Normal rain likely in August and September, forecasts IMD
India Meteorological Department (IMD) has forecast normal rainfall at 104% of the long-period average (LPA) with a model error of +/-8% in the second half of monsoon season in August and September.
As on Friday (July 31), the country has received normal rain at 101% of LPA or 1% excess rain with 12% excess over the north-east and east India; 19 deficiency over northwest India; 3% deficiency over central India and 13% excess over the southern peninsula.
Rainfall in August is likely to be 97% of LPA with an error margin of +/-9%, which is also in the normal category.
The entire monsoon season -- June to September -- rainfall is also likely to be in the normal range (96% -104% of LPA) as was the forecast on June 1, IMD said on Friday.
“This is only a general picture. It doesn’t give day-to-day or weekly variations, which can also be significant. We have to remember that this is also not mentioning the distribution of rainfall,” said K Sathi Devi, head, National Weather Forecasting Centre (NWFC).
In June, the country received 17.6% excess rains, but in July there was a 9.8% deficiency.
Rains in the core monsoon zone are usually dominant in July, but this time around, central and northwest India has recorded a 22% and 26.2% deficiency, respectively.
“There were no low-pressure systems this July. In spite of that, we did get rain and in the June-July period, we have recorded normal rains over the country,” said Devi.
IMD considers rainfall between 96% and 104% of LPA as normal.
IMD’s forecast on June 1 said that monsoon this year is likely to be normal at 102% of the LPA with a model error of 4% (+/-).
LPA is the averages of rainfall received over a 50-year period between 1951 and 2001.
“At present, the sea surface temperatures (SSTs), as well as the atmospheric conditions over the equatorial Pacific Ocean, indicate” cold El Nino neutral conditions,” according to IMD’s long-range forecasting (LRF) for the second half of the monsoon.
The latest forecasts and models indicate that SSTs over the region are likely to cool further.
However, ENSO neutral conditions are likely to continue during the remaining part of the monsoon season.
In June, IMD had said there is an enhanced probability for the development of weak La Niña conditions after the monsoon season, which begins in June and runs until end-September.
La Niña is characterised by unusually cold ocean temperatures in the Equatorial Pacific and is associated with normal or above normal rain over the country.