Since the start of June 1st officially the Southwest Monsoon season starts according to IMD. Though Tamil Nadu is pretty much a rain shadow region during this period there are pockets in the state that receive rainfall numbers during this period that could be compared some of the high rainfall places of West Coast. Places that are present in the windward side of the Western Ghats gets heavy spells of rains during this period. While for the average man places like Valparai are pretty much known as heavy rainfall town there are other places as well that record similar if not higher rainfall during this period.
Today we present the places in Tamil Nadu that has recorded the highest amount of rainfall so far this Southwest Monsoon season. It is no surprise that the highest rainfall places are all close to Western Ghats the reason why during Southwest Monsoon Tamil Nadu ends up being a rain shadow region for most of the state. Chinna Kallar, known as the Cherrapunjee of Tamil Nadu, has recorded 106 cms of rainfall so far almost twice of Naduvattam which has recorded the next highest amount of rainfall at 53 cms. Almost all of the high rainfall are either around the high ranges of the Western Ghats of Tamil Nadu or around South Tamil Nadu particularly around Kanyakumari district which gets benefited by the monsoon winds on their way towards Sri Lanka & subsequently to Bay.
What also strikes out conspicuously is how many places of North Tamil Nadu has managed to get more than 15 cms rainfall during the early part of Southwest Monsoon which is traditionally a weak rainfall period for this part of the state as it reels normally under severe Westerly winds. The June average for Chennai is about 5 cms while it has got about 17 cms so far this year indicating the uniqueness of this year. The reason for high rainfall can be attributed to the synoptic conditions that existed in Bay of Bengal during the month of June in the form of Low Pressure & Upper Air Cyclonic Circulations which were favorable for North Tamil Nadu. During normal years rainfall possibilities exist only on account of convective rainfall during late evenings / night which is very less during June and picks up from July as the monsoon becomes more active across the country.
The importance of being in the right side of the mountain range is possibly highlighted best in the Nilgiris district where the Western side of the district which falls on the windward side possibly gets twice the amount of rainfall in comparison with the eastern parts of the district thanks to the presence of the near continuous mountain range which average above 6000 feet running North to South almost continuously. In what is a classic example of “Quirk of Fate” Devala which sits perched right on top of the Western edge of the Nilgiris biosphere overlooking the Arabian Sea and in normal years averages almost 50 cms of rainfall during the month of June has recorded only 17 cms so far while places like Naduvattam & Gudalur which are little to the East though still falling on the windward side has recorded 53 and 47 cms respectively for the same period.
We reserve the best for the last. Chinna Kallar & Valparai town is possibly seperated by a distance of less than 10 kms as crow flies. But Chinna Kallar Rain Gauge has recorded almost 3 times the rainfall that has been recorded in the two Rain Gauges at Valparai PTO & Valparai Taluk Office.
This post would not have been possible without the help of Selvakumar (Raijinweather) who has beeen meticulously & painstakingly updating the rainfall data for Peninsular India on a daily basis. One can follow the rainfall toppers on a regular basis at http://raijinweather.com/peninsular-rainfall for all the 5 Southern states.
We also take the opportunity to place our sincere thanks to IMD which makes rainfall data available for common public without which such data cannot be maintained by weather bloggers.