Reason for Rains – UAC in South East of Sri Lanka
January masam eppoium namma weather bloggers aal illatha tea kadaila, tea aathitu iruppanga, ennatha solla, rains are adamant this January. The January 1st week rains were from easterly trough / wave. This time it is notch above as we can see a clear Upper Air Circulation South east of Sri Lanka. This UAC pushes the moisture into Tamil Nadu coast.
Movement of UAC
The UAC is expected to move pure west from south of Sri Lanka to South of Comorin (Kanyakumari) Sea and will lie parallel to Kanyakumari coast. One more point to be noted is, very slow moving so more rains bands will keep on coming for next 4 days. There is chance for the UAC to become LPA (Low Pressure Area too.
Rains impact – Great days ahead for Cuddalore to South TN
So initially the widespread & heavy rains will be concentrated in coastal (Cuddalore to Thoothukudi) and south TN, but when UAC moves more west, the easterlies will surge / converge move inside and even South Interior Tamil Nadu, Interior Tamil Nadu, West Tamil Nadu will get rains.
Kerala will get rains too once but not heavy ones like Tamil Nadu.
Chennai (KTC) isolated rains are expected in next 2 – 3 days.
North interior TN will get isolated rains, as it is too far away from the UAC.
Tamil Nadu Great January Rainfall years in last 50 years
in mm (30 mm and above)
2021 – 69.9 (till 10.01.2021) – At this rate century is confirmed, this January in next 4-5 days.
2017 – 37.3
2000 – 30.3
1990 – 86.5
1986 – 65.3
1985 – 89.6
1984 – 34.5
Normal for TN in January is 18 mm. All time Record for January is 141 mm in the year 1921.