Withdrawal of south-west monsoon has paused along Nautanwa and Sultanpur (Uttar Pradesh); Panna, Narmadapuram and Khargone (Madhya Pradesh); Nandurbar (Maharashtra); and Navsari on Tuesday morning as India Meteorological Department (IMD) declared a watch for a low-pressure area over Lakshadweep and adjoining Arabian Sea by Wednesday.
Movement away from coast
The ‘low’ is predicted to move in a north-west direction away from the West Coast, but will help draw in winds from the Bay of Bengal across peninsular India, setting up an easterly wind regime. This is expected to help transition of winds seasonally from being south-westerly monsoon to east-north-easterly. The IMD said conditions are favourable for withdrawal of south-west monsoon from remaining parts of Gujarat, Madhya Pradesh and more parts of Maharashtra during next 2-3 days.
Widespread rain forecast
A helpful trough runs from south-west Bay of Bengal to a preparatory cyclonic circulation over Lakshadweep (which is predicted to deepen as a ‘low’) across south Tamil Nadu and south Kerala. Outlook for a week said fairly widespread to widespread rain is likely over Lakshadweep; Coastal Karnataka, South Interior Karnataka; Kerala & Mahe; North Interior Karnataka; Tamil Nadu and Puducherry & Karaikal and isolated to scattered to moderate over Rayalaseema; Telangana; Coastal Andhra Pradesh & Yanam.
Isolated very heavy rain
Isolated heavy to very heavy rain is likely over Kerala & Mahe during the week; over Tamil Nadu, Puducherry & Karaikal and South Interior Karnataka on Tuesday. Isolated heavy to very heavy rain may break out again and last for three days from Thursday to Saturday over Tamil Nadu, Puducherry and Karaikal. Isolated heavy rain is likely over Kerala & Mahe, Tamil Nadu, Lakshadweep, Puducherry & Karaikal during the week; over Coastal Karnataka on Tuesday; and over South Interior Karnataka until Friday.
More circulations seen
The Climate Prediction Centre of the US said tropical disturbances in the form of cyclonic circulations/’lows’ may spawn over both the Bay and the Arabian Sea as a helpful Madden-Julian Oscillation (MJO) wave moves into the Indian Ocean during the week from October 9 to 15. These conditions may last even into the subsequent week (October 16 to 22), sustaining system formation over the ‘main development region’ in the open waters of the Bay and along the West Coast from Kerala to Konkan & Goa.
Numerical model forecasts
A 10-day outlook by IMD’s numerical weather models suggest one such circulation may form over the south-west Bay to the south-east of Sri Lanka and Tamil Nadu coasts by Thursday. This may likely merge with the ‘low’ over Lakshadweep to set up a trough across south-east Arabian Sea and south-west Bay across Sri Lanka by Saturday. Winds may start to strengthen off Sri Lanka and Tamil Nadu coasts during subsequent two days, with a prominent easterly to south-easterly component.
Fresh ‘low’ likely
Easterly winds over the Arabian Sea may throw up another cyclonic circulation circulation/low-pressure off the Konkan coast by October 17 (Thursday next). It may strengthen, but start to move away from the coast from next day, till when forecast is available. Along side, a fresh but broader circulation will have been generated over the south-west Bay. The European Centre for Medium-Range Weather Forecasts says the Bay waters and coastal waters of the Arabian Sea from may mostly remain under a wet envelope of a trough during most of the next two weeks.