga and Limpopo received heavy rains during this time before it started to move westward towards Botswana during the weekend. A tropical temperate trough developed as a result of the high amount of moisture from the tropical depression, and moist air moved back in over large parts of South Africa during the week of 20-24 February. While the rain caused flooding and damage in North West, the system had a dramatic effect on the dam levels of much of the summer rainfall region with many areas receiving more than 100mm causing the Vaal dam, amongst others, to reach full capacity (100%), for the first time in 6 years.
Rainfall
February 2017 proved to be the wettest month of the summer rainfall region so far with the largest part of the region receiving more than 100mm of rainfall - due to the tropical temperate trough. Tropical storm Dineo had a bigger impact over Mpumalanga than expected, while Limpopo received much less than expected—some areas as little as 50mm only.
Figure 1: Total rainfall estimation in millimetres for 1 to 28 February 2017
Figure 2: Percentage difference - rainfall for 1 to 28 February 2017.
Figure 2 gives a better perspective of the rainfall for February 2017 compared to figure 1. The majority of the summer rainfall region received more than 100% of it's normal rainfall for the month, indicated in the shades of green. The darker green colors indicate areas that received more than 200% of their normal rainfall, and include most areas in North West, and northern Free State. Isolated areas that received more than 200% of their normal rainfall can be seen in Limpopo, Northern Cape, Mpumalanga and KZN.
Figure 3: Cumulative rainfall from 1 September 2016 to 28 February 2017 in millimetres.
The cumulative rainfall map (Figure 3) for 1 September to 28 February highlights areas that received more than 150mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200mm; dark green colours indicate areas that received between 200 and 300mm; areas that received more than 400mm are indicated with the blue colours. Large parts of the summer rainfall region has received more than 500mm during the last 6 months.
Figure 4: Percentage difference - rainfall for 1 September 2016 to 28 February 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (North eastern South Africa) has received normal to above normal rainfall during the last 6 months. Isolated areas, indicated in yellow, received below-normal rainfall and include the southern Free State, KZN and the Eastern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). There is currently no major cooling in the Pacific Ocean which contributes to the neutral conditions. Climate models do indicate a warming in the Pacific Ocean from February 2017. Although conditions will still remain neutral, prediction models indicate the warming of the ocean to continue to near La Nina levels at the end of August 2017. Prediction models tend to be less accurate during the autumn months and will become more accurate as we move into winter.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for February 2017 compared to the long-term (19-year) average.
Figure 6: The map was created by calculating the difference between February 2016 and the long-term (19 year) average for February. Figure 6 is dominated by normal vegetation activity (beige colour) and above-normal vegetation activity (green colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern Cape. Higher vegetation activity (green colours) can be seen over large parts of the summer rainfall region as a result of the good rainfall in February.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in February 2017.
Drought is a long term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the southern Kruger National Park in north-eastern Mpumalanga. Below normal vegetation conditions can also be seen in the Eastern Cape and Western Cape. Higher vegetation conditions can be seen over the northern and central Free State.
General Discussion
Figure 8: South African dam levels between 6 February 2017 and 27 February 2017
Heavy and sustained rains in the northern parts of South Africa over the last few weeks have filled up dams and eased the effects of the drought, although the situation is still critical for crops in parts of the Western Cape.
However, in the short-term the sustained rains have caused problems for vegetable growers. Pests, and particularly diseases, thrive in these conditions. Their control is made even more difficult because sprays are often washed off the plants by the rain. The wet conditions also result in shorter shelf lives of many vegetable crops with some vegetables going soft and mouldy within five hours of arrival at the market, even under cold room conditions.
Affected produce is currently selling at approximately half the usual price, while good quality brassicas and leafy vegetables fetching up to double the normal price. There is a shortage of chillies, spinach, okra and green beans on the market floor.
A consolation for farmers is that the groundwater is being replaced and the dams are filling up. A comment from a farmer was that "It is better to have a wet crop failure than a dry one".
Grain crops have benefited from the rains and maize production is expected to be close to normal levels.
