Sahel Weather Analysis 2000/2001

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Seasonal Vegetation Index - 2000/2001

Seasonal Vegetative Index

Seasonal Rainfall - 2000/2001
in mm

Calculated Rain Line Location Across the Season

River Basin Seasonal Rainfall Analysis
For West Africa
River Basin Rainfall

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Preliminary Monthly Weather Analysis
West Africa 2000/2001

From the African Desk, Climate Prediction Center, NOAA
Note: This information should be used with caution.
Weather data are based on preliminary reports.

April 2001 - Local heavy rain hit the coastal countries, as showers dumped 200 to 300 mm on southern parts of Nigeria, Ghana and Côte d'Ivoire. The rains were somewhat slow to advance northward, with southeastern Burkina Faso and parts of northern Ghana, Togo and Benin recording less than one-half of normal amounts. Temperatures during April averaged 2 to 4 degrees C above normal in northern and southern Senegal but were generally near normal elsewhere. >
April 21-30 2001 - Parts of the Gulf of Guinea Coast reported above-normal rainfall (63-142 mm; 146-256% of normal), including southern Côte d'Ivoire and southern Benin. Satellite estimates indicated 75 to 150 mm in eastern and central Nigeria, central Benin, central Ghana and northern Côte d'Ivoire. Rainfall remained below normal in extreme northern portions of Ghana, Togo, and Benin, as well as southern Burkina Faso and southern Mali. The seasonal rains edged northward into southern Niger. Temperatures averaged 2 to 3 degrees C above normal in southern parts of Mali and Burkina Faso.
April 11-20 2001 - Rains (1-77 mm) fell along the coast of the Gulf of Guinea and continued to slowly advance northward. Satellite estimates indicated heavier rains exceeding 125 mm fell in eastern Cote d’Ivoire and southeastern Nigeria. Abnormal dryness persisted from northeastern Ghana into northern Benin and southern Burkina Faso. Temperatures remained abnormally high over Senegal, Gambia and Mali, averaging 2 to 4 degrees C above normal. Temperatures averaged generally near normal elsewhere.
April 1-10 2001 - Locally heavy showers fell along the coast of the Gulf of Guinea, with amounts in excess of 150 mm striking southern Ghana. In contrast, abnormal dryness persisted over the interior parts of the Gulf of Guinea region and the extreme southern Sahel. Nigeria was an exception, as the seasonal rains advanced into the north during this period. Satellite estimates indicated that southwestern Cameroon also picked up over 150 mm. Temperatures averaged near normal across most of the region, but remained abnormally high over Senegal, Gambia, Guinea and western Mauritania, averaging 1 to 4 degrees C above normal.
March 2001 - Temperatures remained abnormally high over Senegal, Gambia and Mali, averaging 4 degrees C above normal. Isolated heavy rains began to fall across coastal Gulf of Guinea and slowly advance northward. Accumulated amounts ranged from 2 to 180 mm (3-157% of normal), but an area extending from northern Côte d’Ivoire eastward through central and northern Ghana, Togo, Benin and southern Nigeria recorded only 0 to 26 mm (25 to 50% of normal) rainfall.
March 21-31 2001 - Locally light to moderate showers dropped 1 to 26 mm on Côte d'Ivoire, Ghana, Togo, Benin and coastal areas of Nigeria. Amounts stayed under 50% of normal from east-central Côte d’Ivoire eastward across Ghana, Togo, Benin and into Nigeria, continuing a persistent pattern of dryness. Unusually warm weather prevailed across the western Sahel region, as temperatures averaged 2 to 6 degrees C above normal. Readings averaged slightly above normal elsewhere in West Africa.
March 11-20 2001 - Rains continued to slowly advance northward in the Gulf of Guinea region. Amounts ranged from 23 to 89 mm (99-250% of normal) in the southern parts of Côte d'Ivoire and Ghana. Totals were below normal (0-20 mm; 0-65% of normal) in Togo, Benin and southern Nigeria. This area has seen a slow start to the rainy season, with 4-week amounts well under 50% of normal. Seasonably dry weather prevailed in the Sahel region. Temperatures remained abnormally high over Senegal, Gambia and Mali, averaging 2 to 4 degrees C above normal. Temperatures averaged generally near normal elsewhere.
March 1-10 2001 - Isolated light rains were observed across much of coastal Gulf of Guinea, except isolated heavy rains (67-79 mm; 234-250% of normal) recorded in southern Côte d'Ivoire and Ghana. Seasonably dry conditions prevailed across the Sahel. Temperatures were generally near-to-above average over much of the region, except in Nigeria, where they were 3 to 5 degrees C below normal.
