REPUBLIC OF KENYA
MINISTRY OF TRANSPORT
KENYA METEOROLOGICAL DEPARTMENT
Dagoretti Corner, Ngong Road, P. O. Box 30259, 00100 GPO Nairobi, Kenya,
Telephone: 254-20-3867880-5 / 3876957 / 3873682 Fax: 254-20-3876955 / 3877373
E-mail:director@meteo.go.ke, Website: www.meteo.go.ke
Ref. No. Met/ 1622
Date 10 March 2007
THE OUTLOOK FOR THE “LONG-RAINS” (MARCH-MAY) 2007 SEASON AND
REVIEW OF WEATHER DURING THE “SHORT RAINS (OCTOBER-DECEMBER) 2006
SEASON AND JANUARY-FEBRUARY 2007 PERIOD
1.
Summary
Most parts of the country and especially the Northeastern and the Coastal Strip experienced highly enhanced
rainfall during the “Short Rains” (October-December) 2006 season. The excessive rainfall caused serious
flooding in some areas leading to loss of life, extensive destruction of infrastructure worth millions of
shillings and displacement of several families. The floods also resulted into an outbreak of the Rift Valley
Fever disease that claimed several lives of humans and animals. At the same time delivery of essential relief
commodities like food and drugs to affected areas was seriously disrupted after the major roads leading to
these areas were swept away by the raging floods.
During January-February 2007, generally dry conditions prevailed over most parts of the country save for a
few areas in Western Kenya, Central highlands including Nairobi and Southeastern lowlands of Kenya that
continued to experience significant amounts of rainfall.
The outlook for March to May 2007 indicates that most parts of the country are likely to experience near
normal rainfall that is likely to be poorly distributed both in time and space especially in the Arid and Arid
Lands (ASALs). However, the Coastal areas (Lamu, Malindi, Kilifi, Mombasa etc) are likely to experience
slightly enhanced rainfall.
2.
October-December 2006 “Short Rains” Performance
Most parts of the country experienced heavy and continuous rainfall during the October-December
(OND) 2006 “short-rains” season. The rainfall was especially heavy over the Western Kenya,
Northeastern districts, Central highlands and Coastal areas. This rainfall resulted into serious
flooding and loss of life and property as well as destruction of infrastructure. The areas that were
highly affected included the Northeastern districts (such as Garissa, Isiolo and Wajir), Coastal
districts (mainly Kwale, Mombasa and Lamu) and parts of Nyanza Province (Kisumu and Migori
areas).
Apart from Kisii and Nanyuki stations the rest of the meteorological stations recorded rainfall that
was well above 125 percent of their seasonal Long-Term Means (LTMs). Lodwar station in Rift
Valley Province recorded rainfall that was more than six times (618 percent) the amount that would
normally be recorded at the station during the OND season while most of the coastal stations
recorded more than twice the normal amounts. Other meteorological stations which recorded
rainfall that was more than twice what they would normally receive were Eldoret, Kericho and
Narok in Rift Valley Province; Wajir and Mandera in Northeastern Province; Moyale, Machakos
and Makindi in Eastern Province; Nyeri in Central Province and Moi AirBase in Nairobi. Detailed
station analysis indicates that the rainfall amounts recorded at most stations ranked between
second and fourth highest for the season since the stations were opened. The rainfall distribution
both in time and space was quite good in most areas. The rainfall was also characterized by heavy
storms pounding a number of areas. Makindu station recorded the highest daily rainfall of
137.0mm on 27th December while Moyale recorded 124.6mm on the 17th of October. Machakos
(Katumani), Msabaha, Mombasa and Mtwapa stations recorded 114.7, 112.7, 110.5 and 103.7mm
on 27th December, 9th November, 15th October and 9th November respectively.
Meru station recorded the highest seasonal rainfall total of 1035.5mm (151%) as compared to its
seasonal LTM of 688.2 mm. Embu, Kericho, Kisumu, Nyeri, Mtwapa and Machakos received
960.1mm (180%), 801.2mm (198%), 735.2mm (208%), 701.5mm (236%), 700.7mm (266%) and
660.4mm (228%) as compared to their seasonal LTMs of 532.6, 403.8, 354.3, 297.5, 263.3 and
289.9mm respectively. The seasonal rainfall performance is depicted in Figure 1.
