Widespread thundershowers are expected over the plains of northwest India from February 3 to 6, according to India Meteorological Department (IMD).
A fresh Western Disturbance is likely to affect Western Himalayan region from tonight. Under its influence, scattered rain/snow with moderate thunderstorm and lightning is likely over the hills during February 1 and 2. Another Western Disturbance, in quick succession, is also likely to affect Western Himalayan Region from February 2 and plains of northwest India from February 3.
Due to the Western Disturbance, scattered to fairly widespread and moderate rain/snow with isolated thunderstorm and hail is likely over the Western Himalayan region during February 3 and 5.
Due to interaction of southwesterlies associated with the Western Disturbance and lower level southeasterlies from the Bay of Bengal, widespread light to moderate rain/thundershowers is likely over the plains of northwest India and adjoining Central India during February 3 to 6 with maximum intensity on February 4.
Rain and thunderstorms are also expected over adjoining Central India during February 4 and 5 and over adjoining east India on February 6.
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Dense to very dense fog was observed on Monday at isolated places over Uttar Pradesh and Bihar. Visibility recorded at 5.30 am today was less than 26 m over Bareilly, Bahraich, Lucknow, Sultanpur, Gorakhpur; less than 50 m at Varanasi, Patna, Bhagalpur, Purnea, Agartala; less than 500 m at Palam and Safdarjung in Delhi.
“The WD approaching on Sunday night will mostly affect the Western Himalayas. But the next Western Disturbance approaching on February 2 will be more intense and will bring both snowfall to the hills and rain to the plains. In Delhi-NCR on February 4 and 5, its likely to cause thunderstorms with light rain. After the WD passes, minimum temperatures will drop once again over northwest India, but cold wave is unlikely because climatologically, we are moving towards comparatively higher minimum temperatures,” said Kuldeep Shrivastava, head, regional weather forecasting centre.
Skymet Weather, a private weather forecasting company in its initial forecast for monsoon in 2021 released on Sunday projected that its likely to be a “normal” monsoon year with rainfall of 96% to 104% of the long period average (LPA). Last year, monsoon was driven by La Niña which is peaking right now. It will decline during the spring and turn neutral later through the monsoon season. It also means that monsoon 2021 is going to be a devolving La Niña to start with. This trend of Pacific Ocean temperatures may not lead to an above normal or excess rainfall.
“Models and other global weather reports are indicating a normal monsoon this year. Presently, La Nina is at its peak. By the time monsoon arrives, we may see El Niño and the Southern Oscillation (ENSO) Neutral conditions. The sea surface temperatures are likely to rise soon in the equatorial Pacific Ocean and the probability of continued La Niña will fall. We expect good rains in the first half of monsoon, thereafter rains may decrease a bit. Chances of below normal monsoon are almost nil,” said Mahesh Palawat, vice president (Climate change and meteorology), Skymet Weather.
ENSO is a periodic fluctuation in sea surface temperature and the air pressure of the overlying atmosphere across the equatorial Pacific Ocean according to the National Oceanic and Atmospheric Administration.
ENSO has a major influence on weather and climate patterns such as heavy rains, floods and drought. El Niño has a warming influence on global temperatures, while La Niña has the opposite effect. In India, for example, El Nino is associated with drought or weak monsoon while La Nina is associated with strong monsoon and above average rains and colder winters.
This monsoon, IMD is likely to issue a special seasonal forecast for rain-fed areas where there is no irrigation facility. It is also like to use a multi-model ensemble forecast ( a combination of different models) to predict monsoon rains this year.
“Its too early to make a monsoon forecast. We cannot share details now,” said M Mohapatra, director general, IMD. Last year, the total rainfall recorded in monsoon was 108.7% of long period average and in 2019 it was 110% of LPA –consecutive years of above normal monsoon. Before 2020 and 2019, consecutive years of above normal monsoon were recorded in 1958 and 1959.