Rainfall Pattern: Kenya’s Meteorology Department Releases 3-Month Forecast
3 min readThe Meteorological department in Kenya has released the weather forecast and rainfall pattern for the period between October and December 2020. The report indicates that most parts of the country will experience lower rains than usual.
According to the Climate Outlook for the October-November-December (OND) 2020 “Short Rains” season, several parts of the country are likely to experience depressed rainfall while Western Kenya is likely to receive near-average to below-average rainfall.
The forecast as per the reports will be caused by near-average Sea Surface Temperatures (SSTs) over the western Equatorial Indian Ocean (adjacent to the East African coastline), coupled with warmer than average SSTs over the eastern Equatorial Indian Ocean (adjacent to Australia).
“This constitutes a negative Indian Ocean Dipole (IOD) that is not favourable for good rainfall over most of East Africa,” it says in an update on 5th September 2020.
“Also, Equatorial sea surface temperatures (SSTs) are near-to-below average across the central to the eastern Pacific Ocean which implies that mild La-Nina conditions are present.”
The distribution of the rainfall in time and space is expected to be generally poor over several areas especially during the month of October and the peak month of November. In the month of December sunny and dry conditions are expected to prevail over several places in the country as the cessation begins.
September 2020 Weather Outlook
On average, several parts of the country will experience generally sunny and dry weather conditions during the month of September. However, the Lake Victoria Basin, the Highlands West of the Rift Valley and Central Rift Valley are likely to experience near-average rainfall with a tendency to above-average rainfall.
Occasional light morning showers are expected along the Coastal Strip while the Highlands East of the Rift Valley (including Nairobi County) are likely to experience occasional afternoon showers and cloudy conditions especially at the beginning of the month. Sunny and dry conditions are however likely to prevail over the Northeastern, Southeastern and the Coastal counties.
Geographical distribution
The Short Rains in October-November-December (OND) 2020 season constitutes an important rainfall season in Kenya more so in the Central and South-eastern regions of the country.
Despite the depressed rains, isolated incidences of storms are likely, even in the areas expected to receive depressed rains which may cause flash floods.
Water levels in the Rift Valley lakes are also likely to remain high and may cause flooding in the surrounding areas because the catchments feeding the lakes have continued to receive above-normal rainfall from the 2019 OND rainfall season to date.
The areas likely to receive near-average with a tendency to below-average rainfall include Western Counties (Busia, Vihiga, Kakamega, Bungoma); Nyanza Counties (Kisumu, Siaya, Homa Bay, Nyamira, parts of Migori, Kisii); Counties in the Southern, Central and North Rift Valley (Kericho, West Pokot, Nandi, Bomet, Uasin Gishu, Trans Nzoia, Baringo, Elgeyo Marakwet, parts of Nakuru, parts of Narok, parts of Laikipia); Counties in North Western Kenya (Turkana, parts of Samburu).
The areas likely to receive below-average (depressed) rainfall include Counties in Central Kenya (Nyandarua, Kirinyaga, Nyeri, Murang’a, Kiambu), Nairobi County; Counties in the Eastern Region (Meru, Embu, Tharaka Nithi); some counties in southeastern Kenya (Machakos, Makueni and Kitui) and North Eastern Counties (Mandera, Wajir, Garissa, Marsabit, Isiolo); Counties in the Coast Region (Mombasa, Kilifi, Kwale, Lamu and Tana River); counties in the South, North and Central Rift Valley (Kajiado, parts of Narok, parts of Laikipia, parts of Samburu and parts of Nakuru), and in south Nyanza (parts of Migori).
Review of the Rainfall in June-July-August
Several parts of the country experienced significant rainfall during June-July-August (JJA) 2020. Near-average to Above Average rainfall was recorded over several parts of western Kenya while occasional cool and cloudy conditions were observed over the Central Highlands and Nairobi. The July-August temperatures were generally warmer than average over much of the country.
