vf-tropicom Meteorological Analysis for West Africa
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Seasonal Vegetation Index - 1999/2000

Seasonal Vegetative Index

Seasonal Rainfall - 1999/2000
in mm
Seasonal Rainfall
Calculated Rain Line Location Across the Season
Rain Line Location
River Basin Seasonal Rainfall Analysis
For West Africa
River Basin Rainfall
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Preliminary Monthly Weather Analysis
West Africa 1999/2000

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

  • 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.
  • March 2000 - Drier-than-normal conditions prevailed over the region. However, satellite estimates indicated moderate to heavy (20-150 mm) rain over the Gulf coast including Sierra Leone, Liberia, Côte d’Ivoire, Ghana, Togo, Benin and Nigeria.
  • March 21-31 2000 - Seasonably dry conditions continued to prevail over the Sahel, while light to moderate rains (2-101 mm; 2-266% of normal) fell in Côte d’Ivoire and western Ghana. Light rains (1-10 mm) fell over Guinea, Sierra Leone, Liberia, Burkina Faso, Benin, Togo, and most of Nigeria. Meteosat estimates indicated that moderate to heavy rainfall (25-150 mm) covered the southern parts of Liberia, Côte d’Ivoire, Ghana, and Nigeria. Temperatures were near normal except above normal (3 degree C departures) over southwest Mauritania and east-central Mali.
  • March 11-20 2000 - Isolated moderate rains (23-54 mm; 129-304% of normal) fell over Côte d’Ivoire, Ghana, and Togo. Satellite rainfall estimates indicated that dry conditions prevailed over the highlands of Guinea, while light rains (5-50 mm) were estimated over parts of Liberia. Seasonably dry conditions prevailed over the Sahel. Extreme temperatures (3-6 degrees C above normal and 5 to 6 degrees C below normal) were observed over the western part of the Sahel and over the eastern half of Chad, respectively.
  • March 1-10 2000 - The Sahel continued to be seasonably dry while only light rains fell along coastal areas. Reported temperatures over the region were near normal except for below-normal (3-4 degrees C) over Niger and above-normal (3-7 degrees C) over Senegal and Mauritania.
  • February 11-20 2000 - The Sahel continued to be seasonably dry while only light rains dotted the Gulf of Guinea region. Temperatures averaged 2 to 3 degrees C above normal across western Sahel and 1 to 3 degrees C below normal across the central Sahel and Côte d’Ivoire and northern Benin.
  • February 1-10 2000 - The region was dry, with even coastal areas reporting no rainfall. Temperatures were below-normal (departures up to 5 degrees C) over wide areas, stretching from Chad to southern Mali.
  • January 2000 - Seasonably dry conditions prevailed over the Sahel. Over the Gulf of Guinea region, unseasonably light to moderate rains (10-110 mm; 80-725% of normal) were reported over Côte d’Ivoire. Drier conditions prevailed over Togo, Benin, and Nigeria.
  • January 21-31 2000 - The Sahel remained seasonably dry. However, over the Gulf of Guinea region, light to moderate but unseasonable rains (14-68 mm; 189-648% of normal) fell along the coast of Côte d’Ivoire and Ghana. Satellite rainfall estimates indicated light to moderate rains (10-50 mm) over Sierra Leone, Liberia, and southeastern Nigeria. Seasonably dry conditions prevailed over Benin and much of Nigeria. Temperatures were generally 2 to 6 degrees C across the Sahel, and about 1 to 2 degrees C above normal over the Gulf of Guinea region.
  • January 11-20 2000 - Light to heavy rains (2-42 mm) fell over Côte d’Ivoire and isolated areas of the coastline; otherwise, seasonally dry weather prevailed. Above normal-temperatures (up to 3-4 degrees C) extended from eastern Nigeria to central and southern Niger, northern Benin, Togo, and northeastern Ghana, as well as Burkina Faso and south-central Mali. Below-normal temperatures (up to 3 degrees C) covered western Nigeria.
  • January 1-10 2000 - Unseasonal moderate rains (13-55mm, 79-893% of normal) were reported over Côte d’Ivoire. Satellite rainfall estimates indicated light to moderate rains (10-100mm) over Sierra Leone and Liberia. Otherwise seasonally dry weather prevailed over the remaining areas. Temperatures were within the normal range except for central and southern Chad and central northern Nigeria where some low temperatures (minus 3-8 degrees C below normal) were reported.
