The Hindu Business Line : Rain footprint tipped to grow bigger

Thiruvananthapuram, Jan. 18 The prospects of ongoing precipitation in the north and northwest getting replicated to some extent in parts of the east, east-central and peninsular India have received further boost through increasing model convergence.

The European Centre for Medium-Range Weather Forecasting (ECMWF) and the Ensemble Forecasting System (EFS) of the Fleet Numerical Meteorology and Oceanography Centre (FNMOC) of the US Navy have depicted the emerging scenario consistently over the past few days.

This is predicted to come about as the next big southwest Asia snowstorm sends down a “disturbance” across the northwest border. Expected to roll in during mid-week next week, the system would spawn rain away from the hills and into the vast plains extending eastward from Rajasthan right up to West Bengal. The US National Centres for Environmental Prediction too tends to supports this outlook.

FIRST INSTANCE

If this were to happen, this would be the first such instance of a meaningful rainfall event with a footprint matching that of the southwest monsoon of 2007, says Mr Jim Andrews of AccuWeather.com.

In doing so, it would draw liberally from the moisture pool available from the Arabian Sea. Interestingly, this would have taken place close on the heels of an unusually overarching trough of low pressure in the Arabian Sea setting up a cyclonic whirl (even a `low’) over land, which would get pushed to the east in line with the prevailing wind regime. This might set off some unsettled weather along its track, according to the ECMWF.

Some models also project a scenario where the Arabian Sea trough merges with a popping trough in the Bay of Bengal to the east and the land-based `low’ gets embedded into the broader trough towards the southeast coast (Orissa-West Bengal). In between, an easterly wave impacting Sri Lanka might just brush past the southern tip of the peninsula.

WIDESPREAD RAIN

An India Meteorological Department (IMD) update on Friday said that fairly widespread precipitation with isolated heavy fall was reported from the western Himalayan region during the 24 hours ending in the same morning.

The causative western disturbance was located over Jammu & Kashmir and neighbourhood. Under its influence, fairly widespread precipitation with isolated heavy fall is likely over western Himalayan region for another 24 hours.

Fog conditions are also likely over some parts of northern plains. The eastward movement of the system will bring down minimum temperatures by 3-4°C over northwest India and Rajasthan from Saturday.