Issued on 27th February, 2014
No. 10 Special Issue: March – May 2014 Season
Summary
The Bulletin contains a brief review of the performance of September to December (OND), 2013 short rainfall season, the ongoing
seasonal rains over the unimodal areas and outlook for the March to May (MAM), 2014 long rainfall season (Masika) and
advisories on the likely impacts. Outlook for March to May (MAM), 2014 rainfall season indicates that most parts of the bimodal
areas (Lake Victoria basin, northeastern highlands and northern coast) are expected to receive normal to above normal rains over
most parts except for northern coastal areas where below normal rains are expected. On the other hand, the ongoing seasonal rains
over the unimodal areas are expected to be normal to above normal.
parts of the bimodal areas are expected to receive below normal to near normal rainfall.
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ERF
O RMANCE
WEATHER DURING MARCH - MAY 2014
This Outlook is relevant only for seasonal time scales and over relatively large areas and month-to-month variations may occur. It should be
noted that heavy and short duration episodic events are common even in below normal rainfall condition.
October to December 2013 Rainfall Season
During the October to December 2013 short rains (Vuli), most parts of
the country featured normal rainfall. However, some parts of the
coastal and central areas experienced below normal rainfall. Generally
the season was characterized by poor temporal and spatial rainfall
distribution particularly over much of Northeastern highlands and
northern coast areas (Manyara, Arusha, Kilimanjaro, Dar es salaam)
and Musoma over the Lake Victoria Basin. Figure 1 below shows the
rainfall performance during the Vuli season in various areas of the
country as percentages of long average obtained from Satellite
Rainfall Estimates (RFE) merged with gauge data from Tanzania
rainfall stations network.
This outlook is based on a review of the current and expected state of
global climate systems and their likely impacts on the upcoming
March to May (MAM), 2014 rainfall season in the country. Currently,
the Sea Surface Temperatures (SSTs) indicate anomalous warming
condition over the Southwestern Indian Ocean and expected to
gradually increase throughout the season. Meanwhile, near normal
developing into slightly warm SSTs condition over western Indian
and equatorial Pacific Oceans are expected during the season. On the
other hand, cooling condition over eastern Atlantic Ocean is likely to
be sustained throughout the season. These conditions are likely to
favor enhanced westerly winds over western and central parts of the
country particularly during the months of April to May, 2014 thus
enhancing moisture inflow from the Congo Basin. Current anomalous
warming condition off the southern tip of Africa is expected to
continue during March to May 2014 thus likely to weaken the
southern high pressure systems. These conditions suggest the
possibility of diffused Inter-Tropical Convergence Zone (ITCZ) over
the coastal areas of the country leading to suppressed rainfall.
However, towards the end of the season and beyond, enhanced
easterly winds are likely to influence enhanced occasional rains over
the coastal areas.
.
RAINFALL OUTLOOK DURING
MARCH - MAY 2014
From the prevailing climate systems explained above, the
March - May 2014 rainfall outlook is as described below
(i) Long rains (Masika)
Fig. 1: October to December, 2013 rainfall performance as percentage of
long term average rainfall (mm).
The long rainfall season in the northern sector (bimodal areas) of
Tanzania isexpected to commence in the first week of March, 2014 as
explained below:
No 10
Special Issue March – May 2014 Season
Lake Victoria basin (Mwanza, Mara, Geita, Shinyanga, Simiyu and
Kagera regions): Rains are expected to start in the first week of
March, 2014 in Kagera and Geita regions and gradually spreading to
Mwanza, Mara, Shinyanga and Simiyu regions in the second week of
March. Rains in these areas are likely to be above normal except over
eastern parts of Mara where normal to above normal rains are
expected. Northern coast and hinterlands (Dar es Salaam, Tanga,
Coast, northern part of Morogoro regions and isles of Unguja and
Pemba): Rains are expected to start during the second and third week
of March, 2014. The Masika rains over much of these areas are likely
to be below normal and poorly distributed. However, most parts of
Morogoro region are likely to experience normal to above normal
rainfall. Northeastern highlands (Kilimanjaro, Arusha and Manyara
regions): The onset of rainfall is expected during the second to third
week of March, 2014 and the rains are likely to be normal to above
normal over much of these areas except for some parts of Kilimanjaro
region (Same district and surrounding areas) where below normal
rains are likely to occur. The March - May 2014 rainfall outlook
is as shown in figure 2 below.
Fig. 1: Rainfall outlook for March to May 2014
(ii) Seasonal Rains (Msimu): November 2013 to April
2014
Western areas (Kigoma, Tabora and Katavi regions): The ongoing
seasonal rains over these areas are expected to be mainly normal with
pockets of above normal over northeastern parts of Tabora region.
