Night temp likely to fall 1-2 C across the state

South West Monsoon (SWM) has withdrawn from some more parts of the country including Vidharba, Madhya Maharashtra, Gujarat, Konkan & Goa, Marathwada, Telangana and North Interior Karnataka. Further Withdrawal likely in next 2-3 days.

The Upper Air Cyclonic Circulation (UAC) over North Bay of Bengal persists. It is likely to dissipate in next 24- 48 Hours. The dry air extending from North India to North TN, is likely to bring down the night temperatures across interiors.


UAC over Lakshadweep and Maldives has weakened further and continues as a weaker system, resulting in isolated Thunderstorms over Kerala and South Tamilnadu.

Chennai – Day to remain dry and sunny with day temp likely to be around 33C. Night temp likely to fall by 1C and will be around 23-24C.

Coimbatore – To remain comfortable during the day, with temp around 31C.

Vellore – Due to dry air influence, night temp likely to fall to 21C, day to remain moderate and temp will be 33C.

Trichy – Day to remain partly cloudy, with max temp touching 34C.

Madurai – Temple town day temp will be around 34C, with possibility of isolated thunderstorm during evening or night.

979 thoughts on “Night temp likely to fall 1-2 C across the state

      • Wait for onset and then u can see back to back systems and wet weather. Normal to excess NEM possibility this year. Don’t post anything negative before onset. Onset will happen between 22 – 26th oct

      • Yes from oct last week we can see lot of Easterly Waves, LPA and Depression. November going to be very wet

      • What negative posting you are talking about. …off late everything is going negative onnly in spite of talking positive. ….NEM was predicted to set in by oct 18th to 20th…now 22….26 25 …28

      • Oct 18 – 20 is set to be a normal onset for NEM but this year due to western pacific typhoons easterlies getting disturbed and it is expected to enter central BOB within next 2 days. Now Easterlies have reached till andaman and the winds touching 35 knots over there and there is a trough forming near Srilanka and this will provide good Rains to South Tamilnadu and parts of Central Tamilnadu and North Tamilnadu expected to receive light Rains. Onset expected to sets In between oct 22 – 26 by strong easterly wave.
        Just wait till Easterlies arrival to our coasts then everything will turn good

      • Still monsoon hasn’t set, So don’t come to an conclusion.. Late monsoon ‘s not a defi monsoon.. Wait until it sets..

  1. Please let me know if anyone knows about local parameters that can bring the NEM-rainfall onset over TN? I would like to update my knowledge regarding those local effects in bringing monsoonal rainfalls to our shores. Its better to know about these local effects if someone wants to establish RMCs/RSMCs 🙂

  2. At 37.2°C, city equals highest October temp in a decade
    The day temperatures in south Mumbai too was up by two degrees above normal, recorded at 34.8 degrees Celsius. (Arijit Sen/HT photo)
    Badri Chatterjee, Hindustan Times, Mumbai |
    Updated: Oct 16, 2015 00:25 IST

  3. The southwest monsoon has withdrawn from Goa and Konkan region on Thursday.

    India meteorological department (IMD) had forecast on Wednesday that the southwest monsoon would further withdraw over more parts of Jharkhand, most parts of Chhattisgarh, remaining parts of Vidarbha, Madhya Maharashtra, Gujarat state and north Arabian Sea, entire Marathwada, Konkan and Goa and some parts of Odisha, Telangana, North Interior Karnataka and central Arabian Sea within two to three days.

    But it withdrew quicker than expected even as some of the 13 centres in the state witnessed moderate to heavy rainfall during the post-monsoon season.

  4. Global warming may help alleviate China’s drought and flooding problems as monsoons move north, scientists say

    In their recent paper published in the influential research journal the Proceedings of the National Academy of Sciences of the United States of America, a team of scientists led by Professor Yang Shiling

    reported that such a paradigm shift would “soon occur” in China.