The rain in the summer region has been most welcome for crop and livestock farmers alike. Maize prices have been falling and production levels are up. This is good news for livestock farmers as maize is used as a main ingredient in animal feeds. Meat prices will remain high due to higher demands than supplies.
Conditions in the southern half of South Africa is in stark contrast to the northern half. The Western– and Eastern Cape areas still have high water restrictions. Water is an essential element for all living systems and farmers must use water sparingly and fix all leaking taps and limit unnecessary waste.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #13
10 February 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
January 2017 started off with extremely hot temperatures over most areas of the summer rainfall region. Heavy rain brought welcome relief at the end of the first week of January (7th) with flooding reported in some areas, including Centurion (40mm)... Read more
Climate
Climate Watch - Issue #13
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
10 February 2017Monthly Overview
January 2017 started off with extremely hot temperatures over most areas of the summer rainfall region. Heavy rain brought welcome relief at the end of the first week of January (7th) with flooding reported in some areas, including Centurion (40mm), and Heidelberg (80mm). Reports from the areas around Bronkhorstspruit indicated that some places received as much as a 160mm, while good rains fell in parts of the Northern Cape, with Kimberley receiving 40mm.
At the end of the second week (13 January), the South African weather service issued warnings for flooding accompanied by strong winds, over North West — the same storm system that brought rain to the Gauteng area, resulting in flooding in the southern areas of Gauteng.
Good rains were recorded towards the end of the month for the southern Free State, and 40mm was recorded for Aliwal North (24 January).
Rainfall
Large parts of the summer rainfall region received good rainfall during January with more than 100 mm being recorded for most areas, but the same could not be said of the southern Free State, Eastern Cape and coastal regions of KZN.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 January 2017
Figure 2: Percentage difference - rainfall for 1 to 31 January 2017.
Figure 2 gives a better perspective of the rainfall for January 2017 compared to figure 1. The majority of the summer rainfall region received more than 100% of it's normal rainfall for the month, indicated in the shades of green. Some areas in the southern Free State, Eastern Cape and KwaZulu-Natal received between 75% to 100% of its normal rainfall, indicated in yellow.
Figure 3: Cumulative rainfall from 1 June 2016 to 31 January 2017 in millimetres.
The cumulative rainfall map (Figure 3) for 1 June to 31 January highlights areas that received more than 150mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200mm; dark green colours indicate areas that received between 200 and 300mm; areas that received more than 400mm are indicated with the blue colours. The summer rainfall regions are clearly visible in this map with the high rainfall being located in the north eastern half of the country.
Figure 4: Percentage difference - rainfall for 1 June to 31 January 2017.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (North eastern South Africa) has received normal to above normal rainfall during the last 6 months. Isolated areas, indicated in yellow, received below-normal rainfall and include the southern Free State, KZN and the Eastern Cape.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). There is currently no major cooling in the Pacific Ocean which contributes to the neutral conditions. Climate models do indicate a warming in the Pacific Ocean from February 2017. Although conditions will still remain neutral, prediction models indicate the warming of the ocean to continue to near La Nina levels at the end of August 2017.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for January 2017 compared to the long-term (19-year) average.
Figure 6: The map was created by calculating the difference between January 2016 and the long-term (19 year) average for January. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the Eastern and Western Cape. Higher vegetation activity (green colours) can be seen over large parts of the summer rainfall region as a result of the good rainfall in January.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in January 2017.
Drought is a long term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the southern Kruger National Park in north-eastern Mpumalanga. Below normal vegetation conditions can also be seen in the southern Free State and western Eastern Cape. Higher vegetation conditions can be seen over the northern Free State.
General Discussion
Figure 8: South African dam levels between 1 January 2017 and 6 February 2017
During the last month there have been many reports of armyworm particularly in maize crops. The spread of the pest is closely related to weather conditions, especially in countries to the north. The pest is endemic in Tanzania and migrates south towards the end of the year on the winds of the Inter-Tropical Convergence Zone, ITCZ. If the convergence is very strong causing heavy rains, which has been the case this season, then these conditions suit the migration of the pest. Furthermore the heavy rains cause a flush of growth of new vegetation which the pest feeds off. Historically this happens on average about once every 10 years and it is often after a very dry season. Obviously weather conditions have been almost ideal for the pest this rainy season.