3.
January-February 2007
Most parts of the country experienced generally sunny, dry and hot conditions during the two
months. However, some areas in Western Kenya, Central highlands including Nairobi and
Southeastern lowlands experienced significant rainfall amounts especially during the first half of
January and also at the beginning and towards the end of February. In January, Kisii station
recorded the highest monthly total of 271.7 mm which was 246% of its January LTM. It was
followed by Kericho, Narok, Makindu, Kisumu, Meru and Jomo Kenyatta International Airport
(JKIA) with 143.0 (147%), 114.9 (133%), 103.2 (234%), 90.5 (116%), 85.3 (143%) and 83.4mm
(179%) respectively. The rest of the stations recorded less than 70mm.
On 26th February, Thika station recorded a rainfall storm amounting to 102.9mm. This was the
only rainfall recorded at the station during the month. During the month of February, the highest
monthly total rainfall of 164.3mm (133%) was again recorded at Kisii while Narok, Eldoret, Kisumu,
Eldoret Airport, Nakuru, Kitale, Dagoretti Corner, Kericho and Wilson Airport recorded 145.0
(190%), 144.4 (336%), 142.2 (161%), 131.0 (512%), 128.6 (316%), 110.4 (242%), 107.3 (190%),
106.0 (108%) and 104.9mm (222%) respectively. The rest of the stations recorded less than
100mm.
4.
Impacts
The October-December 2006 seasonal rainfall greatly improved agricultural activities especially in
Western Kenya and Central highlands as well as the Southeastern lowlands. Some of these areas
recorded bumper harvest. Pasture for livestock also improved significantly in some parts of
Northeastern districts despite the serious flooding. The Seven-Folks and the Turkwel hydroelectric
power generation dams both recorded maximum capacities.
However, the excessive rainfall was more destructive than beneficial in some parts of the country.
In Northeastern and Northwestern Kenya, the Coastal region and some parts of Western Kenya,
the resultant flooding claimed several human and animal lives and also led to destruction of
property and infrastructure. Property worth millions of shillings perished in the floods. Several
families were rendered homeless following the serious flooding in their residential areas. Transport
system especially in northeastern and coastal areas was totally disrupted. Delivery of essential
relief commodities by road to the affected regions became impossible after the major roads linking
the areas with the rest of the country were washed away by the floods. The outbreak of the
dreaded Rift Valley Fever that was associated with the excessive rainfall climaxed the negative
impacts. The disease claimed several lives while meat industries including individual meat traders
suffered huge losses due to very low consumption of meat for fear of catching the disease.
5.
Forecast for March-May (“Long-Rains”) 2007 Season
This forecast is based on models developed from expected evolution of global Sea Surface
Temperatures (SSTs) and sea surface temperature gradients. The decaying El-Nino conditions in
the Pacific Ocean and also Tropical cyclone activities in the Indian Ocean were also put into
consideration. The predicted onsets, cessation and distribution of rainfall were derived from
statistical analysis of past years, which exhibited similar characteristics to this year.
Figure 2 depicts the mean (normal) March-April-May seasonal rainfall. The figure shows that most
areas in Western, Nyanza, Central and Nairobi Provinces receive normal (mean) rainfall ranging
from 400 to 680mm; The south Rift receives normal (mean) rainfall ranging from 250mm to
350mm while the Central Rift receives normal (mean) rainfall in the range 180mm to 250mm; The
2
North Rift receives rainfall in the range 90mm to 220mm; The Northeastern Province receives
mean rainfall in the range 140 to 250mm; Eastern Province normally receives rainfall 190mm to
390mm while the Coastal Strip receives mean rainfall in the range 300mm to 520mm.
