2.0 Climate Forecasts

CLIMATE FORECAST

The Climate Hazards Center (CHC) of the University of California Santa Barbara (https://www.chc.ucsb.edu/) provides GEOGLAM Crop Monitor with global and regional climate outlooks. These assessments are based on weather and seasonal climate forecasts from a variety of international and national sources. Regional climate outlooks in the CM4EW draw attention to abnormal rainfall and temperature conditions (observed and forecast) that may impact food production or pose other risks to society, with a focus on food insecure regions.

 

February 6th, 2020
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For previous reports visit the Archive.

Global Climate Outlook

Neutral ENSO & IOD

El Niño-Southern Oscillation (ENSO) conditions are neutral and are most likely to remain neutral through June 2020. During late 2019 a strong positive Indian Ocean Dipole (IOD) suppressed rainfall in Australia and enhanced rainfall in East Africa. The IOD is now in a neutral state and is forecast to remain neutral through June 2020.

East Africa Outlook:

Wetter than average conditions expected to continue into February across the south of the region

January 2020 rainfall was above average in equatorial and southern areas of the region, including in western, central, and coastal Kenya, Tanzania, southwest Ethiopia, southeast South Sudan, and eastern and southern Uganda. Elsewhere January rainfall was near average.

Wet conditions and high-intensity rainfall are likely during the first week of February in Tanzania and the Lake Victoria region, as shown by the short term forecast issued January 31st (Figure 1-top left). According to 30-day forecasts from several models, wetter than average conditions are expected for February as a whole, mainly in Tanzania, and also in western and southern Kenya, northern Zambia, and northern Mozambique (Figure 1- bottom left). This largely reflects the forecast heavy rains in early February, but there is consensus for wetter than average conditions in subsequent weeks. For the March to May 2020 season, long-range outlooks indicate the chance of slightly above average rainfall in the region. While the previously influential strong positive Indian Ocean Dipole has relaxed to a neutral state, warmer than average western Indian Ocean temperatures may positively influence rainfall in some areas. Confidence is not high in MAM rainfall forecasts at present, so it will be important to keep watch on short term forecasts closer to and during the season.

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Figure caption: Short term, medium-term, and long-range seasonal forecasts for East Africa. Top left- Chances of rainfall in the first week of February 2020 being much wetter or drier than average. Dry (< 50% of average) or wet (> 150% of average). From the NOAA/NCEP/CPC Global Ensemble Forecast System (GEFS) on 1/31. Bottom left- Forecast rainfall for the 30-day period ending February 28th, shown as the difference from the 1999 to 2016 average. The image shows the average across four Subseasonal Experiment (SubX) model forecasts on 1/30. The 30-day forecast map provides a generalized outlook only and does not accurately depict localized amounts. Right- The most likely outcome for March to May 2020 rainfall (above normal, normal, below normal) and corresponding probabilities, according to the Fifty-Fourth Greater Horn of Africa Climate Outlook Forum (GHACOF54).

 

Southern Africa Outlook:

Rainfall improvements in January while below-average Feb-Mar rainfall is likely across Central and South of the region

Mixed rainfall patterns were seen across the region in January, an important month for regional crop production. Areas with below-average rainfall include southern Madagascar, southern and eastern Mozambique, and parts of Zimbabwe, Zambia, Namibia, South Africa, and Botswana. According to preliminary CHIRPS estimates (Figure 1-left) and other data, the most severe 1-month deficits were in southern Mozambique, southern Madagascar, central Namibia, and parts of central and eastern Zimbabwe and western Zambia. There is increased concern for adverse impacts to crop production in some of these areas, where overall drier than normal conditions have persisted for two to four months and are forecast to continue. Extremely warm (>+7°C) early January Land Surface Temperature anomalies in Zimbabwe, southern Zambia and southern Mozambique exacerbated the adverse impacts of earlier dry and warm conditions and severe crop water stress. In these areas, the combined influence of low and poorly distributed seasonal rainfall totals, and recent low late-January rainfall have resulted in poor growing conditions.

January rainfall was highly above average in the northeast, in Tanzania, northern Mozambique, and northern Madagascar. Areas in northern and southern South Africa and in central and northern Angola also saw higher than average January rainfall totals. Late January storms are also likely to have produced January surpluses in northeast Zambia. Severe storms produced flooding in a number of areas in January. According to Floodlist, some of the worst impacts were in Madagascar (Alaotra-Mangoro, Analamanga, Betsiboka, Boeny, Diana, Melaky, and Sofia) and Mozambique (Zambezia, Cabo Delgado, Sofala provinces), where in total more than 50 people were killed and 150,000 people were displaced.

The two-week forecast, issued January 30th, shows a medium to high chance of below-normal rainfall in central and southern Mozambique, Madagascar, southern and eastern Zimbabwe, northeastern South Africa, Botswana, and Namibia. Northern areas are forecast to receive above-average rainfall, and the forecast high amounts indicate an increased risk for flooding in some areas. This forecast is consistent with ongoing conditions, and earlier seasonal forecasts, which showed a tendency for enhanced rains in the northeast and suppressed rains in the central region, particularly the central-east (see the January 17th, 2020 report). Longer range forecasts have indicated that this regional pattern is likely to persist through February and potentially into March.

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Figure caption: Preliminary estimates for January rainfall and the two-week forecast, each in terms of the difference from average. Left- CHIRPS Preliminary rainfall anomaly for Jan 1-25, 2020. Anomaly based on the CHIRPS 1981-2018 average. Right- Forecast Jan 30-Feb 14, 2020 rainfall anomaly from CHIRPS-GEFS (unbiased GEFS ensemble mean). Anomaly based on CHIRPS-GEFS hindcast 1982-2018 average.

For previous forecasts and assessments, please see the report archive page.