A low-pressure area has formed over west central Bay of Bengal off the Andhra Pradesh coast on Sunday, which is likely to result in increased intensity and distribution of rains in Odisha, coastal Andhra Pradesh and Yaman, according to the India Meteorological Department (IMD) bulletin released on Sunday morning.
The monsoon trough (line of low pressure) lies south of its normal position (Ganganagar to Bay of Bengal). The eastern end of the monsoon trough is likely to shift further southwards due to formation of a low-pressure area over west central Bay of Bengal off Andhra Pradesh coast by around tomorrow.
Heavy to very heavy rains are likely over Odisha, coastal Andhra Pradesh and Yanam on Sunday; Telangana on September 13 and 14 and Gujarat on September 16.
A cyclonic circulation is also lying over east central Arabian Sea off Maharashtra coast. The east-west shear zone– area of change in wind direction and velocity– is running across peninsular India and is likely to persist during the next 3-4 days.
An off-shore trough at mean sea level is also running from north Maharashtra coast to north Kerala coast. Under the influence of these favourable conditions, widespread rain with isolated heavy rain, thunderstorm and lightning is very likely over west peninsular India during the next 4-5 days.
Heavy to very heavy rain at isolated places is very likely over Konkan, Goa, Kerala and Mahe on Sunday and also over south interior Karnataka, parts of Saurashtra and Kutch.
Monsoon rain since June 1 is in 6% excess with 0% excess recorded over east and northeast India, 12% deficient rains over northwest India, 15% excess over central India and 23% excess over south peninsula.
In September, there is 23.5% deficiency over the country with 41.5% deficiency over northwest India, 22.5% deficiency over east and northeast India, 41.4% deficiency over central India and 50.7% excess over south peninsula.
Rainfall is likely to be deficient at least until September 13 in most parts of the country, including northwest and central India, before intensifying after September 17, according to the IMD’s extended range forecast. Normally, withdrawal of monsoon is supposed to begin from September 17 when rain begins reducing across the country until completely withdrawing on October 15.
But this year IMD’s extended range forecast shows extensive and heavy rains along the west coast between September 11 and 24 and then until October 1 over several parts of central India.