Depression weakens into low pressure, but wet weather to stay

The depression over the Gulf of Mannar has weakened two ranks down to a conventional low-pressure area this (Sunday) morning but the India Meteorological Department (IMD) expects it to continue to cause moderate to heavy rain over Tamil Nadu, Puducherry, Karaikal, South Kerala, Mahe and Lakshadweep on Sunday and Monday.

A low-pressure area may be a less intense system than a depression, but the very fact that it can drop anchor at a place for much longer and since the scope for lateral movement, if any, is measured and slower, makes it a different proposition when it comes to its rain generating potential.

Heavy rainfall forecast

The IMD has forecast heavy rainfall at isolated places over Tamil Nadu, Puducherry, Karaikal, Kerala, Mahe, South Coastal Andhra Pradesh and Lakshadweep today (Sunday). Thunderstorms and lightning are likely at isolated places over Andaman & Nicobar Islands, Tamil Nadu, Puducherry, Karaikal, Kerala, Mahe, South Coastal Andhra Pradesh and Lakshadweep.

Squally winds of speeds reaching 35-45 km/hr gusting to 55 km/hr may prevail over the Gulf of Mannar and adjoining South-West Bay of Bengal; along and off the South Tamil Nadu coast; the Lakshadweep-Maldives-Comorin areas and adjoining South-East Arabian Sea; and along and off the Kerala coast. Fishermen are advised not to venture into these areas.

Outlook for Monday suggested conditions along similar lines with heavy rainfall being forecast at isolated places over Tamil Nadu, Puducherry, Karaikal, South Coastal Andhra Pradesh and Lakshadweep. Thunderstorms and lightning may break out at isolated places over Tamil Nadu, Puducherry, Karaikal, South Coastal Andhra Pradesh and Lakshadweep.

Squally winds with speeds reaching 35-45 km/hr gusting to 55 km/hr may prevail over the Lakshadweep-Maldives-Comorin areas and adjoining South-East Arabian Sea and along and off the Kerala coast during the day. Fishermen are advised not to venture into these areas.

Churn in Arabian Sea?

Extended forecasts by the European Centre for Medium-Range Forecasts (ECMWF-IFS-HRES) suggested that the low-pressure area may dig in to the South of Sri Lanka and wriggle out from the confines of the Gulf of Mannar to the open Laccadive Sea-Comorin area where the seas are warmer (29-30 Deg Celsius).

It might find some traction and intensify gradually throwing down a curtain of light to moderate showers along the West Coast of India before the rains get dragged to the North-East into Gujarat, Madhya Pradesh, South-West Uttar Pradesh and Bihar under the influence of incoming western disturbances across the international border.

Western disturbance calls in

The IMD has hinted the arrival of a disturbance already, which may cause scattered to fairly widespread precipitation over Jammu & Kashmir, Ladakh, and Himachal Pradesh from Monday to Wednesday and isolated precipitation over Uttarakhand from Tuesday and Wednesday. Isolated heavy rain/snow is forecast for Jammu & Kashmir and Ladakh on Tuesday. Another fresh western disturbance is expected to chug in at the border today (Sunday).

Winter temperature outlook

An IMD outlook for winter temperatures from December 2020 to February 2021 said that minimum temperatures (night) may be below normal over North, North-West, Central and a few meteorological subdivisions of East India. Most of the subdivisions of North-East India and a few on the West Coast and over the South Peninsula may experience above normal minimum temperatures.

The probability forecast for maximum temperature (day) indicates that above-normal maximum temperatures are likely over most subdivisions of North-West, North, East and North-East India and a few subdivisions of Central and Peninsular India. Most of the subdivisions of the South Peninsula are likely to experience below-normal maximum temperatures, the IMD outlook said.

COMMENT NOW