vf-tropicom Meteorological Analysis for West Africa
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Seasonal Vegetation Index - 1998/1999

Seasonal Vegetative Index

Seasonal Rainfall - 1998/1999
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 1998/1999

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

  • 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.
  • March 1999 - Dry conditions prevailed over much of the Sahel north of the 12th parallel. However, light to moderate rains were noted over southern Mali and Burkina Faso, particularly during the latter part of the month (mango rains - not to be mistaken for an early onset of the rains). Moderate rains fell over the Guinea region, particularly over southern Côte d’Ivoire, Ghana, Benin, and Togo, where rainfall totals were about 70-105% of normal.
  • March 21-31 1999 - The Sahel was seasonably dry but abnormally hot, with temperatures averaging 2 to 6 degrees C above normal. Showers were rather lighter than normal to the south over the Gulf of Guinea countries with the exception of interior southern Côte d’Ivoire, where totals ranged from 25 to 70 mm. Meteosat rainfall estimates suggested rains in the amount of 25-100 mm along coastal Nigeria.
  • March 11-20 1999 - Seasonable dryness again prevailed over the Sahel, but rainfall was mostly near to below normal (50-100 mm) from Liberia to Benin along the coast. Satellite-estimated rainfall ranging from 50 to more than 100 mm was above normal in southern and central Nigeria, as well as interior Ghana, Togo, and Benin. Temperatures were generally near normal except 2 to 3 degrees C above normal in Niger and Burkina Faso.
  • March 1-10 1999 - Seasonable dryness again prevailed over the Sahel and the northern Gulf of Guinea countries, but variable rains (0-50 mm; 0-175% of normal) fell in central and southern Côte d’Ivoire and southern parts of Ghana, Benin, Togo, and Nigeria. Temperatures were generally near normal except 2 to 4 degrees C above normal in Niger and Burkina Faso.
  • February 1999 - Above-normal rains fell in southern and central Côte d’Ivoire, coastal and some interior parts of Ghana, and coastal Togo and Benin. Satellite estimates depicted moderate rains in Liberia and moderate to heavy rains in southeastern Nigeria. The Sahel countries were seasonably dry. Temperatures throughout the region were close to normal.
  • February 21-28 1999 - Seasonable dryness prevailed over the Sahel and the northern Gulf of Guinea countries, but unseasonable rains (10-30 mm; 60-210% of normal) continued in central and southern Côte d’Ivoire, with lighter amounts in southern parts of Ghana, Benin, and Togo. Temperatures were generally near normal.
  • February 11-20 1999 - Seasonable dryness, typical of harmattan, continued over the Sahel and the northern Gulf of Guinea countries, but unseasonably heavy rains (10-80 mm; 40-320% of normal) continued in central and southern Côte d’Ivoire, central and southwestern Ghana, Benin, and the southern half of Togo. Meteosat-based rainfall estimates indicated moderate rainfall (10-50 mm) over east Liberia and southeast Nigeria.
  • February 1-10 1999 - Seasonable dryness, typical of harmattan, prevailed over the Sahel and the northern Guinea countries, with precipitation mostly confined to the Gulf of Guinea coast. Unseasonable rain (1-30 mm; 10-150% of normal) fell over southeast Côte d’Ivoire and southwest Ghana. Meteosat-based rainfall estimates indicated moderate rainfall (10-50 mm) over Liberia and southeast Nigeria. Temperatures were generally near normal.
  • January 1999 - Seasonably dry weather covered interior West Africa, but rainfall was above normal along the Gulf of Guinea coast and in western Côte d’Ivoire (10-70 mm, 100-600% of normal). Temperatures averaged close to normal
  • January 21-31 1999 - Seasonable conditions prevailed, with dry weather over the interior and a few showers (1-50 mm) along the Gulf of Guinea coast. Temperatures generally averaged 1 to 2 degrees C above normal.
  • January 11-20 1999 - Seasonable dryness, typical of harmattan, continued over the Sahel and the northern Guinea countries, but unseasonable rain (around 15 mm) persisted over western Côte d’Ivoire (Man province). Elsewhere, precipitation was mostly confined to the Gulf of Guinea coast, with light to moderate rains (1-35 mm; 5-550% of normal) over coastal Côte d’Ivoire, northeast and coastal Ghana, and coastal Togo and Benin. Meteosat-based rainfall estimates indicated moderate rainfall (10-100 mm) over Liberia and southern Nigeria. Temperatures generally averaged 1 to 3 degrees C above normal.
