Monthly Overview

1 to 10 August 2018
The month started off with light showers over the Western Cape. A large cold front made landfall around the 5th of the month. This front was responsible for good rainfall over the Western Cape as well as over the Free State, northern Eastern Cape and southern KwaZulu-Natal. The front was also responsible for snow on the Drakensberg mountains.

11 to 20 August 2018
The next ten days followed a similar pattern with a large cold front making landfall over the Western Cape. This front was responsible for rainfall over the Western Cape, Eastern Cape, KwaZulu-Natal and Mpumalanga Provinces. Snow was reported on the Drakensberg mountains.

21 to 30 August 2018
The rainfall trend was repeated during the last ten days of the month. Parts of Gauteng, Limpopo and Mpumalanga experienced thunderstorms during this period. A large cold front brought heavy rain and snow to the Western Cape at the end of this period.

Rainfall

Rainfall over the Western Cape was normal to below-normal for August. Good rainfall fell over large parts of the country, with the Free State, northern Eastern Cape and KwaZulu-Natal receiving good rainfall.

Figure 1: Total rainfall estimation in millimetres for 1 to 30 August 2018

Figure 2: Percentage difference - rainfall for 1 to 30 August 2018.

Figure 2 indicates rainfall expressed as a percentage compared to the long-term norms for August. The map highlights below-normal rainfall over large parts of the winter rainfall region during August indicated by the yellow and brown colours. Large parts of the Free State, northern Eastern Cape, KwaZulu-Natal and isolated areas over Mpumalanga, Limpopo and northern Gauteng received above-normal rainfall for August.

Figure 3: Cumulative rainfall from 1 March 2018 to 30 August 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 March to 31 August highlights the 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. With the Winter rainfall season in full swing, green colours are becoming more dominant over the Western Cape highlighting increased rainfall over the area.

Figure 4: Percentage difference - rainfall for 1 March 2018 to 30 August 2018.

Figure 4 highlights areas that received below-normal and above-normal rainfall during the last 6 months. Yellow to light brown shows areas of concern, while isolated areas throughout the country highlighted in green, received above normal rainfall during the last 6 months. Green colours over the Western Cape is a positive sign for the drought hit province, however, large parts of the eastern Western Cape and western Eastern Cape remain areas of concern with below-normal rainfall.

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). Pacific Ocean temperatures expected to increase during the autumn months, and there is a possibility of El Nino developing during the summer months.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

ProbaV difference map for August 2018 compared to the long-term (20-year) average.

Figure 6: This map is created by calculating the difference between August 2018 and the long-term (21-year) average for August - showing dominant normal vegetation activity (beige). Vegetation conditions are normal to above normal over most areas of South Africa. An improvement in the NDVI over the western and southern parts of the Western Cape while the eastern parts still show below normal vegetation activity. Below-normal vegetation activity can also be seen in the western Eastern Cape region. Above-normal vegetation activity can be seen over northern KZN.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in August 2018.

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, western Eastern Cape, and parts of the Northern Cape. Conditions remain neutral over most of the summer rainfall region except for Limpopo with many areas showing stressed vegetation. Positive vegetation activity is dominant over the Free State Province.

General Discussion

Figure 8: South African dam levels during the first week of July and August with a column showing if the level increased or decreased. Red indicate dams below 50% of its capacity.

The winter wheat crop is still at the growth stage where it requires moisture. The key wheat producing provinces are the Western Cape, Free State, Northern Cape and Limpopo, collectively accounting for 95 percent of the estimated area of 508 350 hectares in the 2018-19 production season.

The weather forecasts show prospects of good showers over most parts of these provinces within the next eight days, which should improve soil moisture and therefore benefit the crop.

Good showers in parts of the Western Cape over the past few days have similarly benefitted the crop. South Africa's wheat production could increase by 18% compared with last year, to 1.8 million tons. This is the result of an expansion in area planted and improvement in yield prospects.

Western Cape dam levels currently average 58 percent, up by 3 percent from a week ago and 24 percent higher than the same period last year. These dam levels will bring some relief during the coming summer to grape, fruit and citrus producers in the province, although use of the water is being approached with caution.

As we move out of winter into spring, animals with a negative energy balance will search for any available feed. Many poisonous plants are the first green plants to appear after a long dry period or veld fire. Hungry animals are at risk of consuming poisonous plants that they would otherwise avoid during normal grazing seasons.

Spring is the time for numerous vaccinations, especially those against insect-borne diseases such as Lumpy skin disease, Three-day stiff sickness, Blue tongue, Rift Valley fever, Wesselsbron and African Horse sickness. Animals should be vaccinated in time before the rainy season starts in summer rainfall regions. With the warmer weather insect activity is increasing, but also other parasites such as ticks. Now is the time to re-evaluate all management and vaccination programmes and ensure animals are vaccinated, dewormed and dipped. It is advisable to consult a veterinarian with regards to these programmes and timing of vaccines as some have a negative effect when given to pregnant animals.

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.

Monthly Overview

1 to 10 July 2018
The month started with a large cold front over the Western Cape that slowly moved northwards the following few days. Heavy rain fell over the Western Cape with snow over the mountains. As this system moved northwards along the east coast, snow fell on the Eastern Cape mountains as well as the Drakensberg mountains. South Africa experienced its coldest temperatures this winter during this period.

