The African Monsoon
Recent Evolution and
Current Status
Include Week-1 and Week-2
Outlooks
Update prepared by
Climate Prediction Center / NCEP
17 October 2011
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
• Summary
Highlights:
Last 7 Days
• Southern Somalia, portions of Southeast Ethiopia and Northeast
Kenya saw their heaviest rainfall since the start of the current
rainfall season. Moderate to locally heavy rains continued to fall
across central African region and western Equatorial Africa.
• Week-1 outlooks call for an increased chance for above average
rainfall over much of the central African and portions of the Horn of
Africa countries.
Rainfall Patterns: Last 7 Days
During the past seven days, much of the Gulf of Guinea countries, Gabon, eastern CAR,
many parts of DRC, portions of Uganda, local areas of northern Tanzania, central
Mozambique and portions of Madagascar received above average rainfall. Heavy rains also
resulted in moisture surpluses over southern Somalia, portions of Southeast Ethiopia and
eastern Kenya. Below average rainfall was observed over southern Chad, western CAR,
central Angola, southeastern DRC and portions of Ethiopia.
Rainfall Patterns: Last 30 Days
During the past 30 days, much of the Gulf of Guinea and central African countries,
southern Somalia, parts of southern Ethiopia, eastern Kenya, western Uganda, Rwanda,
Burundi, western Tanzania, local areas of Mozambique and Madagascar had above average
rainfall. Moisture deficits were observed over southern Senegal, parts of southern
Mauritania, central Nigeria, southern Chad, portions of CAR, Sudan, Ethiopia and central
Angola.
Rainfall Patterns: Last 90 Days
During the past 90 days, above average rainfall was observed across the Senegal-
Mali-Guinea border, central Mali, Ghana, eastern Burkina Faso, western Chad,
portions of CAR, Cameroon, Gabon, northern Congo Brazzaville, eastern DRC,
Uganda, western Kenya and southern Somalia. In contrast, coastal Guinea
Conakry, Sierra Leone, parts of Cote D’Ivoire, western Burkina Faso, many parts
of Nigeria, eastern Sudan, Eritrea and Ethiopia had below average rainfall.
Rainfall Patterns: Last 180 Days
During the past 180 days, rainfall was below average Southern Senegal, coastal
Guinea Conakry, Sierra Leone, Cote D’Ivoire, western Niger, Much of Nigeria,
portions of Cameroon, eastern Sudan, Eritrea and Ethiopia. Moisture surpluses were
observed over northern Guinea Conakry, parts of southern and central Mali, Ghana,
local areas of Chad and CAR, northern Congo Brazzaville, central and eastern DRC,
Uganda, western Kenya, southern Somalia, southeastern Ethiopia and costal South
Africa.
Recent Rainfall Evolution
Daily evolution of rainfall over the last 90 days at selected stations reflects the gradual increase
in rainfall across central and East Africa; DRC (bottom panel – left), Uganda (bottom panel-right),
and the recent heavy rainfall in southern Somalia (top panel – right).
Atmospheric Circulation:
Last 7 Days
The 850hPa wind anomaly (left panel) featured westerly anomalies across Gulf of Guinea
coast and easterly anomalies in the Congo Air boundary (CAB) region. The 200hpa wind
anomaly (right panel) featured anomalous easterlies across East Africa and Southeast
Africa.
NCEP GEFS Model Forecasts
Non-Bias Corrected Probability of
precipitation exceedance
Week-1: Valid 18 – 24 October 2011
Week-2: Valid 25 – 31 October 2011
For week-1 (left panel) and week-2 (right panel), there is an increased chance for
rainfall to exceed 50 mm over Gulf of Guinea coast, central African region and portions
of the Horn of Africa countries.
Experimental Week-1 Precipitation Outlooks
Week-1 Outlook
18 – 24 October 2011
1. There is an increased chance for above average
precipitation over Southeast Nigeria, southern Cameroon,
southern CAR, much of DRC, Equatorial Guinea, Gabon
and Congo Brazzaville, western Uganda, Rwanda, Burundi
and western Tanzania: The combination of anomalous wind
convergences across central African region and the projected
phase of the MJO are expected to enhance rainfall in the
region. Confidence: Moderate
2. There is an increased chance for above average
precipitation over southeastern Ethiopia, northeastern
Kenya and portions of Somalia: The combination of
anomalous wind convergences over the Horn of Africa and the
projected phase of the MJO are expected to enhance rainfall in
the region. Confidence: Moderate
Experimental Week-2 Precipitation Outlooks
Week-2 Outlook
25 - 31 October 2011
1. There is an increased chance for above average rainfall
over Equatorial Guinea, Gabon, Congo Brazzaville,
northern Angola and much of DRC: The projected phase of
the MJO is expected to enhance rainfall in the region.
Confidence: Moderate
Summary
• During the past seven days, much of the Gulf of Guinea countries, Gabon, eastern CAR, many
parts of DRC, portions of Uganda, local areas of northern Tanzania, central Mozambique and
portions of Madagascar received above average rainfall. Heavy rains also resulted in moisture
surpluses over southern Somalia, portions of Southeast Ethiopia and eastern Kenya. Below
average rainfall was observed over southern Chad, western CAR, central Angola, southeastern
DRC and portions of Ethiopia.
• During the past 30 days, much of the Gulf of Guinea and central African countries, southern
Somalia, parts of southern Ethiopia, eastern Kenya, western Uganda, Rwanda, Burundi, western
Tanzania, local areas of Mozambique and Madagascar had above average rainfall. Moisture
deficits were observed over southern Senegal, parts of southern Mauritania, central Nigeria,
southern Chad, portions of CAR, Sudan, Ethiopia and central Angola.
• During the past 90 days, above average rainfall was observed across the Senegal-Mali-Guinea
border, central Mali, Ghana, eastern Burkina Faso, western Chad, portions of CAR, Cameroon,
Gabon, northern Congo Brazzaville, eastern DRC, Uganda, western Kenya and southern
Somalia. In contrast, coastal Guinea Conakry, Sierra Leone, parts of Cote D’Ivoire, western
Burkina Faso, many parts of Nigeria, eastern Sudan, Eritrea and Ethiopia had below average
rainfall.
• Week-1 outlooks call for an increased chance for above average rainfall over much of the
central African and portions of the Horn of Africa countries.