Posted Thursday Night:

Rains expected to increase along TN coast (Chennai) and interior TN from Sunday 8th onwards.

1. There is a East -West trough running roughly along the 10N line, eastwards from the East Coast of Sri Lanka. This will embed an UAC and subsequently by the 8th, a Low. .
The Low is expected to deepen and track NW towards the TN Coast. 
 The system can cross the TN coast as a depression by Monday 9th.
There is a slight possibility of system re-emerging in the Arabian Sea off Kerala by mid next week. 

2. Western Disturbance N-3 is likely to bring rains in North Pakistan from Sunday 8th and North India from 9th .
Day and night temperatures are expected to fall in NW and North India next week.
 More on both these systems with weekend forecast on Friday....

AS-3, A depression, at about 1000/1001 mb pressure...monitoring the development as the system tracks West.

Posted Wednesday Night:
Srinagar: With 16 mms of rain in the day, the day temperature dropeed to 13.4c on Wednesday. 

Bangalore City is receiving very good rans since last 3 days. With 95 mms flooding the city on Monday,( see Viayanand's comment) there was a reduction yesterday as 7 mms were measured. But, on Wednesday, the showers picked up with 33 mms till 8.30 pm IST. and day temperature at 28.7c.


AS-3 remains a Well Marked Low at estimated pressure at 1004/1006 mb. Seems possible , seeing "not very favourable conditions", it may not deepen much now .

Posted Wednesday Noon (IST):
AS-3 becomes "Well Marked Low Pressure" at estimated 1006 mb..Located at 13N and 67.5E...NRL Sat Image
 

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Posted Tuesday Night:
Mumbai was hot on Tuesday, with the day at 33c in Colaba and 35c at Scruz. Same conditions for next 2 days, maybe more cloudy and stuffy at night.

Panjim , Goa , is now getting some showers on Tuesday evening/Night. 3 mms recorded till 8.30 pm ...Some towns in South Konkan received slightly heavier showers.

Sporadic showers to continue in North Coastal Karnatak, Goa and South Konkan next 2 days.

Weather Situation:
1. The Low expected in the Arabian Sea has formed off the Karnataka Coast. Currently at 1010 mb, it will deepen fast to 1008 mb and then to 1006 mb , and move West.

2. N-1 which had formed and moved East wards across Kashmir, is followed by N-2, and the trough from N-2 may form an induced Low in North-Central Pakistan.
With some rain on Tuesday, the day temperature drops to 16.5c from yesterday's high. With more rains on Wednesday, the day will be colder at around 11-13c.

New Delhi NCR: Same conditions with max around 31c till Friday. Some decrease in day temperatures from Saturday as we see clouds rolling in on the weekend.

Chennai: Showers in many parts of city, could accumulate around 10-15 mms on Wednesday. But, we may see a decrease in rains again from Thursday till Saturday. Normally, I should be estimating more showers and rains for Chennai at this time of the year. But, the momentum is missing.

Showers expected in Goa & South Konkan on Tuesday 3rd November and Wednesday 4th..

Mumbai again topped to 36.5c at Scruz and 35c at Colaba on Monday.
Mumbai October was hotter than May this year...see averages compiled by Rohit Aroskar

Posted Sunday Night:
Very Severe Cyclone "Chapala" approaching and soon crossing the Southern Coast of Oman and adjoining Yemen. Estimated core pressure 944/950 mb and estimated core winds dangerously high at 195 kmph. 

Mumbai: Monday 2nd Nov and Tuesday 3rd will be sunny and warm. The day temperature which was 35c at Colaba and 36c at Scruz on Sunday. Monday and Tuesday will continue to see above normal temperatures at around 34/35c. Wait for nip in the night continues.

An extremely hot October 2015 for Mumbai...unusual with record highs and record night temperatures...
Mumbai Diagram for October:
1.Diagram shows the average (day and night) temperatures...and the above normal "Red" is seen all through the month.
2. The Second diagram shows the anomaly...The average anomaly was +1.42c above normal.
3. The third diagram shows the actuals..

Goa (Monday /Tuesday) will be partly cloudy with light rains in some regions.

Chennai: Monday and Tuesday can see the thunder shower popping up in parts of the city. Around 10-20 mms per day.
Diagram for Chennai...

And the precipitation deficiency..NEM arrived on 28th October. Total for Chennai in October: AP 159 mms and Chennai 160 mms.
On Sunday, Chennai (Meenabakkam) recorded 45 mms till 8.30 pm IST).

Western Disturbance N-1 approaches Jammu and Kashmir on 2nd/3rd November. Restircted to this Northern State. Srinagar, which has seen a rise in day temperatures to 20c, may see the fall from Tuesday. Wednesday will be rainy.
Another back to back WD, N-2, may follow soon.

Mumbai, oh what a Sunday !...The east winds keep the sea breeze at Bay till late in the day, and warms the day at 35c !

Posted Saturday 31st October Night:

A continuation review from Last Posted Blog on Last Saturday (24th)...(Also gives me a chance to evaluate Vagaries' Outlooks):

1. The Low off Sri Lanka persisted for a few days from Monday, and now today, having tracked North, is located off the North TN Coast. The Low (BB-9), will track NE along the coast (and in the trough) and dissipate off the Odisha coast in a few days.