February 21-28 2001 - Thunderstorms broke a dry spell along the coast of Côte d'Ivoire and Ghana, but abnormally dry, hot weather continued over the southern interior areas from Côte d'Ivoire to Nigeria. Amounts ranged from 10 to 50 mm (50-200% of normal) in southern parts of Liberia, Côte d'Ivoire, Guinea, Togo, Benin, and Nigeria. Seasonably dry weather prevailed over the Sahel region. Temperatures remained abnormally high over Senegal and Gambia, as well as in western Mali and much of Mauritania, averaging 3 to 6 degrees C above normal. Temperatures ranged from 2 to 6 degrees above normal over the Gulf of Guinea countries.
February 2001 - February was abnormally dry over the forest belt of West Africa, with 0 to 25 mm (0-50% of normal) across the interior portions of Côte d'Ivoire and Ghana and the southern coast of Togo, Benin, and Nigeria. The Sahel was seasonably dry, but temperatures averaged 2 to 4 degrees C above normal in Senegal, Gambia, and Guinea.
February 11-20 2001 - Seasonably dry conditions prevailed over the Sahel, but abnormally dry weather prevailed along the Gulf of Guinea coast this period, with no rainfall reported from Côte d'Ivoire to Nigeria. Typical ten-day totals are 10 to 25 mm during February. Temperatures averaged 1 to 3 degrees C below normal over much of the region, except in Senegal and Gambia, where readings averaged 2 to 4 degrees above normal.
February 1-10 2001 - Seasonably dry weather continued over the interior, while light to moderate showers (1-40 mm) dotted the coast from Liberia to western Nigeria. Amounts in southern Côte d’Ivoire (20-40 mm) were 200 to 300% of normal. The heat continued in Senegal and Gambia, with temperatures 2 to 6 degrees C above normal. Readings averaged 2 to 5 degrees above normal in south-central Côte d’Ivoire and mostly near normal elsewhere.
January 2001 - The Sahel countries saw seasonably dry weather, but temperatures were unusually high in the west, ranging from 2 to 4 degrees C above normal across Mali, Mauritania, and Senegal. Rainfall amounts were light (0-10 mm; 0-50% of normal) along the Gulf of Guinea coast from Côte d'Ivoire to Nigeria.
January 21-31 2001 - Seasonably dry weather continued over the entire region, except in southern Nigeria, where isolated rain (1-20 mm) fell on the 31st, according to satellite estimates. Temperatures averaged 2 to 6 degrees C above normal in Senegal and near normal elsewhere in the region.
January 11-20 2001 - The dry season continued over the Sahel and dry weather returned to the entire Gulf of Guinea region. Temperatures were 1 to 3 degrees C above normal except in Chad, where they averaged 1 to 3 degrees C below normal.
January 1-10 2001 - Seasonably dry conditions prevailed over the Sahel and much of the Gulf of Guinea region, except for isolated heavy rains (109-125 mm; 111-124% of normal) over southern Côte d'Ivoire. Temperatures were 1 to 3 degrees C above average across the region, except in Niger, Chad and Nigeria, where they were 1 to 3 degrees C below normal.
December 2000 - Seasonably dry conditions prevailed across much of the Sahel and the Gulf of Guinea region. However, drier than normal conditions prevailed over southern Côte d'Ivoire, except isolated heavy rains that were observed along the coast. Temperatures were near average across much of the region, but were 1 to 2 degrees C above normal over western Sahel, including southern Mauritania and Senegal.
December 21-31 2000 - Seasonably dry conditions prevailed over the Sahel and much of the Gulf of Guinea region, except isolated heavy rains (102 mm; 280% of normal) that soaked extreme southwestern Côte d'Ivoire. Temperatures were 1 to 3 degrees C above average across the region, except northern and eastern Ghana, where they were 1 to 3 degrees C below average.
December 11-20 2000 - Seasonably dry conditions prevailed across the Sahel and the Gulf of Guinea region. Light rains reported along the Guinea Coast, though.
December 1-10 2000 - The dry season continued, with Harmattan dust over the Sahel region.
November 2000 - Seasonably dry weather prevailed over most of the interior with the exception of spotty rains of 10 to 24 mm in southern Mali and northwestern Mauritania. Abnormally heavy rains (122-155 mm, 200-500% of normal) fell in central and southern Côte d’Ivoire and coastal Ghana. Satellite rainfall estimates indicated 100 mm to 200 mm over Liberia and Sierra Leone. Temperatures were 2 to 4 degrees above normal in northern Senegal, southern Guinea and eastern Côte d’Ivoire.
