Skip to main content

Severe rainfall deficits and/or long dry spells across wide areas of northern Sahel in September

  • Seasonal Monitor
  • West Africa
  • October 26, 2023
Severe rainfall deficits and/or long dry spells across wide areas of northern Sahel in September

Download the Report

  • Key Messages
  • Update on Seasonal Progress
  • Forecasts
  • Seasonal Calendar for a Typical Year
  • Key Messages
    • The Intertropical Front (ITF) continues its southward retreat slightly slower than normal.
    • Seasonal rainfall has been mostly average to above-average, over most of the region.
    • Lake Chad area, western Niger, central Burkina Faso and southern Mauritania and northern Senegal experienced severe rainfall deficits and/or long dry spells in September. 
    • A significant drop in yield is expected in areas of the Sahelian zone impacted by dryness. However, overall, an average production is expected over the region.

    Update on Seasonal Progress

    Figure 1

    01May-30Sep CHIRPS & 1-15Oct CHIRP Percent of Average Rainfall
    01May-30Sep CHIRPS & 1-15Oct CHIRP Percent of Average Rainfall

    Source: CHC/UCSB

    • The Intertropical Front (ITF) continues its southward retreat. As of the second dekad of October it was located south of its normal position west of 10°W, around normal between 10°W and Greenwich meridian (0°), south of normal between Greenwich meridian and 18°E, and north of normal east of this longitude and all the way through the eastern limit of the region.
    • Seasonal cumulative rainfall (Figure 1) has been average to above-average over most of the region, though with some slight deficits over localized areas. However, analyzing sub-seasonal accumulations at a monthly timescale reveals periods of severe rainfall deficits and/or long dry spells affected the following areas:
      • In July (Figure 2), an area extending from southern Mali into southwestern Burkina Faso, and another zone extending from northeastern Nigeria to southeastern Niger,
      • In August, Maradi, Zinder regions and southwestern part of Tillaberi region in Niger, an area extending from extreme northeastern Nigeria and Far North Cameroon into Hadjer Lamis region in Chad; parts of Hodh el Gharbi, Assaba and Brakna in southern Mauritania, Saint Louis region in northern Senegal, and the extreme southwestern part of Timbuktu region in Mali.
      • In September (Figure 3), most of the agro-pastoral part of the Sahelian zone from the northern part of Maradi region in Niger all the way west to the Senegal-Mauritania border area, central Burkina Faso, parts of southern Tillaberi region in Niger. Parts of the agro-pastoral area from eastern Niger to eastern Chad have also been affected by long dry spells but mostly under normal to above-normal rainfall conditions.
    • In the Sahelian zone, where crops are most sensitive to dry conditions, rainfall deficits in August are typically not problematic if rainfall is well-distributed in time, because it is the rainiest month of the season during which moisture is almost always adequate for crop and pasture development. Such is not the case for July, when rainfall deficits and/or bad temporal distribution could be the cause of significant planting delays in an area where the length of the growing season is only 7 to 9 dekads long. During July in the Sahelian zone, photoperiod sensitive cereal crops and pastures are vulnerable to planting delays, which lead to dwarfism and subsequent diminished performance. September is the month of the reproductive and maturation period in crop development, phases when crops are extremely sensitive to water stress. Therefore, significant yield reductions are to be expected over areas of the Sahelian zone that experience rainfall deficits or prolonged dry spells in July and/or September.
    • The ITF’s southward retreat is progressing at about a normal speed, resulting in a normal end of the season for the region. Also, given the mostly average to above-average seasonal rainfall, average production is anticipated at the regional level despite the aforementioned areas that experienced dryness and/or long dry spells during the season.

    Figure 2

    July total CHIRPS anomaly & CDD
    July total CHIRPS anomaly & CDD

    Source: CHC/UCSB

    Figure 3

    September total CHIRPS anomaly & CDD
    September total CHIRPS anomaly & CDD

    Source: CHC/UCSB


    Forecasts
    • According to the monthly forecasts from NOAA-CPC, CHC-UCSB and WMO (World Meteorological Organization) there is an expectation for at least average rainfall through the end of November. This forecast augurs a timely end of the season the Sudanian-Guinean and bimodal zones.

    Seasonal Calendar for a Typical Year
    West Africa Seasonal Calendar

    Source: FEWS NET

    Recommended citation: FEWS NET. West Africa Seasonal Monitor October 26, 2023: Severe rainfall deficits and/or long dry spells across wide areas of northern Sahel in September, 2023.

    FEWS NET’s Seasonal Monitor reports are produced for Central America and the Caribbean, West Africa, East Africa, Central Asia, and Somalia every 10-to-30 days during the region’s respective rainy season(s). Seasonal Monitors report updates on weather events (e.g., rainfall patterns) and associated impacts on ground conditions (e.g., cropping conditions, pasture and water availability), as well as the short-term rainfall forecast. Find more remote sensing information here.

    Get the latest food security updates in your inbox Sign up for emails

    The information provided on this Website is not official U.S. Government information and does not represent the views or positions of the U.S. Agency for International Development or the U.S. Government.

    Jump back to top