Back-to-back western disturbances to cool North-West India

In quick succession, two active western disturbances will affect the hills and plains of North-West India and adjoining regions for five days from today (Saturday, May 11).

‘Active’ western disturbances are endowed with better amplitude than normal and affect the regional weather precipitating snow, lightning and thunder showers, and heavy rain, depending on the time of the year.

This is expected to bring down the sizzling hot conditions being reported from many parts of the region, though only briefly, since the next bout of heating would not be too far behind.

Such disturbances are more often accompanied by an offspring circulation in front, which is responsible for creating the rough to violent weather, again depending on the season.

Widespread rain

An India Met Department (IMD) update said that a prevailing first disturbance would induce formation of an offspring cyclonic circulation over West Rajasthan during the course of the day on Saturday.

This would lead to moisture incursion from North-West Arabian Sea, which would fuel thunderstorms over North-West India, and later over North-East India as the larger trough and the disturbance moves East.

This eastward movement would enhance rainfall activity also over Bengal and Sikkim on Sunday and Monday; and over the North-Eastern States for five days from Monday.

The Weather Company, an IBM Business, located the western disturbance and its induced cyclonic circulation over North Pakistan on Saturday morning and agreed that they would affect North India on Saturday.

“Westerly winds from the Arabian Sea would strengthen the activity of the disturbance,” The Weather Company said, bringing scattered to fairly widespread rain or snow and thunderstorms over the hills on Saturday. “Scattered rain and thunderstorms are likely over the plains even as a fresh western disturbance approaches North-West India from Monday,” it added.

A cyclonic circulation over North-East India and the southwesterly winds it generates from the Bay of Bengal would create instability, setting thunderstorms persist through the weekend into next week.

Widespread rain and thunderstorms are likely over North-East India in this period. Heavy rain and thunderstorms are very likely over Arunachal Pradesh, Assam and Meghalaya on Saturday.

A trough lying over the East Coast and a cyclonic circulation over South India are expected to set up heavy rain thunderstorms over Tamil Nadu and Kerala.

Cooler temperatures

Maximum temperatures are below normal by 2- to 3 degree Celsius over the northern half of the country due to rain and cloudy weather. Cooler trends may entrench over the region through the weekend into next week.

Meanwhile, the IMD said that thunderstorms, hail and gusty winds clocking up to 50 km/hour could lash Jammu & Kashmir, Himachal Pradesh, Uttarakhand, West Rajasthan, East Rajasthan, Punjab, Haryana, Chandigarh, Delhi, West Uttar Pradesh, East Uttar Pradesh, West Madhya Pradesh, East Madhya Pradesh, Vidarbha, Chattisgarh, Odisha, Bihar, Jharkhand, plains of Bengal, Arunachal Pradesh, Assam, Meghalaya, Nagaland, Manipur, Mizoram and Tripura over the next five days (up to May 14, Tuesday).

This would practically cover almost the entire northern half of the country from West to East and North-East, save Gujarat and Saurashtra and Kutch in the extreme West.