••••
COME R AI N OR S H I N E
What are the predictions
for the coming season?
THYS GROBBELAAR
SENIOR GRAIN ANALYST,
SENWES GRAINLINK
Article written: 5 September 2017
RAINFALL FOR THE SEASON THUS FAR
As we know, the summer rainfall
season starts on 1 July of every
year. The average rainfall for July
for the traditional Senwes area is
4,0 mm and 9,9 mm for August.
We have received 1,9 mm for July
this year and 0 mm for August.
Not much rain is predicted for
the traditional area for September.
The average rainfall for September
for the traditional Senwes area
is only 15,4 mm. However, it is
bad news for the dryland wheat
planted. It can therefore be a
summer season which starts later
than normal. As we know, the
success of the summer season
depends on whether we managed
to plant early enough and on
the rainfall distribution during
January and February.
INDICATORS FOR THE REST OF THE
2016/2017 SEASON
The International Research
Institute for Climate and Society
of the Columbia University has
been doing intensive research
on the El Niño/La Niña
phenomenon. The next graph
indicates the expectations for the
coming season. It is predicted that
the chances of an El Niño-type
46
Early-Aug CPC/IRI Official Probabilistic ENSO Forecast.
of season are lower than 20%.
Chances are good for a neutral
type of season. A neutral type of
season is more inclined to result
in above-average yields in South
Africa. One of the precursors
of an El Niño/La Niña-type of
season is the ENSO-index, which
is based on the wind direction
between Darwin in Australia and
Tahiti in the Pacific Ocean. The
index is positive at present, which
indicates a probable neutral to La
Niña-type of season.
The following graph reflects
the deviation from each type of
season on the 5-year running
average yield for the traditional
OCT/NOV 2017 • SENWES Scenario
Senwes area. The seasons are
indicated in colour as El Niño,
neutral and La Niña. The neutral
seasons normally realise average
to above-average yields. One of
the exceptions was, however, the
2014/15 season, when a below-
average yield realised. The main
reason was the lack of rain during
February, particularly in the
western districts.
EXPECTED RAINFALL FOR THE PERIOD
SEPTEMBER 2017 TO JANUARY 2018
(SOUTH AFRICAN WEATHER BUREAU)
The Weather Bureau published its
expectations for the 2017 season
at the end of August 2017. The