Somalia experiences an early-to-timely onset of the secondary deyr rains in October

International ensemble forecast models and the IGAD’s Greater Horn Climate Outlook Forecast (GHACOF6x) predicted wetter-than-typical October-December deyr seasonal rainfall associated with strong El Niño and positive Indian Ocean Dipole (IOD) conditions. However, from October 1-20, Somalia experienced mixed precipitation. Ground reports indicated that most of the country received localized light to moderate rains during this period. Compared to the long-term average (1981-2020), remote sensing data indicate that cumulative rainfall from October 1 to 20 was mostly average to above average in much of the northern and central regions, with slight deficits in parts of Juba and Gedo in the south (Figure 2). Moderate to heavy rainfall was reported in much of the pastoral areas of the northern Sool and Nugaal regions, central regions, and parts of southern Bay, Bakool, and Gedo regions. Preliminary CHIRPS remote sensing data support ground reports, indicating cumulative rainfall ranging from 25-150 millimeters (mm) in most areas (Figure 1). However, most of Awdal and Bari and large parts of the pastoral and agropastoral areas of Lower Juba received less than 25 mm of rainfall. According to FAO SWALIM river station gauge data on October 25, rising water levels in key monitoring points along the Shabelle and Juba rivers are observed, causing localized flooding in parts of the Middle Shabelle and Gedo regions due to open breakages. While river levels currently remain below flood risk levels, remote sensing data forecasts widespread above-average rainfall in riverine areas of Somalia and in the Ethiopian highlands through October 31, which is expected to lead to extensive flooding in the coming weeks. 

In the northwest,deyr rainfall performance was mixed from October 1-20. Field reports, corroborated by CHIRPS remote sensing data, indicate moderate and evenly distributed rainfall was observed in most pastoral areas of Sool, Togdheer, and Sanaag regions. In these areas, rainfall totals generally ranged from average to above average relative to the long-term mean. Meanwhile, all livelihood zones of Awdal and Woqooyi Galbeed regions received minimal rainfall – only 5-50mm – which is below average for this period. Across the northwest, the onset of the deyr rains has been beneficial for replenishing rangeland resources and improving livestock access to pasture and water following the historic 2020-2023 drought. 

In the northeast, the performance of the deyr rainfall from October 1-20 was mostly mixed. In most pastoral areas of Bari as well as the Coastal Deeh pastoral areas in Nugaal and southern Mudug regions, reports indicate minimal rainfall occurred in most of October, with localized light to moderate rainfall in Northern Inland Pastoral (NIP) livelihood zone in Bossaso, Iskushuban, and Qardho districts. As such, rangeland conditions and water access in most pastoral areas of Bari, NIP, and Coastal Deeh pastoral livelihood zones remain poor and generally below average. In contrast, most of Hawd and Addun Pastoral livelihood zones received moderate rainfall during the October 1-20 period, leading to improved rangelands and water access for livestock. 

In central regions, field reports confirmed that the deyr rains began in early October and persisted through October 20 in most pastoral and agropastoral areas of Galgaduud and southern Mudug regions. According to field reports and CHIRPS remote-sensing data, rainfall was moderate to heavy and evenly distributed spatially. However, Coastal Deeh Pastoral areas along the Indian Ocean received limited rainfall. However, the livestock in these areas generally have the option to migrate to neighboring inland pastoral areas where rainfall is more abundant. 

In the southern regions, there was a mixed – early-to-timely – onset of deyr rains, with moderate to heavy intensity and normal distribution in Bakool, Gedo, and localized areas of Bay and Hiiraan regions from early to mid-October. However, most livelihood zones in Middle and Lower Juba, Middle and Lower Shabelle, and southern parts of Hiiraan received little to no rainfall during this period. Rain gauge stations recorded moderate to heavy rainfall in localized areas, including 332.5 mm in Baydhaba (Bay), 171.5 mm in Xudur (Bakool), 38.4 mm in Beledweyne (Hiiraan), and 24 mm in Saakow (Middle Juba). Meanwhile, no rainfall was recorded at the rain gauge stations in Jamaame (Lower Juba). Additionally, most SWALIM river gauge stations along the Shabelle and Juba Rivers indicate rising water levels due to increased deyr rainfall in the Ethiopian highlands. Although some localized flooding was already reported in Jowhar (Middle Shabelle) and Luuq and Baardheere (Gedo), the river water levels remain below the threshold for moderate to significant flood risk.

From October 11-20, the satellite-derived eVIIRs Normalized Difference Vegetation Index (NDVI) indicates above-average vegetation conditions in localized areas across the country, thanks to the early-to-timely onset of deyr rainfall in October. However, much of the southern regions still suffer from significant vegetation deficits due to the 2020-2023 drought and insufficient rainfall from October 1-20 (Figure 3). The five-day weather forecast from the NOAA Climate Prediction Center through October 31 suggests localized average to above-average rainfall in the northeast, central, and southern regions (Figure 4). However, a substantial part of the Togdheer, Sool, Sanaag, and Bari regions in the north and the Juba regions in the south are expected to receive little to no rainfall during this period. The Ethiopian highlands and Shabelle River catchments are forecasted to experience heavy rainfall, potentially leading to extensive flooding in both the Juba and Shabelle rivers in the coming weeks. 

For more rain gauge data, please contact So-Hydro@fao.org or visit www.faoswalim.org.