11 to 20 July 2018
Another cold front brought showers to the Western Cape during this week, however, it was significantly less compared to the previous front. Large parts of the Free State, North-West and KwaZulu-Natal received rainfall during this period with snow over the Drakensberg mountains.

21 to 31 July 2018
The end of the month was dry over South Africa. While the Western Cape did receive rainfall, it never exceeded 5 mm during this period. The lack of rainfall also had an effect on dam levels with little to no increase during this time.

Rainfall

July was a much drier month compared to the start of the winter rainfall season with the region receiving below-normal rainfall.

Figure 1: Total rainfall estimation in millimetres for 1 to 31 July 2018

Figure 2: Percentage difference - rainfall for 1 to 31 July 2018.

Figure 2 indicates rainfall expressed as a percentage compared to the long-term for July. The map highlights below-normal rainfall over large parts of the winter rainfall region during July indicated by the yellow and brown colours. Large parts of the summer rainfall region received unexpected but good rainfall during July highlighted in the blue and green colours.

Figure 3: Cumulative rainfall from 1 February 2018 to 31 July 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 February to 31 July highlights the 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. With the Winter rainfall season in full swing, green colours are becoming more dominant over the Western Cape highlighting increased rainfall over the area.

Figure 4: Percentage difference - rainfall for 1 February 2018 to 31 July 2018.

Figure 4 highlights areas that received below-normal 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. Green colours over the Western Cape is a positive sign for the drought hit province, however, large parts of the eastern Western Cape and western Eastern Cape remain areas of concern with below-normal rainfall.

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). Pacific Ocean temperatures expected to increase during the winter months, but conditions are expected to remain neutral.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

ProbaV difference map for July 2018 compared to the long-term (20-year) average.

Figure 6: This map is created by calculating the difference between July 2018 and the long-term (21-year) average for July - showing dominant normal vegetation activity (beige). Vegetation conditions are normal to above normal over most areas of South Africa. An improvement in the NDVI over the western parts of the Western Cape while the eastern parts still show below normal vegetation activity. Below-normal vegetation activity can also be seen in the western Eastern Cape region. Above-normal vegetation activity can be seen over northern KZN.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in July 2018.

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, western Eastern Cape, and parts of the Northern Cape. Conditions remain neutral over most of the summer rainfall region except for Limpopo with many areas showing stressed vegetation. Positive vegetation activity is dominant over the Free State Province.

General Discussion

Figure 8: South African dam levels during the first week of July and August with a column showing if the level increased or decreased. Red indicate dams below 50% of its capacity.

In the Western Cape dam levels increased weekly over the last month. Snow in some areas has contributed to dam levels, as well as adding to the cold units needed for the flowering of stone fruit crops.

On the other hand, the drought in the Eastern Cape continues to frustrate many farmers. In the Gamtoos Valley water allocations have been reduced to 20% of normal, affecting citrus, vegetable and dairy production. Citrus, being a high investment and perennial crop, is being given priority for irrigation. One knock-on effect is that on-farm vegetable production and processing, which creates many jobs, is being reduced.

In the Langkloof area top-fruit farmers are operating at 40% of their normal water allocation, but this could be similarly reduced to 20%.

However, producers have ended the 2017-18 season in a somewhat better position than the previous season, because of rain in October and November last year. In addition to this producers have benefitted from the increasing use of net covering which can reduce water use by up to 20% in some cultivars.

Nets, which are draped over trees (drape-nets) during the period of fruit development, are also increasingly being used.

Moving towards the end of winter, weather changes can be expected. Strong winds - a common occurrence in August, together with dry vegetation, makes conditions favourable for runaway fires. Temperatures are warming up but cold fronts continue bringing along rain and snow. It is very important that farmers keep watch over weather and fire warnings and be prepared.

Internal and external parasite activity continues to be a problem during the winter months and farmers should continue doing 5 point checks for worms and flukes while dipping for ticks and lice and watching out for tick-borne diseases. Parasite activity is likely to increase with the warmer weather and when the first rains come. Insect activity will also increase along with higher incidents of insect-borne diseases. Farmers should consult their vets regarding control of these diseases and begin ordering vaccines for 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.

Monthly Overview

1 to 10 June 2018
Two major cold fronts brought good rainfall to the Western Cape during this period, while light showers fell along the southern and eastern coast of South Africa with the interior of the country remaining dry.

11 to 20 June 2018
The second 10 day period of the month followed a similar trend with two large cold fronts again bringing rainfall to the Western Cape and light snow to the Eastern Cape and Drakensberg mountains, while KwaZulu-Natal, isolated areas in eastern Limpopo and eastern Mpumalanga, received light showers.

21 to 30 June 2018
All across the country there was little to no rain during the last 10 days of the month except for a small cold front that brought some rain to the Western and Eastern Cape near the end of the month. Then right at the end of the month a large cold front (the biggest for 2018 winter season), made landfall, bringing heavy rains to the Western Cape.

Rainfall

Good rainfall, more than 100 mm, fell over catchment areas of the Western Cape during June resulting in a positive rise in the dam levels in the province (See Figure 8).

Figure 1: Total rainfall estimation in millimetres for 1 to 30 June 2018

Figure 2: Percentage difference - rainfall for 1 to 30 June 2018.

Figure 2 indicates rainfall expressed as a percentage compared to the long-term for June. Good news for the Western Cape as large areas of the province received above normal rainfall, especially over the catchment areas of a number of dams. Isolated areas, indicated in green, received above-normal rainfall in the Northern Cape, KwaZulu-Natal and Limpopo. The rest of the country remained dry as expected.

