Low Pressure Area (LPA) off Indian East coast sparks Northwest Bay of Bengal

Under the combined influence of Upper Air Cyclonic circulation over W.Central Bay adjoining the Northwest Bay of Bengal and the dipping of the eastern part of Monsoon trough into the Bay waters, a fresh LPA has formed off North AP/South Odisha coast. Due to this disturbance, rainfall is likely to turn widespread and heavy over the Deccan region including districts of AP, Vidharbha, Odisha, parts of Eastern Madhya Pradesh & Chhattisgarh. This system would slowly move W-NW to merge with the monsoon trough over the next 4-5 days, thus extending the widespread rainfall period for the next 3 to 4 days over the aforementioned states. West Coastal states which are running a deficit this year are likely to see some widespread rainfall for next 3-4 days especially Kerala & Coastal Karnataka with developing off-shore trough in response to active low pressure area.


Chennai – Partly cloudy conditions expected with a possibility of scattered TS in one or two places and temperature settling near 36-37C.

Coimbatore – Expect warm day with isolated evening TS in one or two places with max temp around 31C.

Madurai – Another hot day expected with temperature inching close to 39C

635 thoughts on “Low Pressure Area (LPA) off Indian East coast sparks Northwest Bay of Bengal

  1. Typhoon Soudelor strong winds completely destroyed the antenna cover of the weather radar station in Taipei.

    The globe shapped antenna was, fortunately, insured against damage caused by typhoons.

    Source : Pacific typhoon season

    • Oseto – 169 mm in 3hrs
      Nagauradake – 167 mm in 3hrs
      Omura(Nagasaki AP) – 158 mm in 3hrs
      Sasebo – 108 mm in 3hrs
      Isahaya – 102 mm in 2hrs

      Many stations have recorded over 100mm till10:00 AM JST.

    • Why WP typhoons missing Japan landfall?? Within span of 2 weeks one more super typhoon exactly going to follow recent super typhoon soudelor. Can the track of typhoons depends on classical vs regular ENSO???

  2. Very Intense Storms to the South of LPA Location. Southern Band Consistently Developing. According to Radar Animation Storms Converged very well and It started to Converge to the 100km SE of Nellore and Good Development of Storms seen over 150km East of Chennai presently.

      • After Low Pressure moves away Chennai will get Good Rains. Past few days TS are not looks as a SWM type. Popups looks lifeless and Steering not favours for Chennai. Iam expecting isolated showers today. Good Rains for Chennai will be based on movement of LPA

  3. Good morning..
    “No one can make you feel inferior without your consent.” ..Eleanor Roosevelt

    Some places of Chennai including Royapettah recorded light rain last night.

    Light to medium rain is expected over parts of Chennai city tonight.

    Heat wave hits Japan and atleast 14 dead..

  4. Clockwise spinning monsoon gyre in eq indian ocean hav extended bit north,one indication of active weather for w.coast

  5. Skymet planning to go global, raise $20 million
    SkymetWeather Services Pvt. Ltd, an Indian weather forecaster, plans to raise at least $20 million (about Rs.127 crore) that will fund plans to go global, founder and chief executive officer Jatin Singh said on Tuesday.

    “The plan is to have a stronger pan-India presence and expand all our business lines. We want to make our website a global weather data website, with properties like long- and medium-term forecasts, and serve the under-served geographies like East Asia and Africa,” said Singh.

    Skymet, which competes with government agency India Meteorological Department (IMD), will also use the funds to set up a global research and development (R&D) centre in the US and increase headcount, which currently stands at 200.

    The firm also plans to work with the state governments to increase their capacity in flood and other disaster management and provide them with high-quality, farm-related data.


  6. True to the write up today, W coast has turned active I suppose which is so obvious from the local conditions here in Bangalore. Overcast and cool now with lots of low level clouds.

  7. What makes the convection of the Monsoon low/depression to get concentrated south/southwest of the system?? Now the system is in nw bay but most of the convection/rain associated with the system seen southwest of the center which is nearly 200kms away from the center of the low pressure area.. Well,there hav been lot of hypothesis put forward by many number of experts after analysing the thermodynamic structure of the systems.. one such analysis says the air mass tat flows into system from north is warm,continental air whereas the wind flow that makes southerly component is cool moist winds, just like how two different hemispheric air mass(warm &cold air) makes ITCZ .. tis cool moist winds would be seen till mid tropo (600hpa)so the high moisture content in south -sw helps in developing convection in a frequent trend.. Another hypothesis says the temperature in north-northwest quadrant is warmer,dry & south-sw quadrant remains relatively cooler than the north. .The temp gradient of 1-2c makes the convection to settle southwest of the system.. Another interesting study points the pressure gradient, which is high in southerly quadrant.Tis pressure gradient causes lifting of moist air as we know the process of convergence taking place to fill up the void space created by rising air.. Similar thing during nem, we see the northerly quadrant filled up with active convection ,again the pressure gradient remains high over northerly flow during NEM ..

