With UAC at one end and E_W shear zone passing over north TN, Salem, Namakkal, Erode, Trichy, Madurai, Pudukottai, Sivaganga, Villupuram,Tiruvannamalai, Vellore, Krishnagiri, Dharmapuri, Kancheepuram, Tiruvallur, Cuddalore, Ariyalur, Perambalur and Delta belt all are in for very good rains today. Coonoor may see rains today.
Chennai and suburbs - To see isolated sudden sharp spells from noon and late night chances of rains exists as wind change favorable towards us
Chennai will see rains too but chances are heavy for outskirts in the period before night. At night as the winds improve, so does the chanced of late night rains.
The synoptic analysis of 850 winds (winds above 1.5 kms is put up for reference).
Courtesy: Tamil Nadu Weatherman