Cyclonic circulation triggers IMD warning: Heavy rain alert issued for Andhra, Bengal

The India Meteorological Department (IMD) has issued a heavy rain and thunderstorm alert across multiple states, warning of severe weather until September 14. Andhra Pradesh, Gujarat, Rajasthan, parts of Uttar Pradesh, West Bengal, Sikkim, and the northeastern region are all likely to see heavy to very heavy rainfall over the next week.

In Andhra Pradesh, the weather office said heavy rain and thunderstorms, accompanied by lightning, are expected from September 8 to 12. "Strong winds with speed of 30 to 40 kmph likely at isolated places over NCAP & Yanam, SCAP (South Coastal Andhra Pradesh) and Rayalaseema," IMD said. Rainfall is expected to intensify in North Coastal Andhra Pradesh and Yanam on Monday and Tuesday, spreading to Rayalaseema on September 11 and 12.

A senior IMD official said a cyclonic circulation in the Bay of Bengal will bring "thunderstorms accompanied by heavy rain (7-11 cm) in Andaman and Nicobar Islands on September 10 and 11." He added that sea conditions are expected to be rough and advisories have been issued warning fishermen, locals, and tourists to stay away from the sea until further notice.

The Directorate of Shipping Services (DSS) said vessel schedules to Campbell Bay, Nancowry, Katchal, and other islands may be rescheduled on September 10. 
"There are possibilities of suspension or cancellation of inter-island vessel services at short notice due to the prevailing inclement weather conditions. The operation of harbour/vehicle ferry services between Chatham, Bambooflat, Dundas Point, Hopetown, Phoenix Bay, and outstations is also likely to be affected depending on weather conditions," a DSS official said.

According to IMD's update on Monday, Saurashtra and Kutch will see “heavy to very heavy rainfall with extremely heavy falls (≥21cm) very likely at isolated places” on September 8, with heavy rain continuing in parts of Gujarat on September 9. South Rajasthan is also expected to see heavy to very heavy rainfall on September 8.

Isolated heavy showers are forecast for Uttarakhand on September 8, 12, and 13, for West Uttar Pradesh on September 12 and 13, and for East Uttar Pradesh on September 11 and 12.

East and Central India will also see widespread activity, with IMD warning of isolated heavy rainfall in East Madhya Pradesh from September 10 to 13, West Madhya Pradesh on September 14, Vidarbha from September 11 to 13, Bihar from September 8 to 13, and Odisha from September 10 to 13. Sub-Himalayan West Bengal and Sikkim are expected to see "heavy to very heavy falls" from September 8 to 10.

In the northeast, heavy rain is expected across Nagaland, Manipur, Mizoram, Tripura, Arunachal Pradesh, Assam, and Meghalaya through the week, with "very heavy falls" possible between September 11 and 14.

Tamil Nadu, Kerala, Karnataka, Telangana, and Rayalaseema are also forecast to receive spells of heavy rain with gusty winds at times.