Figure 3: Cumulative rainfall from 1 January 2018 to 30 June 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 January to 31 June highlights the 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. With the Winter rainfall season in full swing, green colours are becoming more dominant over the Western Cape highlighting increased rainfall over the area.

Figure 4: Percentage difference - rainfall for 1 January 2018 to 30 June 2018.

Figure 4 highlights areas that received below-normal 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. Green colours over the Western Cape is a positive sign for the drought-hit province.

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). Pacific Ocean temperatures expected to increase during the winter months, but conditions are expected to remain neutral.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

ProbaV difference map for June 2018 compared to the long-term (20-year) average.

Figure 6: This map is created by calculating the difference between May 2018 and the long-term (21-year) average for May - showing dominant normal vegetation activity (beige). Vegetation conditions are normal to above normal over most areas of South Africa as a result of the good rainfall during the summer months. While the Western Cape shows below-normal vegetation activity for May, the good rainfall during May is expected to show an improvement in the vegetation activity for June.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in June 2018.

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, western Eastern Cape, and parts of the Northern Cape. Conditions remain neutral over most of the summer rainfall region except for Limpopo with many areas showing stressed vegetation.

General Discussion

Figure 8: South African dam levels during the first week of June and July with a column showing if the level increased or decreased. Red indicate dams below 50% of its capacity.

The recent rains have increased the levels Cape Town's supply dams up to 43% full (on 2 July) up from 38% at week ago, the biggest single weekly increase this year. These dam levels are higher than at this time in 2017 or 2016.

Winter wheat farmers have planted into moist soil for the first time in three years. Despite this, the scenario is not as optimistic in all areas, and parts of the Overberg, the southern Cape, Karoo and north of Vredendal on the West Coast are still battling drought conditions.

With this good start and better forecasts for the current season, it is predicted that national wheat production will improve over 2017-18 season.

In that season wheat production was down 47% in the Western Cape and 20% nationally; 1.52 million tons were produced and 1.93 m tons were imported. It is predicted that 1.65 m tons will be produced in 2018-19 and imports will be about 1.8 m tons. This is despite the area being planted to wheat being slightly less than last season; yields will be higher.

On 16 May 2018, a confirmed case of Rift Valley Fever (RVF) was reported on a sheep farm in Jacobsdal in the Free State. Up to 250 sheep deaths occurred. This was followed by 4 confirmed human cases during the month of June. RVF is transmitted by mosquitoes and results in a high number of mortalities mainly in sheep and goats. Cattle are less affected. Humans can get infected by handling infected animal carcasses and materials. Farmers are advised to vaccinate their animals this winter to prevent a serious outbreak from occurring this coming summer that can potentially cause large economic losses and affect animal export.

During winter a wide range of dangers occur - rain and flooding, strong winds and fire, as well as frost and snow. These events can occur simultaneously across the country. Farmers should be aware of the dangers each of these events pose and should always be ready to act. Keeping up to date with weather reports will help farmers stay prepared and take preventative measures before the events 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.

Monthly Overview

1 to 10 May 2018
During the first ten days of May, dry conditions were experienced across the country. Temperatures dropped to below 10°C over the southern half of the country for the first time this year. By the end of the first ten day period, the Cape Town region received rainfall from the first cold fronts of the month.

11 to 20 May 2018
A strong upper air trough brought cold and wet weather to the northern regions of the country. This system was also responsible for the first snow on the Drakensberg mountains. Heavy rain, in excess of 100 mm, fell over the Richards bay area between 15 and 18 May causing flooding in many areas of northern KwaZulu-Natal.

21-31 May 2018
A number of cold fronts brought good rainfall to the Western Cape during this period. These cold fronts moved northwards across the country bringing light showers to large parts of the country. Snow fell over the Drakensberg mountains as well as the high lying areas of the Eastern Cape. Minimum temperatures hit new lows across the country at the end of this period signalling the start of the meteorological winter.

Rainfall

Rain fell over most of South Africa during May, but the most significant rainfall fell around the Richards Bay area as well as the Western Cape and parts of the Northern Cape.

Figure 1: Total rainfall estimation in millimetres for 1 to 31 May 2018

Figure 2: Percentage difference - rainfall for 1 to 31 May 2018.

Figure 2 indicates rainfall expressed as a percentage compared to the long-term for May. Most areas of the country received normal to above-normal rainfall during May. Southern KwaZulu-Natal, north-eastern Northern Cape and the southern coastline were the only areas that received below-normal rainfall. Areas in northern Limpopo and northern KwaZulu-Natal received more than 500% of their normal rainfall during May.

Figure 3: Cumulative rainfall from 1 December 2017 to 31 May 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 December to 31 May highlights the 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. Most areas in the summer rainfall region received more than 400 mm. Yellow colours over the Western Cape indicates the start of the winter rainfall season as a result of the first cold fronts bringing rainfall to the region.

Figure 4: Percentage difference - rainfall for 1 December 2017 to 30 April 2018.

Figure 4 highlights areas that received below-normal and above-normal rainfall during the last 6 months. Yellow to light brown colours show areas of concern, while isolated areas throughout the country highlighted in green received above normal rainfall during the last 6 months. Overall, most areas of the summer rainfall region have received between 75 to 100% of the normal expected rainfall this 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 linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). Pacific Ocean temperatures are expected to increase during the winter months, but overall conditions are expected to remain neutral.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

ProbaV difference map for May 2018 compared to the long-term (20-year) average.

