IMD’s weather forecast raised hope but Delhi remained dry; heavy rain warning for NW India remains

The orange alert sounded for Delhi on Wednesday turned out to be false alarm.

New Delhi: The Regional Meteorological Centre (RMC), Delhi, withdrew its ‘orange’ category moderate rain warning for the national capital on Wednesday, as it turned out to be a modelling error.

IMD has predicted light to moderate rains in Delhi over the next two days. (Biplov Bhuyan/HT PHOTO)

RMC had issued an orange category warning that implied local authorities must remain prepared for traffic disruption and inundation of low-lying areas.

The forecast was due to an error in the model forecast, according to scientists. The models were showing that the monsoon trough (the line of low pressure) would shift northwards from Tuesday and stay over Delhi for a couple of days, but the monsoon trough shifted very fast to the Himalayan foothills, leaving the national capital dry.

There may be light to moderate patchy rain over Delhi-national capital region (NCR) for the next two days but not heavy rain as was expected, India Meteorological Department (IMD) scientists said.

RMC has issued a moderate rain warning for Friday.

“We were expecting the monsoon trough to remain near Delhi for some time. But the western end of the trough shifted to the foothills bringing a lot of rain in Jammu and northern Punjab and the eastern end is near Bahraich. This explains the reason behind southern Uttar Pradesh (UP) is also getting rain. We may record some light rainfall on Friday,” said Kuldeep Shrivastava, head, regional weather forecasting centre (RWFC).

Delhi has an 8% rain deficiency until Thursday. Rain within -19% and +19% category during monsoon season is considered to be in the normal category.

“We had issued a light rain warning. The models showed that monsoon trough would run along Delhi for at least a day or two. There was a low pressure area over south-west Rajasthan, where all the moisture was concentrated. When it weakened, we were expecting the moisture to reach to other parts of north-west India, but that didn’t happen. The monsoon trough is oscillating very frequently and fast this time. The model didn’t capture the shift this time,” said Mahesh Palawat, vice-president, climate change and meteorology, Skymet Weather, a private meteorological forecaster.

A well marked low-pressure area is lying over south-west Jharkhand. It is likely to move west-northwest wards across northern Chhattisgarh, northern Madhya Pradesh (MP) and southern UP during the next three days and then weaken gradually, IMD said in its Thursday bulletin.

The western end of the monsoon trough runs close to the Himalayan foothills and the eastern end runs to the south of its normal position. The western end is very likely to shift southwards from Friday and remain along its normal position for the next two days and shift northwards to the foothills of Himalayas for the next four-five days. “The convergence of strong lower level south-westerly winds from the Arabian Sea and easterly winds from the Bay of Bengal is likely over the plains of north-west India from Saturday onwards for the next two days,” the bulletin said.

Due to these favourable conditions, widespread and extremely heavy rainfall is likely over eastern MP on Friday and Saturday and over Chhattisgarh and Vidarbha on Friday. Heavy rain is also likely over Uttarakhand and western UP until Monday (August 31); over Punjab on Friday and Saturday; over Haryana, Chandigarh and Delhi on Saturday and Sunday; over western Rajasthan between Saturday and Monday; over eastern Rajasthan from Friday to Monday.

“We are expecting widespread and good rains throughout north-west India for the next three to four days,” said Dr Mrutyunjay Mohapatra, director-general (D-G), IMD.

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