REPUBLIC OF KENYA
MINISTRY OF ENVIRONMENT AND MINERAL RESOURCES
KENYA METEOROLOGICAL DEPARTMENT
Dagoretti Corner, Ngong Rd, P. O. Box 30259, 00100 GPO, Nairobi, Kenya
Telephone: 254 (0) 20 3867880-7 / 3876957/60 / 3873682
Mobile: 254(0)724255153/ 254(0)724255154
Fax: 254 (0) 20 3876955/3877373/3867888/3874501
e-mail: director@meteo.go.ke; Website: http://www.meteo.go.ke
Ref. No. Met/ 1622
Date 16 February, 2016
REVIEW OF THE OCTOBER-NOVEMBER-DECEMBER “SHORT RAINS” 2008 SEASON AND THE
OUTLOOK FOR JANUARY-FEBRUARY 2009
1.
Summary
The first half of October-November-December (OND) 2008 “Short Rains” season was characterized by
excessive rainfall in most parts of the country and especially the Western, Central and Northeastern districts.
Sunny and dry weather conditions however prevailed during the second half of the period. The seasonal rainfall
was highly depressed in Southeastern and the Coastal areas of the country throughout the period. The
Southeastern areas were the most affected for some of the areas did not receive any rainfall throughout the
entire period.
The outlook for January-February 2009 indicates that most parts of the country are likely to experience
generally sunny and dry weather conditions throughout the two-month period. However, some parts of western
Kenya especially to the south of Lake Victoria basin are expected to experience occasionally light rainfall
amounts that will be depressed as compared to the long-term mean amounts for the period.
2.0
Review of Weather during the “Short Rains” (October-December) 2008 Season
2. 1
Performance of OND 2008 Short Rains
The OND 2008 “Short Rains” season was characterized by very poor temporal distribution of rainfall. Most parts
of the country experienced heavy and continuous rainfall during the month of October and the first half of
November. The rainfall was especially heavy over the Western, Northeastern and some parts of Central Kenya
including Nairobi. This rainfall resulted into flash floods and landslides/mudslides leading to loss of life and
property as well as destruction of infrastructure in several areas.
However, the entire country remained generally sunny and dry throughout the second half of November and the
entire month of December. During the month of December, for example, most stations in the country recorded
monthly rainfall totals not exceeding 10mm. Apart from Msabaha, Laikipia Airbase and Kisii stations the rest of
the meteorological stations recorded rainfall that was well below 50 percent of their monthly long-term means
(LTMs). Stations like Malindi, Dagoretti Corner, Moi Airbase, Lodwar, Wajir, Mandera, Eldoret, Embu, Jomo
Kenyatta Airport and Lamu recorded less than a millimeter throughout the month of December.
In terms of OND seasonal totals, Kisii station recorded the highest seasonal rainfall total of 566.6mm (105%) as
compared to its seasonal LTM of 538.7mm. Meru, Kericho, Kakamega, Marsabit, Eldoret Airport, Wilson
Airport, Kisumu, Embu and Nakuru received 539.9mm (79%), 493.9mm (122%), 482.1mm (122%), 391.0mm
(132%), 387.9mm (179%), 382.6mm (135%), 326.9mm (92%), 323.1mm (61%) and 309.8mm (171%) as
compared to their seasonal LTMs of 688.2, 403.8, 395.3, 296.0, 216.6, 283.7, 354.3, 532.6 and 180.8mm
respectively. The monthly and seasonal OND rainfall performance is depicted in Figures 1(a, b, c, d). Rainfall
amounts equal to or greater than 75% and not exceeding 125% of the LTMs are described to be within the
near-normal rainfall category, while amounts below 75% of the LTM are described to be within the depressed
(below normal) rainfall category, and amounts greater than 125% of the LTM are within the enhanced (above
normal) rainfall category.