  • January 1-10 1999 - Seasonable dryness, typical of harmattan, prevailed over the Sahel and the northern Guinea countries, but unseasonable rain (5-55 mm; 45-185% of normal) peppered central and western Côte d’Ivoire. Precipitation was mostly confined to the Gulf of Guinea coast, with light to moderate rains (5-50 mm) in coastal Côte d’Ivoire, Ghana, Togo, and Benin. Meteosat-based rainfall estimates indicated moderate rainfall (10-50 mm) over Liberia, south Sierra Leone, and the eastern coast of Nigeria. Temperatures generally averaged 1 to 3 degrees C above normal.
  • December 1998 - Rainfall activity stopped over the Sahel and the northern Guinea countries. Seasonable dryness prevailed in this region as the ITCZ retreated southward. Light to moderate rains (5-75 mm; 5-80% of normal) fell over the southern halves of Côte d’Ivoire, Ghana, and Togo, as well as southern Benin and Guinea. Meteosat-based estimates indicated light to moderate rainfall (20-100 mm) over Sierra Leone, Liberia, and southern Nigeria. Temperatures were generally 1 to 3 degrees C above normal.
  • December 21-31 1998 - Seasonable dryness, typical of harmattan, prevailed over the Sahel and the northern Guinea countries. Precipitation was mostly confined to the Gulf of Guinea coast. Light to moderate rains (10-50 mm; 25-250% of normal) dampened southern Côte d’Ivoire, central Togo, and the coastline of Ghana. Meteosat-based rainfall estimates indicated moderate rainfall (10-50 mm) over Sierra Leone and Liberia. Temperatures were generally 1 to 3 degrees C above normal.
  • December 11-20 1998 - Precipitation was mostly confined to coastal areas. Seasonable dryness prevailed in the region. The area which includes the Sahel countries and northern parts of Côte d’Ivoire, Ghana, and Nigeria was under the influence of the harmattan. Light to moderate rains (5-40 mm; 25-80% of normal) fell over the coastlines of Côte d’Ivoire and Ghana. Meteosat-based rainfall estimates indicated light rainfall (10-25 mm) over southern Sierra Leone, southeast Liberia, and southern Nigeria. Temperatures were generally 1 to 3 degrees above normal in western areas, including Senegal, and near to slightly below normal to the east.
  • December 1-10 1998 - Precipitation was mostly confined to coastal areas. Moderate rains (10-80 mm; 10-500% of normal) fell over the southern half of Côte d’Ivoire, central Ghana, and the coastline of Togo. Light rain (less than 10 mm) fell over central and coastal Benin. Meteosat-based rainfall estimates indicated less than 25 mm of rain in southern Nigeria and moderate rainfall (25-100 mm) in Liberia and southern Sierra Leone. Temperatures were abnormally high across West Africa, generally 2 to 5 degrees C above normal.
  • November 1998 - Rainfall activity stopped over the Sahel countries, the rainfall retreating southward. The monthly reported precipitation from all Sahel areas was 0 mm. Seasonable dryness prevailed from south Senegal to northern Benin and Togo, much of Ghana, the central and northern part of Côte d’Ivoire, southern Burkina Faso, and Mali. Moderate to heavy rains (30-300 mm; 70-290% of normal) fell over the Gulf of Guinea coast, with highest amounts in southern Côte d’Ivoire. Temperatures were generally near normal over much of West Africa.
  • November 21-30 1998 - The dry season has become well established in the Sahel, though significant rains continued to fall along the coastal areas. Between 20 and 100 mm (40-270% of normal) of rain dampened the coastlines of Côte d'Ivoire, Ghana, and Togo, but less than 20 mm fell along the Benin coast. Moderate rains (30-90 mm; 35-145% of normal) fell over Gabon and the Cameroon coast, though heavy showers left more than 210 mm along the extreme northern coast of Gabon. Satellite rainfall estimates indicated moderate rains (25-100 mm) over Liberia and along the coast of Nigeria. The remainder of the region remained seasonably dry. Positive temperature departures from normal of 1 to 3 degrees C continued to dominate the region.
  • November 11-20 1998 - Precipitation was mostly confined to coastal areas, including the coastlines of Ghana and Togo, though heavy showers left more than 200 mm over interior southern Côte d’Ivoire. Moderate to heavy rains (90-140 mm; 80-170% of normal) fell in Gabon. Moderate rains (30-60mm; 35-90% of normal) fell along the coastline of Cameroon, in contrast to heavier amounts reported earlier. Satellite estimates depicted moderate rainfall (25-100 mm) over Liberia and Sierra Leone, but light amounts along the Guinea coast. Positive temperature departures of 1 to 3 degrees C continued to dominate the region.