These rains are expected to recede during the fourth week of April,
2014. Central areas (Singida and Dodoma regions): The ongoing
seasonal rains are likely to be normal to above normal. These rains are
expected to recede during the second week of April, 2014. Southern
coastal areas (Mtwara and Lindi regions): The ongoing seasonal
rains are likely to be normal to above normal except for northeastern
parts of Lindi where below normal rains are expected. Cessation of
rains is expected during the third week of April, 2014. Southern
areas (Ruvuma): The ongoing seasonal rains in these areas are likely
Issued on 27th February, 2014
to be normal to above normal. Cessation of the rains is expected
during the third week of April, 2014. Southwestern highland areas
(Mbeya, Iringa, Njombe, Rukwa and southern part of Morogoro
regions): The ongoing seasonal rains in most of these areas are likely
to be normal to above normal except for Njombe region where above
normal rains are expected. These rains are expected to end during the
first week of May, 2014.
IMPACTS AND ADVISORY
Agriculture and Food Security
Sufficient soil moisture is expected over most areas of the country
except along the Coast, Unguja and Pemba isles and few areas of the
northeastern highlands where soil moisture deficit is likely to occur.
Areas over the Lake Victoria basin (Kagera, Geita, Mwanza,
Shinyanga, Simiyu and Mara regions) together with Morogoro region,
farmers are advised to continue with their normal agricultural
activities. However, above normal rains are likely to produce
excessive soil moisture conditions which can impede crop production,
therefore farmers are encouraged to seek advise from extension
officers in their respective areas. Over the northern coast (Dar es
Salaam, Pwani and Tanga regions including Unguja and Pemba isles)
and north eastern highlands (Manyara, Arusha and Kilimanjaro
regions), farmers are advised to plant drought tolerant and early
maturing crops. On the other hand, sufficient soil moisture is
expected over unimodal areas (Kigoma, Tabora, Rukwa, Katavi,
Dodoma, Iringa, Lindi, and Mtwara together with southern parts of
Morogoro region); farmers are advised to continue with their normal
cropping season activities and to salvage the remaining part of the
season. However, above normal rains over some areas (Singida,
Mbeya, Njombe and Ruvuma regions), are likely to cause excessive
soil moisture which can affect crops at maturity and harvesting
therefore farmers are advised to take necessary precautions.
Pastures and Water for Livestock
Pasture and water availability for livestock and wildlife are likely to
be good over most areas of the country except along the coastal areas
where below normal rains are expected. Areas expected to receive
below normal rains, pastoralists and agro-pastoralists are advised to
harvest and conserve pasture for use during dry season. However,
pastoralists and agro-pastoralists are strongly encouraged to seek more
advice from livestock extension officers. On the other hand, areas
expected to receive normal to above normal rains are likely to have
improved biodiversity, plant flowering, honey/wax production and
reduced animal migration thus expected to reduce human wildlife
conflicts.
Water and Energy
In areas where above normal rains are expected, water levels over the
lakes, dams and river flow discharge are expected to increase during
March to May, 2014 rainfall season. Moreover, it is advised that
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No 10
Special Issue March – May 2014 Season
Issued on 27th February, 2014
water harvesting systems and storage structures be improved to stock
the excess water during the season. Areas with below normal rains,
water harvesting and storage techniques are encouraged.
Health sector
In areas where above and below normal rains are expected, there is a
likelihood of waterborne and water related diseases such as malaria,
trachoma and cholera thus necessary precautions should be taken by
communities and the responsible authorities.
Disaster Management and Local Authorities
Disaster management authorities and other stakeholders are advised to
take necessary measures that would ensure preparedness, response,
and mitigation of any negative impacts resulting from the expected
weather and climate conditions.
Local authorities
During the March to May 2014, rainfall season episodes of heavy
rains are expected to occur and may result into disasters. Therefore,
Municipals are advised to take precautions including open up and
clear of drainage systems to avoid water accumulation due to surface
runoffs so as to reduce the impacts of heavy rains that may result into
floods. Same precautions should be taken for Areas expected to
receive normal and below normal rains (coastal belt and some areas of
the north eastern highlands), due to the fact that there is likelihood of
heavy rain fall episodes.
NOTE: The Agency strongly advices all users including agriculture,
food security, livestock, wildlife, water resources, energy, health
sectors, etc to seek more advice from experts in their respective
sectors.
Planning
Socio-economic sectors are advised to proper utilize March to May,
2014 rainfall outlook in their daily activities and during the
implementation of National Development Plan in order to reduce risk
that may occur.
Prepared by
TANZANIA METEOROLOGICAL AGENCY
3rd, 4th & 10 th Floors - Ubungo Plaza – Morogoro Road.
P.O. Box 3056 Tel. 255 -(0) 22 – 2460706-8 ; Fax: 255 - (0) 22 – 2460718 E-mail: (1) met@meteo.go.tz (2)agromet@meteo.go.tz
Dar es Salaam
UNITED REPUBLIC OF TANZANIA
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