The minimum temperature dropped to 14.4° Celsius in Calcutta on Saturday, 2.5° below normal, as cold northwesterly winds made strong inroads into south
Bengal.
At 26.6°, the maximum was also about two notches below normal, based on a 30-year average.
Successive Western Disturbances had kept conditions warmer for the past few days. A gap in the extra-tropical storms has allowed the northwesterly winds free access to Bengal, said Met officials.
At Birbhum and Kalyani in Nadia, the minimum plunged to 10° on Saturday.
The hint of chill after sundown is likely to persist for the next three to four days, according to the Met forecast.
“The minimum is likely to remain in the range of 14°-15° for the next three to four days and start rising after that,” said a Met official in Alipore.
A fresh Western Disturbance is likely to emerge over northwest India around February 9.
“Under the influence of a Western Disturbance, isolated to scattered rainfall/snowfall likely over the Western Himalayan region during 9th-11th February,” said a national Met bulletin.
“No significant change in minimum temperatures likely over east India during next 4 days and gradual rise by 2-3°C for subsequent 3 days thereafter,” it added.
Western Disturbances are extra-tropical storms that bring rain and snow to northwest and northern Himalayan states. The storms travel from west to east. A powerful Western Disturbance can also cause rain and snow in Sikkim and the upper reaches of Darjeeling. In south Bengal, Western Disturbances prevent the free flow of northwesterly winds, thereby causing a rise in night temperatures.
Previous Western Disturbances have triggered snowfall in states like Kashmir and Himachal Pradesh. As cold winds from these snow-laden areas enter Bengal traveling south, the Celsius readings are sliding.
The current slide is most likely the last such spell this winter, said Met officials.
Calcuttans enjoyed the chill while it lasted. Parks and museums remained busy on Saturday, with Alipore Zoo, the Victoria Memorial and the Maidan crowded.