  • December 1999 - Dry seasonal weather continued except for isolated reports of light to moderate rains (22-162 mm) along the Gulf of Guinea.
  • December 21-31 1999 - The dry season continued except for isolated showers along the Gulf of Guinea coast. Temperatures were near normal over most parts of the region.
  • December 11-20 1999 - The dry season continued except for light showers along the Gulf of Guinea coast. Temperatures were near normal over most of the region.
  • December 1-10 1999 - The dry season continued except along the Gulf of Guinea coast, where satellite rainfall estimates indicated moderate rainfall (50-100 mm) over southwestern Côte d’Ivoire and adjacent Liberia. Temperatures averaged 1 to 3 degrees C above normal over western parts of the region, but below normal by 1 to 3 degrees C over eastern areas.
  • November 1999 - The dry season is well established, except along the Guinea coast from Equatorial Guinea to south Nigeria, where satellite rainfall estimates showed 200 to 300 mm over Sierra Leone and Liberia.
  • November 21-30 1999 - The dry season continued except along the Gulf of Guinea coast, where satellite rainfall estimates indicated moderate rainfall (50-100 mm). Temperatures were 1 to 3 degrees C above normal over most parts of the region.
  • November 11-20 1999 - The dry season is well established. Nevertheless, satellite rainfall estimates indicated heavy rains (100-150 mm) along the coast of Guinea. Temperatures were near normal.
  • November 1-10 1999 - The dry season continued over interior areas. Satellite estimates indicated heavy rains (50-150 mm) over Guinea Bissau, Guinea Conakry, Sierra Leone, and along the coast of Liberia. Moderate rains (25-100 mm) fell from southern Côte d’Ivoire eastward to southern Nigeria. Temperatures ranged up to 3 degrees C above normal in western Mauritania and up to 3 degrees C below normal in southern Mali. Elsewhere, temperatures were near normal.
  • October 1999 - Rainfall was mostly above normal in a band stretching from Senegal across the continent to Ethiopia, closing out an abnormally wet season from the Sahel countries into Sudan. Amounts were closer to normal over the Gulf of Guinea countries eastward into the northern parts of central Africa.
  • October 21-31 1999 - Seasonally dry weather prevailed in the Sahel countries, with moderate to heavy rains (50-100 mm) extending along the coast from Guinea and Sierra Leone south and east across southern parts of Côte d’Ivoire, Ghana, and into southwest Nigeria. Rainfall exceeded 100 mm in southeast Nigeria. Temperatures were near normal.
  • October 11-20 1999 - Moderate rains (38-75 mm) fell in northern and southwestern Senegal, southern Mali, southern Burkina Faso, most of Côte d’Ivoire, Ghana, and southern parts of Togo and Benin. Satellite estimates depicted heavy rains (100-200 mm) over the Gulf of Guinea coast from Guinea Conakry to Liberia. Heavy rainfall (182 mm) drenched southeastern Nigeria and extended northeastward (100-150 mm) along the border with Cameroon. Heavy rains (145 mm; 620% of normal) fell over south-central Chad. Temperatures were near normal except 3 to 4 degrees C below normal over Côte d’Ivoire and northern Nigeria.
  • October 1-10 1999 - Heavy rains fell over southern Senegal (116-129 mm; 357-502% of normal), southwestern Mali (105-141 mm; 331-904% of normal), central and southern Nigeria (103-196 mm), and its southern border region with Cameroon (over 200 mm, based on satellite estimates). Above-normal rains fell over most of Côte d’Ivoire, where the coast had experienced dry conditions since mid-August. Rainfall amounts totaled 40 to 82 mm (124-173% of normal) over the southern part of the country and up to 149 mm (283% of normal) over the north. Above-normal rainfalls also encompassed western Burkina Faso (187-226% of normal), northern Togo (157- 258% of normal), and northern Benin (243-254% of normal). Satellite rainfall estimates indicated heavy rains (100 -150 mm) over the northern border region of Ghana and Togo. Reported data and satellite rainfall estimates showed heavy rains (150-200 mm) along the coast of Nigeria and over its central parts (114 mm). Rainfall may have exceeded 200 mm over the southern border region between Nigeria and Cameroon. Temperatures were near normal over the region.