  8. Another day of overcast sky,keeps us waiting&guessing. We are almost in middle of August. Restless and impatience is the frame of mind, right now, not just for me but most of my farmer friends. A bunch of farmer friends in& around tirukovilur should have sowed paddy this month. Dry lakes and drywells are the reason, they couldn’t do it on time. Once you miss the pattam,difficult to do it later. Unlike those days, it doesn’t rain for pattam anymore. Sad that farmers are turning masons, helpers and watchmen in the city. I wish this year’s rains are overly kind to us. Let it pour, pour&pour & fill every reservoir and lake. Time is short, we have 3 months ahead of us. No exaggeration, but I do wait with a palpitating heart to know what’s in store for us
    Ps. Please bear with my polambal. Most of my friends are clearly not interested and willing to listen to my rain gaga 🙂

  9. To understand the scale of Tamil Nadu’s water woes, let’s understand what the demand is and how much water there is to divvy up. The demand estimate by the various sectors are,
    This 1,894 TMC is well beyond total assessed water resources in the state which is 1,587 TMC. In other words, the demand is 19.3% over and above known supply. So even if there’s good/normal rainfall in Tamil Nadu, the demand exceeds supply. Partly because we discharge fresh water into the sea in some cases and because we haven’t invested enough in processes to recharge aquifers. But even if all of that is done, it’s unlikely this deficit will vanish.
    With agriculture/irrigation taking up 93% of the demand, that becomes the only segment that demands our attention. Sure the City of Chennai and its bourgeoisie waste a lot of water or appear to when measured on per capita consumption of domestic water compared to their rural counterparts. But that’s inconsequential in the overall scheme of things. Water scarcity in Chennai does not cause desertification. While Tamil Nadu’s unsustainable sectoral allocation will.


    • True that paddy cultivation method, which is practised now, consumes a large amount of water. The farmers wouldn’t want to resort to new methods. They can instead grow traditional varieties of paddy, which don’t require so much water. In fact, some varieties are drought resistant and some can be grown in saline water too. Even 7f they decide to grow, the government is not willing to buy such varieties

      • Would be more prudent to gradually shift to millets, oilseeds and pulses. Buying rice from other states should work out cheap.,this should be a template for most semi-arid areas in the peninsula without a perennial water source.

    • but an research paper submitted by water resource organisation estimates in Tamil naduwater demand by various sector at present, Domestic and Industrial needs consumes more water nearly about 70 to 75%,, and it will grow to 80 to 82% in 2050, with Domestic needs expected to consume around 55% and Industrial consumption will be around 27%, and agricultural water needs will reduce due to urbanisation.

  10. Yesterday many regions in telangana received heavy rains except hyderabad…today it is the turn for hyderabad…Rains lashing with occasional continuos drizzles..
    Dark…cool….damp….nice climate

  11. Would like to share few pics I shot on my recent visit to Bombay.
    Monsoon moods from Mumbai.(Bombay)

    The Gentleman with me in the pic is Shri.Gupta, 81 years, has seen 40 years of SWM rains on the trot selling peanuts (Channa) at the Gate Way..An age old practice of feeding “Kabhutar” Porra still continues there. He also said that he never misses a single day during monsoon as most of the pigeons stay rooted to the place for want of peanuts (fresh ones) . Monsoon not just helps the water table to rise, it does help people like Mr.Gupta Ji and the pigeons.
    Was a wonderful experience feeding them.

  12. Right from Saturday till Monday the city (Bombay( saw intermittent drizzles and one or two spells of moderate rains. Monday morning was probably the best in terms of intensity. Surely missed the usual drenching rains the city is known for.Happy to an extent that I could feel and see SWM rains exactly after 10 years.

  13. Chennai, perhaps because the government made rain water harvesting mandatory, has not been as bad as some of the other places. Though, it’s still lost about 15% of its ground water in that period.
    This is desertification of Tamil Nadu. There’s no other way to look at it. And this also means the delta districts will have to switch to something other than paddy as their primary crop as early as possible. Importing rice, surely, is cheaper. The state cannot afford a crop that requires standing water.
    The impact of ground water depletion on soil fertility in the detla region and the impact of declining quality of water on health are aspects that require further study. Hopefully someone in the Tamil Nadu government or another research institution is doing that. Let’s hope that gets published and is accessible to lay readers.
    Desalination on a massive scale within 5 years will be a necessity. Perhaps Madras’ brightest are better off working on these areas compared to adding another app to the sharing economy. Surely, this will have a large enough market for most VCs, even.

