Monday, February 21, 2011

Back-to-back westerlies to trigger heavy weather


Active weather has once again broken out over the western Himalayan region with cascading impact for the plains of northwest India and the east as back-to-back western disturbances were on their course to hit the region.
On Sunday, an incoming western disturbance dropped anchor over north Pakistan and adjoining Jammu and Kashmir and was slowly moving into further east and southeast.

‘ACTIVE’ SYSTEM
This will be followed close on the heels by yet another ‘active’ western disturbance, which will start affecting the western Himalayan region from Tuesday onwards and adjoining plains from Wednesday onwards.
A weather warning issued by India Meteorological Department (IMD) on Sunday evening said isolated thunder squalls or hailstorms may occur over Orissa, Chhattisgarh, Jharkhand, Gangetic West Bengal and north Andhra Pradesh on Sunday and Monday.
Punjab, Haryana, Delhi, north Rajasthan, west Uttar Pradesh and Vidarbha could well be among those regions to have been taken the hit through the day on Sunday itself.

RAIN BELT
Extended forecast valid until Friday spoke about the rain belt shifting entirely to the south with fairly widespread rain or thundershowers indicated for Tamil Nadu and Kerala and scattered over coastal Andhra Pradesh, Rayalaseema and south interior Karnataka.
But fresh fairly widespread rain or snow could be unleashed over western Himalayan region and scattered rain or thundershowers accompanied with isolated squalls or hailstorms over adjoining plains presumably under the influence of a fresh western disturbance.
The emerging pattern of rains had been signalled at least two weeks ahead by some international models, which have largely retained their outlook in the latest updates.

WIDESPRAD RAIN
Meanwhile, overnight on Sunday, fairly widespread rain or snowfall was reported from Jammu and Kashmir, scattered over Himachal Pradesh and isolated over Uttarakhand as the incoming westerly system sat across the northwest border.
Scattered rain or thundershowers also occurred over Orissa, Chhattisgarh, Gangetic West Bengal and Jharkhand while it was isolated over Madhya Pradesh, Andhra Pradesh, west Rajasthan, Vidarbha and Arunachal Pradesh.
Minimum temperatures were below normal by 2 to 3 deg Celsius over east Uttar Pradesh, Bihar, Punjab, sub-Himalayan West Bengal and Assam and above normal by 2 to 3 deg Celsius over Rajasthan, Orissa and Andhra Pradesh.
The lowest minimum temperature of 6 deg Celsius during the last 24 hours ending Sunday morning was recorded at Adampur in Punjab in the plains of the country.

CONVECTIVE CLOUDS
Satellite imagery on Sunday afternoon showed convective (rain-bearing) clouds over parts of Jammu and Kashmir, Himachal Pradesh and Punjab, ready to ‘cream up’ the hills and down the slopes in the northwest. .
A short-term outlook until Wednesday said that scattered rain or thundershowers are likely over Orissa, Chhattisgarh, Vidarbha, Gangetic West Bengal, Telangana and coastal Andhra Pradesh on Sunday and fairly widespread on Monday.
Fairly widespread rain or thundershowers would occur over Punjab, Haryana and Delhi; scattered over east Rajasthan and west Uttar Pradesh; and isolated over west Rajasthan, east Uttar Pradesh and Madhya Pradesh on Monday.

SOUTHERLY RAIN
Isolated rain or thundershowers would occur over Rayalaseema, south interior Karnataka, Tamil Nadu and Kerala on Monday before scaling up thereafter.
Minimum temperatures would fall by 2 to 3 deg Celsius over the plains of northwest and central India during next three days. 

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