Figure 6: This map is created by calculating the difference between May 2018 and the long-term (21-year) average for May - showing dominant normal vegetation activity (beige). Vegetation conditions are normal to above normal over most areas of South Africa as a result of the good rainfall during the summer months. While the Western Cape shows below-normal vegetation activity for May, the good rainfall during May is expected to show an improvement in the vegetation activity for June.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in May 2018.

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, western Eastern Cape, and parts of the Northern Cape. Conditions remain neutral over most of the summer rainfall region except for Limpopo with many areas showing stressed vegetation.

General Discussion

Figure 8: South African dam levels during the first week of May and June with a column showing if the level increased or decreased. Red indicates dams below 50% of its capacity.

Deciduous fruit production has concluded for last season and the industry estimates that the apple export volumes are down 14% on last year, while pear exports only 7% less; this is better than anticipated.

Figure 9: Citrus on the ground after the hail storm.

More positively, the rains in the Cape in May have been better than the three preceding seasons and this bodes well for planting of the winter cereal crops.

In May, a highly unusual hailstorm hit the areas of the Mpumalanga low-veld devastating citrus, banana and vegetable crops. In some orchards entire blocks of citrus were wiped out by the large hail stones; fruit was smashed and blown off the trees. Mango and litchi trees were also badly damaged; avocado damage, on trees around Kiepersol, was more limited. The hail was quite widespread, affecting Malelane, Hazyview and Skukuza areas.

As more cold weather comes in bringing along frost, insect activity decreases and a sharp decline in insect-borne diseases of livestock can be expected. The exception is Lumpy skin disease which is transmitted by both insects and ticks. While insect-borne disease cases will be fewer now than in the autumn months, tick-borne diseases may continue through the winter months as tick larvae and nymphs of multi-host ticks are more prevalent in the cooler months. Tick control should still be carried out throughout the winter months.

As with ticks, internal parasites can also be expected as they do not become dormant in the winter months. Parasite checks such as 5 point check will assist farmers with their treatment plans. Higher incidents of respiratory and lung diseases occur during winter months and farmers should monitor their animals' health. Winter is the time when animals are vaccinated against Asiatic Redwater, farmers should check with their veterinarians about vaccinations in their areas. All heifers from 4 months should also be vaccinated against Brucellosis. Farmers should discuss this disease with their veterinarians as it is a Controlled disease that has severe economic effects if detected in a herd.

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.

Monthly Overview

1 to 10 April 2018
Widespread rainfall continued to fall over most parts of the summer rainfall region during this period. Unseasonably good rain fell over the eastern half of the Northern Cape and southern Free State. The Vaal and Gariep dams was more than 100% full with the levels of many of the other dams on the rise. Reports were received of rainfall totals in Richards Bay (KZN) 100 mm; and Hazyview (Mpumalanga) 70 mm.

11 to 20 April 2018
A similar rainfall trend continued during the next 10 days of April with continued rain over the eastern parts of the Northern Cape and Free State with the Bloemhof dam reaching full capacity. Storms at the beginning of the month caused flash floods in parts of North-West, Gauteng and Limpopo, ending with the first cold front making landfall over the Western Cape bringing up to 20 mm of rain to some parts.

21-30 April 2018
Little to no rain fell over the country during the period except for the Western Cape where two cold fronts made brought as much as 60 mm of rain to some parts.

Rainfall

Good rainfall fell over the eastern Northern Cape, western North-West and the southern Free State during the month of April. Towards the end of the month, the Western Cape received rainfall from the first cold fronts of the winter season.

Figure 1: Total rainfall estimation in millimetres for 1 to 30 April 2018

Figure 2: Percentage difference - rainfall for 1 to 30 April 2018.

Figure 2 indicates rainfall for April. The central regions of South Africa, eastern Northern Cape, western North-West, most areas of the Free State and western Eastern Cape received above normal rainfall during April 2018.

Figure 3: Cumulative rainfall from 1 November 2017 to 30 April 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 November to 30 April highlights those areas receiving more than 150 mm during the period: Light green - 150 to 200 mm; dark green 200 to 300 mm; and blue exceeding 400 mm. Most areas in the summer rainfall region received more than 400 mm.

Figure 4: Percentage difference - rainfall for 1 November 2017 to 30 April 2018.

Figure 4 highlights areas that received below-normal 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. Overall, most areas of the summer rainfall region received between 75 to 100% of the normal expected rainfall this 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 linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). Despite cooling of the pacific ocean, La Nina conditions haven't been reached. Pacific Ocean temperatures expected to increase during the autumn and winter months, but conditions are expected to remain neutral.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

ProbaV difference map for April 2018 compared to the long-term (20-year) average.

Figure 6: This map is created by calculating the difference between April 2018 and the long-term (20-year) average for April - showing dominant normal vegetation activity (beige). Vegetation conditions are normal to above normal over most areas of South Africa as a result of the good rainfall during the summer months.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in April 2018.

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, western Eastern Cape, and parts of the Northern Cape. Conditions remain neutral over most of the summer rainfall region.

General Discussion

Figure 8: South African dam levels during the first week of April and May: Green indicates full capacity; and red indicates below 50% capacity.

