Head Office:
Plot 67 – 75
Clement Hill Road
KAMPALA
E-mail: [email protected]
Tel: +256 414 251798
Fax: +256 414 251797
P.O. Box 7025
KAMPALA
UGANDA NATIONAL METEOROLOGICAL AUTHORITY
Date: 7th January, 2016
REVIEW OF THE RAINFALL PERFORMANCE IN DECEMBER, 2015 AND
THE OUTLOOK FOR JANUARY 2016
1.0
Review of rainfall performance in December 2015
The December 2015 rainfall analysis indicated that most parts of the
country experienced general reduction in rainfall compared with Long Term
Mean (LTM) rainfall.
Reduction in rainfall was evident in northern parts of the country but
moderate rainfall was experienced in South-western, Central and Eastern
parts of Uganda with Kituza station in Mukono recording the highest
monthly total rainfall of 225.1mm followed by Serere with 209.6mm,
Kampala with 192.1mm and Buginyanya in Bulambuli district with
150.4mm.
In terms of percentages of observed rainfall compared with their respective
Long Term Mean (LTM) rainfall, Serere registered the highest with 374%
followed by Buginyanya (358%), Ntusi in Sembabule (324%) and Soroti
(243%). The lowest of 13% was observed at Arua weather station in north
western Uganda.
During the month of December, Bushenyi, Buginyanya and Jinja weather
stations reported 15 rain days (days with more than 1.0mm), registering the
highest number of rain days in the country. They were followed by Entebbe
and Kabale with 14 rain days each, while Kituza and Kampala reported 13
rain days. The lowest rain days were observed at Arua weather station with
only 2 rain days in the entire month of December. (See Figure1&2).
It was noted that most weather stations in northern Uganda experienced
their cessation of rainfall during mid-December while the rest of the stations
observed the reduction of rainfall towards the end of December, 2015.
It should be also noted that several places across the country experienced
high temperatures during the last week of December and first week of
January. This was to due to the following reasons: Presence of High Pressure patterns over Southern Africa continent
that occurred during end of December and first week of January
which drove the dry and warm air to our country and this rendered
the Zonal arm of the ITCZ diffuse leading to reduced wet conditions.
1
 Inflow of dry and dusty winds from Sahara desert and Southern
Continental summer winds which prevailed over Uganda during that
period and hence causing warm and hazy conditions over the country.
Figure 1: Rainfall performance in December, 2015
Figure 2: Spatial rainfall distribution in December, 2015
2.0 Review of Weather/Climate systems
performance during December 2015
that
affected
rainfall
During the month of December 2015, Sea Surface Temperatures (SSTs)
anomalies in the Eastern and Central Equatorial Pacific Ocean continued to
increase and were mainly positive, an indication that El Niño conditions are
still persistent in the Pacific Ocean. The northern hemisphere pressure
systems intensified significantly while the southern hemisphere pressure
2
systems relaxed. This condition allowed the rain bearing Inter Tropical
Convergence Zone (ITCZ) to further shift southwards to its current position
in the southern hemisphere hence reducing wet activities across most parts
of the country.
3.0
Experienced Impacts during December 2015
The moderate rainfall experienced in most parts of the country impacted
both positively and negatively on various sectors of the economy;
 In Agricultural sector, enhanced soil moisture conditions improved crop,
pasture and foliage conditions
 The rains also enabled the replenishment of water reservoirs
 In some areas, the current rainfall resulted into serious violent winds,
hail and thunderstorms that destroyed crops, houses and other
properties;
 Mild floods were reported in several areas of the country but were more
pronounced in Kiboga, Katakwi, Amuria and Serere districts hampering
movement of people and goods. In Kapelebyong and Obalanga in Amuria
district, heavy rains caused water logging resulting in the loss of cassava
and sweet potatoes;
 In transport sector, some bridges were washed away by heavy rains
hampering movement of travellers and business. In Buhweju for
example, three bridges were destroyed. Hoima road was closed due to the
collapse of bridge on R. Kafu.
 Some districts like Hoima, Kibale, Kampala and Busia reported
incidences of Cholera outbreak attributed to poor sanitation during the
wet season.
4.0 Weather/climate systems that are expected to influence rainfall
outlook in January 2016
a) Current El Niño 2015-16 event
The El Niño 2015-16 episode which has been evolving since June 2015 has
reached its peak (100%). It has been ranked to be among the three strongest
El Niño events since 1950. The current El Niño is likely to persist well into
February 2016 (figure 3).
Figure 3: Expected El Niño development season per season
The Sea Surface Temperature (SST) anomaly map for December shows warm
3
SST anomalies extended across nearly the entire equatorial pacific Ocean.
Compared with November, warm anomalies decreased slightly in some areas
along the equator, and over the north east of the pacific ocean. It should be
noted that El Niño indicators, notably sea surface and sub-surface
temperatures, westerly wind anomalies in the central Pacific, and cloudiness
near the Date Line, have remained well above El Niño thresholds though
showing signs of easing. Indian Ocean sea surface temperatures have
remained very much warmer than average across the majority of the Ocean
(Figure 4).
It should be noted that East African region didnot experience severe
heavy rains as it was projected due to the general warming of Indian
Ocean sea surface temperatures that remained very much warmer
than average across the majority of the basin since October 2015 to
date. This led most of moist air over East Africa to converge over the
ocean. However, much of Uganda receieved above normal (enhanced)
rainfall and the seasonal climate forecast that was issued in early
September 2015 by UNMA was in line with the oberved weather
conditions over several places of the country.
Figure 4: 13th December 2015 – 9th January 2016 monthly average SST anomalies
in the Equatorial Pacific Ocean and Indian Ocean
b) Inter Tropical Convergence Zone (ITCZ)
It should be noted that during January, 2016 the northern hemisphere high
pressure systems are expected to intensify significantly, while the southern
hemisphere systems are expected to relax allowing the rain making
mechanism (ITCZ) to continue shifting southward from its current position.
This may cause rains to concentrate in the southern sector of the country
during the month of January.
Based on the above information and other regional prediction indicators,
4
UNMA has come up with a climate forecast update for the months of
January 2016 as follows:5.0 Rainfall Outlook for January 2016
Overall, the forecast indicates that several places across the country are
expected to experience dry spells with hazy conditions and intermittent
rains during January 2016. However, a few areas around Lake Victoria
basin and south western districts are expected to experience episodic
isolated wet spells influenced by local inland systems associated with large
lakes and complex topography; as well as SST and circulation anomalies
over the neighboring Atlantic and Indian Oceans.
The breakdown of the forecast for each region is given as follows:
a) Western region

