Moderate Thunderstorm activity to persists over Interior TN

Weather Update
Chennaiyil Oru Mazhaikkaalam
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With just a week left for October to come to an end the overall rainfall since the start of Northeast Monsoon season (1st October ’21) now stands as on 23rd October at 171.8 mm with another 7 mm to go for October Long Period Average to be reached.  Compared to last year this October is already at about 70% more with still a week to go.  Nevertheless one should not forget it is November that is the most crucial month of Northeast Monsoon.  Just like how July is considered a critical month for Southwest Monsoon it is November’s performance that decides the overall performance of Northeast Monsoon season.

Looking at the wind charts it is quite obvious we are seeing the Easterlies slowly sneak in to the Bay, though they are still no way strong & streamlined enough. [wpdiscuz-feedback id=”t676q85okl” question=”Which is your best memory of NEM Onset?” opened=”0″]But the stage is set though for things to fall in place for Northeast Monsoon Onset in a few days time.[/wpdiscuz-feedback] In about 3 / 4 days time Easterlies will further extend west reaching the coast of  South India & Sri Lanka. After that it could be a matter of time before the rains follow & Northeast Monsoon Onset as well.  But all these are at the moment just possibilities & they are not yet certain events.

But one thing is reasonably certain is the continuing of thunderstorms in interior parts of Tamil Nadu due to wind instabilities. West Interior TN is the biggest beneficiary of these pre NEM thunderstorms as yesterday also many places in the region recorded moderate rains with few places seeing heavy spell of rains as well.  Today similar pattern is likely to continue with places along the Western Ghats, West & NW Interior TN in line to see thunderstorms.  Chennai will possibly miss out on the rains in the city areas though western suburbs about 20 kms away from the coast line may see localized development of thunderstorms.

241 thoughts on “Moderate Thunderstorm activity to persists over Interior TN”

  2. Got this message 👇

    இன்று (24.10.2021) பூண்டி நீர்தேக்கத்திலிருந்து உபரி நீர் வெளியேற்றப்படுவதால், கொசஸ்தலையாற்றின் இருகரையிலும் வசிக்கும் மக்கள் பாதுகாப்பான இடங்களுக்கு செல்லுமாறு எச்சரிக்கப்படுகிறார்கள்.

  3. Back to my native(Pandalkudi),Virudhunagar after a week stay in Thaiyur.

    It have rained very good for 45 minutes on 23-Oct(Previous rainy day was 01-Oct) and also rained lightly on 24-Oct(Yesterday)

    1. Luckily the crops at punjai land have survived the dry spell of 22 days and have come well. The rains on saturday have come at the right time and yesterday rains have further helped the fertilizers used by us to dissolve easily

    1. Have temporarily disabled media uploads because the change in commenting platform has increased the load on server. Need to figure out a way to minimize the load before enabling images back

  10. A historical day by all sorts…

    Off-Topic: Pak beat India in WC
    On-Topic: GFS beat all other models as ECM also aligns to proper LPA kind of onset system finally
    😃

  16. Rainfall till now:

    Adampur – 34.5mm

    Mohali – 24mm

    Sangrur – 21.5mm

    Fategarh sahib – 34.5mm

    Chandigarh – 29mm

    Hamirpur Himachal – 34mm

    Panchkula – 24mm

    Sase chandigarh – 24mm

    Paontasahib – 42.5mm

    Sundernagar – 16mm

    Sujanpur – 21mm

    Karnal kvk – 20.5mm

    Munsiyari – 20mm

  19. TN probably may end up at around 220 mm for October, Chennai could probably end up at around 200 mm for both observatories by the time October ends

      2. Models are not picking because there are multiple signals from Tropics. There is north Bay convection influencing Asia – Pacific mid latitudes wave train.

        There is mid latitude rossby waves propagating east in southern hemisphere result of SW PAC Pac convection.

        This rossby wave over mid late will converge and initiate a fresh equatorial pulse from s america to IO. NOV 2nd week looks more IO forcing to return

      2. Disqus was a really great platform, but spammers were ruining the Privacy of the blog, it will take a little time for everyone to adapt.
        Are there any special security features for WordPress?

