The monsoon has advanced into most parts of Gujarat with the northern limit passing through Deesa, Ratlam, Shivpuri, Rewa and Churk on Monday signalling a minor progress on the West Coast after breaking out of days-long logjam over Porbandar in Gujarat. The wait has cost it badly with rainfall deficit worsening rapidly into double-digits (10 per cent) on Monday from nil during the weekend.
Second hold-up on West Coast
This was the second time that the monsoon was caught in a lock-up over the West Coast after Karwar in Karnataka shortly after onset. The rain deficit had peaked to 43 per cent then, until some record rainfall over East and North-East India made good the loss after June 15. The minor relief from the second deadlock over Porbandar came about even as India Meteorological Department (IMD) predicted a fresh spell of enhanced rain for central India from Monday and north-west India from Tuesday.
The monsoon has kept parts of both regions waiting as its progress came to a nought over Porbandar. The wait has extended by up to a week or more for North Gujarat, fringes of Madhya Pradesh and Uttar Pradesh, and five days for parts of West Uttar Pradesh. Conditions are now favourable for its further advance into remaining parts of Gujarat, Madhya Pradesh and Bihar; some more parts of Uttar Pradesh; some parts of Rajasthan, Uttarakhand, Himachal Pradesh and Jammu & Kashmir during next 3-4 days.
Low-pressure area offers help
The minor progress on the West Coast on Monday was overseen by a low-pressure area, first of the season, hovering on over the North-East Arabian Sea off the North Konkan-Sough Gujarat coasts, not far away from Mumbai. It has also thrown open the offshore trough in full length from South Gujarat to North Kerala. This apart, a cyclonic circulation (non-monsoon) persists over South-West Rajasthan from where a helpful trough originates and dips into the West-Central Bay of Bengal across South-East Rajasthan, Madhya Pradesh, Chhattisgarh and South Odisha.
Troughs from either side
In the return direction, a secondary trough over land extends from a cyclonic circulation over Central Madhya Pradesh and reaches out to the low-pressure area off the Mumbai coast. These features support the cause of rainfall, mostly pre-monsoon turning gradually into monsoon, per the IMD outlook. As on Monday evening, the worst rain deficit came from Central India (30 per cent), almost twice of that accumulating over the other three geographical regions of the country.
Fresh spell of rains
The IMD has now forecast isolated heavy to very heavy rainfall over Konkan and Goa during the next five days. Isolated heavy rainfall is forecast over East Gujarat, Madhya Maharashtra, Coastal Karnataka, Kerala and Mahe during this period; over southern parts of Saurashtra on Wednesday and Thursday; coastal Andhra Pradesh and Telangana on Wednesday; north interior Karnataka on Wednesday and Thursday; and south interior Karnataka From Tuesday from Tuesday to Thursday. Isolated heavy to very heavy rainfall is likely over coastal Karnataka on Wednesday and Thursday.
Exchange of moisture
Exchange of moisture by the Arabian Sea and the Bay of Bengal via the troughs over land will bring isolated heavy rainfall over Jammu & Kashmir, Ladakh, and West Rajasthan on Thursday; over Uttarakhand from Monday to Thursday; East Rajasthan on Wednesday and Thursday; Uttar Pradesh from Tuesday to Thursday; and over Himachal Pradesh on Wednesday and Thursday. Isolated heavy to very heavy rainfall is also likely over Uttarakhand on Wednesday. Isolated heavy rainfall is likely over Madhya Pradesh, Chhattisgarh and Vidarbha during Monday to Thursday; and isolated heavy to very heavy over Bihar on Tuesday and Wednesday.
Southerly to south-westerly winds blowing in from the Bay of Bengal to North-East and adjoining East India will sustain isolated heavy to very heavy rainfall over the hills of West Bengal on Tuesday and Wednesday as a bulk of the moisture leaves the region towards parts of central and north-west India.