  • November 1-10 1998 - The dry season became well established as rainfall ended across the Sahel countries, though light to moderate rains (10-60 mm; 20-160% of normal) continued over Côte d'Ivoire and along the coastlines of Ghana, Togo, Benin, and Nigeria. However, Meteosat-based rainfall estimates and surface reports indicated heavy to very heavy rainfall (100-230 mm; 60-270% of normal) over Gabon and the southern coastline of Cameroon. Satellite estimates depicted moderate rainfall (25-100 mm) over Liberia, Sierra Leone, and the Guinea coast. Temperatures averaged 1 to 3 degrees C higher than normal across much of West Africa.
  • October 1998 - The rainy season was winding down over the Sahel countries, with most areas receiving less than 60 mm of rain. Unseasonably heavy rains fell over southern Chad, but recent reports have suggested a gradual withdrawal of the rains. Senegal, particularly the groundnut basin in the north, has had a poor rainfall season, with the rains starting late and ending somewhat early. Meteosat-based rainfall estimates depicted zones of heavy rains (150-300 mm) over Sierra Leone and along the coast of Guinea, with moderate to heavy rainfall over Liberia. In southern Nigeria, satellite estimates indicated moderate to heavy rainfall. Heavy to very heavy rainfall (100-570 mm; 40-105% of normal) soaked the coastlines of Cameroon and Gabon. Moderate to heavy rains (80-190 mm; 55-150% of normal) fell over Côte d'Ivoire, Ghana, Togo, and Benin. Temperatures were generally near normal over much of West Africa.
  • October 21-31 1998 - The dry season has become well established across most of the Sahel countries. Isolated heavy rains fell along the coast of Ghana. Moderate rains (30-82 mm; 55-200% of normal) covered Côte d'Ivoire, southern Mali, southern Burkina Faso, and the coasts of Togo and Benin. Southern Chad reported less than 10 mm of rain, suggesting a withdrawal of the unseasonably heavy rains which had been reported earlier. Satellite rainfall estimates depicted moderate rainfall (25-100 mm) over Sierra Leone, Guinea, Liberia, and southern Nigeria. According to Meteosat-based rainfall estimates and surface reports, persistent heavy to very heavy rains (90-285 mm; 60-280% of normal) fell along the coastline of Gabon. Satellite estimates, however, suggested a general decrease in precipitation from the previous 10-day period along the coast of Cameroon, where moderate rains (50-100 mm; 15-75 % of normal) fell. Temperatures averaged 1 to 3 degrees C above normal across West Africa.
  • October 11-20 1998 - The rains continued their seasonal retreat southward, confirming the cessation of the rainy season in the Sahel countries. However, persistent heavy to very heavy rains (80-290 mm; 50-165% of normal) fell along the coastline of Cameroon and northern Gabon, according to surface reports and Meteosat-based rainfall estimates. Extreme southern Chad continued to report unseasonably heavy rainfall (40-110 mm; 155-470% of normal). Moderate rains (30-80 mm; 50-210% of normal) covere d Côte d'Ivoire, Ghana, southern Burkina Faso, Togo, and Benin. Satellite rainfall estimates indicated locally heavy rainfall (100-150 mm) along the coast of Guinea. Estimates depicted moderate rainfall (50-100 mm) over Sierra Leone, Liberia, and southern Nigeria. The rest of the region reported fewer than 25 mm of rainfall. Temperatures were mostly normal to 2 degrees C above normal across much of West Africa.
  • October 1-10 1998 - The seasonal southward retreat of the ITCZ and associated rains continued, indicating a normal cessation of the rainy season. Moderate to heavy rains (60-150 mm; 65-190% of normal) fell over Togo, southwestern Ghana, Côte d'Ivoire and all but northern parts of Benin. Meteosat-based rainfall estimates and surface reports indicated persistence of heavy to very heavy rains (50-275 mm; 35-160% of normal) along the coastline of Cameroon and northwestern Gabon. Meteosat imagery depicted moderate rainfall (25-100 mm) over western Guinea, Sierra Leone, Liberia and all but extreme northwestern Nigeria. Most of Senegal, Mali, Burkina Faso, and Niger reported fewer than 25 mm of rainfall. In contrast, rains were unseasonably heavy in Chad, with most crop areas recording 20 to 100 mm. Temperatures averaged 1 to 3 degrees C higher than normal over most of West Africa.
