Bhubaneswar/New Delhi: The India Meteorological Department (IMD) has indicated the likelihood of a cyclonic circulation or low-pressure area developing over the southwest Bay of Bengal and adjoining west-central and southeast sectors during the second half of next week.
While conditions may become favourable, the probability of the system intensifying into a depression or cyclone remains low.
According to the North Indian Ocean Extended Range Outlook for Cyclogenesis issued by IMD on May 7, large-scale environmental features, climatological patterns, and model guidance point to this development during May 8–14, with the most likely window for any cyclogenesis between May 13 and 16.
The outlook assigns a “low” probability (1–33%) to cyclogenesis over the southwest and adjoining west-central Bay of Bengal during the latter part of Week 1 and the early part of Week 2. A separate low-probability development of a depression is also indicated over the east-central Arabian Sea around May 17–18.
Week 1 spans May 8–14, and Week 2 covers May 15–21.
Model Guidance
IMD’s multi-model ensemble (MME-CFSV2) shows a cyclonic circulation over central parts of the south Bay of Bengal in Week 1, along with an east-west trough. In Week 2, it indicates westerly/southwesterly flows and a cyclonic anomaly off the Andhra Pradesh coast. Positive precipitation anomalies are expected over the southeast Arabian Sea and the entire Bay of Bengal, strengthening from Week 1 to Week 2 and extending to Kerala and Karnataka coasts.
Other models provide mixed signals. The NCMRWF’s CNCUM model suggests a feeble cyclonic circulation near South Tamil Nadu in Week 1 and similar patterns later, while indicating slow monsoon progress. ECMWF ensemble forecasts point to a 20–30% probability zone over the west-central Bay of Bengal around May 16 and 30–40% over the east-central Arabian Sea around May 17.
Sub-seasonal guidance from ECMWF also highlights 10–20% and 20–30% probabilities for systems in those regions during May 11–18.
Medium-range numerical weather prediction (NWP) models show divergence. Some, like NCEP GFS and certain AI models (Pangu Weather and GraphCast), indicate possible cyclogenesis over the southwest or west-central Bay of Bengal around May 13. ECMWF suggests a low-pressure area around May 15, while others like IMD GFS show no clear depression formation. Over the Arabian Sea, ECMWF hints at a depression around May 17.
Incidentally, Extremely Severe Cyclonic Storm Fani made landfall near Puri in Odisha, on the morning of May 3, 2019, with wind speeds estimated at 175–185 kmph. The storm crossed the coast between Gopalpur and Chandbali, causing massive disruption with heavy rainfall, high-speed winds, and significant damage to infrastructure.
