Thiruvananthapuram, Dec. 6
While there is no doubting that the north-east monsoon is poised to revive by the weekend, opinions now vary on the likely strength, the causative circulation would gather in the Bay of Bengal.
The US Navy's Fleet Numerical Numerology and Oceanography Centre (FNMOC) and the London-based Tropical Storm Risk Group are both suggesting that a remnant of Tropical Storm Durian will slide into the Andaman Sea early Thursday morning as a tropical depression.
The storm will have wind speeds of around 20 knots gusting to 30 knots as it leaves the Thailand coast and enters the Indian territorial waters, the FNMOC said. As a tropical depression, Durian will be known by the name of its parent wave, 24W.
A preparatory trough of low pressure has already formed over the Andaman Sea, according to a weather update put out by the Ohio State University. Rains or thundershowers are likely to occur at a few places in the Andaman and Nicobar Islands.
A latest update by Mr Jim Andrews of AccuWeather.com ventured to suggest that 24W could even spin up as a tropical cyclone in south Bay of Bengal and hit eastern Sri Lanka and adjoining south Tamil Nadu coast.
"While no longer a tropical storm, Durian bears watching as the parent wave crosses the Malay Peninsula and into south Bay of Bengal," he said.
It will indeed give a leg-up to northeast monsoon in Tamil Nadu, where only minor showers have been reported since November 20.
Mr Andrews had earlier indicated that the Durian remnant could be traceable at best as a tropical (easterly) wave in the Bay. But he recalled that the storm had earlier seemed to fade as it neared southern Vietnam, but had rustled up speed to minimal typhoon strength before crossing the Mekong delta. Indian forecasters begged to differ with projections about the system gathering much strength. The prevailing atmospheric dynamics do not allow this to happen. Things will become clearer in another two days, said Dr K. J. Ramesh of the Department of Science and Technology. "But there's no denying that the southern peninsula is in for an active phase of northeast monsoon," he said. Even assuming that the Durian remnant will grow no more than an easterly wave, its amplitude will be large enough to cause widespread rain over the entire peninsula.