  • September 1998 - Unseasonably heavy rains covered the Sahel region except for the Gulf of Guinea coast, where dryness prevailed during the first 10 days. Across West Africa, amounts ranged from 60 to 350 mm, with heaviest falls recorded in Côte d' Ivoire and along the coast of Cameroon. Meteosat imagery indicated moderate to heavy rainfall (100-200 mm) over Guinea, Sierra Leone, Liberia, and all but southeastern Nigeria, where very heavy amounts were estimated. Temperatures averaged near normal a cross West Africa, including southern Chad and central Cameroon, which had previously reported below-normal readings.
  • September 21-30 1998 - The rain belt continued its retreat southward as the bulk of the rain was confined to the region south of 13 degrees N. Heavy rains (100-305 mm; 120-330% of normal) soaked central Côte d'Ivoire. Heavy to very heavy rainfall (100-405 mm; 80-210% of normal) persisted along the coast of Cameroon and adjacent bordering areas of northwestern Gabon. Locally heavy rains (90-175 mm) fell over northern Togo and bordering areas of northwestern Ghana. Moderate rains (30-75 mm) covered southern Senegal, southwestern Mali, and southern Burkina Faso. This contrasts with the heavy rains which fell over these areas in preceding periods. Moderate rains (20-90 mm) fell over southeastern Côte d'Ivoire, Ghana, southern Togo, and southern Benin, reducing deficits which had accumulated since July. Estimates from satellite imagery indicated diminishing amounts (25-100 mm) over Guinea, Sierra Leone, Liberia, and along the eastern border areas of Nigeria. Over southern Chad, estimated amounts remained moderate to heavy (25-100 mm). The rainy season appears to have ended over the northern (Sahelian) crop areas of Chad and most crop areas in Niger. Moisture supplies should be favorable in both countries due to earlier heavy rains. Temperature s averaged 1 to 3 degrees C above normal over much of West Africa.
  • September 11-20 1998 - In the Sahel and across most of West Africa, rains continued to be unseasonably heavy, though shifting slightly southward. Abundant to excessive rains (100-200 mm; 100-260% of normal) fell over southern Senegal, the southern tip of Mali (Sikasso), extreme western Burkina Faso, northern and western Côte d'Ivoire, and northern parts of Ghana and Togo. Along the coast of Cameroon and Equatorial Guinea, heavy to very heavy rainfall (105-280 mm; 90-450% of normal) persisted. Northern Senegal, east-central Mali, most of Burkina Faso, central Ghana, Benin, southern Niger, northern Cameroon and central Chad continued to report moderate rains (40-100 mm; 40-120% of normal). Rainfall amounts increased over southeastern Côte d'Ivoire and southern parts of Ghana, Togo, and Benin, areas which have been slightly below normal since early July, substantiating the southward shift of the rains over the region. Amounts generally ranged from 10 to 25 mm from southeast Côte d'Ivoire to southern Ghana. Higher amounts (25-100 mm) spread from southern Togo into southwest Nigeria. Extreme southeastern Mauritania and adjacent Mali, one of the few areas with below-normal rainfall, reported 0 to 25 mm. Meteosat rainfall estimates indicated cont inued moderate to heavy rains (50-150 mm) over Guinea, Sierra Leone, Liberia and all but northeastern Nigeria. The latter area collected 25 to 50 mm. Rains picked up over southern Chad, where estimated amounts were moderate to heavy (50-100 mm). Temperatures were near normal over the region except for western Ghana and southern Côte d'Ivoire, where they averaged 2 degrees C above normal.
  • September 1-10 1998 - Rains were widespread and above normal in most countries, the main exception being persistent dryness along the Gulf of Guinea coast. Heavy rains (100-150 mm; 120-200% of normal) fell over southeast Senegal, adjacent areas of Mali, northwestern Côte d'Ivoire, western Burkina Faso and adjacent areas of Mali, and western and southeastern Niger. Along the coast of Cameroon, heavy to very heavy rains (100-250 mm; 50-120% of normal) fell. The rest of Senegal, southern Mauritania , eastern Burkina Faso, northern Benin, southwestern Chad, and eastern Cameroon saw moderate rains (25-100 mm; 50-200% of normal). Over central Niger (Maradi Department), moderate rains (25-100 mm) fell, but these amounts were near normal. A pocket of dryness persisted in northwest Burkina Faso, where rainfall totaled 1 to 40 mm. Estimated rainfall from satellite imagery also indicated below-normal rainfall (1-40 mm) in southeastern Chad. However, rainfall was plentiful during the prior period. Southern Côte d'Ivoire, Ghana, southern Togo, southern Benin, and southwestern Nigeria reported less than 20 mm of rainfall, continuing a dry trend that has affected most of the area since early July. Meteosat rainfall estimates suggested moderate to heavy rains (25-200 mm) over Guinea, Sierra Leone, northern Liberia and all but southwestern parts of Nigeria. Above-normal temperatures (2-4 degree C departures) covered Côte d'Ivoire and Ghana. Elsewhere, temperatures were near normal.
