After some rains in delta & surrounding areas during the weekend drier weather conditions have started to slowly establish over most parts of Tamil Nadu. While lower level atmospheric winds have turned to Northerlies over Peninsular India bringing drier continental winds from Central / North India the associated clearer skies during night time is likely to influence weather conditions in terms reducing night time minimum temperatures.
The diurnal temperature variation is likely to bring land based surface winds over most parts of Coastal areas of Tamil Nadu for the next couple of days. As most would understand now the Easterlies during this time of the year not only bring rains under the right conditions but also modulate the winter conditions over coastal areas of Tamil Nadu. When the easterlies are stronger it brings cloudy skies which increases the minimum temperatures due to higher radiation getting trapped by the clouds.
In contrast if the skies are clearer the ground heat gets radiated back to atmosphere there by making conditions ideal for night time minimum temperatures to reduce. Additionally the diurnal temperature variations also bring land breeze during the night time which will bring dry cool conditions over Coastal areas like Chennai during the early morning hours. The next couple of days we may see such conditions prevail with minimum temperatures expected to stay a degree or so lower than normal for this time of the year. Western suburbs of Chennai will possibly see temperatures drop slightly below 20ยบC.