The dry weather conditions over Peninsular India has brought forth with it cooler nights across the region while the interior places & high ranges of Western Ghats have started seeing the first cold spell of the season. Though there is a Low Pressure Area over the Equatorial Waters of Bay the continental winds from the North are currently ruling the roost over not only Peninsular India but most of the Indian Subcontinent as cold wave conditions are seen over parts of North India as well under the influence of dry continental winds from NW that is carrying the cold from Central Asian region.
Down South Udhagamandalam saw a night time minimum temperature of 6.2ºC on Sunday morning with similar conditions expected to continue during the early part of this week. While Kodaikanal also saw single digit minimum temperature of 9.9ºC on Sunday Coonoor & Valparai recorded 10.4ºC and 13.5ºC respectively. Places in North & NW Interior Tamil Nadu like Tiruttani, Vellore, Dharmapuri all recorded 18ºC or lower on Sunday. Tonight these places are once again expected to record night time minimum temperatures in the region of 15 to 17ºC.
Coastal Places except Parangipettai have mostly stayed above 20ºC partially because of the light cloud cover along the coast which is expected to clear up as the LPA near Sumatra moves further Northeast under the influence of the incoming Westerly Trough. This will bring forth 2 or 3 days of fairly cold conditions over Interior areas of Peninsular India & cool weather over the coastal areas until possibly Christmas before the Easterlies make their way back gradually over Delta & adjoining areas of South Tamil Nadu.
Over the next couple of days most parts of Chennai except the places close to the coastline will possibly see minimum temperatures fall below 20ºC with the western & southwestern suburbs inching closer to 17 / 18ºC as the dry land winds from the West bring the interior cold to coastal areas of Tamil Nadu. This likely to be the trend until Christmas eve possibly before a gradual increase in temperatures happen.