  • August 1998 - Moderate to heavy rains (more than 100 mm) covered the Sahel region, particularly southwest Mauritania, Senegal, Gambia, southern Mali, Burkina Faso, northwestern and western Côte d'Ivoire, northern Ghana,Togo, Benin, and southern border areas of Niger. Elsewhere, rains were light to moderate, varying between 20 and 100 mm. Rainfall was deficient in a few areas, notably southeast Mauritania and northern Burkina Faso, including adjoining border areas of Mali. Satellite imagery depicted heavy to very heavy rains (150-300 mm) over much of Guinea and northwest Nigeria, and less than 50 mm over the Gulf of Guinea countries. Temperatures were generally normal to 1 degree C above normal. However, southern Chad and central Cameroon reported 2 to 3 degrees C below normal and 3 to 4 degrees C above normal, respectively.
  • August 21-31 1998 - For the third consecutive 10-day period the rainy season remained in high gear as moderate to heavy rains fell over much of the Sahel region. Heaviest rains (100-300 mm; 80-200% of normal) fell over southeastern Senegal and adjoining bordering areas of Guinea. Heavy rains (100-175 mm; 80-200% of normal) pounded the northern half of Guinea. The rest of Senegal, southern Mali, southeast and southwest Burkina Faso, southern Niger, and central and southern Chad collected moderate to heavy rains ranging from 20 to 150 mm (50-200% of normal). Southern Mauritania, central Mali, northern parts of Burkina Faso and parts of Niger reported light rains of less than 20 mm. For the second consecutive 10-day period, amounts over northern Burkina Faso were below normal, but southeastern Niger, where previous rainfall has been deficient, saw normal amounts (40-70 mm). The reduced rainfall in southern Mauritania is a concern because of a late and erratic rainy season thus far. In contrast, rainfall continued to pick up over northwestern Côte d'Ivoire, northern Ghana, northern Togo and northern Benin, where amounts ranged from 50 to 190 mm (50-120% of normal). In Cameroon, except for the southeast, which recorded less than 25 mm, moderate to heavy rains fell (25-200 mm; 80-300% of normal). Meteosat rainfall estimates indicated moderate to heavy rains (100-200 mm) over Sierra Leone, northern Liberia, and all but southwestern parts of Nigeria. Amounts were somewhat drier than normal (0-1 5 mm) along the coast from southern Liberia to southwestern Nigeria. Temperatures have generally remained the same, ranging from 1 to 2 degrees C above normal over much of the Sahel except for central Mali and much of Nigeria, where they averaged 2 to 4 degrees C above normal and 1 to 3 degrees C below normal, respectively.
  • August 11-20 1998 - Moderate to heavy rainfall continued over much of the Sahel region. Southern Mauritania, southeastern Senegal, and most of Gambia measured beneficial rainfall ranging from 20 to 100 mm (50-200% of normal). However, the northern groundnut basin of Senegal continued to experience a significant rainfall deficit, with amounts less than 30 mm. Soil moisture over southern Mali, southern Burkina Faso, and southwestern through south-central Niger continued to improve due to abundant rainfall (40-150 mm; 60-200% of normal) for the second consecutive reporting period. Rainfall amounts (10-35 mm) over northern Burkina Faso and southeastern Niger were below normal. Erratic rains have affected both areas during this season. Rainfall picked up over northern Benin, southeast Ghana, northeastern Côte d'Ivoire and Togo, with amounts varying from 30 to 184 mm (70-300% of normal). Southern areas of Côte d'Ivoire, southwest Ghana, and southern coastal Nigeria received less than 25 mm (20-5 0% of normal). These areas have tended to be drier-than-normal since early July. Satellite estimates showed continued moderate rainfall (25-100 mm) over Liberia, Sierra Leone, and Guinea. In Nigeria, abundant rains (25-150 mm) fell across the north. East-central Nigeria, however, only recorded 0 to 15 mm, according to satellite estimates. While rainfall station reports indicate that the Lake Chad area was dry, as does some imagery, other data suggest rain did fall in the area. Temperatures were near normal across much of the Sahel except for western Mauritania and central Mali, where readings averaged 2 to 3 degrees C above normal.