  14. From historical days to till date T.N Delta regions are considered as Ner Kalanjiyum ( Rice bowl) of Tamilnadu, it is not at all applicable to change the tag, of course as in old days farmers should try to cultivate traditional varieties which consumes less water

  15. We all should understand one thing. No one is experts in front of nature throughout world. We are just predictors not an experts. Models prediction is always 50-50. Pls don’t keep hope and finally don’t get disappointed.

  16. Hi Guys,

    Hope you all are fine.

    NEM forecast is not that easy, many great models have failed in the past, we ourselves has seen it. The analysis I am going through right now is for this years NEM comparing with previous ELNINO years with Neutral as well as Positive IOD years coupled with SST and SST anomaly for 3 month period with 850 HPA wind vector anomaly in those years.

    Still need some more time to complete, I am able to see the NEM 2015 picture to some extent. To my analysis with early stage i could see that either NEM will be normal or excess this time. The SST of Bay of Bengal, South China Sea and Equatorial IO from August to October is deciding the NEM probability even though there may be existing global factors like NAO & ENSO or even Siberian Highs.

    Even though we have factors like NAO, ENSO and Siberian Highs supporting those years NEM failed, if you look at those years the SST of Bay, IO and South China Sea was not favourable. We require abnormal SST over Bay and Equatorial IO or either one. Also South China Sea and WP SST should be neutral or above normal during October and November.

    ELNINO + Neutral IOD until August in 1965, 1972 & 1987.
    ELNINO + Positive IOD until July 1957, 1963, 1982, 1991 & 1997.

    3 month SST anomaly of 1987 & 1997 attached.

    Why I have bought these 2 years into picture, the present SST anomaly upto July depicts 1987. From now on how the SST of IO going to proceed will decide the difference in NEM like whether it will be Normal (1987) or Excess (1997).

    This is initial findings of my analysis, will come out with completed one in September.

  17. My Prediction for this NEM 2015 is

    North TN & Chennai – Above Normal Rainfall (5% to 15% of additional rains from Normal)

    South and Central TN – Excess Rainfall (25% to 40% Additional rains from Normal)

  18. As I was saying why the eastern part India was getting excess rainfall in June and July, the WP SST Anomaly was Negative.

    Due to weak Western IO anomaly, West Coast of India did not get good rainfall other than June last week when Mumbai and West Coast recorded excess rainfall.

    SWM will end in deficit in 2015. This is due to Neutral IOD so far, even we get Positive IOD in the coming days, SWM cannot revive.

    I saw that value of IOD increase to 0.5, but remember experts declare Positive IOD when this sustains at least for a month long period, I mean 4 weeks value.

    Add to that Kelvin wave has started to weaken to less than 1 amplitude, saw it going into nutshell. MJO is a question mark for now, it might emerge after 20th into Phase 2 as a weak wave. Kelvin not likely in August again.

    Good hope for September team as ER Wave going to come stronger by Mid of September and will exist until 22nd or 23rd. This is going to be stronger one like we had in July.

    Still August and September forecast for Chennai is below normal rainfall, this indicates the emergence of Positive IOD. Even a weak Positive IOD can hamper the chances for Chennai in the next 2 months rainfall.

    So lets not hurry on Positive IOD. There is low scope for it to sustain in August.

  19. To make the Aug, Sep Contest more interesting…

    Aug team would lose a wicket if it does not rain for three consecutive days.
    You guys could select atleast six places (or more) in chennai ( it could be within 30 Km radius)
    for informing the rainfall recorded. On 1st Sep, target could be set for the
    Sep team after arriving at the average amount of rainfall recorded from these places in Aug. (This is just a
    suggestion, bloggers can solicit more ideas) – If not this year, may be you could incorporate
    this from next year. I have a manual rainguage, I could provide
    the readings of Saligramam from my end.

  20. One of the important thing to note from the latest Jamstec forecast is that they have changed IOD forecast from strong positive to neutral IOD during NEM. Their July forecast was showing strong positive IOD during NEm( because of which they were showing excess NEM) and now their August forecast showing neutral IOD during NEM.
    Also they expect current el nino to peak during ASO period instead of normal ONDJ period.
    I will go with POAMA. It is performing really well from past few years and we can expect good NEM.

