Bay of Bengal has been witnessing dormant conditions after remaining fairly active for the 1st three weeks of July 2022. Series of cyclonic circulations and low pressure areas formed and travelled across Odisha, Chhattisgarh, Madhya Pradesh, Maharashtra, Gujarat and Rajasthan. Decent rains lashed states on either side of the monsoon trough and shear zone, like Uttar Pradesh, Punjab, Haryana, Jharkhand, Telangana, Andhra Pradesh, and Karnataka.
Monsoon systems invariably form at the tail end of monsoon trough dipping over the Bay of Bengal (BoB). This east-west oriented feature mostly stretch along North Rajasthan, Indo Gangetic plains and thence to northwest BoB. The monsoon trough has been oscillating north and south for the last one week, remaining mostly north of its normal position. Accordingly, BoB has not generated any cyclonic vorticity after 20thJuly, which was earlier frequented by ‘relay’ run of weather systems.
Northward position of the monsoon trough and absence of any fresh system led to reduction in the spread and intensity of monsoon rainfall. Daily rainfall has dropped below the normal for the last 6 successive days. Active monsoon conditions remained confined to few areas of North India. The seasonal rainfall which had earlier climbed to 114% of LPA by mid July has now dropped to 107%. Active monsoon conditions will be back with BoB hosting a low pressure area shortly.
Presently, a cyclonic circulation is marked over southwest BoB, off Tamil Nadu and South Coastal Andhra Pradesh. It is rather unusual position at this time of the season and mostly occur when monsoon trough shifts far to the north , leaving mild monsoon activity over large parts of the country. Presence of this circulation and its convergence zone has accentuated the weather activity over South India, particularly Kerala, Tamil Nadu and Karnataka.
The cyclonic circulation will come closer to the shore in the next 24hours. It is likely to traverse along the coastline of Andhra Pradesh and South Coastal Odisha in the subsequent 48hr. The weather system is likely to become organized and more marked along and off Odisha Coast and Northwest BoB. Low pressure area is likely to form on 05th or 06th Aug, supported by circulation up to the medium levels of the atmosphere. Further prognostication will be advisable after having observational watch for 48hr. However, in all probabilities, the weather system will stretch through the central parts of the country. Once deep inland, it may also leave yet another system on its trail over the Bay of Bengal.