Southwest Monsoon in India is conceived as a complex phenomenon. A cautious approach is generally taken before announcing onset or withdrawal of Monsoon in India.
July and August are generally the active Monsoon months for the entire country. June is the onset month which witnesses an outburst of rain while, September is the withdrawal month, receiving more of sporadic rain.
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, sporadic rain and temporary rising tendency of temperatures.
Last year, the monsoon started withdrawing from Rajasthan by 9th of September and from Himachal Pradesh, Punjab, Haryana and Gujarat by the 19th. This year, the track of the present Monsoon system seems to be suggesting a possible retreat of Southwest Monsoon.
Announcement of withdrawal of Monsoon
According to the latest weather update by Skymet Meteorology Division in India, this year, Southwest Monsoon is likely to withdraw from west Rajasthan anytime in the coming week.
The prevailing situation now seems conducive for withdrawal of Monsoon as there has not been any rain in west Rajasthan in last few days. The cities of Barmer, Bikaner, Jodhpur and Jaisalmer have recorded nil rainfall. However, east Rajasthan has been receiving some rainfall.
A bigger picture is taken into consideration, before announcing withdrawal of Monsoon from west Rajasthan. To be more precise, commencement of withdrawal is not announced from the western parts of the state, even if east Rajasthan receives some rain.
Few stations of Pakistan, along the border of Rajasthan have also been dry. Cities like Bahawalnagar, Bahawalpur, Khanpur, Rohri, Pad Idan, Nawabshah, Chhor and Hyderabd have all been dry.
The four-month long Monsoon season, which runs from June to September, brings 70% of the country's annual rainfall. The initial phase of Southwest Monsoon this year was dominated by an evolving El Nino.
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 deficiency of 22% while at present rain deficit stands at 11%. In fact, the cumulative deficiency has been stagnant at 11% for the 6th consecutive day.
The track of Monsoon systems has been suggesting the possible retreat of Monsoon and cessation of rain from Northwest India. Successive systems developing over the Bay of Bengal will dictate the withdrawal line of Monsoon from India. Rain will now be sporadic in nature and not help in reduction of the cumulative rain deficiency, which could show a marginal rise.