  • August 1-10 1998 - The rainy season remained in high gear as moderate to heavy rains fell over much of the Sahel crop region. Near- to above-normal amounts (20-100 mm; 70-300% of normal) fell in Senegal, Gambia, and southern Mauritania, easing dryness caused by the delayed rainy season. In contrast, the southeastern corner of Mauritania and southeastern Senegal experienced rainfall deficits. Southern Mali, Burkina Faso, and southwestern Niger recorded abundant to excessive rainfall (50-150 mm; 70-300% of normal). Increased rainfall (40-100 mm) eased dryness from extreme southeastern Niger to northern Cameroon and westward through north-central Nigeria. In Chad, heavy, with some locally excessive, rains (50-150 mm) fell over a gricultural regions, including previously dry areas near Lake Chad. Conditions that were slightly drier than expected characterized the coastal areas of the Gulf of Guinea countries for a second consecutive 10-day period, with most southern parts of Côte d'Ivoire, Ghana, and Togo receiving less than 25 mm (10-50% of normal). Rainfall estimates from satellite imagery indicated moderate rainfall (25-100 mm) over Nigeria, Liberia, Sierra Leone, and Guinea. Temperatures were near normal across much of the Sahel, except for central Mauritania and southern Senegal, where temperatures averaged 2 to 3 degrees C above normal.
  • July 1998 - July rainfall totals reflected the delayed rainy season in the western Sahel, with Senegal, Gambia, and southern Mauritania measuring 10 to 70 mm (5-50% of normal). The rest of the Sahel saw 50 to 300 mm (75-170% of normal). Dryness over eastern Diffa in Niger eased toward the end of July, with monthly totals of 20 to 50 mm. Monthly amounts, however, were below normal from eastern Diffa southward into northeastern Nigeria, far northern Cameroon, and the Lake Chad area of Chad. Satellite estimates for Sierra Leone, Liberia, and Guinea indicated 100 to 200 mm, while Nigeria ranged from 50 to 300 mm. Monthly rainfall was below normal (20-50 mm; 20-60% of normal) over southeastern Côte d'Ivoire and the southern half of Ghana. Temperatures were generally near normal, with pockets above normal over southern Mauritania and adjacent border areas of Mali (2 to 3 degrees C above normal) and southern Ghana (2 to 4 degrees C above normal). However, southern Chad reported temperatures 2 to 4 degrees C below normal.
  • July 21-31 1998 - Moderate to heavy rainfall covered the Sahel region for the second consecutive reporting period. Welcome precipitation varying from 10 to 70 mm (25-280% of normal) fell over crop areas of Mauritania, signaling the start of the rainy season, which was about 3 weeks late. Over the rest of the Sahel, rainfall amounts were generous, and even locally excessive, with 30 to 140 mm from Senegal through Mali and Burkina Faso to Niger. Niger's eastern Department of Diffa picked up 15 to 36 mm of rain. Though still below normal, it was a marked improvement over previous totals. Coastal areas of the Gulf of Guinea countries recorded below-normal rainfall (2-20 mm; 5-25% of normal). In Cameroon, widespread heavy rains continued, with amounts from 60 mm in the north to 270 mm in the south. Over Chad, satellite estimates showed abundant rainfall, with amounts from 150 mm in eastern crop areas to 10 to 25 mm in the west, near Lake Chad. Meteosat rainfall estimates indicated 25 to 100 mm (50-120% of normal) over Nigeria and 50 to 100 mm over Liberia, Sierra Leone, and Guinea. In Nigeria, estimated rainfall was below normal (10-25 mm) in the north-central, far northeast, and western Gulf of Guinea coast. Temperatures moderated, with readings 1 to 2 degrees C above normal over much of the Sahel.
  • July 11-20 1998 - Rainfall overspread Gambia and much of Senegal, easing dryness over Senegal's groundnut basin. Amounts ranged from around 10 mm (35% of normal) in the northern basin to 110 mm (120% of normal) in southern Senegal. Due to the late start of the rainy season in Senegal, season-to-date totals remain well below normal, especially in northern crop areas. Hot, dry weather prevailed in Mauritania, with little or no rain over crop areas. Normal amounts are 15 to 30 mm for this stage of the growing season. Critical dryness will develop in Mauritania if the rainy season does not begin by the end of the month. Only light rains (1-15 mm) fell over areas in Mali adjacent to the southern Mauritanian border. However, this part of Mali recorded substantial totals during July 1-10, so the situation is not yet critical. Rainfall amounts were generous across the rest of the Sahel region, with 40 to 100 mm from southern Mali to Niger. Needed rains (50-60 mm) fell over Niger's Tahoua Department, but amounts remained light to the east, in Diffa (1-10 mm; 15-50% of normal). Diffa has endured persistent dryness for most of the current growing season. Widespread moderate to heavy rains (25-100 mm) covered crop areas in Chad, with needed moisture even observed in the Lake Chad region. Heavy rains (100-200 mm) fell over the previously dry area of Togo and western Nigeria. In Cameroon, the rainy season has significantly picked up, with rainfall amounts ranging from 70 to 290 mm (125-400% of normal). Meteosat rainfall estimates indicate amounts ranging from 50 to 100 mm over southern Nigeria, Sierra Leone, Liberia, and Guinea. Temperatures ranged from 2 to 4 degrees C above normal over southern Mauritania, southwestern Mali, southern Ghana, and the coastal areas of Togo and Benin.
