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Chennai and Tamil Nadu Weather Forecast: Monday, November 18, 2019

Vinson Kurian | Updated on November 18, 2019 Published on November 18, 2019

File Photo   -  The Hindu

It’s been raining in dribs and drabs with the Sun and clouds fighting it out. We explain why Chennai still hasn’t had that big downpour, while South Tamil Nadu has seen some good rainfall and is expected to get more

Vanakkam! The frustrating wait for the humdinger that will cool minds and lift spirits in Chennai continues. The indelible marks left behind by three back-to-back cyclones -- Kyarr, Maha and Bulbul -- on the North-East monsoon have festered as deep scars, weakening its limbs and slowing its ability to rustle up the power needed to pound the coast with the defining rain spells that the season is best known for.

After all, the North-East monsoon is powered by strong easterly winds. The high humidity drawn from the moisture supplied by the Bay of Bengal, in conjunction with warm temperatures, must create massive amounts of warm, moist air rising into the atmosphere where it can easily form a thunderstorm… followed by a string of others.

Cool Bay

This process has evidently been compromised as a result of cooling of parts of the Bay of Bengal seas after the storms had stalked them — from the heavy precipitation over the waters where the storms stayed for the most part.

Even in ideal conditions, thunderstorms are very difficult to predict — they sometimes flare up on subtle boundaries from previous thunderstorms, the effects of sea breeze, higher terrain or in a more random pattern.

Occasionally, storms may be so isolated that a small part of a region gets drenched while the rest stays dry and possibly even sunny.

Huge thunderstorms in South Tamil Nadu

For instance, if we take the South Peninsula as a region, last night (Sunday) saw massive thunderstorms and heavy rain spells lash Central Kerala, separated from Tamil Nadu by only the Western Ghats — the rain wave had propagated from South Tamil Nadu, meaning the easterly winds are at work, though in parts.

Satellite pictures showed specks of cloud bands approaching Chennai -- though the more heavier and consistent bands were hitting the Puducherry-Cuddalore-Chidamabaram belt even as this was being written.

In fact, an outlook from Skymet Weather says that an easterly wave is active, and might bring moderate rain and thundershowers over the coastal areas of Karaikal, Puducherry, Cuddalore, Nagapattinam, Peramballur and Pudukkkottai.

It all boils down to this -- being in the path of the clouds at the right and time place -- something that Chennai seems to miss out on as revealed by this morning's pattern.

A welcome change is that all the models surveyed this Monday morning agree that the winds are now mostly northerly-north-easterly to easterlies. Which is all very well.

But they appear to lack the speed required to bang it up all along the coastline. So the temperature-pressure differential that works up the wind speed is not in Chennai/Tamil Nadu’s favour.

The Sun and clouds battling it out with a shower of thunderstorms in spots is the call for the day from international forecaster AccuWeather. It goes on to forecast a party cloudy night with spotty showers.

 

 

Weather.com, an IBM Business, raises the possibility of thundershowers to 50 per cent during the night from a low 10 per cent during the day, which will witness partly cloudy conditions.

 

 

 

The Chennai Met Office of the India Met Department agrees, saying that the day would see partly cloudy conditions with light rain forecast for some areas. Scattered rain has been forecast at isolated places for Tamil Nadu for the next three to four days from today (Monday).

 

Meanwhile, Chennai's weather bloggers and their followers have their fingers crossed...

 

 

Published on November 18, 2019
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