REPUBLIC OF MINISTRY OF ENVIRONMENT AND MINERAL RESOURCES KENYA METEOROLOGICAL DEPARTMENT Dagoretti Corner, Ngong Road, P. O. Box 30259, , Kenya, Telephone: 254-20-3867880-5, Fax: 254-20-3876955/387373, E-mail:[email protected]

REVIEW OF RAINFALL DURING THE “LONG RAINS” (MARCH TO MAY) 2011 SEASON AND THE OUTLOOK FOR THE JUNE-JULY-AUGUST (JJA) 2011 PERIOD

Issue Date: 24/05/2011 Ref No: KMD/FCST/5-2011/SO/02

1. SUMMARY

Review of the performance of the “Long Rains” (March-April-May) 2011 season • The March to May 2011 seasonal rainfall has almost ceased over most parts of the country. As per the prediction, the rainfall was highly depressed and poorly distributed, both in time and space, over most parts of the country. This was more so over the North-eastern parts of Kenya and the Coastal strip where most meteorological stations recorded less than 50 percent of their seasonal Long-Term Means (LTMs) for March to May. The rainfall was also characterised by late onset in some parts of the country. A few stations namely , Embu, , Kisii, , , , and , however, recorded rainfall that was within the near-normal category (between 75 and 125% of their seasonal LTMs) but the distribution was also generally poor with a prolonged dry spell in April.

• The poor rainfall performance impacted negatively on the agricultural and pastoral activities in various parts of the country. The water levels in the hydroelectric power generation dams also went down following the generally poor rainfall performance in the catchment areas.

The Outlook for June-July-August period The climate outlook for June-July-August (JJA) 2011 season indicates that the Western highlands (Kericho, , Kakamega, Kisii, Kitale, ) are likely to receive near normal rainfall with a tendency to above normal while generally depressed rainfall is likely to be experienced over the Central Rift Valley (, Nakuru, ) and the coastal Strip (, Mtwapa, Matuga, , , etc). The central highlands including Nairobi area are expected to experience cool, cloudy and drizzly conditions. Rainfall emanating from western Kenya may occasionally spread to the Central districts and Nairobi. Fairly low temperatures are also expected to be experienced in Central Rift Valley (Narok, Nakuru, Nyahururu, Timboroa) and parts of the highlands west of the Rift Valley (Kericho and Eldoret).

2. REVIEW OF MARCH-MAY (LONG-RAINS) 2011 SEASONAL RAINFALL

The “Long Rains” (March-April-May) 2011 seasonal rainfall has almost ceased over most parts of the country. An assessment of the rainfall recorded from 1 March to 22 May 2011 (Figure1a-1d) indicates that the rainfall performance was generally poor over most parts of the country. The poor performance was reflected both in the rainfall amounts received and the distribution in time and space. The total rainfall amounts received over most parts of the country were well below 75% of their LTMs. The northeastern parts of Kenya and the Coastal areas recorded the most depressed rainfall. Mombasa, , Lamu, , and stations for example recorded less than 40% of their seasonal LTMs.

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Kitale, Embu, Machakos, Kisii, Lodwar, Nakuru, Voi, Kericho and Kakamega were the only stations in the country that recorded rainfall above 75 percent of the LTMs. The stations recorded 97%, 90%, 89%, 87%, 85%, 84%, 82%, 79% and 78% of their respective LTMs.

The seasonal rainfall was characterized by long dry spells and low rainfall values in different parts of the country especially in April. A few rainfall storms were however recorded during the period. The heaviest storm of 101.5mm was recorded at Embu station on 27th April. The same station recorded 57.3 and 76.6 mm on 4th and 7th May 2011 respectively. The second heaviest storm amounting to 100.6mm was recorded at Machakos station on 18th March. The same station recorded 62.2mm the following day (19th March). Other rainfall storms recorded during the season include 73.9mm and 91.5 mm recorded at Voi and Kisumu on 24th and 31st March 2011 respectively, and also 55.3 and 60.4 mm recorded at Meru and Kakamega on 21st and 30th April 2011 respectively.

Up to 22nd May, Kisii Meteorological station recorded the highest rainfall amount of 594.5mm, which was 87% of the LTM. Kericho, Kakamega, Embu, Kitale, Kisumu, Msabaha, Meru, , Nakuru, Dagoretti Corner and Mtwapa stations recorded 532.4mm (79%), 530.6mm (78%), 510.6mm (90%), 431.1mm (97%), 347.2mm (64%), 292.9mm (55%), 276.4mm (59%), 274.6mm (63%), 258.2mm (84%), 257.0mm (53%) and 250.3mm (41%) respectively. The rest of the station recorded less than 250mm.

3. EXPERIENCED IMPACTS

The poor rainfall performance experienced over most parts of the country impacted negatively on various sectors such as agriculture and livestock among others. These impacts included:

• Poor crop performance in the southeastern lowlands and parts of central and western highlands as well as central Rift Valley; • Lack of pasture for livestock in the pastoral areas, and more so in the northwestern and northeastern Kenya; • Reduced water levels in the Seven-Forks hydroelectric power generation dams due to depressed rainfall in the catchment area of Tana River in the central highlands. • Problems related to water scarcity. This has also led to outbreak of diseases like Cholera in some parts of the country; • Loss of animals in some of the pastoral areas of the country as a result of the prevailing drought conditions.