  5. அடுத்த 24 மணி நேரத்தில் தென் தமிழகத்தில் கன மழைக்கு வாய்ப்பு.
    In next 24 hrs South Tamilnadu will see Heavy Rains

  6. From next week or in another 10 days all bloggers will be commenting on my area received this much…awesome smashing bucketing pelting rains from the famous our own NEM and all will forget the late onset or whatever uncertainty that remains now.

    this too will pass away (ithuvum kadanthu pogum)

    Experts in blog have rightly said the delay in NEM onset(and not deficient NEM) and belief in their forecast is more important.

    Nature will have the final say.

    Lets thing positive and enjoy the weather pattern be it dew sunshine or rain.

    I certainly believe that we will have a normal NEM this year.

    enjoy blogging and lets learn weather in this forum.

  7. Easterly Clouds roaming around Chennai looking dense and huge Cumulus. Today Clouds are really looking dense and carrying some large water droplets in it and for the first time since winds turned to east on 11th oct.
    Isolated drizzles and Passing Showers possibility in parts of Chennai

  8. Foggy Morning.
    Temp was lower than yesterday morning.
    Long distance buildings are not visible.
    Sun in the morning was in lightish yellow.
    Clouds from East to West.
    HPA dominating.
    We are into winter from today.

    This is pointed out in today’s topic.

  9. Pressure increasing all over bay.. and winds are slowly changing westerly in south.china sea and slowly the impact will b felt in bay.. people who r not convinced with pacific effect can have a look on sat image.. it is expected to go worse in next few days.

  10. Till Koppu makes N/NE turn, West-Pacific will exhibit effect on BOB. Then later onwards BOB will rule for some time😆👍

  11. What a clean slate raised in our favourite Elnino year😂😂😂

  12. Nice to see more and more addition, if rainfall details of other areas of Chennai and Other areas, other than official readings are maintained in an excel sheet it will be useful, and can be witnessed for ready reference all time

    • that is a real mystery. most of the model say west pacific killing our seasonal rains. even thailand meterology says north east monsoon winds set in over gulf of thailand followed by few showers for the past 2 days. But most of IMD models deny that. in the meanwhile IMD announced an UAC over south east bay. totally cotradicting reports. i feel some rains would commence by sunday.


      • see where is thailand and where is scs and bay.
        the latitudinal difference is there, the latitude below 15N of thailand has impact of this WP system, but thailand will not have the same.

      • still thailand distance wise less than 2000 KMS, but where bay of begal still more distance. could be around 3000 KMS. any way let us wait and see for another 2 days.


      • you say south china sea triggers our monsoon winds. the winds can as well reach from top of burma and extreme north andaman sea. even from nepal side, the siberia high pressure can dominate. difficult to understand. any way IMD follows some basis and we have to accept. wait and see.


      • It enters through south andaman sea only, when reaching bay it climbs up in latitude and then reach NTN.

        also in thailand the wind pattern will change from 18th or 19th approx from NE to N or NW winds.

  13. Yesterday evening mangadu TS near Tambaram has moved in SW direction, i saw that movement.
    Now that is shown in PAC as of 08.30 IST today. Moderate rainfall occurred in those regions.

  14. IMD Morning Bulletin,

    ♦ The upper air cyclonic circulation over south Andaman Sea & neighborhood now lies over southeast Bay of Bengal & neighbourhood and extends upto 1.5 km above mean sea level.

  15. All India Institute of Medical Sciences (AIIMS) in collaboration with Melbourne Institute of Technology in Australia is working towards developing low-cost helmets having better ventilation for Indian weather conditions, which is mostly hot and humid.

  16. Ecmwf reconfirmed excess rainfall for south tamilnadu for the NDJ season with very high probability ..chennai including north tn shown as no signal so it can b taken as normal (but anything might happen)..unfortunately nellore under below normal category

  17. Selva ECMWF is not King in rainfall in our basin. I am sure STN will get excess rains but north too will gets its share.

