Southwest Monsoon is a four month long season over the Indian region spanning from June to September, with a Long Period Average (LPA) of 89 cm of rain for this period. Monsoon in India could be conceived as a complex phenomenon, inherited with a variety of phases ranging from active Monsoon to weak, lull, break and the like.
Southwest Monsoon, after ushering in made a sluggish start with subdued activity in the initial phase and made a very slow advancement. After poor Monsoon rains in June, July too commenced with a 43% deficit – highest for the season - and remained so till 12th July. The month ended with a cumulative deficieny of 22% while at present rain deficit stands at 17%.
Monsoon remained extremely weak in terms of both intensity and coverage till mid-July, particularly in northwestern parts, Gujarat and Central India. Central region, including Gujarat, made an astonishing recovery but nothing similar can be said about Northwest India.
June is the onset month which witnesses an outburst of rain while, September is the withdrawal month, receiving more of sporadic rain. July and August are generally the active Monsoon months for the entire country.
Southern parts of the country enjoy the complete four month duration of Monsoon, whereas North India actively observes only about two months of rainy season, before it recedes in September.
Conditions for withdrawal of Monsoon
Withdrawal is generally not attempted before 1st of September and commences from extreme west Rajasthan.
As Southwest Monsoon approaches the withdrawal phase from a particular region, certain conditions become prevalent- change of wind pattern, reduction in cloud cover, decrease in humidity, cessation of rain and temporary rising tendency of temperatures.
Comparison between 2013 and 2014
2013- Last year withdrawal began quite late around 18th September from west Rajasthan, against the normal date of 1st September. Monsoon generally bids farewell from Delhi/NCR and other northern plains by 3rd week of September but was delayed till about 16th October. Consequently, it was delayed from Central and East India as well.
2014- It’s the first day of September but there seems no signs of withdrawal in the coming few days. As per latest weather update by Skymet Meteorology Division in India, a series of cyclonic circulations or Monsoon systems will make their way up to Rajasthan for the entire week. The withdrawal may not commence on the lines of last year but is surely going to surpass the first week.
Picture courtesy- dandapani
