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Active Phase Of Monsoon

Monsoon Revamped



                              After a week long of Rains that lashed the state due to trough of low, the monsoon took a break (halt) for the past couple of days or so . Now the monsoon moved into a vigorous phase with a first low of the season that is forecasted to churn into a cyclone and expected to cross the coast. Now lets see what we can expect in the coming weeks.


Well Marked Low



      



               

                        On 19th Nov a broad convection has formed over southeast Bay of Bengal with a potential to become a organised system. In the early hrs of 20th Nov the convection consolidated into low pressure area influenced by the low level circulation over southwest and adjoining areas of Bay of Bengal. Today the 22nd Nov the LPA intensified into Well marked low pressure area over the same region. 

Further Intensification 


                    The WML is expected to intensify into a depression over the same region within next 12-24 hrs, and it is expected to intensify further in to deep depression status while moving in a west-north-west direction for the subsequent hrs. 




                     On 24th Nov the system is expected to intensify further into a Cyclone , named as NIVAR. The further intensification of the system is uncertain as the model trend shows no further intensification. Though it may intensify little bit as it churns under the favourable environment. 


Cyclone NIVAR


                     The Northeast monsoon's first system (technically for us) named as cyclone NIVAR to be formed within a day or couple of days. The cyclonic storm NIVAR once formed will march towards the coastal Tamilnadu by 24th Nov (Noon). This system is expected to cross the NTN coast between Chennai to Nagapattinam ( probability of crossing Delta latitude is about 20-30%) (probability of crossing above Delta latitude is 70-80%). Though the intensity of the cyclone is uncertain and the intensity will most probably fixed in a day or two.




Favourable Factors 





                            MJO (Madden Julian Oscillation) - King of tropical wave has emerged in Phase 3 (East Indian ocean) with a strong amplitude close to 1, started to influence the WML in Bay of Bengal , this will enhance the system to pack up more moisture content by strengthening the easterlies around the system.

  


                           The sea surface temperatures over Bay of Bengal is around 29*-30* C in most areas and 26*-27* C near the coasts of Odisha. This warm SST's will aid the system to build the convection.


                          TCHP (Tropical Cyclone Heat Potential) This makes the storm to build up its convection and aids in the intensification of the system . At present the TCHP is 80-90 KJ in most parts of the BOB. 





                           The Driving Ridge (Steering Ridge) that drives the system and determines the system whether it should dissipate over the sea or to cross the coast. The system is expected to driven by the INDO-PACIFIC (INDO-CHINA) Ridge which brings the system towards us with 80% probability.

                           Wind Shear the current estimates are around 15-20 knots, while the wind shear is expected to reduce which inturn provides the trouble free environment to the churning of the system.
All in all there is an good agreement in the models that the system will gradually intensify into a cyclone.
 

Cyclone GATI



                           Severe Cyclonic Storm GATI over the southwest Arabian sea is expected to cross the North Somalian coast with same intensity (Slightly higher intensity denoting VSCS), during the night hrs of 22nd & 23rd Nov . The wind speed estimates are 135 to 140 Kmph Gusting at 150 to 165 Kmph at times with heavy downpour. Due to the land interaction it is expected to gradually weaken and likely to re-emerge in the Gulf of Aden.


LPA - Low Pressure Area
WML - Well Marked Low
NTN - North Tamilnadu
BOB - Bay of Bengal


Post created time : 18:15

Post ending time :  20:46

                           NOTE : This is the first interpretation based on the latest observations on my own the forecast is subject to change and further interpretations will be released until the first system breathes.

FOR OFFICIAL FORECAST FOLLOW THE INDIAN METEROLOGICAL DEPARTMENT AND FOR OFFICIAL WARNINGS FOLLOW THE TWITTER HANDLE OF TN STATE DISASTER MANAGEMENT.

FORECAST in Tamil will be put up later

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