  21. Some rains in Telangana and AP gave respite from severe drought
    Rainfall till 8 30 am today….
    Pallepahad – 125 mm
    pusapatirega – 115 mm
    Manthani – 110 mm
    Karimnagar – 108 mm
    Rudrur – 104 mm
    kaleswaram – 102 mm
    Pendurti – 100 mm
    Cheepurupalle – 98 mm
    Kotagiri – 90 mm
    Denkada – 88 mm
    Peddapuram – 85 mm

  22. 1987 chennai (mbk )rainfall annual 1151. 33mm
    NEM 828.25mm

    highest temp 42.7°C on 1 June.
    lowest temp 19°C on 30 January.
    The maximum wind speed 79.5 km/h on 25 February. :O

  23. One of the main challenging problems in Swm for models is choosing the equilibrium between the continental TCZ and the oceanic TCZ. Models like UKMO and Meteo France go on to take the oceanic TCZ alone with change in n factors….

  24. Non stop heavy rain in visakhapatnam city…
    Many areas flooding….
    Gajuvaka kambalkonda vizag steel plant areas are getting heavy rains

  25. There were many years we had ELNINO+Neutral IOD. It does not mean that once ELNINO formed should influence the Indian Ocean. It depends on the Equatorial Western Pacific SST which decides the IOD’s fate.

    NEM depends strongly on Bay and Equatorial IO SST with supporting atmospheric conditions. Lets not derive IOD based on ENSO.

  26. Rami,

    The position of ACC at lower levels near Equatorial IO is very very important for West Coast to get rainfall. If it is located near the central eq io then it is useless for them to get any precipitation, if it is moved westwards over Western IO then it will benefit West Coast.

  27. Machines can do lots of things better than your average human brain. Hell, a $5 calculator is more gifted at math than I’ll ever be. And now machines can even predict the weather more accurately than your local bag-of-bones meteorologist.

    Microsoft researchers Ashish Kapoor and Eric Horvitz are using machine learning to make more accurate weather predictions over a 24-hour period. So while this robo-brain won’t be able to help you with your five-day forecast, it can more accurately tell you if rain or shine is more likely during the course of your day.

    How? By simply not making assumptions. Kapoor and Horvitz’ system can learn from massive data sets of past weather events – because history often has a way of repeating itself, even when it comes to weather. Using this data, Kapoor says we don’t have to make “restrictive assumptions” about Mother Nature. We can just let the data do the talking. Kapoor spoke with Gizmodo over the phone and gave a simple example:


    Today in Seattle udy. There is some kind of pressure profile and temperature profile for Seattle across space and time. So if I have 100 years of history, what I can do is I can look through that history and find the day that matched exactly the weather today. If I find that June 2, 1955, was very similar to today. So consequently I can say the weather tomorrow is going to look June 3, 1955. I haven’t modeled any natural phenomena, but I can leverage the power of data to make predictions that make sense.

    Essentially, researchers are now combining physical modeling (aka the old way of predicting weather with maps of incoming systems) with machine learning techniques that analyze how past weather systems behaved. Specifically, they used deep neural networks that’ve already helped improved artificial sight and speech. Their new models have much lower error rates when it comes to predicting wind, dew point, pressure zones locations (geopotential height), and temperature, up to 24 hours out.

    RMS stands for root mean square error.

    “The deep neural network strives to model the dependencies across variables without making explicit assumptions,” Kapoor says. “You don’t even need to encode that relationship, these models learn that relationship automatically.”

    This isn’t the first time Kapoor has used machine learning to help improve our understanding of complex weather systems. By using public FAA data from tens of thousands of commercial airplane flights per day – things like planned airspeed, distance, altitude, and observed groundspeed – Kapoor’s machine learning algorithms were able to determine higher altitude wind patterns.

    “The machine learning algorithms try to express today as a very complex function of history,” Kapoor says. “Using that function, you try to extrapolate what it’s going to look like in the future.”

    We’ve still got a long way to go before robo-meteorologists are on the local news. For one, this is only accurate in a 24-hour window, though Kapoor is currently investigating how that period of accuracy can be extended. The team also believes the system could help scientists better understand the effects of climate change on weather patterns.

    Whether Al Roker’s successor has a squishy brain or a silicon chip, this research offers a fascinating look at how machine learning is finding its way into every aspect of our lives – from creating artificial sight to determining if we need an umbrella.

  28. something similar to 2013 NEM style we are going to witness i guess…OMG what a tragedy!!!get ready for a mass migration if it happens. We all wanted IOD +ve that is going to happen but now again forecast turned negative how come?