2.2
Prevailing synoptic and meso-scale weather systems during October-December 2008 period
The rain bearing Inter-Tropical Convergence Zone (ITCZ) established itself in Kenya in good time leading to
timely onset of “Short Rains” season in October. However, cool sea surface temperatures (SSTs) occurred over
1
the tropical western Indian Ocean; and La-Niña like conditions (cool SSTs) prevailed in the eastern and central
Equatorial Pacific as the season progressed. This configuration of systems led to reduced moisture influx from
the Indian Ocean to most parts of the country and especially the eastern sector during the second half of the
OND season.
2.3
Observed Impacts
The early season occurrence of heavy rainfall over various parts of the country resulted into flash floods and
landslides/mudslides that led to loss of life and property as well as destruction of infrastructure. The most
affected regions included the Northeastern districts (Mandera, Wajir and Isiolo) where some areas were
periodically submerged in floods. The Ewaso Nyiro River burst its banks in the lower parts of Isiolo District
displacing hundreds of families.
Media reports indicated that thousands of people were displaced and several roads were rendered impassable.
In Tana River district, some people were temporarily displaced by floodwaters emanating from heavy rainfall in
the catchment areas of River Tana. In Central Kenya, tens of people were buried alive due to landslides in
Murang’a districts while swollen seasonal rivers claimed a few lives in Nairobi area. Perennial floods displaced
several people in Western Kenya (Busia, Budalang’i, Trans Nzoia districts) and several people were killed by
mudslides emanating from excessive rainfall in West Pokot.
In terms of agriculture, the timely onset of the seasonal OND rainfall improved agricultural activities especially in
the central highlands and some parts of southeastern districts. However, the very early cessation of rains
impacted negatively on the crops. Most crops withered due to lack of sufficient water. The negative impact is
currently being felt over most parts of the country with most areas suffering food shortage. Looming famine has
been reported in various parts of the country and more so in Eastern, North Eastern, and Coastal Provinces.
Pastures for livestock that initially improved significantly over most parts of northeastern districts have also
deteriorated due to insufficient rainfall as well as prevailing high temperatures.
3.
Forecast for January-February 2009
This forecast is based on the expected evolution of global Sea Surface Temperatures (SSTs) patterns and
composite analysis mainly based on SST gradients. The current moderate La-Niña like conditions and the cool
SSTs in the Indian Ocean are also put into consideration. Hence, the outlook for January-February 2009
indicates that most parts of the country are likely to remain generally sunny and dry except a few areas in the
Lake Basin where occasional light rainfall amounts are likely to be recorded (Figure 2). The specific outlooks
for individual areas are therefore as follows:
The Lake Basin (Kisii, Kisumu, Busia), parts of Highlands west of the Rift Valley (Kericho, Kakamega),
Central Rift Valley (Narok, Nakuru), etc are expected to receive occasional light rainfall that will be generally
depressed as compared to the LTMs.
The Highlands east of the Rift Valley including Nairobi (Nyahururu, Nyeri, Embu, Meru, Murang’a, Thika,
Dagoretti, Wilson) are expected to experience generally dry conditions throughout the period. A few places
especially over the high-ground areas are however likely to experience occasional light rains that are not
expected to have any impact to high temperatures expected during the period.
The North-western (Lodwar, Lokichoggio), North-eastern (Moyale, Marsabit, Wajir, Mandera, Garissa),
Southeastern Kenya (Voi, Makindu, Machakos, Taveta), Coastal Strip (Lamu, Tana River, Mombasa,
Mtwapa, Malindi) etc are expected to be generally sunny and dry throughout the two-month period.
Note: This forecast should be used in conjunction with regular updates issued by this Department.
STANSLAUS M. GACHARA
FOR: DIRECTOR OF METEOROLOGICAL SERVICES
2
Figure 1a: October 2008 Rainfall Performance
Figure 1c: December 2008 Rainfall Performance
Figure 1b: November 2008 Rainfall Performance
Figure 1d: OND 2008 Rainfall Performance
3
Figure 2: January-February 2009 Rainfall Forecast
4