As mentioned during April, maize and soybean supply to markets for the 2018 to 2019 marketing period should be adequate despite lower production compared to the previous period.

Wheat production was 27% less in 2017 compared to the previous year and the weather will be a primary focus in the winter wheat production areas. In many regions of the Western Cape planting starts in May and intense and persistent rainfall is required to improve the soil moisture levels after the drought conditions of the previous winter and hot dry summer, to ensure the best conditions for planting.

Despite rain and accompanying cold fronts over the past few weeks - 20mm in the Cape Town area as predicted - there has not been sufficient soil moisture level improvement to encourage planting.

Optimistically, forecasts over a longer period indicate a favourable winter rainfall season in the Cape, and wheat yields are expected to improve with 10% from the previous year, boding well for wheat production, but perennial crops will continue to suffer from the 2017 drought. Expected production of wine grapes will be lower by 20%; table grapes by 18%; pome fruit by 9%; and stone fruit by 8%.

Predicted consistently good winter rainfall will go a long way to reverse the effects of the drought period. Parasite and insect activity remain high at this time of the year especially after the high late rainfall received in the summer rainfall regions. Farmers should continue to monitor parasite levels and do checks like FAMACHA, the 5 point check, and faecal egg counts. Farmers should consult with their local veterinarian to check the resistance status (particularly of blue ticks) on their farms and to further advice.

Cold fronts bring rain, wind, snow and frost, and farmers are advised to check the weather reports to prepare for adverse conditions and ensure vulnerable animals have access to shelter and warmth. Strong winds increase fire risks and preparations should be made to limit damage and losses. Farmers should monitor the nutritional status of their animals and plan for winter feeding.

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.

Monthly Overview

The first ten days of March started off with rain mainly over the Free State, northern Eastern Cape and KwaZulu-Natal, while the rest of the country remained dry. The rainfall trend during the next ten days (11 - 20 March) remained the same, but this time Gauteng, North West and Mpumalanga were the recipients. The overall rainfall during this period varied from normal to below-normal for this time of year. A trough developed and brought bringing widespread intensive rainfall to large parts of the summer rainfall region between 21 and 25 March. Heavy rain fell over the eastern Northern Cape, North West, Gauteng, the northern Free State and KwaZulu-Natal. During the last six days of March, these areas experienced clear conditions while good rain fell over the western Northern Cape and large parts of the Western Cape.

After the normal to below-normal rainfall in the beginning of the month, the trough brought intensive rainfall breaking a number of rainfall records - Bethlehem received 202 mm, Pretoria 256 mm, Johannesburg 198 mm, Kuruman 109 mm, Bloemfontein 126 mm and Vaalharts 157 mm.

The late rains had a positive effect on the major dams in the country increasing their content: Bloemhof (75% to 90%), Gariep (68% to 100%), and Vaal (84% to 104%).

Rainfall

More than 100 mm of rain fell over Gauteng, western Mpumalanga, the northern Free State, northern Eastern Cape and southern and eastern KwaZulu-Natal.

Figure 1: Total rainfall estimation in millimetres for 1 to 31 March 2018

Figure 2: Percentage difference - rainfall for 1 to 31 March 2018.

Figure 2 indicates rainfall for March. Areas that received above-normal rainfall (most parts of SA), are indicated in green and blue. Yellow to red indicate areas that received below-normal rainfall, including Limpopo (isolated areas); Northern Cape (central Northern Cape); Eastern Cape (the western parts).

Figure 3: Cumulative rainfall from 1 October 2017 to 31 March 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 October to 31 February highlights the 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 northern Eastern Cape, KwaZulu-Natal, Mpumalanga and Gauteng all received more than 500 mm the last six months.

Figure 4: Percentage difference - rainfall for 1 October 2018 to 31 March 2018.

Figure 4 highlights areas that received below-normal 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. Overall, most areas of the summer rainfall region have received between 75 to 100% of the normal expected rainfall this 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 linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). Despite cooling of the pacific ocean, La Nina conditions haven't been reached. Pacific Ocean temperatures expected to increase during the autumn and winter months.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

ProbaV difference map for March 2018 compared to the long-term (20-year) average.

Figure 6: This map is created by calculating the difference between March 2018 and the long-term (20-year)average for March - showing dominant normal vegetation activity (beige). Vegetation conditions are normal to above normal over most areas of South Africa as a result of the good rainfall in March.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in March 2018.

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, western Eastern Cape, western & southern Northern Cape and the Free State. Conditions remain neutral over most of the summer rainfall region.

General Discussion

Figure 8: South African dam levels between March 2018 and April 2018

The grain and oilseed markets should be well supplied during the 2018-19 marketing season, which is from May 2018 to about September 2019 (2017-18 production).

The "National Crop Estimates Committee" predicts the maize crop to be 12.2 million tons for 2017-18 season. This is a decline of 27% from the 2016-17, mainly because the area planted this season was significantly less, especially in the drier western regions (where the drought of 2015-16 is still uppermost in farmers minds). Despite this, good and well dispersed rains have resulted in higher yields. This amount of maize meets the annual local consumption of 10.5 million tons, while the excess will be exported.

It is estimated that soybean production will be 1.4 million tons up by 5% on the previous season as a consequence of higher yields from good rains. The eastern sections of the country received fairly good rainfall throughout the season.

