Showers, thunderstorms and lightning are forecast across large parts of Kenya this weekend, with the Kenya Meteorological Service Authority (KMSA) predicting light to moderate rainfall in several counties between Saturday, 17 October, and Wednesday, 21 October. The Kenya Times, which reviewed the outlook, reported that 45 counties are set to receive rain during the five-day period.

The forecast, dated 15 October on the weather agency's website, comes as Nairobi City County races to finish flood-mitigation works ahead of the El Niño-linked short rains that forecasters expect to set in during the third week of October.

Western Kenya and the Rift Valley to bear the brunt

According to the KMSA bulletin, the wettest conditions are expected in the Lake Victoria basin, the western highlands and parts of the Rift Valley, where afternoon and evening showers are predicted to be accompanied by thunder and lightning on most days.

Trans Nzoia, Uasin Gishu and Nandi are among the counties expected to receive such storms on several days, while West Pokot and Samburu could see thunderstorms on Saturday. Nakuru, Kericho, Bomet, Kisii and Nyamira are also forecast to receive afternoon rain, with moderate showers on some days. Elgeyo-Marakwet, Baringo and Laikipia may record showers at different times.

In western Kenya, Kakamega, Vihiga and Bungoma are expected to receive afternoon showers and thunderstorms on several days, and Busia light to moderate showers. In Nyanza, Kisumu, Siaya, Homa Bay and Migori are forecast to receive showers at different times, some of them at night.

In central Kenya, Nyandarua is expected to receive afternoon showers for much of the period and to record the coldest nights, with minimum temperatures of between 7°C and 9°C. Nyeri, Kirinyaga and Murang'a may receive showers mainly at night and in the mornings.

Mild conditions for Nairobi, heat in the north

For Nairobi, the outlook is relatively calm. Mornings and afternoons are expected to be dominated by sunny intervals from Saturday to Tuesday, with light showers forecast on Monday, Tuesday and Wednesday nights and light rain on Wednesday morning. Night-time temperatures in the capital are expected to range from 12°C to 16°C, with daytime highs of up to 29°C, according to the bulletin.

At the Coast, Mombasa is forecast to experience light showers on Saturday and Sunday nights, with daytime highs of about 30°C. Kwale, Kilifi and Lamu could receive light morning showers on Sunday and Monday, while Tana River may see afternoon showers from Monday.

Northern and north-eastern Kenya will remain largely hot and dry. Turkana is expected to record highs of up to 38°C, and Garissa, Wajir and Mandera up to 36°C, though afternoon showers are possible in Garissa on Monday and Wednesday. Marsabit may receive light morning rain on Monday and Tuesday.

KMSA advised that the five-day outlook should be read together with its daily, 24-hour forecasts, adding that county-specific forecasts are available from its county directors.

Nairobi braces for El Niño

The forecast comes days after Nairobi Governor Johnson Sakaja said the county had identified 227 flood-prone hotspots across its 17 sub-counties ahead of the El Niño rains. Speaking at a national development implementation meeting on Monday, 12 October, he said a worst-case scenario could displace about 100,000 people, or 20,000 households, mainly in informal settlements along the Nairobi, Mathare and Ngong rivers, The Star and The Eastleigh Voice reported.

The governor said the county needed Sh5.17 billion for flood prevention and emergency response, and that 26 of 61 critical drainage sites had been cleared. He said the Kenya Meteorological Department had projected the onset of the rains in the third week of October with a probability of 96 to 98 per cent.

"We must respect science," Mr Sakaja said, according to The Star, dismissing doubts over whether the El Niño rains would materialise. He recalled that the city received 160mm of rain in a single night on 6 March, when lives were lost in areas including Westlands.

Schools, hospitals and social halls have been identified as temporary shelters, and a 24-hour joint command centre has been set up at Charter Hall, The Eastleigh Voice reported. Residents can report emergencies through the county line 1508 or the Kenya Red Cross on 1199.

Photo: Rain clouds over Nairobi. Mwe17 / Wikimedia Commons, CC BY-SA 4.0