A low-pressure area that formed over the Bay of Bengal early on Friday is forecast by the India Meteorological Department to become a depression today and a cyclonic storm by Monday morning, before moving towards north Andhra Pradesh and south Odisha. If it reaches that strength it will be named Arnab. Coastal Andhra Pradesh has been told to expect heavy to extremely heavy rain on 27 and 28 October.
The weather system that forecasters have been watching all week has arrived. At 05:30 IST on Friday 23 October, a low-pressure area formed over the east-central and adjoining south-east Bay of Bengal, under the influence of an upper-air cyclonic circulation, according to the India Meteorological Department (IMD) as reported by PTI.
IMD’s forecast sets out a steady intensification. The low is expected to concentrate into a depression on Saturday 24 October, strengthen into a deep depression on 25 October, and become a cyclonic storm over the west-central Bay of Bengal by the morning of 26 October. It is then expected to move west-north-westwards and intensify further over the following two days as it approaches the north Andhra Pradesh and adjoining south Odisha coasts.
If it becomes a cyclonic storm, the system will be named Arnab, the next name on the list maintained for the north Indian Ocean by the World Meteorological Organization and its regional panel. The name was contributed by Bangladesh and means “ocean” or “sea” in Bengali. NSH has seen the name in several reports citing IMD, but has not been able to read IMD’s own bulletin.
How a low becomes a cyclone
Tropical cyclones in the Bay of Bengal grow from disturbances over warm sea water. Moist air rises, condenses and releases heat, which lowers surface pressure further and draws in more air. If upper-level winds are light enough not to shear the developing system apart, the circulation tightens and strengthens.
IMD classifies these systems by sustained wind speed. A depression has winds of roughly 31–49 km/h; a deep depression 50–61 km/h; and a cyclonic storm 62 km/h or more. Severe and very severe categories follow at higher speeds. Today’s forecast does not yet say how strong the system will become at its peak.
Where and when it may come ashore
IMD has not issued a landfall forecast. Its stated track is west-north-westwards towards the coast of north Andhra Pradesh and south Odisha. According to Sambad English, IMD expects the system to be near that coastline around the morning of 28 October.
The same report says at least two global forecast models, the American GFS and the European ECMWF, place a crossing south of Visakhapatnam, around the Kakinada–Visakhapatnam stretch, on the afternoon of 28 October. That is model guidance, not an official forecast, and model tracks several days ahead often shift by hundreds of kilometres. NSH advises readers to follow IMD and state disaster-management bulletins rather than circulating model maps.
What it means for Andhra Pradesh
The Andhra Pradesh State Disaster Management Authority (APSDMA) expects light to moderate rain over the weekend, rising to heavy to extremely heavy rain with squally winds along the coast on Tuesday and Wednesday, 27 and 28 October, according to The Hans India. Reports citing IMD forecast extremely heavy rain over coastal Andhra Pradesh on those dates and over Odisha from 27 to 29 October.
Prakhar Jain, APSDMA’s managing director, has told fishermen at sea to return to the coast. IMD has advised fishermen not to venture into the sea from 26 October. APSDMA’s helplines are 112, 1070 and 1800-425-0101. Rain was already falling in the south of the state before the system formed: Alivelumangapuram in Tirupati district recorded 87.5 mm in the 24 hours to 17:00 IST on Thursday.
The track carries a familiar risk. Late October and November are a peak season for cyclones striking India’s east coast, and the stretch between Machilipatnam and Visakhapatnam was hit by Cyclone Montha in late October 2025. For coastal districts, the main dangers are not only wind but flooding from extremely heavy rain, storm surge in low-lying areas, and damage to standing kharif paddy that is close to harvest. Fishing communities lose income for every day boats stay ashore.
Beyond Andhra Pradesh
In Odisha, the southern districts nearest the forecast track are likely to face the heaviest rain. The Federal reports thunderstorms and heavy rain in south Bengal from 28 October, and IMD rain warnings also cover parts of Tamil Nadu, Karnataka and the Andaman and Nicobar Islands.
Little relief for Telangana
For Telangana, which is in a deepening drought, the question is whether the system will bring meaningful rain inland. The Hans India reports moderate rain over two days, but neither IMD’s national forecast nor the PTI report singles out the state. Systems that cross the north Andhra coast and move west-north-west tend to bring their heaviest rain to coastal districts and southern Odisha; how much reaches the Telangana plateau depends on the landfall point and how quickly the storm weakens over land.
Points of uncertainty
- Intensity. Whether Arnab peaks as a cyclonic storm or a severe one is not yet forecast.
- Timing and location. The landfall window rests on model guidance and a single report of IMD’s expectation.
- Rainfall. Reports differ in wording, from “heavy to very heavy” to “extremely heavy”; IMD’s district-level warnings will settle it.
What to watch
Today’s IMD bulletins should confirm whether the depression has formed, and give its first official track and landfall window. Once a cyclone is named, IMD typically issues three-hourly updates and port warnings, and state governments begin moving people from vulnerable areas. The next 48 hours will determine the scale of preparation.
Lead time is the main defence. IMD’s cyclone track forecasts have improved markedly over the past two decades, and the large reductions in cyclone deaths along India’s east coast since the 1999 Odisha super cyclone owe much to earlier, more precise warnings combined with organised evacuation. For residents of the coastal districts, the practical advice is simple: keep phones charged, follow district administration instructions, and do not wait for landfall to move from low-lying or kutcha housing.
– Rashmi Kumari
