Chance of any rain from the Low dissapears for Chennai

There was high anticipation from the system, but the end result was dissapointing.  Minimum of 100 mm was possible if the High pressure had moved away. Only hope now for chennai is to look forward to rains in December

1,048 thoughts on “Chance of any rain from the Low dissapears for Chennai

  1. Are we missing something?

    IMD and Vagaries are expecting heavy rains tomorrow evening upto monday morning. Total accumulation will be around 80 mm.

    Not too sure what to make out of it. They are the experts.

  2. IMD:
    Rain/thundershowers would occur at many places over south peninsular India on 2nd & 3rd December and decrease thereafter

  3. Kea brought the following 100yrs old record? Do u all wanted to know the possible equation for this record?

    “24 hour record for December is 261.6 recorded on 10/12/1901.
    Can we beat that?”

  4. A Low is
    currently located over Sri Lanka. The extended trough will form off the
    Southern TN coast, and the Low will get embedded in the trough. As a
    result, the Low will then get re located to a position off the TN coast
    by Saturday night.

    Rainfall expected to increase in Southern and Central Tamil Nadu from Saturday

    Chennai will
    get increasing thunder showers from Saturday night thru Sunday and
    Monday. Would expect arond 70-80 mms Sunday morning to Monday night..

    http://www.vagaries.in/

  5. Hats off to Vela sir,for correctly predicting this. He clearly mentioned NTN will be left out and only STN will get the rains.

  6. Well… if anything at all, NEM is becoming really damn uncertain and we can’t trust something that is this elusive. Hopes, hopes, and hopes. We are going no where. It’s time we seriously consider lots of factors and importantly have to implement them. We have to definitely plant a lot of trees because planting of trees on a large scale will bring more rainfall and reduce temperatures. One more thing that can possibly be done is cloud seeding and trust me that is something super effective. If cloud seeding is done properly, NEM will never fail.

  7. Where is kea? I put my following analysis for December 10th, 1901 heavy rain of 263 mm in just 24 hrs based on single factor that is SOI.

    I think all others have some data for this to explain in their technical terms?

    Reason:
    SOI values in 1901-NEM:
    November 1st: -8.6
    December 1st: -1.9,
    January 1st (1902): +17.0

    The above values clearly tells SOI is at near neutral value, which resulted in heavy rains on December 10th, 1901.

    BoM SOI: http://www.bom.gov.au/climate/current/soihtm1.shtml

  8. Team ,Here is what I feel on this LPA system. (Just a layman understanding). This circulation had fantastic energy when it was near below first and 2nd east of Srilanka . Once it moved near Nagapattinam and moved NNE ,it started loosing the clouds. The Northern bands ,when they came parallel to Cuddalore,they started fizzling out.

    Clearly ,I beginning to believe SST played a role here. It never allowed huge water vapour conversion to Clouds.

    Today, we were hoping that TS’s 200 KM east of us will develop and come to Chennai. They also got fizzled out. You can clearly see SST is not normal (That is why it is an anomaly ) in the below URL . Check from SAP to Cuddalore.

    Also ,look at the North America SST. no wonder it was a CALM Atlantic hurricane season. Both BOB and Atlantic didn’t generate enough systems this year.

      • :-).I am still not clear on understanding MJO ,SOI, QBO and IOD etc. Also,no idea on Kelvin /Rossby waves. Trying to see weather only from SST,HPA and MSLP perspective.

      • If u don’t understand SOI concept, then try to understand ENSO effect (Elnino/Lanina) on BOB-cyclogensis and monsoon effects from the literature.

        No need to pay attention on MJO, IOD & QBO at this moment.

      • Nope..Its quite common to find Hpa over north India during this time of the year and many a times we had systems giving plenty of rains as vinodh said, even a marginal cyclone or a DD during this time of the year has given good rains for N TN and South Ap..In this case the system was not that strong enough to intensify or gain latitude and Hpa had less role to play..I feel too much hype has been created over the Hpa over North India..Every year around this time we find the Hpa prevailing oner that area and its no surprise this year,,The current low just did not have enough intensity to gain latitude the role of Hpa is minimal..Had the low moved west towards Park straight and ventured into Arb sea, the trough alone would have given sufficient rains from GOM area and more moisture pulling from BOB would have given us rains when it would have moved in to ARB sea..
        In short the system tracked in the wrong direction for we missing the rains..It should have moved west into Palk straight..

  9. @RSRao – I feel SOI failed us this time. If the current SOI (-7) was prevailing during Oct 4th week to Nov 2nd week, we could have got bountiful rains. The ‘PRIME’ NEM time was killed by a hugely negative (-13) SOI.

