Mumbai: The city barely had time to bid goodbye to rains before it got its first heatwave warning of the post-monsoon season. India Meteorological Department (IMD) on Thursday issued a yellow alert for a heatwave in isolated pockets of Mumbai and Raigad for Friday, as temperatures continued to hover several degrees above normal.The heatwave warning comes six days after IMD announced the withdrawal of the southwest monsoon from Mumbai on Oct 3. On Thursday, IMD also declared the withdrawal of the southwest monsoon from Maharashtra.Mumbai sweltered on Thursday as IMD’s Santacruz observatory logged a maximum temperature of 37.6°C, a sharp 4.5°C above normal, making it the highest day temperature recorded this year so far. Just a day earlier, Santacruz recorded 35.4°C. The all-time highest day temperature recorded by the Santacruz observatory, representative of Mumbai, for the month of Oct was 38.6°C on Oct 17, 2015.Colaba recorded 36.5°C, 3.9°C above normal, compared to Wednesday’s 34°C. The Thane-Belapur belt was also reeling under the heat, recording a maximum of 37.2°C.Despite the scorching afternoons, minimum temperatures have not shown a similar spike. Santacruz recorded a minimum of 24.7°C, close to normal, while Colaba recorded 26.5°C, 1.1°C above normal. Relative humidity remained high at 78% at Santacruz and 89% at Colaba.Weather experts expect the hot spell to continue through Oct 14 or possibly into the middle of next week.Independent weather observer Abhijit Modak said the current weather pattern was particularly favourable for a sharp rise in daytime temperatures. “The combination of a persistent high-pressure area over Gujarat and easterly to northeasterly winds is currently suppressing the sea breeze over Konkan, allowing temperatures to rise sharply during the day. Mumbai and parts of MMR could therefore see temperatures approach 39°C in the coming days. The early withdrawal of the monsoon, below-normal rainfall in Sept and the lack of a significant post-monsoon thunderstorm spell have further reduced moisture and cloud cover, allowing the land surface to heat up quickly. With these conditions likely to persist, the first half of Oct could remain unusually hot, with temperatures potentially peaking around Oct 14,” he said.For Mumbai and other coastal areas, the IMD’s heatwave criteria take into account both the absolute temperature and its departure from normal. A heatwave is declared when the maximum temperature reaches at least 37°C and is 4.5°C or more above normal for two consecutive days.Dr Nitin Karnik, head of the department of medicine at Sion Hospital, noted that severe dehydration is common during high-temperature seasons. He said there are classic symptoms of heat exhaustion observed by the hospital every time temperatures rise: heavy sweating, dizziness, headache, fatigue, and fainting.“These are commonly seen in people who are on the move or outdoors throughout the day,” he said.Dr Gautam Bhansali, senior consultant physician at Bombay Hospital, said that limited air circulation in the city due to the way it is structured creates an urban heat island-like condition.“This, combined with high humidity, leads to severe dehydration. The condition can also impact the kidneys. We are currently managing two patients who were admitted with severely low blood pressure. People must remain hydrated and cover their heads outdoors,” he advised.(Inputs by Eshan Kalyanikar)Maximum temp on ThursdaySantacruz: 37.6°C; 4.5°C above normalColaba: 36.5°C; 3.9°C above normalThane-Belapur: 37.2°CMumbai/MMR could witness max temp of 39°C in coming daysRelative humidity on ThursdaySantacruz: 78%Colaba: 89%Highest max temp in OctSantacruz: 38.6°C on Oct 17, 2015Colaba: 39.5°C on Oct 22, 1968