November 21-30 2000 - Unseasonably heavy rains (10-90 mm, 200-500% of normal) fell in central and southern Côte d’Ivoire and central and southern Ghana. Satellite rainfall estimates indicated 50 to 100 mm over Liberia. Seasonably dry weather prevailed elsewhere. Temperatures averaged 2 to 3 degrees C below normal in northern and central Chad, northern Mali, and northeastern Ghana, and 2 to 3 degrees C above normal in northern Niger, northern Senegal and northern Burkina Faso.
November 11-20 2000 - Unseasonable rains of 16 to 24 mm fell in northwestern Mauritania. Up to 11 mm fell in south-central Mali, where normally 0 to 1 mm is expected. Light to moderate rains (1-65 mm, 12-250% of normal) fell in southern Guinea, central and southern Côte d'Ivoire, central and southern Ghana, southern Togo, southern Benin and southern Nigeria. Satellite rainfall estimates indicated 50 mm to 100 mm over northern Sierra Leone and eastern Liberia. Temperatures were normal except for 2 to 4 degrees C above normal in central Mali, Senegal, southern Guinea, eastern Côte d'Ivoire and Burkina Faso.
November 1-10 2000 - Rains were mainly confined to coastal areas, with light to moderate amounts (1-48 mm, 2-275% of normal) in southern Benin, southern Togo, southern and central Ghana, Côte d'Ivoire and interior Guinea. Satellite rainfall estimates indicated 50 to100 mm over Sierra Leone, southern Nigeria and southern Liberia. Temperatures were normal except for 2 to 4 degrees C above normal in central Mali, coastal Mauritania, Senegal, southern Guinea, interior Côte d'Ivoire, southern Ghana, northern Benin and central Chad.
October 2000 - Some of the areas that experienced the driest growing season reported the heaviest October rains, as the season ended on a wet note. Rainfall was well above normal over much of the Sahel, including Senegal, Mauritania, Burkina Faso, and Niger. Specifically, light rains (1- 49 mm, 1-328% of normal) fell in southern and central Chad, southern Niger, central and eastern Mali, Mauritania, north Burkina Faso, northern Senegal, Nigeria, Guinea, northern Benin, northern Togo, Ghana and northern Côte d'Ivoire. Moderate to heavy rainfall (53-171 mm, 32-885% of normal) occurred in central and southern Nigeria, southern Burkina Faso, southern Benin, southern Mali, southern Senegal, and southern Mauritania. Very heavy rain (335 mm, 316% of normal) hit coastal Côte d'Ivoire. Satellite estimates put rainfall over Liberia and Sierra Leone at 200 to 300 mm. Temperatures were normal except for 2 degrees C above normal in southwestern Guinea and central eastern Côte d'Ivoire.
October 21-31 2000 - Light to moderate rains (1-60 mm, 3-1000% of normal) fell in southern Senegal, southern Mali, southwestern Burkina Faso, southern Niger, southern Benin, southern Togo, southern Ghana, southern Côte d'Ivoire, and southwestern Guinea. Isolated heavy rainfall (184mm, 415% of normal) occurred in coastal Côte d'Ivoire. Satellite estimates put rainfall over Liberia, Sierra Leone and southern Nigeria at 25 to 150 mm. Temperatures were normal except for 2 to 3 degrees C above normal in northern Benin, central Ghana, eastern Côte d'Ivoire and western Guinea.
October 11-20 2000 - Light to moderate rains (1-94mm, 1-1000% of normal) fell in Burkina Faso, southern Mali, central and southern Mauritania, interior Senegal, Guinea, central and northern Côte d'Ivoire, central and northern Ghana, northern Togo and northern Benin. Isolated heavy rainfall (111-116mm, 1000% of normal) was reported in southwestern Mali and coastal Senegal. Satellite estimates put rainfall over Liberia, Sierra Leone and southern Nigeria at between 100 to 200mm. Temperatures were normal except for 2 to 4 degrees C above normal in central and southern Niger, and eastern Côte d'Ivoire. They were 2 to 4 degrees C below normal in northern Mali, southern Mauritania, Senegal, Ghana, and Togo.