4. FORECAST FOR JUNE-JULY-AUGUST 2011

The climate outlook for June to August 2011 is based on regression of sea surface temperatures (SSTs), Sea Surface Temperature (SST) gradients and the expected evolution of global SST patterns as well as upper air circulations patterns on Kenyan rainfall. The expected performance is also based on statistical analysis of past years, whose characteristics were found to be similar to this year.

During the June to August (JJA) season, rainfall is normally concentrated over the western and coastal parts of the country (Figure 2). The forecast for June to August 2011 indicates that the Western highlands and the Lake Victoria Basin are likely to receive near-normal rainfall with a tendency towards above normal (enhanced rainfall), while the central Rift Valley as well as the Coastal strip is expected to receive generally depressed rainfall. The rest of the country is expected to remain generally dry (Figure 3). Most areas in the Central Highlands and Nairobi area are expected to experience cool and cloudy conditions with occasional drizzles or light rains. The specific outlooks for individual areas are as follows:

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The Western Highlands (Kitale, Kericho, Nandi, Eldoret, Kakamega, , Butere/, etc) and Lake Victoria Basin (Kisumu, Nyando, Kisii, Busia) are likely to receive near-normal rainfall tending to above normal (enhanced) rainfall.

The Central Rift Valley (Nakuru,Narok, , Ol Kalao, Nyahururu) and the Coastal strip (Mombasa, Mtwapa, Msabaha Malindi, Lamu etc) is likely to receive near-normal rainfall with a tendency to below normal (generally depressed) rainfall.

The Central Highlands (, , Embu, Meru, Murang’a); Nairobi Area (Dagoretti, Kabete, Wilson, International Airport, Eastleigh etc); will experience cool and cloudy conditions with occasional light rains. Occasional prolonged hours of overcast skies (cloudy conditions) resulting to cold and chilly conditions are expected. The daytime temperatures are expected to be slightly warmer than average during the period.

Northwestern (Lodwar, Lokichoggio, Lokitaung, North Horr); Southeastern lowlands (Machakos, , , , , Voi, Taveta) and Northeastern Kenya (Wajir, , Garissa, Moyale, Marsabit, , Garbatulla) are expected to remain generally dry throughout the period. The southeastern regions bordering the central districts (Machakos area) are likely to experience occasional cool and cloudy conditions with light rains.

5. POTENTIAL IMPACTS EXPECTED The following are the expected impacts during the coming season: a. Agriculture and Food Security Sector Good crop performance is expected in the western parts of the country where good rainfall performance is expected. This will be more so in Trans Nzoia and Uasin Gishu districts where near normal to enhanced rainfall is expected. b. Disaster Management Sector In the Arid and Semi-Arid Lands (ASALs), problems related to water scarcity and lack of pasture for livestock is expected to deteriorate following the poor rainfall performance during the “Long Rains” (March-May) 2011 season and the expected sunny and dry condition in June-July-August 2011. Conflicts between Human and wildlife and also between communities themselves are also expected to increase in these areas. Strategic should therefore be put in place to avert such incidences.

The expected cool and chilly conditions force people to light jikos in houses with closed windows and doors. This is a recipe for inhaling the poisonous carbon monoxide that is generated by the burning charcoal and can lead to fatalities. c. Health Sector In areas such as Nairobi, Central highlands, Central Rift Valley and parts of the highlands west of the Rift Valley, cases of respiratory diseases like asthma, pneumonia and common colds (flu) are expected to be on the increase due to the expected cool/cold conditions. The general public is advised to put on warm clothing during this period to minimize chances of being affected. Health authorities are hence expected to be on the lookout to facilitate supply of drugs necessary to combat these diseases. d. Transport and Public Safety During the night and early morning, foggy and drizzly conditions are likely to result in reduced visibility in Nairobi, and parts of Rift Valley. The frequency for such

3 occurrence may be high along the Nairobi- highway. Motorists driving on such roads are advised to drive carefully in order to minimize accidents that would result from such weather conditions.

Occasionally, thick fog and associated very poor visibility may render landing at Jomo Kenyatta International Airport (JKIA) impossible. This may lead to diversion of aircrafts to other airports. Afternoon flights on the Nairobi-Kisumu route are also advised to be weary of turbulent conditions around Kericho due to thick cumulonimbus cloud formations. Small aircrafts should avoid such areas of thick clouds.

Pollution mainly resulting from erosion by strong winds in the Arid and Semi Arid Lands (ASALs) is likely to reduce visibility in the ASALs and affect small aircrafts flying in low levels, especially over Garissa and Marsabit areas where the low level jet steams have their core. e. Water Resources Management and the Energy Sectors The poor performance of “Long Rains” March-May 2011 led to lower water levels in hydro- electric power generating dams and also reduced water capacity for domestic use. This situation is likely to deteriorate during the coming three months due to the expected generally dry weather conditions over most of central highlands including Nairobi. f. Environment The risk for forest fires in the Arid and Semi Arid Lands (ASALs) remains quite high due to the expected sunny and dry conditions combined with relatively strong winds during June-August period.

DR. JOSEPH R. MUKABANA DIRECTOR OF METEOROLOGICAL SERVICES & PERMANENT REPRESENTATIVE OF KENYA WITH WMO

Figure 1a: %March 2011 Rainfall Performance Figure 1b: %April 2011 Rainfall Performance

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Figure 1c: %May 2011 Rainfall Performance Figure 1d: %MAM 2011 Rainfall Performance

Figure 2: Normal JJA Rainfall Distribution Figure 3: JJA 2011 Rainfall Outlook

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