City’s only functioning doppler radar conks again amid heavy rains

A doppler radar scans the cloud bands and gives updates about rain every 15 to 20 minutes. It typically has a range of 250 kilometres

Mumbai: The city’s only functioning doppler radar at Veravali, Jogeshwari, was out of order for the second time in the season on Tuesday morning due to heavy rains.

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A doppler radar scans the cloud bands and gives updates about rain every 15 to 20 minutes. It typically has a range of 250 kilometres.

“This is the second time the radar’s updates on the website got stuck this season at 9:30am,” said Athreya Shetty, an amateur meteorologist. “The doppler radar is helpful for a short-range nowcast, especially as Mumbai is prone to rainfall in the triple digits in short intervals.”

The only other doppler radar in the city, at Colaba, is being upgraded and is currently non-functional.

“The update frequency of the new radar is a lot better than the old one at Colaba, which used to update every 30 minutes, within which the rain bands would travel a lot. It would also break down very frequently,” added Shetty. “As it was an S-band radar and had a range of 500 kilometres, it was helpful for long-term forecasts in especially grim situations, like cyclones.”

The IMD uses manual observations, automatic weather stations (AWS), the doppler radar and satellites to forecast the weather.

After an orange alert for Tuesday, a yellow alert – signifying heavy to very heavy rain very likely at isolated places – has been issued for Wednesday and Thursday. “Heavy rains were very likely on Tuesday because of a low-pressure system over Chhattisgarh, a cyclonic circulation in the mid-tropospheric level/middle level of the atmosphere over south Gujarat and an offshore trough. These factors aid the entry of moisture-laden winds,” said Sushma Nair, IMD.

From 8am to 5:30pm on Tuesday, rainfall recorded was 11mm at Colaba and 31.8mm at Santacruz.