CHENNAI: The Regional Meteorological Centre (RMC) has forecast deep depression over the southwest Bay of Bengal and adjoining East Equatorial Indian Ocean on Thursday, moving at a speed of 15 kmph and centred about 940 km off Chennai. Under its influence, an orange alert (heavy to very heavy rain) was issued for Nagapattinam, Tiruvarur districts and Karaikal for Friday.
The city is expected to witness thunderstorms and lightning with light to moderate rain likely to occur in some pockets on Friday.
According to the agency, deep depression will move northwestwards in the next 36 hours and cross the Sri Lankan coast between Hambantota and Batticaloa around Friday evening or night.
The RMC bulletin issued a yellow alert (moderate rain) for Ramanathapuram, Thanjavur, Mayiladuthurai and Pudukottai for Friday. For Saturday, an orange alert was issued for Cuddalore, Mayiladuthurai, Nagapattinam, Tiruvarur and Puducherry, and a yellow alert for Ramanathapuram, Pudukkottai, Ariyalur, Villuppuram, Kallakurichi, Chengalpattu and Thanjavur.
Squally weather with wind speed reaching 35-45 kmph gusting to 55 kmph is very likely to prevail on Friday and Saturday, and decrease thereafter.
The agency also said the sea condition is likely to be rough till Saturday and advised fishermen not to venture into the sea. It is expected to improve thereafter.
Those out at the deep sea should avoid the southeast and southwest Bay of Bengal and the adjoining East Equatorial Indian Ocean, along and off Tamil Nadu and the Puducherry-Karaikal coasts, the Gulf of Mannar and the Comorin area till Saturday.
Distant cautionary signal number one with section signal IV and signal V hoisted at Chennai, Cuddalore, and Nagapattinam ports. Also, the distant cautionary signal number one was hoisted at Ennore, Kattuppalli, Puducherry, Karaikal, Pamban and Thoothukudi ports.