Thursday, February 5, 2009

IMD Report on High Temperatures during January 2009

A report on high temperatures during January 2009 released by India Meteorological Department today says that during 1st week of January 2009, both maximum and minimum temperatures were below to appreciably below normal over many parts of Indo-Gangetic plains and also over some pockets of adjoining central India. Thereafter, there was a gradual increase in the temperatures. During 2nd half of the month, both minimum and maximum temperatures were considerably above normal on many days. 

During the last ten days of January 2009, particularly from 22nd of the month, a number of stations recorded high maximum temperatures ranging as high as 13 ºC above normal. Commencing from 23rd of the month, during the respective days in succession, 21, 39, 44, 32, 13, 25, 29, 25 and 13 stations have recorded temperatures which were above the normal by 5 ºC or more. Several stations have recorded abnormally above normal temperatures, surpassing the past records of extreme maximum temperatures. 

On 27th alone, 12 stations broke the earlier records such as Raipur (Chhattisgarh) with 35 ºC temperature which was 2.8 ºC above the earlier extreme record temperature of 33.2 on 29th 2003. Similarly, on 26th and 25th, 11 station each and on 29th, 8 stations surpassed the earlier records. In this spell of exceptionally high temperatures, Mukteshwar (Uttarakhand) recorded maximum departure of 13 ºC on 23rd, which however, was slightly (0.2ºC) short of earlier extreme. 

Mean maximum temperatures of the month were above normal by 2ºC or more over Chhattisgarh, south Madhya Pradesh, Vidarbha , Marathwada, north Andhra Pradesh, Himachal Pradesh, Manipur & Nagaland and parts of Jammu & Kashmir, Jharkhand, Konkan & Goa and Orissa. 

Similarly mean minimum temperatures of the month were above normal by 2ºC or more over many parts of Himachal Pradesh, Rajasthan, Madhya Pradesh & Gujarat and some parts of Chhattisgarh, Orissa, Gangetic West Bengal, Madhya Maharashtra, Vidarbha, Punjab, Haryana, Uttar Pradesh & Himachal Pradesh. 

The mean minimum temperature of January was 8.9ºC against the normal of 7.3ºC over Delhi which is the highest during the past 19 years. Similarly, mean maximum temperature of January was 21.7ºC against the normal of 21.1ºC over Delhi which is the second highest during the past 19 years. Average (mean of maximum & minimum) temperature of 15.3ºC is also a record highest during the past 19 years. 

The main reasons for such abnormally high temperatures include western disturbances affected only the extreme northern and north-western parts of the country, anticyclone over central India caused southerly & southeasterly flow which prevented the cold northerlies sweeping the region and the Northward shift of the subtropical Ridge and persistence of anticyclone right from the lower levels resulted in the enhanced subsidence and hence warming.

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