The long waited official forecast of the Indian
Meteorological Department (IMD) was finally announced last Thursday
evening. The country is set to receive normal South West Monsoon rains in 2012,
for a third year in a row. “It is a normal forecast,” said Mr Vilasrao
Deshmukh, Union Minister for Science and Technology.
A forecast of normal rainfall at 99% of LPA should
be reassuring news for India where the monsoon is the lifeline of a farm-dependent economy.
But as they say “The
devil is in the details”. So what’s the fine print? These read as follows:
(a) Southwest
monsoon seasonal rainfall for the country as a whole is most likely to be
Normal (96-104%) of Long Period Average (LPA)) with the probability of 47%.
Quantitatively, monsoon season rainfall is likely to be 99% of the LPA with a
model error of ± 5%. The LPA of the season rainfall over the country as a whole
for the period 1951-2000 is 89 cm.
(b) The
probability (24%) of season rainfall to be below normal (90-96% of LPA) is also
higher than its climatological value.
(c)
However, the probability of season rainfall to be
deficient (below 90% of LPA) or excess (above 110% of LPA) is relatively low
(less than 10%).rainfall to be deficient (below 90% of LPA) or excess (above 110% of
LPA) is relatively low (less than 10%).
The IMD’s forecast of a “Normal Monsoon” lacks
a high confidence level as they preferred to actually hedge their bets. As the
Business Standard noted - reading between the lines, two facts emerge: one that
the probability of “normal” rains at 47 % is lower than around 51%,
issued last year, and two, the likelihood of “below normal rains” at 24%
is higher than that of 20% during 2011.
