Weather Alert: Heavy Rainfall Likely Over Chennai

Spell of heavy rainfall is coming up for the capital city Chennai and suburbs, during this week.  The city and neibhourhood has remained quiet for the last one week or even more.  Weak monsoon stream along Tamil Nadu coast has kept the monsoon activity rather low over the last 3-4 days, across the complete state. Extreme South Coastal Tamil Nadu covering Karaikal, Tondi, Pamban, Atiramapattinam and Tuticorin did receive moderate to heavy rainfall till first half of last week. The rains receded that part of the state as well and mostly remained dry for the last four days.

Month of November is the rainiest month for Chennai. Mean monthly normal rainfall is 373.6mm. However, Nungambakkam has recorded mere 147mm and Meenambakkam is shade better with 182mm rainfall. Both the observatories struggling to reach, even the half way mark, with just five days remaining of this month.  There is some hope of having moderate to heavy showers, anytime between 26^th and 30^thNovember.  Peak intensity  and large spread is likely between 27^th and 29^thNovember.

A well marked low pressure area is lying over Southwest Bay of Bengal and the proximous equatorial region.  The low pressure is centered around 4.5°N and 84°E, far to the south of capital city.  However, the cloud clusters have gathered over Sri Lanka, Gulf of Mannar and Southwest Bay of Bengal. The location of this system, far to the south, near the equator has the disadvantage and may not pick up strength rapidly. Still, it will become a depression/deep depression and move closer to the coast of Sri Lanka and South Tamil Nadu in the next 24 hours.

Heavy rainfall is expected for Chennai and suburbs between 26^th and 29^thNov, more crucial between 27^th and 28^thNov 2024.  Coastal stations have large variability of force  and scale of rainfall associated with such systems. The meso scale systems embedded in the large spread of cloud clusters are difficult to locate and predict. Still, the city of Chennai and suburbs need to exercise caution for heavy to very heavy spells of rainfall during this week.