Showers over 3 days reduce July rain deficit to 10% in Kolkata
Times of India | 23 July 2024
Kolkata: Frequent spells of drizzles since Saturday have narrowed down the July rain deficit in Kolkata to a mere 10%, though the deficit remains a wider 28% in Gangetic West Bengal or south Bengal. The seasonal deficit in Kolkata is 30% which could get reduced by the month end, said weather scientists at Regional Meteorological Centre, Alipore. In south Bengal, the seasonal deficit stood at 48% on Monday.Kolkata had a deficit of 49% in June.
The city has received 242.8 mm rain between July 1 and 22 against a normal count 269.1 mm. “This is taken as normal rain since a deficit or surplus of up to 19% is taken to be within the acceptable range. Since the city is now getting regular showers, the rain count could rise fast. One heavy spell could wipe out the narrow deficit and take the count beyond the normal mark,” said RMC weather scientists HR Biswas.
But the seasonal deficit for Kolkata remains wider. The period for the seasonal count begins from June 1, though the official date for onset of monsoon in Kolkata and south Bengal is June 11. This year, monsoon had set in Kolkata on June 22. “While monsoon arrived late, the monsoon trough remained weak and often moved away from south Bengal and remained stationed across north Bengal triggering heavy rain there. There were few low-pressure systems over Bay of Bengal that could trigger consistent rain, keeping the rain count low. Now, we are having more frequent low-pressures that have started pushing the count up,” explained Biswas.
Between June 1 and July 22, Kolkata has received 386 mm rain against a normal count of 552 mm, a deficit of 30%. Like Kolkata, the July deficit in south Bengal has come down to 28%. July is the rainiest monsoon month in Bengal.
Between 2010 and 2017, Kolkata received less than normal in July on five occasions. It doesn’t necessarily indicate a deficiency for the season, though, said Biswas. “Even though the seasonal deficiency is high so far, there is still enough time for a make-up. August is also peak monsoon period and it often rains heavily in September. So, the final count will depend on the number of systems that we have in the region in the coming weeks,” said Biswas.
A depression over northwest and adjoining westcentral Bay of Bengal entered Odisha on Sunday, turning into a low-pressure system. Along with the monsoon trough passing through Chandbali in Odisha, the system has been triggering frequent spells of rain since the weekend. On Monday, Kolkata got 14.4 mm rain and 34.2 mm between Sunday and Monday evening.
“The monsoon trough is expected move northward and enter south Bengal within the next two days. Once it does, the spells of rain could get frequent. Kolkata and south Bengal will continue to be drenched by showers till at least Friday,” said Biswas.