The outlook for March-May 2007 (Figure 3) indicates that most parts of the country are likely to
experience near normal rainfall that will be characterized by poor distribution both in time and
space especially in the Arid and Semi-Arid Lands (ASALs). The Coastal areas of the country are
however expected to realize slightly enhanced rainfall while the performance in the Western
highlands, Central Rift Valley, Lake Victoria Basin and Central highlands including Nairobi is
expected to be normal with a slight tendency to below normal. The specific outlooks for individual
areas are as follows:
The following areas are expected to receive near-normal rainfall tending to below normal (Slightly
depressed):
i.
Nyanza Province (Kisii, Kisumu, Nyamira, etc);
ii.
Western Province (Busia, Butere, Mumias, Vihiga, Kakamega, Bungoma);
iii.
Central and southern parts of Rift Valley Province (Kericho, Kitale, Eldoret, Narok,
Naivasha, Nakuru, Maralal etc);
iv.
Central Province (Nyandarua, Nyeri, Thika, Murang’a, Kirinyaga);
v.
Nairobi Province (Kabete, Wilson Airport, Dagoretti, Moi AirBase etc); and
vi.
Parts of Eastern Province mainly bordering Central Province (Embu, Meru, Machakos
etc)
The following areas are expected to receive near-normal rainfall tending to below normal
(depressed):
i.
ii.
iii.
The northern parts of Rift Valley Province (Lodwar, Lokichoggio etc);
Most parts of Eastern Province (Moyale, Marsabit, Makindu, Isiolo, Kitui, Masaku, etc);
The western parts of the Coast Province (Taita Taveta, Tana River, parts of Kilifi etc);
and
Most parts of Northeastern Province (Garissa, Wajir, Mandera etc).
iv.
The Coastal Strip of the Coast Province (Malindi, Msabaha, Lamu, parts of Kilifi, Mombasa,
Mtwapa etc) is expected to receive near normal rainfall with slight tendency to above normal
(slightly enhanced).
6.
Expected Onset And Cessations





The Western parts of the country (Nyanza, Western and Southern parts of the Rift
Valley Provinces) are expected to experience the onset of the “Long Rains” in the second
to third week of March. The rains are expected to continue into June.
The Northwestern parts (Lokichoggio, Turkana, Lokitaung etc) are expected to start
receiving rainfall in the fourth week of March with cessation occurring in the fourth week of
April to the first week of May.
Onset over the highlands east of the Rift valley (Central and Nairobi Provinces as well
as parts of Eastern Province bordering the Central Province) is expected in the third to
fourth week of March while cessation is expected in the third to fourth week of May.
The Northeastern districts (Garissa, Wajir, Mandera etc) and Northern parts of Eastern
Province (Isiolo, Marsabit, Moyale etc) are likely to realize the onset during fourth week
of March while cessation is likely to occur in the first to second week of May.
The Central parts of the Rift Valley Province (Baringo, Laikipia, Samburu, Pokot,
Maralal etc) will experience the onset in the third to fourth week of March and cessation in
the second to third week of May.
3


7.
The southeastern lowlands (Taita Taveta, Kitui, Masaku, Voi, Makindu etc) are expected
to realize the onset in the third to fourth week of March. The cessation is expected in the
second to third week of May.
Onset over the Coastal strip (Mombasa, Mtwapa, Msabaha, Malindi, Lamu etc) is
expected in the third to fourth week of March. The rains are expected to continue into June.
Expected Distribution
The March to May 2007 rainfall is expected to be poorly distributed in time and space especially in
the eastern sector of the country.
 In Northwestern Kenya, the rainfall performance is likely to be normal in March but
depressed in April and May.
 In the Western highlands, Lake Basin, Central Rift and Central highlands including Nairobi,
the rainfall is likely to be near normal during March and April but depressed in May.
 The Northeastern districts are likely to experience depressed rainfall throughout the
season. However, the performance is likely to be better in Moyale and the neighbouring
areas.
 The Southeastern districts are expected to receive near normal rainfall in March but
depressed in April and May.
 The performance along the Coastal Strip is expected to be near normal in March and April
and enhanced in May.
8.