      3. Human tendency is to resist change always including me. The other issue we need to solve is load on the server, with disqus the load was on their server

      4. Yeah, it was a great decision to change Disqus and try to find something better, Word Press is ok but it takes a while to like a comment or edit it
        Please do something about that if you can.

  32. it’s pouring like anything aam in my native ☹️ …3 days not even a drop while I stayed there..im crossing Thiruvallur now😭

  36. Looks like models caving into adamant GFS solution, truly appreciate GFS and its warriors if it happens, only some change that has happened with GFS was delaying initial trough bands by 2 days as other models did as well

    1. அது படமாக இருந்தால் நன்றாக இருக்கும் ஐயா படம் அனுப்புங்கள்

    1. This is actually more like OHD induced due to mid-level CC near North TN mentioned in IMD post today, actual onset will happen when cloud bands form facing us than sea

  46. On a humoristic note, may be because easterlies are sneaking in, admin has represented it with a snake-like arrow 🤣

  47. Just noticed from the post , The individual years and decadal averages are really a better way to understand a trend and do some analysis on variability in rainfall patterns, the decadal average clearly seems to follow a sine wave kind of pattern averaged over a mean of 170 mm, will be happy to see similar plots for November and December as well for past 70 years

    1. I read your article, it was way beyond my comprehension skills. Only thing I can say is we might have had Tropical / Mid Tropical Interactions in the past to which possibly we had not picked earlier

  52. Couldn’t even see cloudy skies for past 1 week since i returned to thaiyur where as city bloggers often post about rains that too decent numbers.

  53. ♦ With likely setting in of northeasterly winds in the lower tropospheric levels over Bay of Bengal and extreme south Peninsular India, the Southwest Monsoon is likely to withdraw from entire country during next 48 hours. Simultaneously, the Northeast Monsoon rains are also likely to commence over Southeast Peninsular India during next 48 hours. – Courtesy IMD Mid-Day Report

  61. During SWM, we are cheated by western, northwest and southwest suburbs , during NEM , we are cheated by extreme coasts , more so, life of Mambalam and Anna nagar will go in between cheaters 😝😜🤣

  71. Surface level Northeasterlies setting in from today afternoon /evening , atleast there is some model consensus for that , waiting to see the transition on my weather station and welcome first signs of NEM 😍,perfect Sankatahara Chathurthi day to step in and remove our obstacles for rains 🙏

      2. I read and commented with reflecting mirror image (this is Chirality in chemistry like our both palms) in +ve/-ve anomalies.

        FOr example if we see both 2005 & 1997 0.2101 Velocity anomalies, it looks both are reflecting mirror images in terms of ascending (-ve anomalies) and descending (+ve anomalies) cells.

        SO as per the atmospheric circulation patten view, I would consider both 1997 & 2005 dynamics are same at least till West Pacific & Indian Ocean despite having minor changes at Atlantic ocean side.

        Thus both 1997 (Super Elnino) & 2005 (cool ENSO) seen normal SWM and super NEM.

        However if we see one more Super Elnino 1982 (0.2101 Velocity potential anomalies), that resulted in both worst SWM & NEM rains.

        Here I found the major difference between 1997 & 1982’s is in ascending cell at East-pacific. 1982’s ascending cell is far west and close to date-line and more distorted/unsymmetrical spread into Southern Hemisphere.

        However both 2005’s descending cell & 1997’s ascending cell had very symmetrical on the equator and far east orientation at east-pacific.

        Note:
        All three 2005, 1982, 1997 had very nice major two-cell component spread in walker cell pattern along the tropics.

      6. Hi Rao ,nice presentation ,you did your PhD in Chemistry? ,nice to see analogies from chiral point of view , loved to read as a kid in all sugar-base compounds (I always used to think the similarity between Tamizh Sarkkarai and scientific name Saccharide, may be the term went from here)

        Okay Rao , 1982 seems to be more of a Modoki flavour in Atmospheric pattern, whichever Modoki on either side of ENSO coin more so has resulted in drought as per available data

        Will be happy to know your native at Andhra 😊

      7. Thank you though don’t with whom I am chatting.

        Anyhow I am enjoying your nice presentation in the weather dynamics, which matters most :))

        MY Native is Vijayawada, Central AP.

      8. Yes….1982 is having more-modoki (non-classical/non-canonical) type atmospheric circulation unlike both 2005 & 1997’s East-pacific (classical/canonical) atmospheric circulations.

