Southwest Monsoon is one of the biggest if not the biggest weather event globally. Just like onset Southwest Monsoon withdrawal is also eagerly followed. Southwest Monsoon withdrawal may be the final phase of the Monsoon Journey for most of the country. But for the weather bloggers of Chennai and rest of Tamil Nadu it is the start of a fresh journey. A journey that brings about “Chennaiyil Oru Mazhaikkaalam” the Northeast Monsoon. IMD announced the withdrawal of Monsoon over parts of Kutch and Rajasthan. This is about 6 days behind the traditional withdrawal date for these regions.
In the meanwhile most parts of Chennai and many suburbs received moderate to intense rains last night from thunderstorms. Weather models were indicating for the past few days about yesterday and today being the best window for Chennai to catch some rains. Right on cue from weak thunderstorms that moved across from interior areas of Peninsular India thunderstorms bloomed just west of Chennai. The GCC automatic weather station at Manali recorded 144 mm while many other parts of the city and western suburbs recorded between 5 to 8 cms.
The embedded circulation in the East West Shear Zone is likely to become an LPA over West Central Bay today. Subsequently it will possibly move gradually in a WNW direction over Peninsular India. This phase of strengthening into an LPA over West Central Bay gives another day of wind convergence today. South interior Karnataka, South AP and adjoining parts of North TN may be in line for this wind convergence. As has been the case yesterday and a couple of days back thunderstorms will possibly see intensification during the night.
There could be a slight lull in thunderstorm activity once the LPA forms and starts moving across. But overall things are falling in place for widespread thunderstorms to start over most parts of Peninsular India. This will be primarily triggered by the transition season as Southwest Monsoon withdrawal starts to pick up pace once the LPA completes its life cycle. All in all soon it will be time to look East rather than west for the rains.