  • September 1999 - Rainfall decreased in September over most parts of the Sahelian region, but amounts were generally normal to above normal, continuing the wet pattern observed since July. Above-normal rains fell across southern Mauritania, west-central Senegal, southern Mali, and southern and western Niger. Maximum monthly rainfall totaled 158 mm in Senegal, 252 mm in Mali and 265 mm Niger. Satellite estimates indicated higher monthly values exceeding 300 mm further south along the coast of Guinea Conakry and Sierra Leone, over northern Togo, northwestern Benin, and central Nigeria and its border region with Cameroon. Dryness persisted over the Gulf of Guinea coast from Côte d’Ivoire to Ghana. Temperatures were near normal except 2 degrees C below normal in Ghana.
  • September 21-30 1999 - Reported rainfall amounts did not exceed 100 mm over most parts of the region, though satellite estimates indicated higher values (100-150 mm) over central Nigeria and its central border region with Cameroon, along the coast of Guinea Conakry, and over central Ghana. Above-normal rainfalls prevailed over southern Mauritania (120-366% of normal), western Mali (122-249% of normal), southern and northern Burkina Faso (111-239% of normal), and southern Niger (141-790% of normal). Temperatures were near to below normal, except in Senegal, where they were near to above normal.
  • September 11-20 1999 - Abundant rains continued in the Sahel although a slight decrease from the previous period has been noted as the Intertropical Discontinuity (ITD) retreated southward. Moderate to heavy rains (20-110 mm; 90-235% of normal) was again registered over the peanut basin of Senegal, southwestern Mali, eastern Burkina Faso, and southern Niger. Isolated pockets of dryness prevailed over western Mali, southwestern Mauritania, and central Chad, though. Light rains (5-35 mm; 20-70% of normal) were reported over the Gulf of Guinea regions including Côte d’Ivoire and Ghana, while heavier rainfall (25-110 mm) soaked Benin and Togo. Satellite rainfall estimates indicated abundant rains (50-20 mm) over the Guineas, while lighter rains to dry conditions were indicated over Sierra Leone and Liberia. Temperatures were 1 to 2 degrees C above normal across much of the Sahel, except southeastern Mauritania and central Mali, where they were 3 to 4 degrees C below normal. They were also 2 to 3 degrees C below normal across much of the Guinea coast.
  • September 1-10 1999 - Heavy rains (72-103 mm; 105-184% of normal) fell over central Burkina Faso while moderate rains (47-51 mm) hit southern and western Niger. Satellite estimates indicated heavy rains in northwestern Nigeria and along its southern border with Cameroon (150-200 mm). Reported rains and satellite estimates denoted very dry conditions over most of Côte d’Ivoire, southeastern Liberia, southwestern Ghana, and northeastern Nigeria. Some lingering dryness is not unusual over southern Côte d’Ivoire and southwestern Ghana in early September, but this dryness was more widespread than usual. After recording heavy rains last month, southern Senegal experienced below-normal rains during this period (33-59 % of normal). Temperatures were 2 to 3 degrees C below normal over Côte d’Ivoire and eastern Ghana and near to below normal elsewhere, except in western Mauritania, where they averaged 2 to 3 degrees C above normal.
  • August 1999 - West Africa was unusually wet in August across both the Sahel countries and the Guinea Coast regions. In the Sahel, amounts exceeded 300 mm (150% of normal) in southwest Senegal, southwest Mali, southeastern Burkina Faso, and isolated parts of central Chad. Few places in the Sahel were below normal. Rainfall amounts were 70 to 100% of normal in extreme northern Senegal and southeastern Mali. Several stations in Ghana reported under 50% of normal. Over south Senegal, most of the monthly rain fell during the last two ten-day periods. The Gulf of Guinea coast from Côte d’Ivoire to Benin experienced dry conditions during the first two ten-day periods, but rainfall picked up late in the month. Satellite estimates indicated heavy rains exceeding 300 mm in many parts of Nigeria. Temperatures were near normal except 2 to 3 degrees C below normal over southwestern Mauritania, north Mali, north Niger and central Chad.