Wheat production estimates are less encouraging - yields in 2017 were well below average because of the low winter rainfall in the Western Cape and drier conditions in the Free State. It is estimated that the national production of wheat will be 1.48 million tons, 23% lower than the 2016 harvest. It will be necessary to import a roughly equivalent amount to meet miller's demands, which is be more than usual.

Livestock farmers should be on the lookout for parasites at this time of the year and treat their animals accordingly. Internal parasites such as roundworms can be a problem due to late rains in the in the summer rainfall regions. Grasses will start losing their nutritional value as winter approaches and animals will start losing their condition - making them more them more susceptible to parasitic infestations. Liver flukes pose a threat to animals grazing wet vlei areas and young animals are susceptible to coccidiosis, a parasite commonly found in muddy conditions.

External parasites including ticks, mites and flies continue to be active in the late summer and autumn months. Many carry diseases and farmers need to take preventative measures even if animals are vaccinated. Despite vaccines being highly effective against many diseases carried by external parasites, external parasites can also cause irritation and stress which adversely affects production. Farmers should consult their local veterinarians or health technicians on which parasites are a problem in their area and what products are effective since many parasites have developed resistance to many broad spectrum anthelmintics and pesticides.

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.

Monthly Overview

February 2018 turned out to be the wettest month of the summer rainfall season. Widespread rain fell over large parts of the country with northern Limpopo registering the highest rainfall figures. During the first ten days of February thunderstorms brought good rains to large parts of the region (Bloemfontein and Pretoria 40 mm each), with as much as 80mm on a Hartbeesfontein farm in North West during one such storm.

During the second ten days of the month, rainfall mainly occurred over the central regions of the country with isolated showers over the rest of the summer rainfall region. Between 40 to 100 mm were recorded in Free State (Rouxville area), and at Gariep Dam (91 mm). Rare thunderstorms in Cape Town, also brought some welcome relief. During the end of this ten day period rainfall shifted to the north and east of the country.

On 20 February Limpopo (109 mm and Tzaneen 134 mm), and northern KwaZulu-Natal (Richards Bay 50 mm to 80 mm) reported good rains and the Hluhluwe dam started to overflow as a result of good rains. During the last 8 days of the month, rain fell mainly over Limpopo and the north Eastern Cape and southern KwaZulu-Natal. Rainfall in Mpumalanga - Sabie, Mbombela and Phalaborwa - measured between 50 and 60 mm, while KwaZulu-Natal - Pongola (100 mm) and Estcourt (112 mm) also receiving their fare share. In the Eastern Cape, Coffee Bay recorded the highest rainfall (133 mm) during the period.

Rainfall

The highest accumulated rainfall fell over the north eastern Free State, north western Eastern Cape, southern Gauteng and northern Limpopo during the period.

Figure 1: Total rainfall estimation in millimetres for 1 to 28 February 2018

Figure 2: Percentage difference - rainfall for 1 to 28 February 2018.

Figure 2 gives a perspective for February: Areas that received above normal rainfall are indicated in green and blue. Normal to above-normal rainfall fell over parts of the Western Cape, southern Northern Cape, most of the Eastern Cape, northern Free State, central and northern KwaZulu-Natal as well as Limpopo.

Figure 3: Cumulative rainfall from 1 September 2017 to 28 February 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 September to 28 February highlights the 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 September 2018 to 28 February 2018.

Figure 4 highlights those areas that received below-normal 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. Overall, most areas of the summer rainfall region have received between 75 to 100% of the normal expected rainfall this 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 linked to La Nina. The latest predictions issued by the Australian Bureau of Meteorology indicate neutral conditions (Figure 5). Despite cooling of the pacific ocean, La Nina conditions haven't been reached. Pacific Ocean temperatures expected to increase during the autumn months.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

Figure 6: Current model predictions for rainfall during February 2018.

Figure 6 show the expected rainfall for March 2018 as calculated from the NOAA Climate Forecast system. Areas in blue highlight above-normal rainfall while the areas in red highlight below-normal rainfall. Beige highlights areas receiving normal rainfall. A dry start to Autumn is expected for the country with only the northern Eastern Cape, KwaZulu-Natal and parts of Mpumalanga expected to receive normal to above-normal rainfall.

NDVI

Figure 7: ProbaV difference map for January 2018 compared to the long-term (20-year) average.

Figure 7: This map is created by calculating the difference between February 2018 and the long-term (20-year) average for February - showing dominant normal vegetation activity (beige). The Limpopo Province shows below-normal vegetation activity, but this might be the result of cloud cover since the province received good rainfall in February. The March NDVI image should reflect the effect of the rainfall. The rest of the summer rainfall region show normal to above normal vegetation conditions as a result of the good rainfall in February.

Figure 8: Percentage of Average Seasonal Greenness for the last 6 months ending in February 2018.

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, western Eastern Cape, western & southern Northern Cape and the Free State. Conditions remain neutral over most of the summer rainfall region.

General Discussion

Figure 9: South African dam levels between February 2018 and March 2018

The good rains in the northern parts of the country supports an optimistic prognosis for the current season's crops, particularly in Limpopo province. The harvest of avocados has started in the Mooketsi and Levubu areas. It is estimated that total exports will be up to 50% higher than last year's drought-affected crop. The bulk of the avocado crop is exported to the European Union where demand is increasing. Other export avenues, such as China, are also being explored.