  10. Weather modelling is very very difficult , to my knowledge that is one tedious job ..
    Day by day I realize the nature of difficulty and the “n” number of situations when analysts and experts are forced to take a relation by approximation and even more conditions that go countless .. And over this all these decisions are made with so much time constraint ..
    So going forward I have decided not to blame any model when they go wrong at times , ….
    My friend who does M.Tech design in IIT Chennai , had showed me the real difficulties that they face even in designing a solid object(man made ) considering so many factors like stress , strain , thermal stress ..
    So a man made object , if it needs , this much , will the atmospheric dynamics be that easy ????????
    “HATS OFF experts !!!!!!!!!!!!!”

      • No jst can’t say lik tat it has failed this sys s. But we ve been following for over 10yrs now it has proven right on most times…

      • Yes , situations occur when some models outperform the others , last year ECMWF wasn’t this perfect , but this year , they lead the others ….
        We shd know abt . the situations during when which model controls and leads such scenarios

    • There may be climate change in coming years due to global warming. Yes, predicting the weather is getting very difficult and we may see more extreme weather after 15-20 years.

    • Yea.. v r nothing without models..they r predicting right from a to z with lot of assumptions. Parameters what they r feeding into super computers r not really static whether it is temp or humidity to say in simple terms..

    • The influence of various known and unknown parameters and the interaction among them is not correctly captured by even the super computers. I doubt they (we) will never achieve it.

    • Friends ,
      I will not blame BBC / UKMO completely , I have seen this model more accurate 3 or 4 years before …
      They were bang on predicting that 25 cm excess in N.TN coast post Nisha landfall , and that day Chennai AP got 28 cm . They have also predicted so many minute T’storms perfectly in the past ,
      Only recently the situation has changed

    • why can’t IMD have its own model instead of following gfs to predict do we not have enough funds to build a weather supercomputer or not much skilled people to work in it ??.Surely it will save a lot of money from loss by to an extent correct prediction of SWM/NEM.

      • but gfs predicts they only do some correction work to it .not their own supercomputer predicting

      • But it could save crores of rupees from loss especially for farmers.hopefully one day we will get our own weather forecasting model.

      • Hey , one more thing ,is that predicting weather in Tropics is very difficult ..
        Monsoons are a great mystery

      • yeah but IMD officals with good knowledge of our monsoons would help to be more accurate in prediction using their own supercomputer inputting values to their model instead of following some other model and making changes in it.

      • No IMD has other outputs apart from IMD GFS , for example India runs the world no. 52 super computer at Pune Tropmet , a friend from vagaries studies there ,,, He said there are several researches being conducted reg Monsoons ..Hope in the years to come ,,,,Indians would come out with good Monsoon predictions

  11. Farmers and olden days people simply said that, if cold comes no chance of rain, the same thing just happened once again, hattsoff to them

    • Strange.. then i guess some other bigger forms of CCN were deposited in other countries like Australia (west coast) and in USA esp. California because cloud seeding at those coasts met with success

    • True..when I am in pune one of my colleague brother who is doing environmental science attended conference related to cloud seeding..i got the chance to interact with him and he said the same thing when I questioned about chances in Chennai..i didn’t understand his points clearly but he said in Chennai its not possible and it has to be 50KM away from coast at least..
      But why cant we try 50 KM west of Chennai?

  12. Weather modeling is really very toughest job. We must not feel bad about the weather models’ missing forecasts.

    For the above reason I am getting very +ve support for my “simple 2 component MJSOI-1 model”. Slowly would like to incorporate IOD & QBO concepts based on elaborative study.

    Thanks for everyone to encourage me constantly πŸ™‚

    • What to do , he was expecting rains that would have bijlis in it that leads to bijli cut because of it , and nothing happened 😦

  13. In general cyclone will be having 500 KM diameter (rain bands). Cyclone will take 2-3 days to travel 500 KM.

    So by looking satellite animation we can able to predict in advance by 2-3 days, where the cyclone will take landfall.

    • Models can able to tell accurately in 2-3 days advance regarding BOB-cylones. This 2-3 days time period is equaling our naked eye satellite animation-technique.

      In conclusion Models’ prediction “equaling satellite animation effect” regarding BOB-cyclones.

      • If SOI doesn’t increase in value towards 0 or +ve in December, we can sign-off NEM-2014 season for CTN-NTN/SAP.

        STN/SL can not be considered for signing off NEM-2014 this much early due to equator proximity.

      • The cold NEM winds and continuos cold week easterlies made the bay to sleep by decreasing the sea surface temparature….then no chance of circulaions

  14. If for the third consequent year NEM fails I am afraid that the farming community of the Interior Western TN districts could not sustain at all.