  • August 21-31 1999 - Moderate to heavy rains (90-148 mm; 108-174 % of normal) persisted over south Senegal. Light to moderate rains (37-86 mm) fell elsewhere over the country. Unusual and isolated heavy rains (100 mm ) fell over the desert area of northeastern Mali, with 90 mm recorded on August 21. Heavy rains (92-121 mm;113-232%) fell over southeastern Mali and southern Burkina Faso (107-417 mm;145-550%). Isolated heavy rains (up to 171mm; 457%) poured over central and western Niger and central and northern Nigeria (179 mm). Satellite estimates and sparse reports indicated over 100 mm in central Chad, where excessive rains caused flooding in late July and early August. Abundant showers of up to 141 mm also fell in extreme southwestern Chad, an area that had been persistently dry earlier in the season. After dry conditions during the last two ten-day periods, light to moderate rains fell along the Gulf of Guinea coast from southeastern Liberia to Ghana. Below-normal temperatures extended from southeastern Mauritania to northern Mali. Near-normal temperatures prevailed elsewhere, except for readings up to 3 degrees C below normal in central Chad.
  • August 11-20 1999 - Moderate to heavy rains (40-215 mm; 120-305% of normal) pounded Senegal as the African waves became very active and started to swing westward. The heaviest amounts were registered over the southern part and over the peanut basin. Heavy rains (50-205 mm; 120-225% of normal) also soaked western and central Mali, while the northeastern part recorded an unusual 25-40 mm. However, isolated pockets of dryness were observed in the central part of the country. Below normal rainfall (5-45 mm; 60-80 % of normal) was also observed over western Niger. However, the southern region bordering Nigeria received abundant rains (45-75 mm; 120-155% of normal). Elsewhere in the Sahel, drier than normal conditions were observed over much of Burkina Faso and Chad. Dry conditions also prevailed along the Guinea coast from Sierra Leone to Benin. However, Meteosat rainfall estimates indicated moderate to heavy rains (50-200 mm) over northern and central Ghana, Togo, Benin, and much of Nigeria. Temperatures were generally near normal.
  • August 1-10 1999 - Chad endured another week of heavy rains, with up to 168 mm recorded in the south and up to 150 mm estimated by satellite in central Chad. During the past 3 weeks, up to 300 mm of rain has fallen in central Chad, including southern Batha and northern Guéra prefectures, according to satellite estimates. Heavy rains also fell over Niger’s crop areas (60-125 mm; 100-280% of normal) as well as in northern Nigeria (estimated 100-200 mm), relieving most of the earlier dryness in both countries. Wet weather (100-200 mm) also hit northern Cameroon for the second consecutive period. Abnormally heavy rains fell over southwestern Mauritania (154-306% of normal ). Isolated heavy rains fell near the boundary between Guinea (Conakry) and Sierra Leone. Heavy rainfall (104-217 mm) also struck southern Mali, northern Côte d’Ivoire, and southern Burkina Faso. In contrast, below-normal rains fell over Senegal north of the groundnut basin (10-35 mm) and in the extreme south (25-50 mm). The dryness previously observed continued over the Gulf of Guinea coast, spreading from southern Côted’Ivoire and Ghana into southern parts of Benin, Togo, and Nigeria. Though decreased rainfall is expected around this time of year in the region, amounts of near 0 mm were about 10 to 30 mm less than normal. Temperatures were near normal over West Africa except in central Chad, where the heavy rains kept readings 3 to 4 degrees C below normal.
  • July 1999 - Rainfall increased during late July across the Sahel countries, easing dryness caused by below-normal rainfall during June and early. Amounts totaled 100 to 200 mm (100-200% of normal) from southern and eastern Senegal to western Niger. Totals exceeded 150 mm over Chad’s northern crop areas, and may have topped 300 mm locally, according to satellite estimates. Below-normal rainfall (50-100 mm) was mainly limited to northern Senegal, southeastern Mauritania, southwestern Burkina Faso, far southern Chad, and central and eastern Niger. Amounts totaled under 50% of normal in northeastern Côte d’Ivoire and central Ghana. Heavy rains, exceeding 300 mm in places, fell over central and southeastern Nigeria and southwestern Cameroon. Monthly temperatures averaged 1 to 2 degrees C above normal in Senegal and Cote d’Ivoire and near normal elsewhere.
