Ref.
No.
Met/
1622
Date
26 April 2007
REPUBLIC OF KENYA
MINISTRY OF TRANSPORT
KENYA METEOROLOGICAL DEPARTMENT
Dagoretti Corner, Ngong Road, P. O. Box 30259, 00100 (GPO) Nairobi, Kenya,
Telephone: 254-20-3867880-7, Fax: 254-20-3876955/3877373,
E-mail:director@meteo.go.ke
WEATHER REVIEW FOR THE LAST SEVEN DAYS, 19TH TO 25TH APRIL 2007 AND
THE EXPECTED CONDITIONS DURING THE NEXT SEVEN DAYS VALID, 27TH APRIL
TO 3RD MAY 2007.
1. WEATHER HIGHLIGHTS
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Heavy rainfall was recorded over south Coast and some parts of Central highlands including Nairobi
area towards the end of the last seven-day period (19th to 25th April 2007). The Western sector on the
other hand experienced a drastic reduction towards the end of the review period after t he heavy
rainfall that pounded the River Nzoia catchment areas leading to serious flooding in the flood-prone
areas of Bundalangi. Dry conditions persisted in the Northeastern areas of Garissa and Southeastern
lowlands, around Voi that just recorded 11.7mm during the last day of the review period.
Maximum (daytime) temperatures dipped significantly over most parts of the country and especially
the Central highlands following the persistent overcast skies and continuous rainfall that prevailed
especially towards the end of the review period. The minimum (nighttime) temperatures remained fairly
high even in the Central Rift Valley.
The forecast for the next seven days (27th April to 3rd May 2007) indicates that most parts of the
country are likely to experience a reduction in rainfall amounts and distribution especially at the
beginning of the forecast period.
2. WEATHER SUMMARY
2.1 Rainfall review
A significant increase in rainfall amounts was recorded in the southern Coastal Strip and the
Central highlands including Nairobi area towards the end of the last seven-day period (19th to 25th
April 2007). A number of stations in these areas experienced short-lived intense rainfall. On 24th
April 2007, Mtwapa and Msabaha meteorological stations at the Coast recorded 83.5 and 67.7mm
of rainfall respectively while Moi Airbase and Wilson Airport meteorological stations both in Nairobi
recorded 50.3 and 45.4mm respectively. In western Kenya, most stations recorded a drastic
reduction in rainfall towards the end of the review period. This followed the heavy rainfall in the
River Nzioa catchment at the beginning of the period that caused serious flooding in the floodprone area of Bundalangi. During that period, Butere station recorded 61.0mm in a day (on 20 th
April). Voi meteorological station in southeastern lowlands recorded 11.7mm on the last day of the
review period after a prolonged dry spell. Dry conditions persisted in Garissa area of North eastern
Kenya.
Thika station in Central Kenya recorded the highest seven-day rainfall total of 117.1mm while
Mtwapa, Embu, Msabaha, Wilson Airport, Butere, Moi Airbase, Dagoretti Corner, Jomo Kenyatta
International Airport, Kisii, Machakos, Marsabit, Meru, Mombasa, Laikipia Airbase and Malindi
stations recorded 108.1, 102.5, 88.9, 88.7, 84.5, 82.3, 80.4, 76.6, 75.0, 66.6, 60.4, 60.2, 57.5,
56.3 and 53.8mm respectively. The rest of the stations recorded below 50mm of rainfall as seen in
figure 1.
2.2 Temperature review
Most parts of the country recorded a significant reduction in maximum (daytime) temperatures
towards the end of the review period. This came as a result of overcast skies and continuous
rainfall. The temperatures at Dagoretti Corner for example fell to below 20°C (19.4°C) during the
last day of the review period. The Northeastern and Northwestern areas of the country however
continued to record high maximum temperatures of above 36°C. The highest daily maximum
temperature of 37.3°C was recorded at Garissa station. The same station recorded the highest
seven-day average maximum temperature 36.5°C.
Minimum (nighttime) temperatures continued to be fairly high over most parts of the country
including Central Rift Valley. The temperatures were as high as 11.9°C at Nyahururu station. The
station still recorded the lowest seven-day average minimum temperature of 9.5°C. (see details in
figure 2).
NB: Maximum temperature data for Marsabit and Kericho stations was not available.
3. EXPECTED DEVELOPMENTS (FROM 27TH APRIL TO 3RD MAY 2007)
The forecast for the seven-day period (27th April to 3rd May 2007) is based on moderately strong
pressures expected over the South Atlantic Ocean (St. Hellena) and the Mediterranean Sea
weakening as the forecast period progresses; weak pressures over the Mozambique channel
strengthening as the forecast period progresses; strong pressures over South Western Indian
Ocean (Mascarene) weakening with time and generally weak pressures over the Arabian region
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strengthening slightly with time. Increased convergence of winds in the upper levels is expected
and this will highly suppress convection and the formation of significant rain clouds.
In view of these developments, it is expected that most parts of the country are likely to experience
a reduction in rainfall amounts especially at the beginning of the forecast period.
4:
FORECAST FOR THE NEXT SEVEN DAYS FROM 27TH APRIL TO 3RD MAY 2007
Based on the aforementioned developments, it is expected that:
The Lake Victoria basin, Highlands west of the Rift Valley and Central Rift Valley (Kitale,
Kakamega, Kisumu, Kisii, Kericho, Eldoret, Nakuru, Narok, Nyahururu, etc) will experience
afternoon showers and thunderstorms over few places increasing to several places as the period
progresses. Occasional night showers and thunderstorms are also expected to occur over few
places.
The Central highlands including Nairobi area (Nyeri, Meru, Dagoretti, Embu, etc) will
experience morning rains over few places and afternoon/night showers over several places
reducing to few places as the period progresses.
The Northwestern districts (Lodwar, Lokitaung, Lokichoggio, etc) will experience generally
sunny conditions with afternoon showers and thunderstorms over few places.
The Northeastern districts (Marsabit, Moyale, Mandera, Wajir, Garissa etc) and
Southeastern lowlands (Voi, Makindu, Machakos etc) are expected to experience morning
rains/showers and occasional afternoon showers over few places.
The Coastal region (Mombasa, Kilifi, Malindi, Lamu etc) will experience morning showers over
several places occasionally reducing to few places. Occasional afternoon/night are expected to
occur over few places. The south coast is expected to experience relatively heavier rainfall than
the north coast.
N.B: This forecast should be used in conjunction with the daily 24-hour forecast
issued by this Department
KEY OF SCIENTIFIC WORDS USED
High Pressure System (Anticyclone): An area associated with clear skies or fine
weather.
Ridge: An elongated area of high pressure from which winds flow outward.
Most Places:
Between 66% and 100%.
Several Places:
Between 33% and 66%
Few Places:
Between 0 and 33%
P. G. AMBENJE
FOR: DIRECTOR OF METEOROLOGICAL SERVICES
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