    1. Go to page 3 on delete screen for example. Delete any comment. GO Back to page 1. It shows no comments and shows the value 0.

      However when we reopen the window the comments are retained

    2. Looks like you have been in software testing team in some IT sector , developer ah undu illa nu senjurvenga polruku ,paavam😂

      2. aama…my east getting heavy dark…seems it’s gonna rain in 30mins..I’m in bus now to tiruttani from my native…it’s all fate☹️😭

  79. Rao jo,

    Basically when southern eastern IO near AUS is cool compared to Madagascar means, the climatological position of mascarene high will be eastward and close to Australia and not typical position where it favors Indian monsoon.

    This cold south eastern IO in normal case coincides with warm ENSO decadal signal.

    How this happens is Pacific warm pool when it is displaced eastward than normal and extended to Hawaio and SPCZ, the convection there shifts the High pressure to SE IO and cools the SE IO.

    This cooler south IO will weaken pressure gradient between Tahiti and Darwin. This will mean frequent MJO circuit around western hemisphere.

    My thinking is if we analyse the Pacific warm pool longtitudnal location and its symmetrical and non symmetrical orientation, we will be able to derive more answers and assist long range forecasting in Tropics

      1. Also is it must the MH’s position to stay near Madagascar coast or MH’s strength irrespective its position that decides the fate of SWM?

  85. Konni 105mm
    Thodupuzha 87.2
    Punalur 75.2
    Neyyattinkara 68.5
    Kanjirappally 47
    Varkala 38.2
    Vythiri 26
    Peermade 25.3
    Aryankavu 25.1
    Kuppady 24.7
    Idukki 22.8
    Mannarkad 21

    1. Good one, which you used to tell us for last 3-4 yrs. I went through this completely. Here I had couple of points.

      (1) +SIOD means SW/W Indian Ocean having +ve SSTA. This means strong trades flowing towards Somalia coast thus towards Indian subcontinent?

      (2) Also I generally consider +ve & -ve anomaly equally. But only see whether overall trend missing any symmetry.

      To understand this point, we would take tropically SWM & NEM good years like 2005 & 1997 for June-September. For these two years just plot .2101 velocity potential anomalies.

      After plotting just see EIO-MTC region. In 1997 we had super strong +ve anomaly, which is quite contrary to 2005’s strong -ve anomaly.

      But how both 2005 (Neutral to cool ENSO) & 1997 (Super Elnino) years given normal SWM & bumper NEM.

      This means before thinking about decadanal/multidecadanal shift, our style of understanding +ve anomaly and -ve anomaly need to be changed/corrected?

      If need to change/correct then in what way it must be? As per my understanding, we need to see the overall symmetry in the anomalies.

      For example, you plotted last 0.2101 streamfunction anomalies for last 3-4 year & few Lanina years. Those 2 plots, please try to super-impose each other instead of just judging based on seeing any deviation in the terms of +ve/-ve anomalies.

      So overall please try to super-impose both plots irrespective of +ve/-ve anomalies. If both plots of super-imposing mirror images (in chemisy this phenomenon is called Chirality like our both palms), then need to understand there is no big problem in the weather dynamics in terms of yearwise/decadanal/multidecadanal shifts.

  93. Rainfall in Punjab. Under the influence of Western disturbance:

    Gurudaspur aws – 39mm

    Nur mahal kvk – 34mm

    Ludhiana – 23mm

    Ferozpur kvk – 35.5mm

    Ferozpur – 31mm

    Fategarh sahib – 14mm

    Moga – 12mm

    Ropar kvk – 28mm

    Sangrur – 12.5mm

    Budhsingh wala kvk – 13mm

  95. As long as this upper level WAF acting from Indo-Pacific region, it will not allow MJO to enter Indian Ocean.

    When Tropics influence from western hemisphere we need IO to shut down. However , we still have this north Bay altering mid latitude pattern and you see a coherent burst of convection source in SPCZ.

    Once these relax and Indo is shut down, we will see pressures reduce over Asia.

    Until then any systems forming inbetween will influence southern hemisphere of IO than N IO

    2. Already yesterday I found and commented…

      BOB is with ER Convection, that need to weaken further prior MJO/CCKW Convection to bloom @ NEM onset.

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