South Western: (Kisoro, Kabale, Rukungiri, Kanungu, Ntungamo,
Mbarara, Kiruhura, Isingiro, Ibanda, Bushenyi, Buhweju, Mitooma,
Sheema, Rubirizi and Kasese) districts
The region is currently experiencing dry spells with intermittent rains.
This situation is expected to continue over several places until around
the end of January. However, occasional light to moderate rains are
expected to be experienced over isolated places of Kabale, Kisoro and
Kanungu during the mid of January 2016.

Central Western: (Bundibugyo, Ntoroko, Kabarole, Kyenjojo, Kyegegwa,
Kamwenge, Masindi, Buliisa, Hoima and Kibaale) districts
The region is expected to experience generally dry spells with intermittent
rains for the month of January. Occasional light to moderate rains are
however likely to be experienced over isolated places especially closer to
the Mt. Rwenzori.

North Western: (Moyo, Yumbe, Adjumani, Arua, Terego, Zombo, Nebbi,
Koboko) districts
The region is expected to experience generally dry conditions during the
forecast period of January.
b) Central Uganda

Western Parts of Central:
Nakaseke Kiboga, Mubende,
Lyantonde, and Rakai) districts
(Nakasongola, Luwero, Kyankwanzi,
Sembabule, Lwengo, Bukomasimbi,
The region is expected to experience dry spells with intermittent rains for
the month of January.

Eastern parts of Central: (Mukono, Buikwe, Kayunga, Buvuma) districts
The region is expected to experience dry spells with intermittent rains
5
over several places for the month of January.
c) Lake Victoria Basin

Central and Western Lake Victoria Basin: (Kalangala, Buvuma,
Kampala, Wakiso, Masaka, Mpigi, Butambala, Kalungu, Bukomansimbi,
Gomba, and Mityana) districts
The region is expected to experience generally intermittent rains over
several places during January 2016.

Eastern Lake Victoria and South Eastern: (Jinja, South Bugiri and
Busia) districts
The region is currently experiencing generally occasional light rains. This
situation is expected to continue during the month of January.
d) Eastern region

Eastern Central: (Kamuli, Iganga, North Bugiri, Luuka, Namutumba,
Buyende, Kaliro and Tororo) districts.
The region is expected to experience generally dry spells with intermittent
rains during the month of January. Occasional light to moderate rains
are however, likely to be experienced over isolated places during mid
January.

Eastern Central: (Pallisa, Budaka, Mbale, Sironko, Manafwa, Bududa,
Kapchorwa, Kumi, Kaberamaido, Soroti, Serere, Amolatar, Butaleja,
Bulambuli, Kween, Bukedea, and Ngora) districts.
The region is expected to experience occasional light to moderate rains
over several places during the month of January.

North Eastern region: (Katakwi, Otuke, Moroto, Kotido, Nakapiripirit,
Abim, Napak, Amudat, Amuria, and Kaabong) districts
The region is expected to experience generally dry conditions for the
month of January.
e) Northern region

Northern Parts: (Gulu, Apac, Lira, Kitgum, Pader, Amuru, Lamwo, Nwoya,
Oyam, Kole, Dokolo and Kiryandongo) districts
The region is expected to experience generally dry conditions for the
month of January.
6.0 Potential impacts for January climate outlook
The sunny and dry spells expected over several areas of the country will
have the following impacts;

In pastoral areas especially in cattle corridor, the dry conditions will lead
to further reduction in foliage and pasture for livestock
6





Water resource availability is likely to decline especially in cattle corridor
areas
There is a high risk of air borne diseases due to dust and dust storms in
most areas especially Karamoja region as a result of dry conditions
In some areas irrigation can be used for short maturing crops like
vegetables
The dry spell can be used for proper drying of produce like cereals
Land preparation is encouraged in order to utilise the long rains of March
to May 2016
Festus Luboyera
EXECUTIVE DIRECTOR
7