Much against our expectations, Chennai received 14 mms as on (last) Thursday morning and another 13 mms only as on Friday morning Around 28/30 mms against 50 mms estimated in Vagaries). Some International models had shown 150/170 mms for Thursday and Friday, enlightening the hopes of the Chennaites.
Some parts of Chennai got heavy showers on Saturday, the official Minambakkam station recorded 10 mms till 8.30 pm IST.
For Chennai, the wait for good meaningful rains continues. Well, BB-9 is moving NE, along a well defined trough, so at the most another day of moderate thunder shower for Chennai...maybe around 20 mms ?

So, with BB-9 "showing its pace", East coast towns can expect showers on Sunday.

Kolkata, which is waiting for a good effect from BB-9,  will see some overnight showers, light to medium on Saturday night, and extending into passing showers on Sunday.

AS-2, as we all now, has become a super Cyclone, Chapala at estimated 950 mb core pressure, and is moving towards the Yemen Coast.
With favourable conditions and lack of dry air (dry air is only to the South, which now has no decreasing effect) Chapala will remain strong and as a severe cyclone on landfall. Landfall on the Yemen /South Oman coast will be around night of 1st or 2nd November.
Kerala was dumped with heavy rains last week.

Another factor on expected lines was that with the passing of the Western Disturbance O-3, the nights in North plains and Central India started showing the marginal drop.
Punjab towns are now between 12-15c, Delhi S'jung is about 15/16c and Rajasthan towns are around 15-17c.
From Thursday/Friday morning, Gujarat and interior Mah saw a slight fall in night temperatures.

Posted Saturday 24th Evening:

1. Continuing from yesterday's Post, the  latest shows  the Low, off the East coast  of Sri Lanka has formed as expected.
The Sri Lanka Low, BB-7, should track North, towards the TN coast, and approach Chennai. The system will deepen to a depression and track into the A.P. coast by mid next week.
The trough in the Arabian Sea persists, and a Low is expected in the trough West off Kerala.
Tuesday heavy rains expected in Kerala.

Chennai: Few showers till Monday. Rains and NEM expected from 27th, Tuesday. By Wednesday, the rains pick up in intensity, and Chennai can expect around 55-60 mms by Thursday morning, and another (about) 40 mms by Friday morning. 
( A  4 day advance forecast may vary a bit.)

2.The AS-2, will also track North initially, and dump rains in Kerala and Coastal Karnataka on Wednesday and Thursday.
Goa can expect some spill over light showers on Tuesday and Wednesday.

3.O-3 now moving into North India from Pakistan. Rain/Snow expected in Kashmir and H.P. on Sunday and Monday. Punjab and parts of Haryana can expect winter showers on Sunday and Monday. 
The passing of the WD will see clear skies and sharp fall in night temperatures in North and NW India. Places in Punjab may see the nights falling to 12-13c on Thursday/Friday morning.
( A  4 day advance forecast may vary a bit.)

Delhi NCR can expect thunder showers in many parts of the region on Tuesday. Some chances of extension of showers on Wednesday morning.. From Thursday, NCR may see a fall in night temperatures, touching around 14-15c.

Cooler nights and drop by 2/3c expected from Thursday/Friday morning in Gujarat, Rajasthan, Maharashtra. Showers will be occurring in regions of M.P. on Wednesday...after which there will be a sharp fall in night temperatures.

Light rain expected in Mumbai on Sunday.

There will be no Vagaries Update on Sunday 25th, Monday 26th and Tuesday 27th.

Posted Friday Night:

Mumbai: Finally, finally we see the day temperatures drop (exactly by 2c from peak as estimated)...With the day's high at 35.3c at Scruz on Friday and 33.9c at Colaba. Now, we will see the nights getting more comfortable also, after  a record 28.2c minimum at Colaba on Friday morning.

1. UAC in both the Arabian Sea and South Bay persist, and will become Lows as predicted...As of now, we predict the same as given yesterday...
NEM rains can start in Chennai from 27th as expected...
Next Update on Saturday evening by 5 pm IST.

2. Western Disturbance O-3 Precipitating over North Pakistan from Saturday. coming on schedule..

Posted Thursday Night:

NEM:
Normally, MJO activity is very much subdued or is virtually absent during the maxima of some El Niño episode.
Currently, the Madden- Julian Oscillation (MJO) is seen strengthening ( slightly to neutral stage) in our seas from the 26th...and its effect could last till around 5 th November. 

The existing UAC in the Southern Bay, embedded in an Easterly trough, will in all likely hood descend as a Low, and deepen . The system should track North towards Tamil Nadu.
NEM is likely to set in by the 28th of October. 
Good rains are likely, as the rains push into interior TN.

Chennai: Getting ready for the NEM rains...starting from Tuesday 27th and gradually increasing to downpours by Thursday 29th. Heavy thunder showers on Wednesday night. Thursday could accumulate  around 50 mms in 24 hrs.

Western Disturbance O-4 to precipitate rains in the lower regions of Kashmir and plains of NW India from 24th ...and snow in the middle hills of Kashmir and higher reaches of H.P.

Srinagar will be cold and rainy on Saturday 24th and Sunday 25th, with day temp going down to around 12-14c. About 35 mms rain expected on these 2 days.
Punjab and adjoining Haryana can get medium showers.

As the induced Low forms in the WD trough, the location is around Punjab region. The NE movement of this Low may just about bring light rains on 26th/27th to the Delhi region.
Light to medium rains likely in North Pakistan this weekend. Islamabad will be cool with rains this weekend.

Mumbai: Very marginal drop to 36.4c on Thursday, and 23.6c as minimum. Should see a change for the better now as WD moves in.