First Tropical Threat of 2020 to form in Bay of Bengal

The last tropical feature in the Bay of Bengal was Very Severe Cyclonic Storm Bulbul back in early November of 2019. The storm made landfall in West Bengal, India, on 9 November. The Bay of Bengal has been void of tropical activity since Bulbul or over five months.

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The northern Indian Ocean tropical season officially is boundless, meaning tropical cyclones can form anytime of year. However, the northern Indian Ocean tropical season has two peaks. The first peak is from April to June, or pre-monsoon, and the second peak spans from September into December, or post-monsoon.

Development occurred in the Bay of Bengal in late April/early May of 2019 with Extremely Severe Cyclonic Storm Fani, so tropical formation this time of year is not unusual.

The latest satellite image shows that the northern Indian Ocean is quiet now, but we are watching for the first tropical feature of the year to develop near the Andaman Islands between 30 April and 5 May. The models are in better agreement that a low will form over the Andaman Sea.

The ECMWF ensemble does show a low to moderate risk of development around the Andaman Islands around the beginning of May as does the Genesis Potential Parameter from the India Meteorological Department.

An MJO pulse moving through phase 3 coupled with an Equatorial Rossby Wave and a Kelvin Wave pushing into the Bay of Bengal as shown on the CFS would also favor the development of an area of low pressure near the Andaman Sea late this week.

Conditions should then be favorable for any low to strengthen into a well marked low and depression heading into the first weekend of May. The GFS and GEFS have backed off significantly on the intensity of the low since runs of the models late last week, so we are leaning toward any low only reaching a peak strength of a depression or deep depression on the IMD scale before striking Myanmar around 4 or 5 May.

It is looking less likely that the possible depression will impact India or Bangladesh, but these areas should continue to watch over the next few days. Regardless of the exact track and intensity of any tropical low, heavy rain and flash flooding will likely impact the Andaman and Nicobar islands from Friday into the weekend. AccuWeather meteorologists will continue to monitor the situation so check back at AccuWeather.com for the latest.