October 1-10 2000 - Light to moderate rains (1-89 mm, 3-404% of normal) fell in central and southern Chad, southern Niger, Burkina Faso, southern Mali, central and southern Mauritania, Senegal, Guinea, central and northern Côte d'Ivoire, central and northern Ghana, Togo, Benin and Nigeria. Heavy rainfall (101-121mm, 194-219% of normal) covered southwestern Côte d'Ivoire. Amounts were mostly above normal from Côte d’Ivoire to Nigeria. Satellite estimates put rainfall over Liberia and Sierra Leone at between 50 and 150 mm. Cumulative rainfall since May remained below 80% of normal in Senegal, Gambia, southeastern Mauritania, southern Burkina, western Niger, and the coastal areas of the Gulf of Guinea countries from Liberia to Benin. Temperatures averaged near normal except for 2 to 4 degrees C above normal in Ghana, southeastern Mali and southern Senegal.
September 2000 - Rainfall was mostly below normal. Unseasonably light rains (5-60 mm, 5-60% of normal) fell in Senegal’s northern and eastern groundnut basin and extended southward through eastern Gambia and southern Senegal into Guinea Bissau. This area’s season-to-date rainfall (May-September) has been abnormally low, totaling under 60% of normal. Similarly low amounts fell in southeastern Mauritania, the northern pastoral areas of Niger and Chad, the northeast pastoral areas of Mali (Gao), as well as east-central Chad. May to September rainfall totaled as little as 60% of normal in these areas. Below-normal rainfall of 40 to 70 mm (30 to 70% of normal) fell in western Mali (Segou, Koulikoro), central and southern Burkina Faso, and southwestern Niger. Five-month rainfall totals range from 60 to 80% of normal in these areas as well as in extreme southeastern Niger. Heavier rains (5-150 mm, 70-200% of normal) fell in west-central and southwestern Chad, eastern Niger, south-central and southwestern Mauritania, and coastal Senegal and Gambia. Amounts of 100 to 200 mm fell in Guinea and the northern and central Gulf of Guinea countries. Isolated cases of heavy rains (102-244 mm, 100-228% of normal) occurred in southern Chad, southeastern Niger, southwestern Burkina Faso, southern Mali, Côte d'Ivoire, northern Ghana and northern Benin. Satellite estimates indicated 50 to 300 mm of rainfall in Nigeria and 50 to 150 mm in Sierra Leone and Liberia. Temperatures were normal in most places although central Chad, southwestern Niger and southern Guinea experienced readings 2 to 3 degrees C above normal.
September 21-30 2000 - The ITCZ in West Africa retreated southward 1.5 degrees latitude to 16.5 N, which equals the 1979-98 mean. The June-September mean location of 17.8 N also equals the 1979-98 mean, but is 0.4 degrees south of last year's position. The ITCZ was south of normal from eastern Mali to Sudan. As the ITCZ movement implies, rainfall amounts decreased sharply in the Sahel. The overall season appears to be drier than last year across the region and drier than the long-term mean. The driest areas during the past growing season include west-central Sudan; southern Burkina Faso and adjacent parts of Ghana, Togo, and Benin; Senegal and Gambia; and parts of Niger, Chad, Mali, and Mauritania.
The rains retreated southward as most places reported below-normal rainfall for the period. There were isolated cases of above-normal rainfall, with amounts between 123 and 1000% of normal in southeastern Niger, eastern central Chad, southern Mali and the northern coast of Senegal. In contrast, the Sahel region, including eastern Chad, Niger, central Mali, central and southern Mauritania, southern Senegal and northern Guinea reported mostly light rains (1-10 mm, 14-249% normal). Places with reports of moderate rains (11-89 mm, 11-1000% of normal) included southern Chad, southern Mali, Senegal, coastal Gambia, southeastern Guinea, Burkina Faso, northern Benin, northern Togo, Ghana and Côte d'Ivoire. Satellite rainfall estimates indicated 25 to 150 mm over Sierra Leone, Liberia and Nigeria. Temperatures averaged 2 to 4 degrees C above normal in southwestern Niger, central Mali, northern Senegal, southern Guinea and northern Burkina Faso.
September 11-20 2000 - The rains returned in most areas following the relatively dry sequence of the previous period. In the Sahel, the heaviest rains (26-121 mm, 115-153% of normal) were observed over southwestern and northwestern Senegal, southern Mauritania, the extreme western part of Mali at the frontier with Senegal and Mauritania, the eastern half of Mali, much of Burkina Faso, western and southern Niger. Lighter rains (4-51 mm; 51-78% of normal) fell over western Mauritania, parts of western Mali, and central Chad. Satellite rainfall estimates indicated that dry conditions prevailed in the northern areas of the Sahel from Chad eastward to Mauritania. In contrast, heavy downpours (51-141 mm; 100-158% of normal) pounded parts of the Gulf of Guinea, including the eastern half of Côte d'Ivoire, Togo, and Benin. Satellite rainfall estimates indicated heavy rains (50-200 mm) across Nigeria and lighter rains (2-25 mm)over Liberia, Sierra Leone, and the western half of Guinea Conakry. Temperatures were near average across much of West Africa, except northern and southern Senegal, and southwestern Mauritania where the observed temperatures were 2 degrees C above normal.
