Monsoon enters lull phase; Pacific typhoon may revive it from weekend bl-premium-article-image

Vinson Kurian Updated - January 24, 2018 at 03:24 AM.

weather

The monsoon has entered a subdued phase and is likely to lie low for the first 15 days in July except along the foothills of Himalayas and parts of east India.

The India Met Department said that the monsoon was vigorous (marked by heavy rain) over east Uttar Pradesh, east Madhya Pradesh and Arunachal Pradesh during the 24 hours ending on Monday morning.

The Met has already predicted that July is likely to deliver below normal rainfall (at 92 per cent of long-period average) this year.

Weather systems
The two main rain-driving systems are a low-pressure area (erstwhile deep depression from the Arabian Sea) over east Uttar Pradesh and a truncated offshore trough from Maharashtra to Kerala.

The ‘low’ will continue to loiter in the region for a couple of days and then weaken and merge with the land-based monsoon trough extending from north-west to south-east (northwest India to Bay of Bengal). But indications are that a fresh low-pressure area may form over the head end of the Bay of Bengal (northernmost part of the Bay) by the weekend.

This would happen as the monsoon flows get energised from ‘pull’ exerted by a projected typhoon in the west Pacific, southeast of Philippines and heading towards east China according to initial assessments.

The revived flows are expected to touch off activity in the Arabian Sea, peninsular India and the Bay of Bengal from Friday/Saturday.

US models predict that the initial west-northwest movement of the typhoon would trigger the formation of a ‘low’ in South China Sea that lies next to the east.

Fresh bay ‘low’ The Pacific and South China Sea teaming up in this manner has sent its own ‘pulse’ into the Bay of Bengal which is the next big sea body that is located further east in a straight line.

No wonder models point to the ‘sweet spot’ in the head Bay where they expect a fresh ‘low’ to materialise. It would most possibly take the path along foothills and keep the monsoon in full flow in that region only.

This promises another round of heavy to very rainfall and suspected landslides in northeast and east India from the weekend.

Meanwhile, the offshore trough has been delivering good rainfall over Kerala and adjoining region in the south peninsula over the past couple of days.

It is now a feeble formation and will cause rainfall over isolated places over Kerala and coastal Karnataka during the next couple of days.

Published on June 29, 2015 16:42