Residents in parts of 32 counties are set for another wet spell, with the Kenya Meteorological Department forecasting rainfall from September 29 to October 5 as attention turns to the expected October-December rains.
The latest weekly forecast covers parts of the Coast, North Eastern, Central, Eastern, Western and Rift Valley regions, as well as Nairobi, and follows rainfall recorded in several areas between September 21 and 27.
The counties expected to receive rainfall are Lamu, Kwale, Kilifi, Mombasa, Tana River, Taita Taveta, Mandera, Marsabit, Meru, Embu, Garissa, Kiambu, Kirinyaga, Kisumu, Kitui, Laikipia, Machakos, Makueni, Murang'a, Nairobi, Nakuru, Nyandarua, Nyeri, Tharaka-Nithi, Trans Nzoia, Bungoma, Elgeyo Marakwet, Bomet, Kericho, Kisii, Nyamira and Wajir.
Last week, rainfall was recorded in Bungoma, Busia, Migori, Siaya, Nyamira, Kakamega, Kisii, Nakuru and Kericho.
Bungoma recorded the highest total rainfall during the seven-day period, with the Kibabii University rainfall station receiving 125.1mm.
The highest rainfall recorded within 24 hours was reported in Migori County, where the Miyare rainfall station received 61.2mm on September 21.
The new forecast comes as meteorologists continue to study how ocean conditions could affect the amount and distribution of rainfall during the October-December period.
Jemima Gacheru, a principal meteorologist at the Kenya Meteorological Service Authority, said El Niño should not be viewed as a direct guarantee of increased rainfall in Kenya.
"So this is just to demystify that notion that El Niño is always equal to rainfall. That is not always the case," Gacheru said during a webinar hosted by the authority.
She said the Indian Ocean Dipole was also an important factor in determining rainfall patterns.
The weather system measures the difference in sea temperatures between the western Indian Ocean near East Africa and the eastern Indian Ocean close to Indonesia.
When waters near the East African coast are warmer than normal, a positive Indian Ocean Dipole can support increased rainfall in East Africa.
Gacheru said the Indian Ocean Dipole index was currently at 0.7 degrees Celsius and was expected to rise to about 1.0 degrees in October.
However, the Australian Bureau of Meteorology reported a weekly Indian Ocean Dipole index of +0.65°C for the week ending September 13. The bureau classified the reading as neutral, noting that a single observation above +0.4°C does not confirm a positive Indian Ocean Dipole event.
Gacheru said the strength of the Indian Ocean Dipole would help determine whether Kenya experiences extremely heavy rainfall or a more mixed pattern during the October-December season.
She cited 1997, when strong El Niño conditions occurred together with a strong positive Indian Ocean Dipole, resulting in heavy rainfall across most parts of Kenya.
In 2015, however, strong El Niño conditions coincided with a weaker Indian Ocean Dipole of about 0.5 degrees.
That combination produced a mixed rainfall pattern, with some parts of the country recording above-normal rainfall while others experienced near-normal or below-normal amounts.
Gacheru said the current forecast points to above-normal rainfall in most counties, although the expected amounts will differ from one area to another.
"Most areas are expected to have fair to good distribution, meaning the dry spells will not be as many," she said.