Retreating SW Monsoon:
The anticyclone over Rajasthan and adjoining regions has all but dis-integrated the seasonal low, and with a vengence, is all set to "wipe it off" from the Western region by Friday.
The seasonal low, if we can now call it so, over the Rajasthan region is 1004 mb, and soon will be a huge region of "high" at 1010 mb.
Favourable conditions will withdraw SWM out of Rajasthan, Haryana, Kashmir, Delhi, HP, Utteranchal and West UP by Wednesday 26th.
The axis moves towards Northern Maharashtra by Thursday, 27th/Friday 28th, and the SWM is all set to call it a "season" from Gujarat, MP and UP by Friday 28th.
Resultantly, once the above scenario takes shape, the Westerlies winds in the NW and Northern India will become N/NW, and will cover all of Northern and Central India, down South upto the Vidharbha region.
These Northerly winds, will change direction South of the Monsoon axis over Maharashtra.
For convienance, I'll call this region "Region A", where the North winds cease and line of dis-continuity starts, and where the axis will be located.
Now, South of this, the axis line diverts the wind, and in the State of Karnataka, a line of wind dis-continuity can form, creating turbulent weather.
Please note, that this "Region A" may occur slightly North or South of Vidharbha, cannot be too sure today.
As the anticyclone grips the Northern and Central States, the winds go "haywire" and turn a drastic Northerly in Northern and Central India upto Vidarbha.
Thundershowers will be trying to "pop up" in Maharashtra on Wed 26th/Thursday 27th/Friday 28th/Saturday 29th, as the monsoon current weakens fast over the state.
A sticky local mini vortex aloft brings some rains to Saurashtra and Eastern Gujarat Tuesday 25th/Wednesday 26th.
A weak Low forms in the Bay on Wednesday 26th, and rapidly moves into Jharkhand/W.Bengal (Heavy rains).
Mumbai: For many of Vagaries' Mumbai readers, it will be a short lived monsoon farewell (compared to what we have seen last few years). Two or Three thunderstorms at the most, between Wednesday and Sunday.
SWM retreat will be somewhat "stuck" for some time after retreating upto Karnataka.
Immiedietly, on the withdrawal line reaching coastal Karnataka, the shortened "pigmy" off shore trough strengthens, and the strong "diverted " inland winds may give rise to an UAC/Low off the Karnataka Coast by Saturday 29th, and heavy rains likely in coastal Karnataka Saturday 29th/Sunday 30th.(Again, since this is a long term estimate, the UAC/Low may form a bit North or South).
Thats not all ! The rainfall moves eastwards into Karnataka, and even Bangalore can expect heavy rains for a couple of days early next week.
So, the SWM will not move away from the Southern Indian Peninsula till mid week next, at least.
Presuming it retreats after the 5th of October, NEM can be, in calculable probibilities, NEM can start its advance between 16th October and 20th October...as of the situation today.
btw, IMD annonced Monsoon withdrawal from extreme west Rajasthan and Kashmir....on 24th, as hinted by vagaries a few days ago..