Mumbai: The city continued to swelter for the second consecutive day on Friday with the Santacruz weather station — which is considered the benchmark for Mumbai — recording a maximum temperature of 37.8°C, slightly higher than Thursday’s 37.6°C and 4.7°C above normal.The last seven days saw the Santacruz observatory record three of the 10 highest Oct temperatures since 1951 when record keeping started — 37.4°C on Oct 3, 37.6°C on Oct 8 and 37.8°C on Oct 9.The India Meteorological Department (IMD) retained its yellow alert for a heatwave in Mumbai and Thane on Friday, and issued a yellow alert for hot and humid conditions at isolated places on Saturday.IMD attributed the spike in temperatures to an anticyclone over Mumbai and its neighbouring areas, which has stalled the sea breeze that normally brings relief from daytime heat along the coast.IMD’s Colaba observatory logged a maximum of 37°C, which was 4.4°C above normal and also among the highest Oct recordings since 2014, when it recorded 37°C on Oct 17. The highest during the period was 37.2°C on Oct 30, 2018. Santacruz station’s reading of 37.8°C was the third highest for the month of Oct in 12 years, along with Oct 10, 2018, with the highest being 38.6°C on Oct 17, 2015, followed by 38°C on Oct 29, 2018.Relative humidity recorded by Colaba and Santacruz observatories were 81% and 73%, respectively.IMD scientist Sushma Nair explained: “An anticyclone is a circulation pattern that causes air to sink towards the ground. The system over Mumbai is well organised, and clear, cloudless skies have further contributed to the rise in temperatures.” She said the system was expected to become less organised and shift slightly on Saturday, bringing some relief. Easterly and northerly winds, which are relatively dry, are also influencing weather conditions over the region.Weather experts said prevailing northeasterly and easterly winds over Maharashtra were delaying the development of the sea breeze, allowing temperatures to climb across the Konkan region, where several locations have recorded 38–39°C.Despite the withdrawal of the monsoon from Mumbai on Oct 3, which is earlier than is normal withdrawal date of Oct 8, Sept saw largely dry conditions with limited thunderstorm activity which is generally observed during withdrawal of monsoons also being absent.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.Graphics:MUMBAI’S OCTOBER HEAT:37.8°C — Santacruz, Friday37°C — Colaba, Friday+4.7°C — Santacruz above normal+4.4°C — Colaba above normal38.6°C — Santacruz’s October high since 2014 (Oct 17, 2015)37.2°C — Colaba’s October high since 2014 (Oct 30, 2018)
