The continued march of the monsoon across the expanse of the Bay of Bengal waters is resonating well with the far-off South Indian Peninsula and the North-East where its two arms — from the Arabian Sea and the Bay — will eventually make an onset. Isolated heavy to very heavy rainfall with extremely heavy falls fell over Kerala and Meghalaya during the 24 hours ending on Wednesday morning. It was heavy to very heavy over Assam, south interior Karnataka and Tamil Nadu and heavy over Arunachal Pradesh, Tripura and Rayalaseema.
Short-to-medium outlook
The US National Centres for Environmental Prediction expects the Kerala coast to stay active during May 18-26 during when India Meteorological Department (IMD) expects the monsoon to set in over Kerala. The rains may propagate further North along the coast to Konkan until June 3 though the North Peninsula (interior Maharashtra and parts of south Madhya Pradesh) may stay relatively dry. Likely western disturbance activity will keep the North and East cool (except Rajasthan and Punjab) during this period.
Progress in Arabian Sea
The IMD said in an update on Wednesday that conditions are becoming favourable for further advance of the monsoon into more parts of the South and Central Bay and parts of south Arabian Sea (closer to Kerala) during the next two-three days. A cyclonic circulation lies over north interior Tamil Nadu while a typical pre-monsoon trough runs from Central Madhya Pradesh into it, drawing in moist south-westerlies and easterlies from the Arabian Sea and the Bay. Fairly widespread to widespread light to moderate rain, thunderstorms, lightning and gusty winds will continue to lash Kerala, Mahe, Tamil Nadu, Karnataka, Lakshadweep and Rayalaseema for next five days.
Red, orange alerts
Red and orange alerts were declared over Kerala and Mahe on Wednesday with more heavy to very heavy falls forecast on Thursday. Similar conditions will pan out over coastal and south interior Karnataka as well on Thursday. This is after extremely heavy rain pulverised isolated places over Kerala, Mahe, coastal and south interior Karnataka on Wednesday while it was isolated over Rayalaseema and Lakshadweep.
To the North, strong south-westerly winds from the Bay towards the North-East and adjoining East India, and an East-West trough from north-west Rajasthan to west Assam will bring fairly widespread to widespread light to moderate rain with isolated heavy to very heavy falls over Assam, Meghalaya and hills of West Bengal and Sikkim during next five days. Isolated to scattered light rainfall with isolated thunderstorms, lightning and gusty winds is likely over Bihar, Jharkhand, plains of West Bengal and Odisha during next five days.