  18. There is yet another typhoon, named ‘Champi’ located even farther out into the West Pacific, whichis expected to veer off course towards Japan much before it can reach anywhere near the Philippines.
    ‘Koppu,’ and to a lesser extent, ‘Champi’ would impact the wind flows over the Bay of Bengal, which are
    just about turning northeasterly, as is what is seasonally expected.
    These flows will be progressively forced to turn clockwise to feed the twin typhoons in the
    Pacific; the net-effect is that the onset of northeast monsoon would bedelayed.

  19. An upper air cyclonic circulation now prevailing over south east bay of bengal. expected to spread to south central bay by tomorrow.


  20. This is the place above my hostel in Srivenkateswara University where I used to visit a loads of times whenever it rains.
    2010 – 2014 (Golden time for me)

  21. Even today the recurvature scenarios are challenging for computer models. In west Pacific, they have been facing this one since the early 1900 s , when it was all to deal with upper air sounding data to interpolate and come up with synoptic charts. The break point in the ridge, ridge extension that happens unexpectedly, or eastward moving upper level anticyclone…the list goes on…

  22. gulf of thailand 9.5 north & 120 east. so longtitude wise nearly 25 degree east of bay of bengal. but Thailand says north east monsoon sets in over southern thailand. all reports – lot of mismatch. interesting to observe. let us see, how wind changes in gulf of thailand tomorrow.


    • As i said yesterday that Eastward movement of Trade winds would have caused a Mid to Low level ridge over West Pacific, this is making the system to move westwards, otherwise this would have moved northerly from the beginning and NEM would have not got disturbed and would have set already.

  23. what i feel apart from south china sea, the high pressure zones over central & north burma also contributes to NEM winds over bay of bengal. Once SWM totally withdrawn from bangaladesh, myanmar & west bengal, probably the high pressure would dominate over central & north burma. I think this would happen with in a day or two, once SWM winds totally cease over remaining parts of extreme east india.


  24. Prominent ensemble models continues to expect High intensity mjo wave to move into indian ocean by early nov !!! watchout fro some action in arb sea and bob!!

  25. In School, we are taught that SW Monsoon winds will hit himalayas and turn back as NE Monsoon since it is not possible for that go beyond that.

  26. Here you go on the update of trade winds.

    Westerly anomaly has extended westward towards WP as on 12th.
    Easterly anomaly over EQ IO is continuing, this shows the strength of Positive IOD as of 12th.

    Upper level easterly winds weakened as of 12th over WP, MTC and EIO.

    As of now MJO related positive olr prevailing over IO, this will become weak in next 7 days and start to change negative by 23rd. Hence we need to wait for NEM till 25th.

  27. paul roundy’s page expects twin event possibilities in indian ocean!! one in arb sea on nov 3rd , and the other one in andaman sea around 6th of november with very high prob

  28. Does anyone know the tamil translations for LPA, WML, DD etc?, like குறைந்த காற்றழுத்த தாழ்வு மண்டலம் for?

  29. Many of us are running the Dusk to Dawn Night marathon scheduled to be held on November 28th. This marathon is held for a charitable cause.
    3k, 5k, 10k and 21k categories available or if you want to do cycling you can take part too.
    Hoping to see many bloggers turn up for the run that night

  30. Churning out to the east of Philippine archipelago…CDO has obscured llcc….but it’s just stacked well and looks explosive…

  31. Same typical climate happened on last year before onset day that is October 16…
    But Tommorrow we can’t expect rains like October 17,2014 the day which has gave 161 mm to nungambakkam and 181 mm to marina

  32. Cumulus clouds in East in vellore too..
    On and off sunny with pleasant climate…
    But today feeling some humid compare to last 3-4 days

  33. winds turned totally easterly. from tomorrow early morning mild showers drizzling not ruled out. normally early morning showers are quite common to NEM Season. Even dry air dominating in the last 3 days are absent. now we only feel and mild breeze from east. if upper air circulation forms, can bring thundershowers from east, north east by night.