September 1-10 2000 - The ITCZ in West Africa (10 degrees W to 10 degrees E) dropped sharply southward to 17.4 degrees north latitude, 1.3 degrees latitude south of the August 21 - 31 position and 0.8 degrees south of the 1979 - 1998 mean position of 18.2N. This is the farthest south location for this period since 1984, when it dipped to 16.6N. Over East Africa (20 to 35 degrees east longitude), the ITCZ retreated southward 0.5 degrees latitude to 15.3N, which is 0.7 degrees south of the 1988-99 mean. This was the fourth consecutive period that the ITCZ was south of normal in the east and the second week it was south of normal in the west. As a consequence, rainfall amounts were below normal and temperatures above normal from Senegal to Sudan. The rainy season may have ended prematurely in the northern-most crop areas from Niger to western Sudan. The apparent southward retreat of rains was evident with reduced rainfall amounts in the sub-region. Light rains (1-10 mm, 2-100% of normal) fell in southern Sahel, stretching from southern Chad to southern Mauritania, central Burkina Faso, northern Benin and interior Senegal. Relatively moderate rainfall (11-67 mm, 11-217% of normal), although generally below normal for the period, occurred in the remaining areas of the sub-region. Satellite rainfall estimates ranged from 2 to 10 mm, 50 to 100 mm and 50 to 200 mm over Liberia, Sierra Leone and Nigeria respectively. Temperatures averaged 2 to 4 degrees C above normal in most places. The rainy season performance generally ranges from average to below average across the region, with cumulative rainfall since May 1 under 80% of normal over much of Senegal and Gambia, as well as southeastern Mauritania, adjacent Mali (Koulikoro), northeastern Mali (Gao), eastern Niger (Zinder and Diffa), the northeastern agricultural areas of Mali, northern parts of Ghana, Togo, and Benin, southeastern Burkina Faso, and the northern crop and pasture areas of Chad.
August 2000 - Rainfall in West Africa picked up from the July situation over Senegal, Guinea, southern Mauritania, Burkina Faso and northern Côte d'Ivoire while the central Sahel on the average measured slightly lower rainfall. Rainfall was near normal (100-200 mm) over most crop areas, with the driest areas (25-100 mm, 25-50% of normal) located over northeastern Senegal and adjacent south-central Mauritania, northeastern Mali and the northern pastoral areas of Niger, the Lake Chad area of Niger and Chad, Benin and adjacent parts of Nigeria. Areas which recorded heavy rainfall (112-317 mm, 98-188% of normal) included the southern Sahel, extending from southern Chad through southern Niger to southern Mauritania, Burkina Faso and Côte d'Ivoire. Satellite estimation of precipitation indicated 50 to 150 mm amounts in Liberia and Sierra Leone, with the lowest totals in southern Liberia, which has seen persistently below-normal rainfall this season. Temperatures during the period were mostly near normal, although central Chad saw 2 to 4 degrees C below normal while southern Ghana and southeastern Guinea recorded 2 to 3 degrees C above normal.
August 21-31 2000 - The ITCZ in West Africa (10 degrees W to 10 degrees E) retreated southward 0.7 degrees latitude. Its mean position of latitude 18.7 degrees north was slightly south of the 1979-98 mean position of 19.0N. Though the ITCZ has peaked and started its seasonal migration southward, there was little evidence of the rain band sliding southward across West Africa. The overall rainy season has been generally favorable across West Africa, with the rains mostly near or north of their long-term location since April. Favorable rains fell over the Sahel as heavy rains (14-125 mm, 117-356 % of normal) occurred along the northern coast of Senegal and southern Mali. The remaining areas in the sub-region experienced light to moderate rainfalls (1-100 mm, 2-153% of normal). Satellite rainfall estimates ranged between 10 and 100 mm over Liberia and Sierra Leone. Temperatures were near normal in most places except for 2 to 3 degrees C above normal in western and eastern Chad, Niger, Burkina Faso, Benin and Nigeria.