  • July 21-31 1999 - Rainfall totaled 50 to 100 mm (100-200% of normal) at stations from Senegal eastward to Niger, with isolated amounts exceeding 100 mm in Mali and Burkina Faso. Satellite estimates indicated heavy rains (100-150 mm) over Chad’s northern crop areas. Abundant rains (100-175 mm) also struck northeastern Nigeria and extreme northern Cameroon, relieving dryness in Nigeria. Pockets of below-normal rainfall (10-25 mm; 20-60% of normal) continued to develop in Senegal’s northern groundnut basin, eastern Niger, and parts of southern Mauritania. Amounts failed to exceed 20 mm over southern and eastern Côte d’Ivoire and much of Ghana, but the mini-dry period usually begins earlier in both countries. Torrential rains fell over southeastern coastal Nigeria and coastal Cameroon, with amounts over 200 mm. Temperatures were near normal except along the Gulf of Guinea coast, where readings averaged 1 to 2 degrees C above normal.
  • July 11-20 1999 - Rainfall was variable in the Sahel. Moderate to heavy rains (35-105 mm; 100-215% of normal) fell over much of Senegal, the eastern half of Burkina Faso, the crop region of Niger, and the agricultural areas of Chad. The driest spots included the northern agricultural areas in southern Mauritania, southeastern Senegal, western Mali, and southwest Burkina Faso, with rainfall totals not exceeding 35 mm. Four-week rainfall totals have been less than 50% of normal in southwestern Burkina Faso and a number of stations in Mali, especially in the west and extreme south. Above-normal rains reduced the dryness over Niger, especially in the west, but more rain is needed in the east. Over the Gulf of Guinea region, moderate to heavy rains (30-110 mm; 105-280% of normal) hit the western half of Côte d’Ivoire and southern Togo and Benin. Lighter rains, however, fell over the eastern half of Côte d’Ivoire and northern Togo and Benin. Satellite rainfall estimates indicated moderate to heavy rains (25-150 mm) over Nigeria, Sierra Leone, Liberia, and the Guineas (Conakry and Bissau). Showers eased dryness in northeastern Nigeria, but satellite estimates indicated that dry pockets persisted. Temperatures were near normal except in central Chad, where they averaged 3 degrees C below normal.
  • July 1-10 1999 - Below normal rainfall persisted over much of the Sahel, except the western half of Senegal, southwestern Mali, and southeastern Burkina Faso, where rainfall amounts ranged between 15 and 115 mm (90-185% of normal). Moderate rains also fell over the Lake Chad region. Lighter rains were observed in southeastern Mali, Niger, and much of Chad. Rainfall totals were only 5-25 mm (10-85% of normal). To the south, heavy rains (55-110 mm; 100-190% of normal) pounded Côte d’Ivoire, parts of Ghana, Togo , and Benin, eliminating most remaining dryness in the latter two countries. Meteosat rainfall estimates indicated that moderate to heavy rains (25-150 mm) over north central Nigeria, Sierra Leone, Liberia, and Guinea Bissau. Temperatures were near normal over Côte d’Ivoire, Senegal, and Southern Mali; 2 to 4 degrees C below normal over western Mauritania, and 1 to 2 degrees C above normal over Burkina Faso and Niger.
  • June 1999 - Monthly rainfall was below normal across much of West Africa. Rainfall totals ranged between 5 and 115 mm (15-85 % of normal) across the Sahel. In contrast, heavy rains (200-300 mm; 105-170% of normal) covered large parts of the coastal Gulf of Guinea region, including the southern half of Côte d’Ivoire, southwestern Ghana, and central and southern Nigeria. Drier weather, with rainfall of 15 to 90 mm (30-80% of normal), prevailed over Benin, Togo, and southeastern Ghana. Totals were also unusually light (0-50 mm) in northeastern Nigeria, according to satellite imagery. Monthly temperatures averaged 1 to 2 degrees C above normal over the Sahel, and generally near normal in the Gulf of Guinea region.
