# Presentation: 249678

## The African Monsoon Recent Evolution and Current Status

**Update prepared by**
**Climate Prediction Center / NCEP**
**19 May 2008**

**For more information, visit:**
**http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/African_Monsoons/precip_monitoring.shtml**

## Outline

**  ****Highlights**
**  ****Recent Evolution and Current Conditions**
**  ****NCEP GEFS Forecasts**
**  ****Experimental Week-1 Outlook**
**  ****Summary**

## Highlights:Last 7 Days

- Moderate to heavy rains fell in parts of the Gulf of Guinea region over the past 2 to 3 days and resulted in a reduction of moisture deficits over the past week.
- Showers fell in local areas in southern Sahel.

## Rainfall Patterns: Last 180 Days

**Over the past 180 days, rainfall was below average over central Ethiopia, western Kenya, Uganda, most of DRC, stretching south to include the northern areas of Angola and Zambia.  Rainfall was also below average over most areas in the Gulf of Guinea region.  Rainfall was above average over portions of Tanzania and in parts of southern Africa, except for northern and eastern Madagascar, and locally in southern areas of Zimbabwe and Mozambique. **

## Rainfall Patterns: Last 90 Days

**Over the past 90 days, rainfall was below average over central Ethiopia southward into northern Kenya and Uganda, extending west to the Gulf of Guinea region.   Rainfall was also below average over most areas in central Africa and the northern sector of southern Africa.   Rainfall was above average over northeastern Mozambique, along the coast of Tanzania, and over central Namibia.  **

## Rainfall Patterns: Last 30 Days

**Over the last 30 days, rainfall was below average over most of Ethiopia, Kenya, Uganda, northwestern Tanzania, Rwanda, and Burundi.  Rainfall was also below average over portions of central Africa and along portions of the Gulf of Guinea coast.  In the south, rainfall was below average along the east coast of  Madagascar and central Mozambique.**

## Rainfall Patterns: Last 7 Days

**During the past 7 days, rainfall was near average across most crop areas in Africa, except in local areas along the Guinean coast and in central Kenya, where rainfall was slightly below average.**

## Recent Rainfall Evolution

**Recent Rainfall Evolution**

**	****Moisture deficits persisted in portions of the northern Horn of Africa (top panel - right); Despite a few showers over the past few days,  western Kenya and Uganda continued to register below average rainfall (bottom panel – right); Below average rains also sustained moisture deficits over parts of the Gulf of Guinea region (bottom panel – left).  **

## Atmospheric Circulation:Last 7 Days

**Over the past 7 days, the 850 hPa wind anomaly (left panel) featured a weakening of both the southern hemisphere and northern hemisphere subtropical ridges.  This low level circulation is associated with an anomalous upper level cyclonic circulation across northwestern Africa (right panel).**

## Rainfall Climatology: 20-26 May

- Rainfall totals for the week 20-26 May range between 15 and 45 mm over the Gulf of Guinea region, extending north into the southern areas of the Sahel, western Ethiopia, southwestern Kenya, eastern Uganda, and along coastal Kenya and northeast Tanzania.

## NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance – Week-1Valid 20-26 May, 2008

**NCEP global ensemble forecast system (GEFS) suggests a high tilt in the odds (90% or above) for precipitation to exceed 25 mm along the Guinean coast, as well as coastal Kenya and northeastern Tanzania, the western Ethiopian highlands, and central Africa (left panel).  Areas with the highest chance for precipitation to exceed 50 mm (right panel) include the coastal boundary between Kenya and Tanzania, locally in western Ethiopia, Gabon, and sections along coastal Gulf of Guinea.**

## Experimental Week-1 Precipitation OutlookValid 20-26 May, 2008

**An increased chance for above average**
**rainfall along the Guinean coastline:**
- The enhanced phase of the MJO and the low level
- moisture advection from the Gulf of Guinea
- Are expected to enhance rainfall in this region.
**Confidence: High**
**An increased chance for above average**
**rainfall over the western Ethiopia Highlands:**
**The enhanced phase of the MJO and low level**
**moisture advection from the Indian Ocean will**
**favor above average rainfall in the region.**
**Confidence: Moderate**
**An increased chance for above average**
**rainfall along coastal Kenya: Low level moisture**
**advection from the western Indian Ocean is**
**expected to enhance rainfall in this region.**
**Confidence: Moderate**

## Summary

**Over the past 7 days, light rains fell over most areas in the Greater Horn of Africa as the rainy season has begun to wind down in Kenya, Uganda, and northern Tanzania.  Rainfall was only slightly below average over central Kenya.  Late showers in portions of the Gulf of Guinea region during the period helped reduce the moisture deficits observed earlier in the period.  Local areas in southern Sahel, including areas in southern Niger and southern Mali registered light to moderate rains. **
**Despite the showers of the past week, cumulative rainfall over many areas in the Gulf of Guinea region over the past 30 and 90 days remain below average.  The areas most severely affected  include western Cote d’Ivoire, which registered only 50% of the cumulative 90-day rainfall totals.   As the rainy season begins to wind down in many parts of the Greater Horn of Africa, Parts of the region are likely to end the season with significant moisture deficits.  Parts of Kenya, Uganda, and Ethiopia registered only about 50% of the cumulative 90-day total rainfall. **
**For the period 20–26 May 2008, there is an increase chance for above average rainfall along the Guinean coastline.**