Bay of Bengal readies for unusual activity as N-E monsoon enters November end

Weather watchers are anticipating unusual activity to unfold over the Bay of Bengal which continues to host among the warmest waters around the global tropics as the North-East monsoon enters into the last week of November. Southern parts of Tamil Nadu are already feeling the heat, which could propagate into the northern coast and interior.

India Meteorological Department (IMD) has extended its outlook for a fresh low-pressure area over the South-West Bay for another day with a preparatory cyclonic circulation having been hoisted over the South Bay for the past few days. An underlying easterly wave has already started affecting Sri Lanka and parts of South Tamil Nadu, and hence the ongoing rains over parts of the state.

Lankan agency ‘more optimistic’

The Sri Lankan Meteorological Department is more optimistic and said this (Wednesday) morning that the prevailing low-level atmospheric disturbance located to the South-East of the island is expected to intensify into a low-pressure area during the ‘next few hours.’ Cloudy skies can be expected over the island. Showers or thundershowers will occur at times over most parts.

Heavy showers about 10 cm can be expected at some places in Northern, North-Central, Eastern, Uva, Sabaragamuwa, Central and Southern provinces. Fairly heavy showers above 7.5 cm can be expected at some places elsewhere, the Lankan forecaster said.

Bay warms to close second

The warmest waters along the tropics are currently lying around the Maritime Continent (Indonesia et al) at an improbable 31 degrees Celsius (way above the 27.5 deg Celsius required for cyclogenesis). Parts of the North Bay around the Myanmar coast have warmed to the next highest level of 30 degrees Celsius and most of the rest of the Bay to 29 degrees Celsius.

This is what makes it ripe for cyclogenesis (formation of low-pressure systems, depressions or cyclones) and hence the outlook for the low-pressure area over the South-West Bay. Going forward, some global models point to the possibility of a stronger system being lobbed in from around the Indonesian seas which may go on to become a potential storm in the Bay

Storms in the making seek out the warmest available waters in the neighbourhood and an early outlook puts the brewing one towards the northern parts of the Bay. It is forecast to pop up over the South-East Bay around the month-end (in a weeks’ time) from where it would likely head towards the Myanmar coast, as per IMD’s numerical model projections.

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