  • July 1-10, 1998 - Widespread rainfall improved moisture conditions from Mali to Chad, with reported amounts ranging from 25 to 100 mm at most locations. However, the rainy season has been significantly delayed in Senegal's groundnut basin, where little or no rain fell (0-10 mm). The rains are now several weeks late in central and northern Senegal, which is experiencing the slowest start to its rainy season in at least the past 5 years. Gambia saw its rainy season begin with 10 to 25 mm of rainfall. In Mauritania, rainfall ranged from 0 to 25 mm over the agricultural areas in the south, with the highest amounts near the Mali border. This is a rather slow start to the season for Mauritania, where typical amounts are 10 to 30 mm by early July. There were a couple of dry pockets in Niger, including the Tahoua and Diffa Departments, where amounts ranged from 0 to 10 mm and 0 to 15 mm, respectively. Eastern Diffa has been unusually dry since mid-June. In Chad, the area south of Lake Chad recorded improved rainfall (more than 25 mm), but areas near the lake to the east and north recorded 0 to 25 mm of rain, continuing the tendency for below-normal rainfall. Moderate rains (10-50 mm) eased dryness in northern Cameroon, where June rainfall was well below normal. Southeastern Côte d'Ivoire and southern Ghana measured below-normal rainfall (0-40 mm). The southeastern coast of Côte d'Ivoire and southern coast of Ghana have seen below-normal rainfall for the past 3 weeks. Another area of below-normal rains included Benin and western Nigeria, with 5 to 25 mm (5-50% of normal). Temperatures across West Africa remained above normal, averaging around 2 degrees C above normal.
  • June 1998 - The coastal areas of the Gulf of Guinea countries experienced near-normal to above-normal rainfall (80-200 mm; 60-250% of normal). However, rainfall decreased significantly in the northern areas, where rainfall was less than 70% of normal except over Côte d`Ivoire, which recorded near- to above-normal rainfall (120-250 mm; 90-200% of normal) across the whole country. Moderate rains (50-180 mm) fell over the southern parts of Mali and Niger, but northwestern areas measured less than normal rains. Senegal received isolated light rainfall (5-23 mm; 15-70% of normal), while Gambia continued to experience dry conditions. Temperatures averaged 1 to 2 degrees C above normal in most countries.
  • June 21-30, 1998 - Rainfall intensity decreased, and most countries reported below-normal rainfall. In the Sahel, dry conditions characterized southeastern Mali, much of Senegal, Gambia, and Burkina Faso, where amounts ranged from 0 to 10 mm. The rainy season is now about 2 weeks late in Senegal's groundnut basin. Light to moderate rains (15-65 mm; 90-220% of normal) fell in southwestern Niger, but most stations in the eastern crop areas reported less than 10 mm. Côte d'Ivoire received near-normal rainfall (30-200 mm; 70-130 % of normal). Satellite imagery indicated that Nigeria, Liberia, Sierra Leone, and Guinea picked up moderate to heavy rainfall (30-150 mm), as did southern Chad. However, the area near Lake Chad remained unseasonably dry. All countries in West Africa recorded unusually high temperatures (2 to 5 degrees C above normal), with the largest departures across the Sahel.
  • June 11-20 1998 - There was a significant increase in rainfall intensity and a notable northward progression of the rain belt during the period under review, with moderate to heavy rainfall (25-200 mm; 75-250% of normal) in northern and central Ghana, Côte d'Ivoire, much of the Central African Republic, northern and central Togo, and Benin. Satellite imagery depicted well-organized, westward-propagating convective systems on June 16-19 between Nigeria and Sierra Leone. These systems enhanced rainfall in the region during their passage. However, rainfall was below normal (5-50 mm; 10-50% of normal) along the coastal areas of Togo, Benin, and Ghana. Satellite estimates suggest near- to above-normal rainfall (25-150 mm; 80-200% of normal) over Liberia, Guinea, and western and southern Nigeria. Near- to above-normal rains (15-85 mm; 75->200% of normal) also fell in southwestern Mali, southeastern Burkina Faso, and southern Niger. The previously dry region around Lake Chad picked up some moisture from showers and thunderstorms, according to satellite imagery. Rains spread northward into southern Senegal, where amounts ranged between 15 and 70 mm (70-330% of normal). Temperatures averaged 2 to 5 degrees C above normal over Mauritania, Ghana, and southern Senegal.