August 11-20 2000 - The ITCZ advanced northward 1.2 degrees latitude, bringing more rain to parts of the Sahel where rainfall was quite variable. Abundant rains (70-105 mm; 90-180% of normal) continued to fall in Gambia and the southern fringe of Senegal’s peanut basin. However, the northern and central parts of Senegal eastward into western Mali recorded much less rain (8-81 mm; 16-88% of normal). Light to moderate rains (1-40 mm; 4-72% of normal) prevailed over much of the central Sahel, including eastern Mali, Niger, and Chad. Heavier rains (70-190 mm; 90-260% of normal) pounded Burkina Faso and the northern borders of Côte d’Ivoire, Ghana, Togo, and Benin. Near-normal to above-normal rain (22-66 mm; 91-222% of normal) also fell along the southern border of Mauritania, while the rest of the country remained dry. The southern part of the Gulf of Guinea region was also drier than normal with rainfall totals ranging from 2 to 50 mm (8-59% of normal). Satellite rainfall estimates indicated moderate to heavy rains (50-150 mm) over the western half of Nigeria and along the border with Cameroon, while drier conditions (2-25 mm ) prevailed in the northeastern and central parts of Nigeria. Light rains also fell over Liberia, while moderate rains covered northern Sierra Leone and the Guineas. Temperatures were near average across much of the region, except in eastern Niger, where they averaged 2 degrees C above normal.
August 1-10 2000 - Heavy rains (50-130 mm) relieved dryness in Gambia and Senegal’s groundnut basin, but below-normal rainfall persisted in Senegal’s east and extreme north. In Mauritania, significant rains (over 25 mm) were confined to the southern border following widespread showers the previous period. Below-normal rains continued in the Gao area of Mali and extreme southeastern Niger, with rainfall under 40% of normal. Northern Sahel pastoral areas saw mostly below-normal rains because of the ITCZ's retreat. Moderate to heavy rains (12-135 mm, 21-300% of normal) prevailed in the southern Sahel as well as Côte d’Ivoire, Ghana, Togo and Benin. Light rains fell along the coast of Côte d’Ivoire and Ghana, which is typical for the mid-summer. Temperatures were near normal except about 2 C below normal in Benin, north and central Chad, northwestern and southern Mali and southeastern Mauritania.
July 2000 - The ITCZ attained a mean position of latitude 19.5 degrees N, which is 0.6 degrees higher than the normal. Its highest position in the western Sahel was 21.2 degrees while the eastern Sahel saw 18.7 degrees. Monthly rainfall was generally near normal in the Sahel, with the main exceptions found in Senegal, Gambia, southwestern Mauritania, northeastern Mali, and extreme southeastern Niger (20-70 mm, 20-55% of normal). In West Africa, light to moderate rains (1-100 mm, 38-107% of normal) fell in Sierra Leone, Liberia, and southwestern Côte d’Ivoire. Moderate rainfall (70-150 mm, 48-144% of normal) covered southeastern Chad, central Mali, southeastern Mauritania and, in general, Ghana, Togo and Benin. Heavy rains (106-245 mm, 45-194% of normal) fell in southwestern Niger, southern Mali, isolated parts of southern Mauritania, Burkina Faso, Côte d’Ivoire and coastal areas of Senegal. Satellite rainfall estimates totaled 200 mm and above south of latitude 12 degrees except under 100 mm near the Gulf of Guinea coast. Temperatures generally averaged near normal but 3 to 4 degrees C above normal in Guinea and 2 to 3 degrees C lower than normal in central Nigeria.
July 21-31 2000 - The ITCZ remained quasi-stationary, advancing northward by just 0.3 degree of latitude on average. It moved north of the long-term mean over eastern Mauritania and western Mali but remained south of the mean from eastern Niger to western Sudan. As a result, rains generally tracked northward into the northern Sahel. Abnormal dryness persisted in interior areas of Senegal, where amounts ranged from 2-25 mm (4-40% of normal). Heavy rains (148 mm) that struck Dakar failed to penetrate inland, leaving the groundnut basin unusually dry. Dryness also extended to eastern Gambia, with some locations measuring under 25 mm. Dry pockets also persisted in northeastern Mali in the Gao area and near the northern Lake Chad areas of Niger and Chad. Light rains (1-10 mm; 25-35% of normal) fell in central Mauritania and northern Niger. Most locations in the region reported moderate to heavy rainfalls (10-148 mm, 13-706% of normal). Southwestern Niger, southeastern Mali, coastal Senegal and northern Côte d’Ivoire measured abundant rains (103-148 mm, 111-436% of normal). Rainfall estimates from satellite indicated very heavy rains (greater than 200 mm) over the eastern half of Nigeria and moderate rains (25-100 mm) over the western half of Nigeria, Liberia and Sierra Leone. In Liberia and Sierra Leone, amounts continued to be less than expected during this time of the year. Temperatures averaged about 2 to 3 degrees C lower than normal in Chad, northeastern Mali and southeastern Mauritania while southwestern Mali saw readings up to 2 degrees C above normal.
