Saturday, September 17, 2011

Chennai got battered by Bubble Thunder Storms yesterday

People in Chennai cant forget the record rains we got in August 2011, where 120 year records were shattered by a distance. Particularly the 156 mm rainfall on 24th August, 2011 when thunderstorms formed in the evening kept on coming like a bubble till early morning.

Yesterdays rainfall is also similar, first storms were spotted in radar in the evening and the storms kept on coming like a bubble till early morning. Chennai got 76 mm from this TS, thus crossing 800 mm for the year before the start of NE monsoon. Recently, Chennai's annual rainfall is increased from 1220 mm to 1400 mm by IMD and the last 10 year average works out 1460 mm with 2560 mm received in 2005 being the highest.

We have received 836 mm till today morning, considering the rainfall and daily thunderstorms coming close to Chennai, we have to rethink whether Chennai really falls under rain shadow region. More studies have to initiated by IMD to study this daily phenomenon of Thunderstorms coming above and below belts of Chennai (from Pulicat to Pondicherry). The Radar at Chennai is also the best in India, because of less interference from height restrictions IMD has put in place for Construction of High Rise buildings.

* The name bubble Thunder Storms was given by members of Kea blog

Rainfall ending 8.30 am today in mm around Chennai

Nungambakkam (Chennai) – 76
Chembarampakkam – 60
Arakkonam – 45
Redhills – 42
Kadambathur – 41
Madhavaram – 34
Ennore – 32
Veeranam – 25
Meenambakam (Chennai AP) - 21

4 comments:

  1. Thanks Pradeep for your online statistics on rainfall measures. It is very informative.

    1. Rain over chennai seems to be pure local effect- thunder stroms arise due to morning heat also - TN,Chennai temperatures are between 35-37degress, which is high when compared to other places where SW monsoon is in place. Any rain over TN is always welcome. Also rains are not that heavy compared to what Mumbai / other places in Maharastra receive.

    2. Your measures show Amboli Maharastra most extreme rain spot. Also major top rainy places are from Maharastra. Does this prove change in climate - central Indian belt becoming more rain volatile. In past 10years, think Maharastra was not in top position, but now it is, rain quantity keeps increasing every year over Maharastra,Guj,Raj.

    3. Still many places over South interior Karnataka, Rayalseema have rains below 300mm from 01-june-2011.

    ReplyDelete
  2. Correct Pradeep, 2005 was very luck year for TN (not sure EL-NINO or LA-NINA year). Think around 4-5 depressions crossed TN. We hope this continues.

    Same year Mumbai received around 3800mm of rain (950mm in single day), but overall 2010 was rain intense. We are yet see 2011 will break records.

    ReplyDelete
  3. Every year the onset, the spread and the withdrawal of SWM has different signatures. The pattern is typical in each year and it is unique too. But from too many years [SWM] pattern a general consensus of onset, spread and withdrawal can be arrived at. Based on this only onset /[NLM]/ withdrawal and rainfall departures are emulated. [Of course pertaining to statistical evaluation only]This predictions may be useful for certain level Economical planners / water managers. Even though the quantum increase or decrease in annual rainfall or seasonal rainfall [departures]matters much, application of technological advancement in analysis can bring better picture of the season. This has to be emphasized.

    ReplyDelete
  4. Coining of 'BUBLE' thunderstorm is new to weather glossary. There has been incidences that in - situ thunderstorms form during cyclone periods. The TS activity that Chennai witnessed is NOT LOCALIZED As pointed out by my colleague perhaps this is extension of SWM wind and it is a sign of start of withdrawal of SWM.

    ReplyDelete