Foggy and cold weather in north-west India would undergo a sharp change to being stormy and raining from next week. This is on account of expected arrival of a deep and heavily endowed (moisture-laden) western disturbance into the region.
LOW PRESSURE
Currently located around the Mediterranean, the system is expected to start moving to the east over the next few days. The low-pressure system is forecast to weaken as it traverses the dry West Asia and limp into Afghanistan/Pakistan by Friday next.
But from here, it would start drawing in moisture heavily from the northeast Arabian Sea and throw up a low-pressure area. The system may weaken suddenly as it crosses into north-west India. But it would already have started influencing local weather.
RAIN AND SNOW
The India Meteorological Department (IMD) has come out with a bulletin forecasting moderate to heavy rain over the region. It said on Thursday that the strong western disturbance would bring rain or snow to many places over western Himalayas.
An upper air trough lay extended from northeast Arabian Sea to north Rajasthan as if in wait for the ‘big westerly system.’ This trough features embedded cyclonic circulations over Gujarat and adjoining south Rajasthan. This is expected to act as a ‘step-up facility’ for the incoming westerly to draw in moisture from the adjoining Arabian Sea.
The IMD has predicted heavy to very heavy rain or snow at a few places over western Himalayas on Friday and Saturday.
US FORECASTS
Rain or thundershowers has been forecast over Punjab, Haryana, Delhi, Uttar Pradesh and Rajasthan until Sunday. Rain or thundershowers may break out at few places over Madhya Pradesh from Friday.
The IMD has warned the possibility of hailstorm over Himachal Pradesh, Uttarakhand, Punjab, Haryana, Delhi, Rajasthan and Uttar Pradesh.
DIPPING SOUTH
This outlook seemed to suggest arrival of another western disturbance more or less keeping with the features of the predecessor. This could venture down to the south and interact with an easterly wave to spark off rain over central India and adjoining western peninsula.
vinson.kurian@thehindu.co.in