  • June 21-30 1999 - Rainfall was variable over the Sahel. The wettest spots were mostly confined to the southern Sahel, from southern Chad westward into southern Senegal, including western Burkina Faso and southwestern Mali. Rainfall amounts ranged between 40 and 140 mm (90-305% of normal) in this region. Dry conditions prevailed north of the 13th parallel, and rainfall was below normal (0-40 mm; 0-50% of normal) over Niger, south-central Burkina Faso, western Mali, northern Senegal, and northeastern Nigeria. There was also patchy dryness (10-50 mm) in extreme southern Mali. Over the Gulf of Guinea region, heavy rains (80-125 mm; 100-220% of normal) fell along the Guinean coast over Côte d’Ivoire and southwestern Ghana. Prolific showers (over 100 mm) fell in central and southeastern Nigeria, according to satellite estimates. Drier conditions prevailed elsewhere. The central and northern parts of Ghana, Togo, and Benin picked up only 15 to 60 mm of rainfall (20-80% of normal). Meteosat rainfall estimates indicated that heavy rains (100-200 mm) pounded the coastlines of Guinea, Liberia, and Sierra Leone. Temperatures were generally 1 to 2 degrees C above normal across West Africa.
  • June 11-20 1999 - Rainfall totaled 0 to 20 mm (0-50% of normal) in a band stretching from central Mali to northern Burkina Faso, Niger, and central Chad. Scattered heavier rains (greater than 50 mm) provided some relief from recent dryness in southern Mali and southern Burkina Faso, but much of southern Mali and Niger as well as northern and central Burkina Faso have recorded less than one-half normal rainfall during the past 4 weeks, placing the region in a near-drought situation. Light to moderate rains fell over Gambia and southern Senegal as the rainy season progressed northward. Mauritania and northern Senegal remained seasonably dry with isolated showers. Central Chad turned drier this period, with amounts mostly 1 mm or less. Moderate rains (25-50 mm) in southern Chad were slightly below normal. Additional rainfall will be needed soon to avoid drought developing across much of the Sahel from Mali to Chad. To the south, pockets of drought persisted in eastern Ghana and in Togo, with rainfall less than 10 mm. According to satellite estimates, heavy rains (100-200 mm) fell from southwestern Guinea through Sierra Leone, Liberia and southern Côte d’Ivoire. Rains were abnormally light (0-10 mm) over much of northeastern Nigeria and northern Cameroon. Temperatures averaged 2 to 4 degrees C above normal in Mauritania, Senegal, northern Mali, Burkina Faso, and western Niger. Similar heat also affected northeastern Nigeria, northern Cameroon, and the Lake Chad region in Chad.
  • June 1-10 1999 - Rainfall continued to be below normal in much of West Africa, with Burkina Faso, Niger, Mali, and Chad reporting about 5 to 30 mm (5-50% of normal). Local amounts exceeded 60 mm in southern Mali. Seasonably dry weather prevailed over most of Mauritania and Senegal, though the rainy season appears to have started in extreme southern Senegal (up to 82 mm) and 1 to 20 mm fell in southeastern Mauritania and Sahelian Mali. The rains are late in getting established in southern parts of Mali and Burkina Faso, as rainfall totals for the past 4 weeks have been less than 50% of normal in both countries. Patchy dryness continued in Ghana, Togo, and Benin, where a few stations have collected under 50% of normal in the past 4 weeks. This period, rainfall was less than one-half normal over northwestern Côte d’Ivoire, much of Ghana, and northern parts of Togo and Benin. As a result, drought continued in several areas in Ghana, Togo, and Benin. Temperatures averaged 1 to 2 degrees C above normal across West Africa, except 3 degrees above normal in parts of Mali, Burkina Faso, and western Niger.
  • May 1999 - Rainfall was normal to below normal, with amounts especially low in Togo (5-35% of normal) and portions of Ghana and northern Côte d’Ivoire. In southern Mali, monthly totals of 10 to 60 mm were only 20 to 60% of normal. Elsewhere in the Sahel countries, rainfall was mostly normal to somewhat below normal. Temperatures for May were near normal except in Mauritania, where readings averaged 2 to 5 degrees C above normal except in the southwest. These temperature anomalies were unusually great for a monthly time period.