July 11-20 2000 - Light rains (1-10 mm; 30-157% of normal) fell in southeastern Mauritania, central Mali, central Niger and central Chad. Little or no rain fell in central and northern Senegal, including the northern groundnut basin, and south-central and southwestern Mauritania. Rainfall deficits have totaled 150 to 200 mm in parts of Senegal for the past 8 weeks. Amounts ranged from moderate to heavy (30-125 mm; 40-223% of normal) in southern Mali, southern Niger, southern Chad, Burkina Faso, central Côte d’Ivoire, Ghana, Togo and northern Benin. Reported rainfall has totaled under 50% of normal in the past 4 weeks in some northern agricultural areas of Mali, including Gao and Tombouctou. Rainfall estimates from satellite indicated very heavy rains (greater than 200 mm) over southeastern Nigeria and heavy to moderate rains (50-150 mm) over southwestern and northern Nigeria and light rains (2-50 mm) over Sierra Leone and Liberia. Temperatures were within the normal range, although Guinea reported temperatures 3 degrees C or more above normal while temperatures averaged about 3 degrees C below normal in northeastern Mali.
July 1-10 2000 - Moderate to heavy rains (15-118 mm; 15-518% of normal) fell in Benin, Togo, Ghana, southern Côte d’Ivoire, Guinea, Burkina Faso, coastal Senegal, and southern parts of Mali, Niger, and Chad. Light to moderate rains (10-100 mm) fell in central Chad. Light rains (1-10 mm; 6-86%) fell in Senegal’s inland areas, southern Mauritania, central Mali and Niger. Satellite precipitation estimates indicated over 250 mm of rainfall in the eastern half of northern Nigeria, but only about 10 mm in Liberia and southern Sierra Leone-very light amounts for this time of the year. Temperatures were generally normal, though readings ranged up to 4 degrees C above normal over the coastal areas of Guinea and 2 degrees C or more below normal over eastern Nigeria.
June 11-20 2000 - Light to moderate rain (10-53 mm; 59-131% of normal) associated with the northward migration of the Intertropical Convergence Zone (ITCZ) fell from southern Mali to western Niger, but amounts (0-10 mm) were unseasonably light over central Senegal and south-central Niger. Light to moderate rains (8-100 mm; 21-161%) fell in southern Senegal, southern Chad, Guinea, Côte d’Ivoire, Ghana, Togo, Benin and much of Nigeria. Southeast Nigeria experienced heavy rainfall (222 mm; 400%). Estimated totals locally exceeded 150 mm in western Guinea and northern Sierra Leone. Northern parts of Senegal, Mali and Chad continued seasonably dry. Temperatures were near normal except 2 to 5 degrees C above normal in southern Mauritania and eastern Senegal.
June 1-10 2000 - Moderate rain (11-68 mm, 23-160% of normal) fell over Togo, Benin, northern and central Côte d’Ivoire and Liberia. Satellite estimates indicated heavy rain in central Nigeria and coastal regions of Ghana, Côte d’Ivoire and Liberia. Light to moderate rains continued over much of the southern Sahel in Mali, Burkina Faso, Niger and southern Chad, but the northern Sahel from Senegal through northern Mali and Niger to Chad continued to be dry. Temperatures were near normal over the region.
May 2000 - Moderate to heavy rain (100-200 mm; 100-133%) fell in northern Côte d’Ivoire, western Ghana, southern Mali and central and southern Burkina Faso. Meteosat estimates indicated heavy to very heavy rainfall (150-300 mm) over central, southern, and southeastern Nigeria, southern Guinea, Sierra Leone, Liberia and northeastern Côte d’Ivoire. Monthly rainfall ranged up to 235% of normal in Burkina Faso and 133% in northern Benin. Below-normal rainfall persisted in southern Côte d’Ivoire and central and southern parts of Ghana, Togo, and Benin. Estimated cumulative rainfall deficits since February exceed 100 mm in this area.
May 21-31 2000 - Moderate to heavy rain (50-150 mm, 120-430% of normal) fell over Togo, Benin, Burkina Faso and coastal south Liberia. Over 300 mm of rain pelted extreme southwestern Côte d’Ivoire, while amounts ranged mostly from 25 to 100 mm elsewhere in Côte d’Ivoire and in Ghana. These rains fell over areas that had experienced some earlier dryness. Abundant rains (50-150 mm) fell over Nigeria, except in the extreme north, where amounts were negligible near the border with Niger. The seasonal rains have been a little slow to start in northern Nigeria and southern Niger. The dry season continued in Mauritania, Senegal, central Chad, Gambia, Guinea-Bissau, and the western and northern agricultural areas of Mali. Above-normal temperatures (departures of 3 to 4 degrees C) extended from eastern Senegal to southern Mauritania and western Mali. Temperatures averaged as much as 4 to 5 degrees C above normal in Guinea.
