Weather
Weather -
Seasonal Climate Watch
January 2016 to May 2016
Advisory
Most models are showing the continuation of
a strong El-Niño episode towards the latesummer season with the expectation to start
gradually decaying during the autumn and
early winter seasons. The forecasting system
is confidently showing that going towards the
late-summer and early autumn seasons, the
likelihood of dry conditions over most parts
of the country is still high. In addition the
late-summer season forecast indicates the
likelihood of extremely below-normal rainfall
totals, which is a continuation of the midsummer expectation. The likelihood of warmer
than normal temperatures over most of South
Africa is predicted to be high throughout
the summer season. Other international
forecasting systems also similarly indicate a
tendency of drier and warmer conditions for
South Africa.
Recommendation
It is highly likely that the country would
continue to experience consistently dry
and hot conditions toward the late-summer
season. These drier and warmer conditions
are expected to be extreme during late
summer through early autumn. Even though
the country is expected to be generally dry
and warm, it is important to take note that
extreme rainfall events may still occur, as
is the norm for the summer season. This
persisting extreme dry and warm conditions
for the summer season may worsen the
current drought conditions which the
country is already experiencing. It is highly
recommended that medium- and shorterrange weather forecasts be monitored for
the development of conditions that may
alter or strengthen the expectation of the
current forecast.
Rainfall
Minimum and Maximum Temperatures
The forecasting system indicates enhanced
probabilities of below-normal rainfall for the
late-summer season as well as early autumn
countrywide. Mid-autumn indicates some
chances for above-normal rainfall for parts
of the eastern half of the country. The latesummer period also indicates the likelihood
for extremely below-normal rainfall totals.
(Figure1).
The forecasting system indicates generally above-normal temperatures across the country through
late-summer towards mid-autumn, with an exception of below-normal minimum temperatures for
the south western parts of South Africa (Figure 2).
For improved confidence in a probabilistic prediction use is made of skill scores most notably
the Relative Operating Characteristic (ROC) which indicates the ability of the forecasting system
to distinguish events from non-events. As noted earlier, areas of ROC scores above 0.5 may be
considered as areas of added confidence for the prediction (Figure A2).
For improved confidence in a probabilistic
prediction use is made of skill scores most
notably the Relative Operating Characteristic
(ROC) which indicates the relative performance
of the prediction system. Areas of ROC scores
above 0.5 may be considered as areas of
added confidence for the prediction (Figure
A1).
Figure 2: Probabilistic minimum (left panel) and maximum (right panel) temperature forecasts for the three overlapping
seasons valid for the period of January to May 2016.
Figure 1: Rainfall forecasts for the three overlapping seasons
valid for the period of January to May 2016.
Information supplied by South African Weather Service. Enhanced Probabilities is considered to be more than
45% probability for a specific category.
If there are areas that do not show an indication of more than 45% probability, then the forecasts for that area
is considered to be uncertain.
For more information: email [email protected]
Weatherlines: 082 162 - *120*555*3 - 083 123 0500
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SABI | FEBRUARY/MARCH 2016