  • May 21-31 1999 - Rainfall continued to be below normal in much of West Africa, though heavy showers (25-100 mm; 80 to 200% of normal) fell over southwestern Niger, northern Benin, southern Togo, and much of Nigeria. As is typical for this time of year, heavy rains (100-350 mm) drenched southeastern Nigeria. The recent rains have eased drought in Togo and Benin, though more rain was needed in Togo, where 4-week totals remained under 50% of normal at some stations. In the Sahel, the seasonal rains continued to make little progress northward. As a result, totals this period ranged from 0 to 50 mm (0-50% of normal) in southern Mali and western Burkina Faso, with isolated higher amounts. No rain fell in Guinea Bissau, while mostly low amounts (0-50 mm) fell in Guinea. Seasonably dry weather prevailed in Senegal, Mauritania, and eastern Niger. Near-normal rains (10-30 mm) fell in southern Chad, according to satellite estimates. Temperatures averaged 2 to 4 degrees C above normal in southwestern Mali and most of Mauritania and near normal elsewhere.
  • May 11-20 1999 - Rainfall was again below normal in West Africa, though heavy showers fell over Liberia, southern Côte d’Ivoire, southwestern Ghana, and southern and eastern Nigeria. Totals in Togo and Benin mostly ranged from 0 to 25 mm (0-70% of normal). Four-week totals have been 25 to 50% of normal, with temperatures above normal. March and April rainfall was somewhat below normal in Togo and Benin, and the dryness has intensified this month, likely leading to drought conditions in both countries. To the north, in the Sahel, the seasonal rains have made little progress since April. Totals ranged from 0 to 30 mm (0-30% of normal) in southern Mali, southeastern Burkina Faso, and southwestern Niger. In contrast, rainfall (0-100 mm) increased in southern Chad, according to satellite estimates. Temperatures were near normal except in eastern and northern Mauritania, western Niger, and southeastern Burkina Faso, where readings averaged 2 to 3 degrees C above normal.
  • May 1-10 1999 - Rainfall decreased over West Africa, with amounts mostly in the 0 to 50 mm range from Côte d’Ivoire eastward into western Nigeria. Cumulative rainfall over the past 4 weeks has totaled under 50% of normal in parts of the region, especially in Côte d’Ivoire and Togo. Sahel rainfall was mainly confined to southern Burkina Faso, which measured 10 to 65 mm. Sahel rains were more widespread during late April. Temperatures were near normal except in Mauritania, which recorded readings 2 to 5 degrees C above normal.
  • April 1999 - Monthly rainfall was generally seasonable, although rains advanced northward into the southern Sahel somewhat early. Unusual heat covered parts of the Sahel, monthly temperatures averaging 2 to 3 degrees C above normal in Mauritania, northern Mali, and western Côte d’Ivoire.
  • April 21-30 1999 - The rainy season was progressing northward into the Sahel countries. Amounts this period were above normal in southern parts of Mali, Niger, and Burkina Faso, with reported totals up to 86 mm in Burkina Faso and 26 mm in Mali. The rainy season intensified over the Gulf of Guinea countries, where amounts mostly ranged from 50 to 150 mm from Liberia and southern Guinea eastward to central and southern parts of Nigeria and Cameroon. Abnormal heat lingered in Mauritania and northern and central Mali, with temperatures averaging 2 to 4 degrees C above normal. Readings were near normal elsewhere.
  • April 11-20 1999 - Except for a few scattered showers, seasonably dry conditions prevailed over the Sahel. However, the rainy season may have started early in southern Burkina Faso, where amounts totaled 25 to 50 mm. Moderate rains (25-100 mm; 20-200% of normal) fell over the Gulf of Guinea region from Guinea to southern Nigeria and southern Cameroon, with isolated heavy rains (over 100 mm) in Ghana, central Nigeria, and southwestern Cameroon. Temperatures averaged 1 to 3 degrees C above normal over Senegal, Mauritania, Mali, Guinea, and western Côte d’Ivoire.
  • April 1-10 1999 - Except for a few scattered showers, seasonably dry conditions prevailed over the Sahel. Moderate rains (20-80 mm; 20-200% of normal) fell over the Gulf of Guinea region from eastern Côte d’Ivoire to southern Nigeria, with isolated heavy rains (over 100 mm) in Nigeria. Temperatures averaged 2 to 4 degrees C above normal over Senegal, Mauritania, Mali, Guinea, and western Côte d’Ivoire.
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