May 11-20 2000 - Light to moderate rain (1-50 mm; 9-641% of normal) fell over southern Mali, central and western Burkina Faso, and southwest Niger, all in the Sahel. Light to moderate rains (25-100 mm) spread into southern Chad, while light to moderate rains (2-98 mm; 2-96% of normal) fell over southern and northern Côte d’Ivoire and widely scattered areas in Ghana, Togo, and Benin. Below-normal rainfall persisted in central Côte d’Ivoire and much of Ghana, Togo and Benin. Cumulative rainfall has been under 25% of normal in this region over the past 4 weeks. In contrast, Meteosat estimates indicated moderate to heavy rainfall (50-150 mm) over south and central Nigeria, Sierra Leone and Liberia. Senegal, Gambia, Mauritania and Niger were seasonably dry. Temperatures were near normal except for 3 to 6 degrees C above normal over central Mauritania and northeast Mali. Readings averaged 3 to 5 degrees C below normal over northern Nigeria and central Niger and 7 degrees C below normal over central Mali.
May 1-10 2000 - Scattered light to moderate rains (1-32 mm; 48-364% of normal) fell over southern Mali and southern and central Burkina Faso, while the remainder of the Sahel countries were seasonably dry. Light to moderate rains(2-51 mm; 8-341% of normal) fell over Benin, Togo, Côte d'Ivoire and eastern Guinea. Meteosat estimates indicated light to moderate rains (10-100 mm) over south and central Nigeria, Liberia, and Sierra Leone. Temperatures in this region were near normal except for isolated reports of 3 degrees C below normal over central Mali and eastern Mauritania and 3 degrees C above normal over northern Mali.
April 2000 - Light to moderate rains (11-98 mm; 14-160% of normal) fell over Benin, Togo, Ghana, Côte d’Ivoire, Burkina Faso, southwest Niger and southern Mali, while the Sahel area remained seasonably dry. However, Meteosat estimates indicated heavy to very heavy rains (100-350 mm) over south and central Nigeria, Liberia, Sierra Leone, southwest Ghana and east and central Guinea. Estimates of April rainfall compared with normal indicated above normal over Sierra Leone, Guinea, Liberia, south and central Nigeria; normal over southern Côte d’Ivoire, southwest Niger, northern Nigeria, and Burkina Faso; and below normal over northern and central Côte d’Ivoire and most of Ghana. Monthly rainfall ranged up to 50 mm below normal in both countries.
April 21-30 2000 - Meteosat estimates indicated moderate to heavy rainfall (50-150 mm) over central and southern Nigeria, Guinea, Sierra Leone and Liberia. Light to moderate rains (10-50 mm) fell over Benin, Togo, Ghana, and Burkina Faso. Niger, Mali, Mauritania, Senegal, and Gambia (the Sahelian countries) were seasonably dry. A dry area has intensified in Ghana and northern and central Côte d’Ivoire. Temperatures were near normal except for 3 to 4 degrees C above normal over southwest Mauritania and northwest Senegal.
April 11-20 2000 - Meteosat estimates indicated moderate to heavy rainfall (25-150 mm) over south and central Nigeria, southern Benin, Togo, Ghana, Côte d’Ivoire, Liberia, Sierra Leone, and Guinea. The Sahelien countries remained seasonably dry. Temperatures were near normal except 3 degrees C above normal over central Ghana and 3 to 6 degrees C above normal over northern Senegal and southern Mauritania. Maximum temperatures reached 42 to 44 degrees C in the Sahel, where anomalous warmth has persisted as long as 8 weeks in the west.
April 1-10 2000 - Seasonably dry conditions continued to prevail over the Sahel while light to moderate rains (0-41 mm;11-435% of normal) fell over Côte d’Ivoire, Burkina Faso, Togo and Benin. Satellite estimates depicted moderate to heavy rainfall (50-150 mm) over southern Nigeria, Liberia, Sierra Leone and eastern Guinea. This is evidence of the onset of rainfall associated with the rainy season. Cumulative rainfall so far since early March has been below normal over the Gulf of Guinea countries. Above-normal temperatures (departures 3-5 degrees C) covered southern Mauritania, central Mali and southeast Nigeria. Below-normal temperatures (departures 6-7 degrees C) extended over northern Ghana and northeast Mali.