Friday October 8th: Over the course of this week, the weather in Mumbai has remained more or less the same: typically warm October mornings and afternoons, followed by evenings full of rumbling clouds, lightning and thunderbolts!
Those scary evening thunderstorms and the intensity with which they occurred throughout the week have taken the City of Dreams by storm. And they can very well go ahead, with projections showing the prevalence of such conditions for at least the next week.
To learn more about these thunderstorms and understand why Mumbai is experiencing these dramatic conditions, The Weather Channel India contacted Sridhar Balasubramanian, an associate professor at IIT-Bombay and a weather expert.
We asked him about some FAQs on this phenomenon, the answers of which are given below:
First, how do these thunderstorms arise?
Thunderstorms are usually an evening feature. Two main factors are essential for their formation: high daytime temperatures (which cause great instability in the atmosphere); followed by the ingress of moisture from the seas / oceans (usually favored by sea breezes or the presence of cyclonic circulation in the sea).
Due to the high daytime temperature, the warm air tends to store more moisture and rise very high vertically. That is why we see very high cumulonimbus clouds during thunderstorms.
When warm air rises, it condenses; and as it continues to rise, it freezes into ice. The instability of the atmosphere (triggered by high daytime temperatures) leads to a violent collision of these ice particles, creating thunder and lightning.
As soon as the clouds are big enough, they fall out and cause thunderstorms.
Why do these thunderstorms occur in Mumbai?
Warm daytime temperatures, triggered by a weak anticyclone, and warm winds blowing from land to sea are the main factors behind the occurrence of thunderstorms in Mumbai. The latter is expected considering that the monsoons are currently showing signs of retreat.
In addition, a cyclonic circulation currently found in the Arabian Sea is causing enormous amounts of moisture, which is effective in fueling these thunderstorms.
Are these thunderstorms unusual for Mumbai?
No, they are very common in October when the monsoons recede. The wind pattern begins to change, resulting in high daytime temperatures. In the evening, a monsoon circulation system brings moisture into the interior, which leads to such thunderstorms.
However, the intensity of the thunderstorms is unusual. Such strength and intensity is usually observed in the inland regions rather than the coastal zones. But with climate change, temperatures rise during the day, which can create such intense thunderclouds.
How long are these conditions likely to last in Mumbai?
Mumbai could have this thunderstorm until 14-15. October see, depending on how high the daytime temperatures get and how much moisture is being pulled inland by the prevailing monsoon systems, mostly from the Arabian Sea.
It may not be a daily apparition, but by May 14-15. October, such activities should come as no surprise, considering that meteorological factors continue to be conducive.
For more insights, follow Professor Sridhar on Twitter.
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