1. WEATHER SUMMARY FOR JANUARY 1999
1.1 Rainfall Summary.
Most parts of the country experienced mainly sunny and dry weather conditions
in the month of January. Most stations in the country recorded rainfall
far below their long term means(L.T.Mís). The Southeastern districts and
the Highlands east of the Rift Valley including Nairobi area received rainfall
over a few places mainly in the second week of the month. The rainfall
performance over the western sector of the country was generally poor throughout
the month. The highest rainfall total of 117.4 mm was recorded over Kisumu
which was 106.1% of the stationís L.T.M followed by Kakamega with 110.2
1.2 SYNOPTIC SITUATION DURING JANUARY 1999
The pressures over the Southwestern Indian Ocean, Mediterranean region and the southern Atlantic Ocean were generally weak during the month. In contrast, pressures over the Arabian peninsular remained relatively strong.
Thus, the Inter-Tropical Convergence Zone (ITCZ) was situated to the southern and central parts of Africa, rendering most parts of the country sunny and dry.
2. DAIRY FARMING WEATHER CONDITIONS DURING JANUARY 1999.
Dry and hot weather conditions were dominant in most areas of central rift with Nakuru and Eldoret recording 13.4 and 38.3mm of rainfall respectively. Temperatures of 28 degrees Celsius and above were recorded over Nakuru and Kitale areas while Eldoret was cooler with 25 degrees Celsius in most of the days. Some of the drinking water points may have dried up as a result of these conditions. Milk production is also likely to go down due to inadequate dry pasture as there is no replenishment following the setting in of the dry weather conditions characteristic of this time of the year.
3. EXPECTED SYNOPTIC SITUATION DURING FEBRUARY 1999.
Due to the cooling of Sea Surface Temperatures(SSTs) over the Mediterranean sea and some parts of southern Atlantic Ocean, a gradual build-up of pressures over these regions will continue and achieve near normal intensities towards the end of the month. This will lead to a slight eastward shift of the Meridional (north-south) arm of the ITCZ and give rise to some little improvement of rainfall performance over the western sector of the country.
Sea surface temperatures over the Mozambique channel will remain warm during the month of February and hence the pressures over the Southwestern Indian Ocean will remain relatively weak. The pressures over the Arabian region are expected to start weakening gradually though the Arabian ridge will retain a continental axis thus enhancing surface diffluence over the eastern sector of the country.
As a result the zonal (east-west) arm of the ITCZ will continue being located far to the south covering southern Tanzania, Madagascar areas and other south African countries but diffuse. Occasional formation of tropical cyclones (or deep lows) over the southwestern Indian Ocean will further reduce the moisture influx into the eastern parts of our country.
In general, sunny and dry weather conditions will prevail over
the eastern sector of Kenya.
4. EXPECTED WEATHER IMPACTS OF DAIRY PRODUCTION DURING THE MONTH OF FEBRUARY 1999.
4.1 The Lake Victoria Basin, Highlands West of the Rift Valley and Central Rift Valley will experience occasional afternoon showers and thunderstorms spread over few places. The rainfall performance will be below normal. The level of pasture production is likely to be affected and in turn, will lower dairy production. In order to maintain production levels, Dairy farmers may have to supplement with artificial feeds from the suppliers.
4.2 The Northwestern and Northeastern districts will experiencemainly sunny and dry conditions. Farmers within these areas may have to destock due to lack of adequate water and dry pasture.
4.3 The Southeastern, highlands east of the Rift valley and Nairobi area will experience mainly long sunny periods with occasional afternoon showers covering few places. The quality of pasture is likely to have deteriorated due to the persistent of dry and hot weather conditions. However, areas near the mountains are likely to maintain relatively higher amounts of pasture to feed the animals and thus maintain the level of production.
4.4 The Coastal areas will experience mainly sunny intervals
with occasional morning showers spread over few places.
KEY OF SCIENTIFIC WORDS USED
INTER-TROPICAL CONVERGENCE ZONE (ITCZ): An extensive area of seasonal low pressure caused by the seasonal migration of the sun and associated with heavy rainfall, lightning and thunder.
HIGH PRESSURE SYSTEM: An area associated with clear skies or fine weather clouds.
RIDGE: Asymptote of high pressure from which winds flow outward.
TROUGH: Asymptote of low pressure towards which winds flow and meet.
MOST PLACES: Between 66% and 100%.
SEVERAL PLACES: Between 33% and 66%
FEW PLACES: Between 0 and 33%