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Fresh Arabian Sea depression to pop up over Lakshadweep-Maldives by Wednesday

Vinson Kurian Thiruvananthapuram | Updated on October 29, 2019 Published on October 29, 2019

IMD forecast a light to moderate rainfall at most places over South Kerala and South Tamil Nadu, with heavy falls at isolated places in the next three days

The India Met Department (IMD) said this (Tuesday) morning that a low-pressure area persisting over the Equatorial Indian Ocean off the South Sri Lanka coast from the previous day, has become well-marked.

The IMD has maintained its outlook for the low to become the next monsoon depression over the South-East Arabian Sea and the adjoining Lakshadweep-Maldives area by tomorrow (Wednesday).

IMD update on super cyclone Kyarr and second monsoon depression over Comorin area

SECOND DEPRESSION

The depression is the second in the Arabian Sea of the North-East monsoon, after a predecessor went on to become supercyclone Kyarr, which is set to weaken off the coast of Oman in the Arabian Gulf.

The IMD has forecast light to moderate rainfall at most places over South Kerala and South Tamil Nadu, with heavy falls at isolated places during the next three days.

The showers would escalate to become very heavy falls at isolated places over the same region both today (Tuesday) and tomorrow (Wednesday). Light to moderate rainfall is also forecast at most places today, with very heavy falls at isolated places over Lakshadweep and extremely heavy falls on Wednesday and Thursday.

Strong winds clocking 30-40 km/hr and gusting to 50 km/hr may prevail over the Comorin and adjoining Equatorial Indian Ocean and its neighbourhood today, the IMD said.

Squally winds with speeds reaching 40-50 km/hr and gusting to 60 km/hr (associated with a depression) are forecast over the South-East Arabian Sea and the adjoining Lakshadweep-Maldives areas on Wednesday and Thursday.

The sea condition will be rough to very rough (wave heights of up to 13-20 ft) over the Comorin area and its neighbourhood today, and the South-East Arabian Sea and the adjoining Lakshadweep-Maldives areas on both Wednesday and Thursday.

Fishermen have been advised not to venture into the Comorin-Maldives-Lakshadweep areas and the adjoining South-East Arabian Sea on Wednesday and Thursday.

NO CONSENSUS

Meanwhile, international forecasters do not have a consensus view on the intensity and track of the projected second depression in the Arabian Sea.

The Canadian Meteorological Centre is the most outspoken of these models, predicting a minimal cyclone heading towards Oman/ Yemen from India's West Coast

 

The US Naval Global Environmental Model and the UK Met Office model (see below) show almost identical tracks towards the Gujarat coast - made infamous by very severe cyclone Ockhi of 2017 - for a much weaker system this time round.

While the US Navy model shows no more than a depression travelling along India's West Coast all the way up to Gujarat, the UK Met Office model suspects a stronger system is there for the asking.

 

 

GROUND ASSESSMENT

The US Joint Typhoon Warning Centre has located the well-marked low to 574 km to the South of Kochi, with satellite imagery depicting a flaring convection (clouding) above a consolidating low-level circulation centre.

It assessed that the environment is favourable for further development, given the low vertical wind shear values (up to 27 km/hr) and strong window effect on top.

The vertical wind shear represents the change of wind direction and speed with height, higher values of which can cap storm development by slicing off the head of the building storm tower.

The window effect, or strong upper level divergence on top, allows the storm to breath out and keep itself healthy even as the warm waters (up to 30 deg C) provide it ample moisture to feed itself.

The US agency, too, cites the apparent lack of consensus among various weather models with respect to the system credentials - some show a North-ward track along India's West Coast and turning West towards the Arabian Gulf, as was the case with predecessor supercyclone Kyarr - while others contested it.

IMD GETS IT RIGHT, AGAIN

Meanwhile, supercyclone Kyarr was located 980 km West of Mumbai, 1,020 km East-North-East of Salalah (Oman) and 510 km East-South-East of Masirah (Oman) early on Tuesday morning.

The IMD expects it to move West-North-West till Wednesday morning, re-curve West-South-West thereafter, and move towards Gulf of Aden, off the South Oman-Yemen coasts during the subsequent three days.

It is very likely to weaken into an extremely severe cyclone later on Tuesday, a very severe cyclone by tomorrow (Wednesday) and further into a severe cyclone by Thursday morning.

As mentioned already, the IMD has once again underlined its credentials as the best among the storm tracking agencies, by getting it right with supercyclone Kyarr.

In its latest forecast track, even the US Joint Typhoon Warning Centre has plumped for a track that the IMD has stuck with from the word go, i.e. West-North-West initially and later recurving West-South-West into the Gulf of Aden.

 

Published on October 29, 2019
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