Posted Wednesday Night:

BB-17 has been upgraded to Cyclone "Nada" status by IMD and International Weather Models.

As per IMD Bulletin .." The cyclonic storm “Nada” over southwest Bay of Bengal moved northwestwards during past six hours with a speed of about 27 kmph and lay centred at 1730 hrs IST of today, the 30th November, 2016 near Latitude 9.8ºN and Longitude 84.0ºE over southwest Bay of Bengal, about 550 km southeast of Chennai,"

Moving along the Southern Edge of the Sub Tropical Ridge, this "Cyclone" will track towards the Tamil Nadu coast. 

Please not I have put "Cyclone" into inverted commas.Estimated central Pressure is 1000 mb and estimated core winds at 40 knts, 

Heavy showers expected in Chennai from 1st December, amounting to around 50 mms. Rains will decrease to half the amount on 2nd and substantially decrease thereafter.

Posted Tuesday 29th Night:

BB-17 is now a Depression, estimated location on Tuesday night is at 6.5N and 87.1E. No change in track forecast.
Chennai: Squally weather from 30th, with very windy conditions on 1st, winds gusts upto 45-50 kmph. Thunder showers on 1st December.Around 50 mms of precipitation expected.
Bangalore: Showers on 1st December, with cool day at around 24c, Can expect around 25 mms on 1st.

Mumbai: Mumbai skies will get partly cloudy the next 3 days, Wednesday 30th - Friday 2nd December. 
Days, which are quite hot currently at 34-35c, will see a fall to 31/32c levels. But, no appreciable fall seen in the night temperatures.Maybe a marginal rise in the minimum temperatures from Wednesday night.

Pune: Next 3 days will be partly cloudy to cloudy on Thursday. Substantial drop in day temperatures from the 34/35c levels. But rise in night temperatures, maybe by 5c...minimum rising to around 15c from Wednesday night.

Posted 28th November Night:
Initial Gear Up of NEM ...

As mentioned yesterday, BB-17 has formed and is a Well Marked Low in the South -East Bay Region as on Monday evening. System is intensifying fast, and can become a depression by Tuesday Night. 
Tracking NW and heading towards Tamil Nadu Coast as expected.Could cross South of Chennai around 1st. By 3rd, BB-17 ( Weak Low) re-emerges in the Arabian Sea off Kerala Coast.
Squally winds likely along TN coast from 30th, and rains commencing from 1st December.
BB-18 follows soon...

Chennai: Rains expected from 30th evening. Around 55-60 mms from  30th Night-1st Night. Gusty winds and squally weather, with wind speeds peaking around 55-60 kmph on 1st December.
Bangalore: Thursday 1st December, and the city will cool down with heavy showers in most parts. With around 15-20 mms on Thursday, the day's high will be around 25c. Friday 2nd, will be overcast with lesser rains, but cooler day at around 22/23c.

Mahableshwar (Maharashtra) , a hill station at an average height of 4400 feet above sea level, recorded its hottest ever November day at 32c !
Bangalore, the Garden City, also saw a new November record at 33c !
The Day Night range continues in Maharshtra. 
Shivkumar Mogal sends this table of 28th November.

Posted 28th November Night:
Initial Gear Up of NEM ...

As mentioned yesterday, BB-17 has formed and is a Well Marked Low as on Monday evening. System is intensifying fast, and can become a depression by Tuesday Night. 
Tracking NW and heading towards Tamil Nadu Coast as expected.Could cross South of Chennai around 1st. By 3rd, BB-17 ( Weak Low) re-emerges in the Arabian Sea off Kerala Coast.
Squally winds likely along TN coast from 30th, and rains commencing from 1st December.
BB-18 follows soon...

Chennai: Rains expected from 30th evening. Around 55-60 mms from  30th Night-1st Night. Gusty winds and squally weather, with wind speeds peaking around 55-60 kmph on 1st December.
Bangalore: Thursday 1st December, and the city will cool down with heavy showers in most parts. With around 15-20 mms on Thursday, the day's high will be around 25c. Friday 2nd, will be overcast with lesser rains, but cooler day at around 22/23c.

Mahableshwar (Maharashtra) , a hill station at an average height of 4400 feet above sea level, recorded its hottest ever November day at 32c !
Bangalore, the Garden City, also saw a new November record at 33c !
The Day Night range continues in Maharshtra. 
Shivkumar Mogal sends this table of 28th November.

Thirivallur & Puducherry -92%, Kancheepuram -88%, Nammakal -87%, Salem & Vellore -86% and Chennai -83%...to mention a few,a very poor picture is depicted for Tamil Nadu. (Below)

i) After a very Poor November Start for the North East Monsoon, things seem to be looking bright soon.
After the formation of the much awaited trough, On 28th November, low pressure (BB-17) is forming at 5N and 90.5E in the South East Bay.....System will intensify, and track towards the Tamil Nadu coast. The intensified system may cross as a Deep Depression South of Chennai around 1st December.
Squally winds are likely along the T.N. coast from 30th November.
Studying the current possible scenario and BB-17 strength, the estimated rain amounts ( estimated as on 27th November) for Chennai would be around 55-60 mms on 1st, and then reducing to around 15-20 mms on 2nd December. But we will judge and monitor the developments daily.
BB-17 will weaken on crossing, and a weak Low will re-emerge in the Arabian Sea.

Another back to back Low, BB-18, is possibly forming in the same 5N and 90E region around the 3rd of December. Along a trough, the BB- 18 will track almost along the BB-17 track towards TN.


ii) Massive temperature variations were seen in some Maharashtra towns on 26th/27th November...

On 26th November Ahmednagar (Maharashtra) max temp 35.4°C and min temp 6.6°C. So, Temperature difference was 28.8°C.(Ahmednagar record and India range record is 29.2c on 15th December 2003.See here on the page for more variation ranges and Sub Continent record of 29.5c...
on 27th, Mumbai Scruz saw a difference of 19.6c, (high for a coastal city), when the day was 36.2c and night 16.6c. 
Pune saw a range of 22.8c, with 32.1c as the high and 9.3c as the low.

RAINFALL REPORT (01-10-2016 TO 23-11-2016)
TOTAL ALL INDIA RAINFALL (as on 23-11-2016)	61.3 mm
SEASON +/- (from 1-10-2016 to 23-11-2016)	-42%
RAINFALL PER DAY this season	1.14 mm
TOP FIVE SUBDIVISIONS THIS MONTH upto 23rd Nov	mm
A & N ISLAND	425.0
N M M T   #	202.7
ARUNACHAL PRADESH	184.8
KERALA	162.3
SHWB & SIKKIM	155.6
BOTTOM FIVE SUBDIVISIONS THIS MONTH upto 23rd Nov	mm
WEST UTTAR PRADESH	9.6
HIMACHAL PRADESH	5.3
HAR. CHD & DELHI	5.2
JAMMU & KASHMIR	3.3
PUNJAB	2.4
TOP FIVE SUBDIVISIONS ABOVE NORMAL (1-10-2016 to 23-11-2016)	%
WEST RAJASTHAN	159%
SAURASHTRA & KUTCH	134%
GUJARAT REGION	116%
EAST RAJASTHAN	44%
CHHATTISGARH	14%
BOTTOM FIVE SUBDIVISIONS BELOW NORMAL (1-10-2016 to 23-11-2016)	%
S. I. KARNATAKA	-83%
RAYALASEEMA	-90%
HIMACHAL PRADESH	-90%
PUNJAB	-91%
JAMMU & KASHMIR	-95%
#    NMMT : NAGALAND,MANIPUR,MIZORAM AND TRIPURA	source -IMD