Potential Impacts
8.1
Agriculture and Food Security Sector
In the agricultural areas of Western and Central highlands where rainfall is expected to be near
normal, the farming communities should take advantage and maximize crop yield through
appropriate land-use management. It is advisable that farmers work closely with the Ministry of
Agriculture on ways to taking advantage of the expected near normal rainfall with a possible poor
distribution performance to maximize on the crop yield.
In the areas like Southeastern lowlands where rainfall is expected to be depressed, farmers should
also liaise with the Ministry of Agriculture to make use of fast maturing crops.
In view of this forecast, the Ministry of Agriculture is requested to advice farmers accordingly on
the right farming practices to undertake and the right seeds to plant.
8.2
Disaster Management Sector
Although the “Short Rains” (October to December) of 2006 improved forage and water in the
ASAL parts of the country, problems related to water and pasture scarcity are likely to occur once
again in the pastoral areas of the Northwestern and Northeastern parts in the coming season.
There is also potential for Human-Wildlife conflicts over limited water resources in these areas.
However, the rainfall deficiencies will not be to a large scale like the recent ones of 2005/06
period. These areas are undergoing recovery and so close monitoring of the conditions on the
ground and contingency measures are necessary in order to adequately build the resilience of
resident households and communities to cope with the situation.
The National Operations Centre is advised to take the necessary measures that would ensure
minimization of any negative impacts arising from the depressed and poorly distributed rainfall.
8.3
Energy Sector
The seven-folks and Turkwel catchments areas are expected to experience normal rainfall with a
slight tendency to below normal during the coming season (March-May). The energy sector is
therefore advised to optimize on the generation and distribution of hydroelectric power to
consumers.
4
8.4
Transport and Public Safety
Flash floods may still be experienced in some parts of Central, Western and Coast Provinces. This
may lead to transport problems especially during rush hours and more so in areas where the roads
become impassable when it rains. Slippery roads may also pose danger to motorists and
pedestrians. All should therefore take utmost care during the rainy period.
Although the western areas are expected to receive normal rainfall with a slight tendency to below
normal, cases of lightening strikes may still occur and the public is therefore advised not to shelter
under trees as this act renders them vulnerable to such strikes. Small aircrafts are advised to take
utmost care in the western routes and avoid flying through deep cumulus clouds especially in the
afternoon hours. Such clouds are associated with severe turbulence (rapid updrafts (vertical air
movement) / downdrafts (downward air movement) and cross winds) and lightning is common.
8.5
Water Resources Management Sector
Water resources for drinking, sanitation and industrial use in Nairobi and the better part of the
country should be well managed in case of any rainfall deficits. This should be more so in the
marginal areas in order to cater for the animal and human population needs and minimize the
likely conflict between them.
8.6
Local Authorities
Municipalities are advised to open up drainage systems to avoid water accumulation on the
surface that leads to flooding.
8.7
Health
Diseases associated with water scarcity and poor sanitation may emerge in areas expected to
receive depressed rainfall. Health authorities are, therefore, expected to be on the look out and
equip hospitals with necessary drugs to be able to deal with such situations as they arise.
The Ministry of Health is therefore requested use the seasonal climate outlook and take the
necessary mitigation measures such as stocking of appropriate drugs in order to cope with any
outbreaks of such water-related diseases.
8.8
Environment
There are possibilities of soil degradation through soil erosion in some areas. The Ministry of
Environment is therefore advised to advocate for planting of trees, grass, fodder and even Napier
NB
This forecast should be used in conjunction with regular updates issued by this
Department.
More detailed sector-specific forecasts may be obtained from Kenya
Meteorological Department on request.
grass in some of these areas and even terracing where the topography is steep.
5
Dr. Joseph R. Mukabana
DIRECTOR OF METEOROLOGICAL SERVICES & PERMANENT REPRESENTATIVE OF KENYA WITH THE WORLD METEOROLOGICAL ORGANIZATION
FIG. 2: MEAN MARCH-MAY SEASONAL RAINFALL DISTRIBUTION
FIG.3: MARCH-MAY 2007 RAINFALL FORECAST
6