Based on the maps it can be seen that much of South Africa is still very much experiencing drought with the Eastern Cape and Western Cape being the most severely affected. A large percentage of South Africa’s sheep are produced in these regions and most Angora goats are farmed in the Eastern Cape. It is important that farmers select for animals that are well adapted to the veld in the area and are able to reproduce even under unfavourable conditions. Supplements and licks should be provided and the veld should be well managed.
For the summer rainfall regions, conditions are quite favourable with increasing vegetation activity and rises in dam water levels. This is good news for farmers rebuilding herd numbers, however farmers should not let their guard down and continue to use resources sparingly, keep to their budgets and plan farming activities accordingly.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
Climate Watch - Issue #12
16 January 2017Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
The beginning of December 2016 announced the end of the second heat wave over the summer rainfall region and the month was characterised by continual storm and flood warnings over the Gauteng Province. Flooding was reported in Muldersdrift and other parts of... Read more
Climate
Climate Watch - Issue #12
Juanita van Zyl, contributions from John Lapham and Colleen Janse van Rensburg
16 January 2017Monthly Overview
The beginning of December 2016 announced the end of the second heat wave over the summer rainfall region and the month was characterised by continual storm and flood warnings over the Gauteng Province. Flooding was reported in Muldersdrift and other parts of the West Rand on 7 December; flooding occurred in parts of Pretoria on the evening of 10 December and on 12 December as well as in the Vanderbijlpark area. A second heat wave hit Gauteng between 20 to 23 December and broke on 24 December when heavy rain fell over the area. Temperatures dropped and large parts of South Africa experienced a colder Christmas while temperatures started to increase towards the end of the month.
The results of the good rainfall over large parts of the summer rainfall region can be seen in the increased volumes of a number of major dams. The water level of the Vaal Dam that provides most of Gauteng's water, had increased from 38% at the beginning of December 2016 to 53% by 10 January 2017.
Despite the good rainfall over much of the summer rainfall region during December and the increase of water in our dams, readers are urged to continue using water sparingly due to the uncertainty about the rest of the summer rainfall season, making accurate prediction very difficult.
Rainfall
Large parts of the summer rainfall region received good rainfall during December with more than 100 mm being recorded for most areas. Western Limpopo, western North West, the southern and central Free State and the Natal East coast received less than 80 mm. Rainfall in the Eastern Cape and north eastern Northern Cape was below 60 mm. The Western Cape and the majority of the Northern Cape remained dry.
Figure 1: Total rainfall estimation in millimetres for 1 to 31 December 2016
Figure 2: Percentage difference - rainfall for 1 to 31 December 2016.
Figure 2 gives a better perspective of the rainfall for December 2016 compared to figure 1. The majority of the summer rainfall region received more than 100% of it's normal rainfall for the month, indicated in the shades of green. Some areas in North West, Limpopo and KwaZulu-Natal received between 75% to 100% of its normal rainfall, indicated in yellow. Areas of concern that received less than 75% of its normal rainfall include the southern Free State, and the KwaZulu-Natal eastern coastline. Summer rainfall were patchy in the summer rainfall regions of the Northern and Eastern Cape with small areas receiving good rainfall while most areas received below normal rainfall.
Figure 3: Cumulative rainfall from 1 July 2016 to 31 December 2016 in millimetres.
The cumulative rainfall map (Figure 3) for 1 July to 31 December highlights areas that received more than 150mm during the last 6 months: Light green colours indicate areas receiving between 150 to 200mm; dark green colours indicate areas that received between 200 and 300mm; areas that received more than 400mm are indicated with the blue colours. The summer rainfall regions are clearly visible in this map with the high rainfall being located in the north eastern half of the country.
Figure 4: Percentage difference - rainfall for 1 July to 31 December 2016.