In the south of the country the outlook is less positive. The Western Cape Department of Agriculture economists estimate a decline of up to R 6.0 billion in income in the agricultural sector for the province. A major consequence is that about 30 000 jobs could be lost and because many of these workers are semi-skilled or unskilled, reducing their chances of absorption by other sectors of the economy.

As we head towards autumn, farmers can start to expect the normal changes in vegetative growth with many veld grasses beginning to seed. Thus nutritional value of natural grazing will begin to decrease especially in sourveld regions. It is important that animals be in good condition before the winter months - animals that are underweight before winter when the grasses offer little or no nutrition will lose even more condition and will struggle to regain a good condition again. Animals in poor condition are less fertile and more susceptible to parasites and diseases. It is good practice to deworm animals against internal parasites. Local veterinarians will be able to advise on which parasites are a problem at this time of year, and which products to use.

During late summer and autumn months, Cullicoides midge numbers reach a peak before dropping after the first frost. These blood sucking midges are important carriers of the African Horse sickness and Bluetongue virus affecting horses and sheep respectively. Unvaccinated animals are especially at risk of contracting these diseases. Farmers can treat shelters and animals with approved insecticides and monitor their animals' condition daily.

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.

Monthly Overview

In comparison to 2017, January 2018 was a much drier month across the summer rainfall region, typified by regular scattered thundershowers and high temperatures. Despite areas around Bloemfontein receiving as much as 40mm early in the month with other areas across the region receiving a bit of rain during the first ten days of the month, rainfall in general was not of much significance.

Rainfall during the second ten days of the month was mainly concentrated over the Northern Cape and Eastern Cape and isolated places like Christiana in Northwest receiving 49 mm from a thunderstorm moving through the area. The rest of the region received little or no rain.

The last 11 days of January turned out to be the wettest as good rains fell over the Eastern Cape, Free State and Northern Cape while Gauteng enjoyed a welcome return to their customary afternoon thunder showers after the earlier dry period and extreme summer temperatures in the area. Significant rainfall statistics for this period include Kokstad (40 mm), Welkom (90 mm), the areas between Ventersdorp and Klerksdorp with (65 mm) and Nylstroom (75 mm). Despite these statistics, most areas in the summer rainfall region received less than the normal rainfall for January.

Rainfall

Despite widespread rainfall over various provinces during January, most accumulated rainfall fell over the north eastern Free State, north western Eastern Cape and western KwaZulu-Natal.

Figure 1: Total rainfall estimation in millimetres for 1 to 31 January 2018

Figure 2: Percentage difference - rainfall for 1 to 31 January 2018.

Figure 2 supplies perspective for January. Areas that received above normal rainfall are indicated in green and blue. Normal to above-normal rainfall fell over the eastern parts of the Western Cape, southern Northern Cape, most of the Eastern Cape, southern Free State, central and north eastern Free State and the western regions of KwaZulu-Natal. Most of the summer rainfall region, especially Gauteng, Limpopo and Mpumalanga received below normal rainfall during January.

Figure 3: Cumulative rainfall from 1 August 2017 to 31 January 2018 in millimetres.

This cumulative rainfall map (Figure 3) for 1 August to 31 January highlights the areas that received more than 150 mm during the period: Light green indicates those that received 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 August 2018 to 31 January 2018.

Figure 4 highlights those areas that received below-normal 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. Almost the entire summer rainfall region is in desperate need for good rains during February and March 2018.

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). Despite cooling of the pacific ocean, La Nina conditions haven't been reached. There is still a small likelihood of La Nina developing during February and March 2018.

Figure 5: Current model predictions for Sea Surface Temperature in the Pacific.

Figure 6: Current model predictions for rainfall during February 2018.

Figure 6 show the expected rainfall for February 2018 as calculated from the NOAA Climate Forecast system. Areas in blue highlight above-normal rainfall while the areas in red highlight below-normal rainfall. Beige highlights areas receiving normal rainfall.

NDVI

Figure 7: ProbaV difference map for January 2018 compared to the long-term (20-year) average.

Figure 7: This map is created by calculating the difference between January 2018 and the long-term (20-year) average for January - showing dominant normal vegetation activity (beige). Areas of concern with below-normal vegetation activity (red) include the North West, Free State and isolated areas in Limpopo and the Eastern Cape. Despite widespread rainfall over the summer rainfall region during January, only small areas received normal to above normal rainfall. This, together with extremely hot temperatures, caused vegetation stress in January.

Figure 8: Percentage of Average Seasonal Greenness for the last 6 months ending in December 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, western Eastern Cape, western & southern Northern Cape and the Free State. Conditions remain neutral over the summer rainfall region.

General Discussion

Figure 9: South African dam levels between January 2018 and February 2018

Despite the unevenly distributed rainfall in the northern parts of the country during January, it still contributed towards maize growth to especially those crops that were struggling. The main production concern however, remains the winter rainfall area of the Western Cape. Estimates for top fruit production (harvest has just begun) indicate a decline of 8% in apple exports and a 3% decrease in pears. Areas most affected by the drought are Villiersdorp, Koue Bokkeveld and Klein Karoo. The Langkloof had rain recently that brought some measure of relief.

Restricted water use has resulted in lower than expected production and preliminary estimates are pointing towards a 12% decline. Wineries are predicting 12 - 16% lower crop yields for 2018 (compared to 2017), while some estimates say that it may well be the smallest yield since 2005.

