Thread by @weatherindia

#CycloneAmphan to Form and Intensify Over BoB; Threat Lingers Over North AP, Odisha and #WestBengal Coasts

weather.com/en-IN/india/ne…

📷: (N Kanaka / BCCL, Visakhapatnam)

After two weeks of intense debate, most model projections are now agreeing that a cyclone will form over the Bay of Bengal by Saturday.

(Image credit: TWC Met Team)
#CycloneAmphan

The India Meteorological Department (IMD) confirmed on Thursday that the low-pressure area over the southeast Bay of Bengal is now well marked.

#CycloneAmphan

#CycloneAmphan | The forecasts suggest that the system will intensify further into a depression on Friday and then into a cyclonic storm over the southwest Bay of Bengal on Saturday.

Once formed, the storm will be named Amphan, as per the naming guidelines set by the World Meteorological Organisation (WMO).

#CycloneAmphan

Projected track

As per the current forecasts from the IMD, the storm would move northwestwards (towards India) till Sunday and recurve north-northeastwards after that.

#CycloneAmphan

In this case, the impact would be minimal for the Andhra Pradesh and Odisha coast, except for rough sea conditions and possible heavy rain spells. The maximum impact could be for West Bengal and Bangladesh coasts, as the storm approaches these regions.

#CycloneAmphan

The European model, ECMWF, on the other hand, paints a much grimmer picture. It projects that the storm will continue to move northwest to northwards till Tuesday evening and will come very close to the coast near Visakhapatnam in north Andhra Pradesh.

After that, the cyclonic storm could turn north and make landfall in Odisha somewhere between Brahmapur and Puri on Wednesday night.

As per these projections, the coastal regions of north Andhra Pradesh, Odisha and West Bengal are under an increased risk of heavy rainfalls, strong winds and possible flooding.

However, experts warn that given the lack of meteorological data due to #COVID19 pandemic and the timing of the storm, the model projections, especially ECMWF, may not be as accurate as they used to be during the normal times.

Strength of the cyclone

As the low-pressure brews over the Bay of Bengal, IMD reports that two seasonal factors remain favourable to the further intensification of the system.

One, the Madden-Julian Oscillation (MJO) is in a wet phase that could enhance the formation of rain-bearing clouds over the Bay of Bengal for the next seven days.

Two, the sea surface temperature is in the range of 30-31°C—ideal for the moist, warm air currents to feed the system further.

Given the favourable conditions, the storm is very likely to keep intensifying to become a severe cyclonic storm by Monday over the southwest Bay of Bengal. Most model projections, including IMD's GFS and European model ECMWF, agree on this point.

However, the projected storm track differs as it is too early to predict the ocean dynamics. Experts believe that, over the weekend, most models could agree on the potential path and intensity of the storm.

#CycloneAmphan

Potential impacts

Under the influence of the potential storm, squally winds gusting up to 60 kmph will prevail over the Andaman Sea till Sunday. Widespread heavy rainfall and thunderstorm are forecast over Andaman and Nicobar Islands till Sunday.

Wind speeds gusting up to 100 kmph are forecast over west-central and east-central Bay of Bengal on Monday. The maximum sustained wind speed of the cyclonic storm is likely to reach up to 160 kmph by Tuesday night.

#CycloneAmphan

If the storm approaches the coast at this intensity, severe damage can be expected across the coastal region.

#CycloneAmphan

The name Amphan is suggested by Thailand and will be the last name from the original list of 64 cyclone names proposed back in September 2004 for storms over the north Indian Ocean.

#CycloneAmphan

The WMO guidelines stipulate that the countries in the region must name storms in any ocean basin. For the northern Indian Ocean, now thirteen countries suggest the names.

#CycloneAmphan

The IMD's regional specialised meteorological centre (RSMC) in New Delhi monitors the cyclogenesis, issues advisories and names the cyclones.
#CycloneAmphan