Fresh Low Pressure Area in Andaman Sea Likely; Rain Chance for Odisha, Andhra Pradesh

Key Takeaways:

• A low-pressure area is likely to form over the north Andaman Sea around the evening of 19 September.
• The system may gradually intensify and move towards the South Odisha–North Andhra Pradesh coast over the subsequent three to four days.
• Andaman and Nicobar Islands may receive isolated very heavy rainfall on 18 September, along with squally marine conditions.
• Rainfall may increase over Odisha, Andhra Pradesh, Telangana and later Chhattisgarh as the system moves westwards.
• Forecast Validity: Next one week.

A new weather system may soon develop over the north Andaman Sea and travel towards India’s eastern coast. The India Meteorological Department expects a low-pressure area to form around the evening of 19 September, followed by gradual intensification and west-northwestward movement.

The projected destination is the South Odisha–North Andhra Pradesh coastal belt during the subsequent three to four days. However, the low has not yet formed, making its exact track, strength and rainfall distribution uncertain.

Circulation Approaching Andaman Sea

An upper-air cyclonic circulation was located over northern Thailand on 16 September. It is expected to emerge over the north Andaman Sea around the evening of 18 September.

A cyclonic circulation is a rotating wind pattern in the atmosphere. When it moves over warm tropical waters, persistent thunderstorms can lower surface pressure and sometimes organise into a low-pressure area.

INSAT-3DS imagery at 00:00 UTC, or 05:30 IST on 17 September, showed intense to very intense convection over the southern Bay of Bengal, Andaman Sea, Gulf of Martaban and Tenasserim coast. Moderate to intense cloud development was present over the Andaman and Nicobar Islands.

These satellite observations show a moisture-rich, convectively active environment. They do not confirm that the predicted surface low has formed.

Initial Rain Threat for the Islands

Isolated heavy rainfall is possible over the Andaman and Nicobar Islands throughout the coming seven days. Isolated very heavy rain, representing 115.6–204.4 mm in 24 hours, is possible on 18 September.

Squally conditions are also forecast over the Andaman Sea and parts of the southeast and southwest Bay. Fishermen, ferry operators and small vessels should follow the latest marine warnings.

Intense showers could temporarily affect flights and inter-island ferry services. Local flooding, poor visibility, falling branches and damage to banana or papaya plantations are possible.

Possible Mainland Implications

After forming around 19 September, the low is forecast to intensify gradually and move west-northwestwards towards the South Odisha–North Andhra Pradesh coast over the following three to four days.

Rainfall is expected to increase over Odisha from 19 September. Coastal Andhra Pradesh, Rayalaseema and Telangana may also see a wetter spell during 19–22 September. Chhattisgarh could receive isolated heavy rain from 20 September.

These are broad forecasts, not district-level guarantees. A small change in the system’s path could shift the heaviest rain north or south.

The projected system may also interfere with the larger monsoon-withdrawal pattern. Retreat could begin over parts of West Rajasthan while eastern and central India enter another active phase.

Trending:

Kerala Heavy Rain Alert: Isolated Heavy Showers Likely From 17–20 September