  29. Heavy rains in visakhapatnam
    100mm rains in just 2 hours
    kothakota (vizag) – 107 mm
    Ravikamantham (vizag) – 98 mm

  30. Oh no.. models are now slowly starting to let us down regarding NEM… and jamstec which was showing a good NEM so far is showing a horrible Sep-Nov for coastal TN. Why does this happen all the time?? :,(

  31. Enna pa ellarum epdi negative ah solringa…. if models do over build up NEM may miserably fail but more 48 days to go…so don’t worry…

    • Same model forecasted good nem last month..now they changed..Still the OND forecast not came..our Nem r based on bob & its sst..This year bob is active. Our NEM will be a surplus one this year..

  32. I think its better not to wear a worried face now during the SWM period thinking about NEM.

    Technical discussions and predictions for NEM can go ahead that is why this blog is for.

    We still have a long way to go and anything can change over a period of time.See how telengana is getting rains.

    lets wait hopefully for the remainder of SWM and welcome our NEM with smile.

    Nature will have the final say.

  33. Bowlers done the job, now its for batsman to do..,if they bat well tomorrow & take a lead of 200 runs, we have a nice chance to win..pujara is a quality test player..

  34. Jamstec model considering strong elnino plus neural iod (0.4 to 0.5)
    Determining iod now a days is flop by most of the models…then how come anyone decide the performance of NEM now..Still it is nearly 2 months away..
    Why the blog became dull by this jamstec seasonal outlook..
    South AP and TN will definitely have a normal NEM

      • If we go by that jamstec model…then Nellore Ongole will become deserts where swm also flop….

      • yes SAP suffering for 3 years like NTN .. @jupijove:disqus is very confident about +IOD and Good NEM…lets see what happens…

  35. Why all are panicking???

    The current trend of SST reflecting 1987, ENSO and IOD.

    1987 – ENSO in August was 1.6 and IOD 0.4 in July and 0.5 in August
    2015 – ENSO in August is 1.7 and IOD 0.5 currently, this needs to sustain for +.

    When I am comparing with 1987, i was seeing the OLR, SST and Precipitation anomaly from August to November period. In August near normal rainfall and in September below normal, Positive OLR suppressed the rainfall activity.

    Watch out September team.

    In October and December 1987 the OLR Anomaly was Positive still we were able to get excess rainfall in that month.

    Note – So far the conditions travelled as per 1987, from now if Positive IOD emerges then it NEM will follow 1997 path in excess mode, otherwise 1987 path in Normal mode.

  36. Depressions and uac’s will turn the NEM excess….at least 2-3 deep Depressions will fetch 600mm+ rainfall in Chennai…bringing overall to 900mm+..
    This time cyclones not possible due to elnino effect….
    Strong easterlies will start touching Chennai from 17 Oct itself….

  37. Ok let’s divide this blog into 3teams:
    Team A: who says excess NEM this year
    Team B:who says average NEM
    TeamC:who says below average NEM to Chennai and suburbs…..
    if it is excess by 20% or plus…Team A will win
    average rain between -17% to +17%…Team B wins
    less than -17%…..Team C wins
    I always want Chennai to win…hence I am in Team A
    let’s see who prefers which???

  38. Sometimes all that matters is just one system. One depression can turn the tables. Last year’s lpa gave 400 mm in one week… something similar should happen multiple times this NEM. Just praying that will happen

  39. NEM over TN have had finished normal to excess in 93% cases when there was an elnino in pacific… Only in the elnino year of 1982, NEM failed badly.. there is another hidden pic in elnino years where Chennai got below avg rains and south got excess rains but overall status gets balanced and appears as good monsoon year…

  40. Hope some wave activity enters IO each month during OND ,and make conditions favourable for cyclogenesis.. let 2 or 3 develop & pound TN

  41. Selva,

    One cannot say that South TN gets more during ELNINO and overall it covers up in averages, look at the following data during ELNINO years since 1991.

    ELNINO year rainfall in Chennai and Tamilnadu since 1991.

    1991 – Chennai Deficit, TN Normal. Positive IOD since April.
    1997 – Chennai Excess, TN Excess. Positive IOD from July.
    2002 – Chennai Excess, TN Deficit. Positive IOD from September.
    2009 – Chennai and TN Normal. Neutral IOD.

    NEM – Chennai gets normal rainfall during ELNINO+Neutral & excess if Positive IOD emerges after May or June.

  42. Good news for us!
    Latest CFS MODEL expects a good NEM with October November and December getting good rainfall!

  43. 40% ENSO,20% IOD (indian ocean sst conditions),20% intraseasonal oscillation, 20% Siberian high .. the main problem is all the above factors have teleconnection with each other. So it’s not tat easy to predict the nem with any one parameter.

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