      • except chennai and interior western districts all other places in TN received good rain..We must feel very happy for that..last 2 yrs entire TN left dry..
        Also if it rains well in cuddalore dist then veeranam will be full which will help Chennai..

  15. Feel a bit upset for Chennai. I was hoping that something will turn up november end. But i guess this system fooled all of us. Hopeful that something good will turnup in December. The total lake levels storage is about 25% lesser than on the same day last year.Real estate prices especially in draught areas are going to fall . Praying for a miracle now.

  16. oiswww.eumetsat.org/IPPS/html/MTP/PRODUCTS/MPE/SOUTHERNASIA/index.htm
    There is a big reddot can i know the wind direction does it moving away or it will hit central tamilnadu any one please let me know

    • Jon, yesterday night when I logged in by 9.45 I strongly believed that the system is intact and certainly not gone or dissipated. Have a look at the convention now. We are just about unlucky as of now and Pondy/Cdl belt getting everything.

  17. except not ntn and sap nem monson was very good…you can have a look at the statistics….
    God please bring us the remaining quoto for chennai please in december,,chennai needs more water than any other plance in tn

      • then what else…may be the system last moisture lost the intensity in srilanka..first of all it formed way too low in lat

      • ACC formation is common phenomenon during NEM-season. Without this ACC/hpa there won’t be NEM-season. But too negative value in SOI makes this ACC dips further south till NTN.

        If IOD was in +ve values, then at least this ACC/hpa might have stayed little north so that there couldn’t have been any problem for NTN/SAP in terms of rainfall condensation.

      • i feel this year winter is quite early and powerful in india…e.g.hyderabad dipping well below normal for this time of the year…this has any association with too much -ve SOI and subsequent failure of NEM in ntn

  18. Karaikal to marakkonam stretch battering with early morning heavy rains. Chennai missing by few inches (interms of geological distances) to get these heavy rains 😦

  19. Good morning, it’s been very cold in the nights and mornings in periyapalayam. Feels like markazhi. It’s a huge disappointment not having rains this month. But for the distant loudspeakers, enjoying this morning

  20. Sat. pic is deceptive. It shows Chennai under thick rain bearing clouds but no rain yet. Hope the cloud mass actually moves a bit north to give us at least a few cms.

  21. All the our bloggers hope for rainfall figures in chennai totally goes to cuddalore.
    Its rocking now with heavy showers never rain stops there and in next 24 hours pondy to nagai will get heavy showers.

  22. If you have a look at the radar the cloud mass is all across the border looks like it is afraid to enter the land near chennai.

      • normally the ridge will come down by mid of dec and it lies over north TN..but this time because of MJO,QBO HPA exists in dec..yesterday partha mentioned HPA exists in Chennai becoz MJO moved to phase 4 which triggered system in china blocking easterlies in Chennai which allowed strong HPA..I am not an expert and learning from this blog only..experts can explain better

  23. OMG….people are injected too negatively regarding HPA/ACC. No one is believing my moderate-heavy rains forecast for Chennai before afternoon/late evening 😦

    • Why cant the current HPA move away?
      My interpretation and please don’t scold me..
      When we have 1 bucket of water which is too much hot and to make it normal if we need 3 buckets of cold water..but as of now only 2 buckets of cold water has been mixed and still need 1 bucket..After some time if we pour 1 more bucket it will be normal..

      same way the current system would have fought with HPA to some extent but still some high pressure exists..
      Rami can you explain in ur words

      • Due to persistent -ve values in SOI can make more southerly in HPA. But at present more moisture ladden winds making the heavy rains towards Chennai.

        Do u know one thing the mid-latitude westerly systems are flanked/crushed/squeezed by 2 powerful HPA-regions. Still USA and other sub-tropical regions are getting either snow/heavy rains.

        So in real sense we should not look HPA as the villain. But due to weakness in tropical dynamics, NEM-pulses in 2014 are not gaining good strength.

    • Rao..great forecast. Please let us know what makes you think the cloud mass will reach chennai today. Whats different than last two days?

  24. Just heard in the news that as the system has moved a little north there are brighter chances for North Coastal TN to get good rains.

    How true is this??

  25. I think news papers r not knowledgable enough to report rains…they meet IMD today- they say next 48 hrs rain….next day in newspapers they put 48 hrs…but it is actually 24 hrs…have any one noticed ? but i may be wrong.

    • Today ts has little more strength. It is fighting with HPA , Let us see who will win. It is more cold than yesterday here in Uthiramerur.

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