‘Powerful’, ‘U-shaped’ jet streams: Experts say cold, stormy Western Disturbance coming up to shake North, West India

WEather experts feature warned of a warm western sandwich perturbation that is expected to take intense rain and hailstorm in some parts of India and bring down temperatures sharply while travelling through Northwest India.According to the India Meteorological Department (IMD) bulletin issued on April 1, the active Western Disturbance is to hit its peak activity along with hailstorm on April 3 and 4 with isolated heavy rainfall over primary impact zone Kashmir valley on the 3rd.Wet spell with thunderstorm and lightning is likely to take place over central parts of the country till April 6 with isolated hailstorm activity likely April 3, IMD said, adding that day temperatures are likely to remain near normal to below normal over Northwest India the 6th.The weather has been colder than usual for this time of the year for many parts of the country with rare weather systems bringing rain. The second half of last month also saw a western disturbance bringing rain and lowering mercury over northwest India, including parts of Delhi-NCR.‘Powerful’ Western Disturbance, ‘U-shaped jet streams’Weather experts described the disturbance as powerful, with its “U-shaped” jet streams set to bring hailstorms along with rain in parts of the country. Rain and hailstorms did lash several places in Haryana and Punjab on Tuesday, raising worries among wheat growers, who anticipated damage to their crop which was ready for harvesting.Dr. Pradeep, who describes himself as a climate scientist on X, shared a post saying, “A powerful Severe Western Disturbance is set to track across Northwest India, passing critically close to the Gujarat and Rajasthan border. This system will trigger a significant spell of extreme weather across multiple states.”Also Read | 'Insane cover': What's making Delhi unusually cold? It is a '1,000-km' rain bandHe said the primary impact zones (Heavy rain/snow and storms) will likely be Jammu and Kashmir and Ladakh, where intense rain and heavy mountain snowfall are expected; Punjab and Rajasthan, where widespread thunderstorms and gusty winds are expected; and Gujarat, where significant impact along the northern borders and interior regions is likely. Isolated to scattered thunderstorms will develop across the plains and central/eastern belts, including north/central Haryana, Delhi NCR, West Uttar Pradesh, Himachal Pradesh, and West Madhya Pradesh, Dr Pradeep said in his post.Central/South parts of Maharashtra (Vidarbha/Marathwada), Chhattisgarh, and Telangana and parts of Odisha and West Bengal are also likely to receive rain and thunderstorm as the system moves through.Expect a sharp fall in mercury levels following the rain, he said in the post on Tuesday but added in another post that summer is probably gonna start kicking in during the second half of April.Navdeep Dahiya, an amateur weatherman, said on X “jet streams perfectly U Shaped for the upcoming western disturbance starting from 3rd April.”Mahesh Palawat, vice president, climate and meteorology, Skymet Weather., also said that when the westerly jet stream is particularly wavy, “we sometimes see an increase in the impact of the WDs in lower latitudes”. "The wavy jet stream is linked to rapid warming of the Arctic,” an earlier HT report quoted Palawat. “Entire north, west India to experience cold front rains, hails and storms. States in center and southern peninsula to experience intense evening storms,” Dahiya said in his X post, describing it as “too much weather action for the third driest month of the year”.He also said the delayed summer season is likely to pick up after April 15 only.According to the earlier HT report, March recorded eight western disturbances against a normal of five to six, and at least three more are expected through mid-April. The spike is made more striking by what preceded it: January and February saw far fewer WDs than usual, resulting in low snowfall across the Himalayas. The systems have intensified sharply since mid-March.Western disturbances refer to moisture-laden cyclonic systems that originate over the Mediterranean and travel eastward along the jet stream — the narrow, high-altitude band of fast-moving winds that circles the globe around 30,000 feet.(With inputs from Jayashree Nandi)