During the summer months insect activity increase and many cases of insect and tick-borne diseases were reported during those months. Timely vaccines are important preventative measures and farmers should already start planning now towards the vaccination of animals before the next rainy season. Veterinarians can help set up vaccination, dipping and dosing programmes and advise on the control of insects.

Farmers in the drought stressed Cape provinces are under pressure to use less water for agricultural activities. The lack of water and feed also has a negative effect on the health of animals. The unnecessary handling of animals adds to their stress levels - making them more prone to diseases. There are also high fire risks due to the hot and dry conditions, that are increased by the lack of available dam water to control fires.

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.

Monthly Overview

December 2017 started with good rainfall over most of the summer rainfall region, with Mpumalanga and northern KwaZulu-Natal receiving more than 50 mm during the first 10 days of the month, while the second 10 day period of the month followed the same trend with rains over most of the summer rainfall region. Major damage, however, was caused by storms around the Vaal Dam area, with reports of a tornado over the Vaal Marina. Over the northern parts (Limpopo, North-West, Gauteng & Mpumalanga), the last good rain fell between the 12th and 13th, while the northern Cape, Free State, and parts of the Western and Eastern Cape received good rainfall between 13 and 18 December.

Northern and Eastern Cape, as well as Free State received good rains during the last 10 days of December. By the end of the month, the rainfall trend shifted northward towards Gauteng, Mpumalanga, Limpopo and North West Provinces.

Another major storm caused damage over parts of Johannesburg with reports of another tornado - trees were uprooted - and hail over the southern parts of Gauteng.

The promise of a good rainfall month for the whole summer region proved to be empty as rainfall was mostly scattered over the northern and western summer rainfall region. Only the northern Free State, Gauteng, Mpumalanga and northern KwaZulu-Natal received above normal rainfall during December.

Rainfall

Good rainfall - more than 80 mm - fell over large parts of the summer rainfall region, most notably Gauteng, Mpumalanga, KwaZulu-Natal and the northern Free State.

Figure 1: Total rainfall estimation in millimetres for 1 to 31 December 2017

Figure 2: Percentage difference - rainfall for 1 to 31 December 2017.

Figure 2 supplies perspective for December. Areas that received above normal rainfall are indicated in green and blue. Isolated areas over the Northern Cape and southern Free State received above normal rainfall, while the highest rainfall fell over the northern Free State, Gauteng, Mpumalanga and northern KwaZulu-Natal. Below normal rainfall fell over Limpopo and the North-West. Good rainfall is needed over these areas for the rest of the rainfall season to avoid drought conditions developing.

Figure 3: Cumulative rainfall from 1 July 2017 to 31 December 2017 in millimetres.

This cumulative rainfall map (Figure 3) for 1 July to 31 December highlights the 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 July to 31 December 2017.

Figure 4 highlights those areas that received below-normal 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. Only Gauteng and large parts of Mpumalanga have received above-normal rainfall, while the rest of the summer rainfall region received 50 to 75% of their normal rainfall so far this 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 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 January 2018. 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 (19-year) average.

Figure 6: This map is created by calculating the difference between December 2017, and the long-term (20-year) average for December - showing dominant normal vegetation activity (beige). Areas of concern with below-normal vegetation activity (red) include the southern Free State, the eastern parts of Limpopo, Mpumalanga and isolated areas of North West.

Figure 7: Percentage of Average Seasonal Greenness for the last 6 months ending in December 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, western Eastern Cape, western & southern Northern Cape and the Free State. Conditions remain neutral over the summer rainfall region but these conditions could change with continued summer rains.

General Discussion

Figure 8: South African dam levels between December 2017 and January 2018

Rainfall over South Africa was erratic in December with some areas experiencing below-average rainfall. In the western Free State and North West rains have been had been sporadic and many farmers have had to plant maize later than usual.

In the eastern summer planting area, including Mpumalanga, most farmers have planted as normal, but are now desperate for follow-up rain to replenish soil moisture levels; this is critical because many maize crops will soon be in the "silking" stage of growth and water stress can reduce final yields significantly. Hopefully, the La Niña weather pattern could result in rains in the second half of January.

The drought persists in the Western Cape. The Western Cape Department of Agriculture is providing a service based on satellite technology (from a Dutch company, eLeaf) which indicates the efficiency of irrigating various crops. Satellite data shows the continual production of biomass (indicator of production) in relation to the water requirements of a specific crop. It is then possible to determine if the crop is currently being under-watered or over-watered and to estimate the future water needs of the crop in the short-term; this has improved the efficient use of water and yields by up to 10% in apples.

With hot conditions prevailing, livestock farmers are cautioned to keep an eye on their animals for heat stress. High producing animals, such as dairy cattle, are especially vulnerable, however all animals are susceptible when temperatures are very high. High humidity levels will exasperate the situation as will drought conditions when water availability is limited. A further risk for all livestock farmers during hot and dry conditions is fire. The risks are particularly high in the Western Cape areas.

Severe storms easily displace animals as well as damages infrastructure causing both structural and livestock losses. Farmers should always keep an eye out for severe weather warnings and prepare in advance for them as much as possible. For the summer rainfall regions receiving good rains and high temperatures, problems with intestinal roundworms can be expected to increase. Farmers should do regular observations and look out for signs of bottle jaw and anaemia (Famacha system) and high faecal egg counts. Treatment efficiency should be evaluated as many parasites are resistant to most active ingredients. A programme can be discussed with a vet.

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.