CLIMATE OUTLOOK
january - june, 2016; ISSUED: December, 2015
T
he IRI has prepared this experimental
Climate Outlook for Africa for January June 2016. Of relevance in the preparation
of this outlook is a likelihood that the central
and eastern tropical Pacific Sea Surface
Temeperatures (SSTs) will be substantially
above average during the entire forecast
period, indicative of strong El Nino conditions
during the January and February, moderate/
strong for March/April and moderate for May/
June.
Near-average SSTs are predicted for the
western tropical Pacific for the entire forecast
period. Such tropical Pacific conditions are
indicated in the SST predictions on which
these climate forecasts are based. Well aboveaverage SST is predicted over virtually all of
the equatorial Indian Ocean for the entire
forecast period. SSTs in the equatorial Atlantic
are predicted to be below average during
the entire forecast period, particularly in the
eastern portion close to Africa. Surrounding
this predicted cool region to the north or south
of the equatorial zone, above average SSTs are
predicted for the entire forecast period.
The procedures, models, and data used to
derive this Climate Outlook may be somewhat
different from those used by the national
meteorological services in the region. Thus,
this product may differ from the official
forecasts issued in those areas. The Climate
Outlook for January - June 2016 is dependent
on the accuracy of the SST predictions. For
the tropical Pacific, these predictions can be
expected to provide useful information, but
there is some uncertainty concerning the
evolution of SSTs. Variation in global SST
predictions is a source of uncertainty in the
Outlook provided here. In particular, the
forecasts for the tropical Indian and Atlantic
oceans have been an important influence on
the forecasts over Africa. Note that even if
perfectly accurate SST forecasts were possible,
there would still be uncertainty in the climate
forecast due to chaotic internal variability
of the atmosphere. These uncertainties are
reflected in the probabilities given in the
forecast.
This Outlook is relevant only to seasonal
time scales and relatively large areas; local
6
FARMERS GAZETTE
November 2015
variations should be expected.
This Outlook covers the six month period from
January - June 2016. The precipitation map
shows the probabilities of the total seasonal
precipitation falling into three different levels.
For each of the zones on the map there are
three boxes containing a number that indicates
the percentage probability of each of these
levels.
The top number indicates the percentage
probability of higher than normal rains. The
middle number indicates the percentage
probability of there being normal rains and
the bottom number indicates the percentage
probability of there being lower rainfall than
normal. These levels are taken as the wettest
ten, the driest ten and the median rains over
the last thirty years.
The colour shading in each of the zones
indicates the likelihood of the most dominant
probability, the one with the highest forecast
percentage probability.
The colour bar at the bottom of the map
defines these probability levels. The left hand
side of the colour bar, from yellow to brown,
shows the colours used for increasingly
strong probabilities of below normal rains,
while the right hand side, from light green
to blue, shows likewise for the above normal
probabilities of rain.
The grey colour indicates an enhanced
probability for the near-normal rains, nearly
always limited to 40%.
For example, in the case of most of South
Western Zambia in the January – March 2016,
there is a 60% probability that the precipitation
will be in the driest third of the last 30 years,
a 30% chance it will be in the near-normal
third of the years, and a 10% chance that the
precipitation will be in the wettest third of the
years. Even Northern Zambia is indicating that
the rains will be in the driest third of the last
30 years.
Boundaries between sub-regions should be
considered as transition zones, and their
location considered to be only qualitatively
correct.
We are looking at a drought of biblical
magnitude.