  • June 1-10, 1998 - The season is progressing normally, with moderate to heavy rainfall (15-110 mm; 75-240% of normal) in Ghana, Côte d'Ivoire, southern Mali, and Burkina Faso. However, a few locations in southern Mali and Burkina Faso reported under 20 mm of rain this period, which is well below expected amounts for early June. Rainfall was above normal over southern Niger (10-50 mm; 85-300% of normal) and below normal over northern agricultural areas of Mali (1-10 mm; 5-65% of normal). Senegal and Gambia remained dry, but the rainy season in both countries typically does not begin until mid-June. Satellite imagery indicated beneficial showers over most southern and eastern agricultural areas of Chad. Estimated rainfall was very low near Lake Chad. Temperatures averaged 2 to 3 degrees C above normal over Mauritania and Senegal and normal elsewhere across the region.
  • May 1998 - Amounts were near to above normal (50-200 mm; 75-330% of normal) over Burkina Faso, Benin, and southern parts of Niger and Mali. Rainfall tended to be below normal in northeastern Côte d'Ivoire and central Ghana, with most stations reporting less than 60% of normal. Satellite-estimated rainfall was heavy (over 200 mm) in central and southern Nigeria. However, amounts were negligible in southwestern Chad and extreme northern Cameroon south of Lake Chad. This area typically records 20 to 80 mm of rain during May. Temperatures remained near normal across West Africa except for Senegal and Ghana, where readings averaged up to 2 degrees C above normal.
  • Late in the month, widespread showers covered most of the region south of the Sahel, easing local dryness in northern parts of Côte d'Ivoire and Ghana. Though the progress of the rains northward into the Sahel has slowed, rainfall amounts were not unusual for this time of year. Moderate rains fell in northern parts of Ghana, most of Togo and Benin, southern Chad, and northern Cameroon (40-135 mm; 20-230% of normal). Rainfall was normal to above normal in much of Burkina Faso and western Côte d'Ivoire (30-170 mm; 90-450% of normal) and normal to below normal (20-70 mm; 20-90% of normal) in southeastern Côte d'Ivoire and central and southern Ghana. Senegal and Gambia were seasonably dry. Satellite-estimated amounts were moderate to heavy (50-150 mm) over Nigeria, Sierra Leone, and Liberia. Most of Mali and Niger was dry except for moderate rains (50-75 mm) in southern Mali. Temperatures averaged 1 to 5 degrees C above normal in West Africa.
  • Through midmonth, rainfall moderated across West Africa, with several countries reporting below-normal amounts. Ghana and northern Côte d'Ivoire have recorded below-normal rainfall for two successive 10-day periods. Rainfall amounts ranged from 10 to 50 mm (10-80% of normal). Rainfall was above normal in Burkina Faso and Benin, where amounts reached 60 mm. Moderate to heavy rains fell over western Nigeria, Sierra Leone, and Liberia. Satellite-estimated rainfall ranged from 50 to 150 mm in this area.
  • April 1998 - Over the month in West Africa, rainfall was near to above normal across the Gulf of Guinea countries, with temperatures averaging around 2 degrees C above normal. The Sahel was seasonably dry, the exception being Burkina Faso, where late-month rains raised monthly totals over 100 mm in the southwest.
  • In late April, the rains continued their seasonal march northward across West Africa, with showers (up to 32 mm) as far north as western Niger. Unusually heavy showers fell in Burkina Faso, with amounts as high as 148 mm (871% of normal). Amounts were mostly normal to above normal from Liberia to Cameroon.
  • In early April, heavy rains broke the drought over the Gulf of Guinea countries as the main rainy season appears to have finally become established. Light to moderate rains (25-100 mm; 10-483% of normal) fell over the southern sectors of Togo, Benin, Ghana, and Côte d'Ivoire.
  • March 1998 - Throughout the month, it was seasonably dry. There were severe dust storms across much of the area.
  • February 1998 - Rains continued at seasonably low levels. Reports of a severe harmattan continue.
  • January 1998 - Rains continued at seasonably low levels. Satellite-detected "rainfall" early in the month in Mauritania was very likely just a misreading by the satellite of very high cirrus clouds. The harmattan is reported to be particularly severe this season.
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