  34. Mumbai will be hot for another 3 weeks, as they have to live up with north & north east winds which are from land and that too from hotter regions. By November first week, the maximum would come down to less than 32. this is quite common for mumbai in october. even some times the maximum touches 100f in western india.


  35. Now the updates of OLR map shows that there is a system forming on 27th over SW bay of bengal and moves towards TN and crosses the coast by 30th.

    This system is likely to be a D or DD max.

  36. Selva,

    Lets say that is D or DD and having mid level interaction.

    If i am right that month end system from SW to TN is moving due to this push from Myanmar at mid level. Correct me if i am wrong.

    We will have this scenario for clearing doubt, dont think whether this will happen or not.

  37. IMD model now says rains possible over coastal tamil nadu from 19th. they also say west pacific system delays the seasonal rains by a week. what is that they are trying to communicate. no clear cut predictions. cat on the wall predictions. I still insist that rains have to commence by early morning of 18th though on reduced intensity to start with.


  38. In simple terms i will explain why 19th rainfall is not considered as onset of NEM, lets forget the wind pattern or any other system effect.

    The point is whenever there is an onset the real time OLR should become Negative and it should be Widespread covering at least entire south india approx. This is the condition during any monsoonal start. This condition likely to get fulfilled only after 23rd. MJO likely to enter phase 2 from 25th, that is when the Positive OLR will start to move eastwards towards MTC from Bay of Bengal.

  39. IMD MID Day,

    A trough in the easterlies extends from southwest Bay of Bengal to west central Bay of Bengal off north Andhra Pradesh coast between
    3.1 & 4.5 km above mean sea level.

  40. sun enters libra on sunday the 18th october,2015. at 09.50 nazigai. approximately 9.45 Am. On that day moon is waterly sign scorpio with conjunction of satrun. Mercury is exalted in virgo. only venus is not favorably placed. Hence we can astrologically say, rainy season to commence from Sunday. But venus is placed in its own constellation, even heavy rains are possible from that day. The period between 17th midnight – 20th midnight, wet conditions would prevail.

  41. Normally when sun is in virgo, and mercury enters virgo, the south west winds would vanish. On october 4th itself, this had happened. hence we can conclude by october 10th the real SWM winds over in india.


  42. Trough in the easterlies at app. 700 hPa and above could be due to anticyclones on either side .Cumulus scale convection all across east coast up to east Indian plains….

  43. GTS,

    During NEM, there is wind uplift happening over Andaman Sea right.

    When lower level wind comes from SCS, it reaches South Andaman Sea and after that it climbs above and reaches up to Chennai latitude. Will you call that as inverted trough?

    • do you mean to say all these winds are from South china sea alone. what about burma, & north bay of bengal. i feel the winds are combination of so many such. Actually high pressure zones over burma made to re-curve winds and also the sea surface temperatures over lower latitudes less than 14 C were also contributes so much to rains over tamil nadu.


  44. Partha,

    This is one scenario where an active easterly wave and the associated inverted trough would look like ..During cyclone OGNI in 2006 there was a similar situation

  45. in the below diagram…this also looks like normal trough only can you throw a bit more on the difference between the normal trough and the inverted one

  46. really a good clear, sunny and hot day outside. but dry air is totally absent – mild easterly breeze we can feel. this the typical before monsoon conditions. end of puratasi- very ideal weather. possibly after midnight chances of some rains.


    • yes. it looks like thundershower formation, due to strong trough-line running closer to coast. in fact places close to machli coast getting heavy showers uncommon to this period, as normally this can occur during good SWM period.


  47. As day progresses, we can expect cells formation up to 13 latitude, as we could see the trough exists almost close to chennai coast.

  48. Inverted troughs are common in the areas affected by Easterly Trade Winds. The barotropic instability that occurs from 0-30 N/S latitude. The area of maximum vorticity is where the axis of the inverted trough resides

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