RT @senthilvijay: Dark clouds started covering the sky at #chennai #Tiruvottiyur @weatherofindia http://t.co/rUnDhZ0L 11:37am

A high pressure is likely to form in the Bay by Saturday. This High is expected to last for 2 days till 15th October. The sea level pressure required during NEM is a large formation of low over the Bay.
But what we need for the NEM to advance is a prominent anti-cyclone at 500 hpa over the Central Myanmar region. This may start forming around the 16th of October. 

Till then, only the western side will get some precipitation, with west winds rushing towards the high. Thus keeping the SWM "alive" in Kerala and adjoining TN.

Negative Parameter: 200Hpa westerly jet streams are still not perfectly formed, and upper level high is weak.
Positive Parameters for the NEM may commence from 16th October.

Chennai - 12:54pm, now having good cloud formation. Showers possible in another 1.5hr or it'll vanish

Today, scattered showers expected along W.Ghats of Kerala & Tamilnadu, S,W,N-W.and N.Tamilnadu.. http://ow.ly/i/114lW

Showers over Orissa & N-E.Andhra to continue for next 48hrs... http://ow.ly/i/114mk

COLA model suggests that scattered showers over most of Tamilnadu, W.ghats of Kerala & S,S-W.Karnataka to continue even till 16/17-Oct.

Last of rain over N-E states to continue for another 24hrs and then go down drastically.

#chennai - may get 1 or 2 showers before 18-Oct.. but most of Tamilnadu showers will be over Interior zones and not along coastal regions.

N-E monsoon to break open over #chennai & N,central Tamilnadu coast on 18-Oct... http://ow.ly/i/114jC

Onset of monsoon over Tamilnadu coast is expected to be followed by a Low pressure system frm Bay crashing along #chennai coast on 19/20-Oct 

8am, early morning isolated t.shower seen over s-e.Tamilnadu and s.karnataka.

A WD, with extended trough will cross eastwards from Pakistan thru Northern India from the 16th October. Rains will be moderate in Extreme North Pakistan. On the 16th and 17th of October, Northern Indian states of Kashmir and HP will get some rains, with snow in the medium ranges. (Gulmarg/Pahalgam may get first snowfall).
Both Punjabs will get light rains on the 16th October. 
Cloudy weather in Delhi on 16th and 17th.the nights will drop to below 15c in the NCR after the 18th of October, once the cloudiness clears.

As the Southern UAC weakens, we see a change of wind direction to NE over Chennai region from 15th/16th October. The final withdrawal of SWm from Southern most India, and the NEM setting, may happen between 16th and 20th October.

More on Vagaries..

RT @aash_tvm: Rain is waiting to shower. Hopefully, when I start frm home. #Trivandrum @weatherofindia  (6:22pm)

RT @midhun536: Rainy cloud in trivandrum...... http://t.co/ODxfZVTU (5:46pm)

5:30pm, Heavy showers seen all along W.Ghats of Kerala, S,S-E.Tamilnadu and over N-E.Andhra & S.Orissa.. http://ow.ly/i/10S6Y

 5:30pm, Remnant of "94B" over S,S-E.Bangladesh & South N-E states is still active. Rain may last for another 12hrs.. http://ow.ly/i/10S6Y

#Chennai - "Rain Centre is now decade-old" ... http://ow.ly/eoiaf