Southwest monsoon 2011: End of-season report

Originally published
View original



• For the country as a whole, the rainfall for the season (June-September) was 101% of its long period average (LPA).

• Seasonal rainfall was 107% of its LPA over Northwest India, 110% of its LPA over Central India, 100% of its LPA over south Peninsula and 86% of its LPA over Northeast (NE) India.

• Out of the total 36 meteorological subdivisions, 33 subdivisions constituting 92% of the total area of the country received excess/normal season rainfall and the remaining 3 subdivisions (Arunachal Pradesh, Assam & Meghalaya, and NMMT constituting 8% of the total area of the country) received deficient season rainfall.

• Out of 603 meteorological districts for which data are available, 453 districts (76%) received excess/normal rainfall and the remaining 150 districts (24%) received deficient/scanty rainfall during the season.

• Monthly rainfall over the country as a whole was 112% of LPA in June, 85% of LPA in July, 110% of LPA in August and 106% of LPA in September.

• Advance of Southwest monsoon over the Andaman Sea was delayed by about 10 days. The monsoon set in over Kerala on 29th May, three days before its normal date of 1st June and covered the entire country by 9th July, 6 days earlier than its normal date of 15th July. The withdrawal of monsoon from west Rajasthan was delayed and it commenced only on 23rd September.

• Four depressions formed during 2011 monsoon season as against the normal of 4-6 monsoon depressions per season.

• The forecast for monsoon onset over Kerala for this year was correct, which is the seventh consecutive correct forecast for this event.

• Most of the operational long range forecasts issued for the 2011 southwest monsoon rainfall were underestimating the actual rainfall and therefore were not very accurate.