The Hindu Business Line : Storm threat for Bay, Arabian Sea in early Oct

Thiruvananthapuram, Sept 24 More indications of intense to severe thunderstorms exiting equatorial Africa to wind their way into the Indian Ocean during the course of the week, and increasingly so during the next, are becoming available.

Convective activity is forecast to gradually shift in an east-northeast direction to propagate into India and further into East Asia, according to these forecasts. The Climate Prediction Centre of the US National Weather Services has already come out with an almost similar outlook.

Going forward, there is also an elevated risk of tropical cyclones spinning up in the Arabian Sea and the Bay of Bengal during the period from end-September to October 11, according to outlook by another group of numerical weather models.

TRANSITION PHASE

This coincides with the monsoon transition phase from southwest to northeast, and is known to be conducive for cyclone formation. These early-October systems normally originate over the lower latitudes in the Bay and move in a north-northwest direction, according to Dr Akhilesh Gupta, Senior Advisor, Department of Science and Technology.

This is unlike the monsoon ‘low’s/depressions, which take a west-northwest track. In this manner, the Orissa coast provides the ideal landfall destination for the early-October systems. But May and November provide the peak storm season in the Bay.

In the Arabian Sea, the October storms originate over the central waters, and they move west-northwest to head towards Oman/Yemen, Dr Gupta said.

BUSY PACIFIC

The Northwest Pacific typhoon season is getting into top gear with Hagupit, the raging storm in the region reaching Category-3 status briefly before impacting the Chinese coast.

A successor tropical storm (as yet unnamed) has already taken shape east of the Philippines and is threatening to grow into a destructive Category-4 storm (to be named Typhoon Jangmi as per protocol) by September 29, still some distance away from landfall.

Once again, a west-northwest movement is indicated that would take the rampaging storm into China after being made to squeeze its way between northern Philippines and Taiwan, according to the London-based Tropical Storm Risk Group.

IMPACT FOR BAY

No models as on date has picked any signs of successive strong typhoons moving west-northwest in the Northwest Pacific impacting either the adjacent South China Sea or, by implication, the Bay of Bengal.

This is just as well, Dr Gupta said, since only patently westward-moving systems originating from the South China Sea can be expected to impact the Bay of Bengal/North Andaman Sea. But this is an activity climatologically reserved for November/December.

More Stories on : Climate & Weather | Climate & Weather

Article E-Mail :: Comment :: Syndication :: Printer Friendly Page