Jim Andrews

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Tropical Cyclone Threat for Bay of Bengal

October 12, 2010; 12:01 PM ET


Numerical forecast models, such as the GFS, are showing a likely tropical cyclone for the northern Bay of Bengal on or after Wednesday.

As I understand it, the scenario shows a tropical wave drifting west out of Myanmar, whereupon it spins up a tropical cyclone south of Bangladesh by Thursday. This cyclone is then forecast to track to the northern east coast of India (Orissa or northeastern Andhra Pradesh) on Saturday, local time.

GFS run of 0000 GMT, Tuesday, valid 0600 GMT, Saturday, showing sea-level pressure and rainfall

There have been enough model runs showing a tropical cyclone scenario for the northern bay that I am inclined to believe this will happen in some way.

With October now nearly halfway through, the time of highest tropical cyclone risk for the Bay of Bengal has begun.


The IMD have plotted, as of Oct. 11, the leading edge of SW Monsoon pullback from easternmost Bihar state (and easternmost Nepal) through Jharkhand, thence west through Kathiawar Peninsula in Gujarat state.

Yet the GFS has consistently been showing significant, for the last week or so, rain backing west to north-central India and west-central India. Maybe it has been "sensing" that a bay tropical cyclone would be in the works.

Anyways, there is potential for significant rain, however localized or spotty, in those northern states that were slighted during the South West Monsoon.

This is to say nothing of the potential for destructive wind, flooding and storm tides along the upper east coast of India.


The IMD End of Season Report is here. The upshot is that seasonal (June-September) rainfall for India as a whole is reckoned to have been 102 percent of long-term average.

September closed out wetter than normal, thereby helping to boost seasonal rainfall above the 100-percent mark.

Note, however, that the northeastern quadrant of India (and Bangladesh) had a significant dearth of rainfall during the four-month South West Monsoon period.


A spot to watch during the next few days will be the Philippine Sea westward from Guam. The JTWC have an alert for the area (as of this writing), and some numerical forecast scenarios have shown a tropical cyclone.

Another area to watch will be the South China Sea off central Vietnam later in the week.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com


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