Figure 4 highlights the areas of South Africa that received below-normal and above-normal rainfall over the last 6 months. The yellow to light brown colours highlight areas of concern. The majority of the summer rainfall region (North eastern South Africa) has received normal to above normal rainfall during the last 6 months. Isolated areas, indicated in yellow, received below-normal rainfall. In contrast, the south western half of the country has received below normal rainfall for the last 6 months.
El Nino/La Nina
Background: Periods of below normal rainfall in South Africa are often linked with the El Nino event while above normal rainfall is usually linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions. (Figure 5). There is currently no major cooling in the Pacific Ocean which contributes to the neutral conditions. Climate models do indicate a warming in the Pacific Ocean from February 2017. Although conditions will still remain neutral, prediction models indicate the warming of the ocean to continue to near La Nina levels at the end of October 2017. The South Africa n Weather Service issued a statement on 6 January 2017 indicating that they believe South Africa will receive below normal rainfall between January 2017 and March 2017.
Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.
NDVI
Figure 6: ProbaV difference map for November 2016 compared to the long-term (19-year) average.
Figure 6: The map was created by calculating the difference between December 2016 and the long-term (19 year) average for December. Figure 6 is dominated by normal vegetation activity (beige colour). Areas of concern with below-normal vegetation activity (red colours) can be seen in the southern Eastern Cape, north eastern Mpumalanga, southern Free State and North West. Higher vegetation activity can be seen in the northern Free State, southern Gauteng and Limpopo.
Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in December 2016.
Drought is a long term phenomenon. Focusing on longer time-periods is a more reliable method to monitor and map drought. Areas of concern include the southern Kruger National Park in north-eastern Mpumalanga. Below normal vegetation conditions can also be seen in the southern Free State and western Eastern Cape. Higher vegetation conditions can be seen along the KZN coastline and in the northern Free State.
General Discussion
Vaal Dam Storage vs Inflow Discharge: Graph provided by the Department of Water and Sanitation.
This graph shows the sharp increase in the Vaal Dam from 38% at the beginning of December 2016 to 53% by 10 January 2017 after a spell of intense and good rainfall over the catchment area early in January 2017.
The rainfall in December increased the dam levels in many areas which will ensure water reserves for crop irrigation in the future. However, of immediate consequence are the effects on growing crops. Obviously most benefited from the good rains but on sandy soils there is always leaching of nutrients, particularly nitrogen, resulting in yellowing of leaves and inhibited growth. This can be overcome with regular top-dressings of nitrogen fertiliser in small amounts. Nitrogen must be applied during the growth stage of the crop before flowering.
The end of December 2016 and beginning of January 2017 brought many extremes in weather conditions. Flooding in numerous areas around the country and fires in the Western Cape have had devastating consequences for many livestock farmers. Fires have cause both livestock deaths and loss of grazing land and several homes and farming infrastructure was damaged or destroyed. Animals that survive bushveld fires need to be inspected over several weeks as burn injuries continue to progress and may worsen for up to 6 weeks afterwards.
Keeping up with daily and weekly weather reports can help farmers prepare in advance for possible adverse weather conditions. Being aware of dangerous situations that may arise such as flooding and lightning and hail damage during storms and smoke inhalation and disorientation and exhaustion during fires can help a farmer plan long in advance ahead of the seasons when these dangers are likely to occur.
Acknowledgements:
SPOT Vegetation Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on VEGETATION data ((c) CNES).
PROBA-V Data: The product was generated by the land service of Copernicus, the Earth Observation program of the European Commission. The research leading to the current version of the product has received funding from various European Commission Research and Technical Development programs. The product is based on PROBA-V data ((c) ESA).
El-Nina/La Nina predictions: POAMA graph provided by courtesy of the Australian Bureau of Meteorology, (c) 2016.
Rainfall Estimation (RFE): Data provided by the National Oceanic and Atmospheric Administration (NOAA), Centre for Weather and Climate Prediction. http://www.cpc.noaa.gov/...
Click here for a .PDF Version of this information.
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