LOW in the Bay to intensify into WML

An active Low Pressure Area ( LPA) in the NW bay, is seen intensifying as wind shear is expected to relax a bit, allowing the disturbance to develop into “Well Marked” Low pressure area (WML).Under its influence, heavy rainfall is likely along the coasts of South /North AP and Odisha. The system will also set up interesting possibilities as it moves slowly inland in the next 2 or 3 days. This low has also caused a favourable wind flow in the West coast along Coastal Karnataka, North interior Karnataka, Goa & Konkan stretch, resulting in heavy rainfall in those regions. Rain or thunderstorms is also likely to be seen in few parts of interior Maharashtra, Marathwada, Chhattisgarh & Telangana.

Turbulent, unstable Atmospheric wind flow caused by Shear zone still seen along 16/17N in mid-troposphere.

GFS

Chennai – Day likely to see partly cloudy, windy conditions with max temp reaching 34-35 with slight chance of rains in one or two places in the suburbs and the city

Madurai- Expected to remain hot with clear sky. Max temp may flare up to 37-38c.

Trichy-City can expect clear sky with temp expected to stay around 35-36c.

Vellore- Windy conditions would prevail with temp settling near 33c.Slight possibility of showers by afternoon/evening.

Coimbatore-Expected to see partly cloudy skies. Max temp may hover around 32c

849 thoughts on “LOW in the Bay to intensify into WML

  1. It’s heavily tilted.. LLCC is near Puri and 500 hPa circulation is near Kakinada.. Convection is also mostly near Vizag

      • Exactly Partha. I was expecting this +IOD (ENSO might have some influence?) answer for the past 2-3 days. You had given perfect answer. If its neutral or -ve IOD then very strong convection (wide-spread) towards its SW-periphery might have been there to give very good TS-probabilities till NTN (including Chennai).

      • Easterly wind anomaly going on equatorial to 15N latitude, this will suppress the moisture over southern area, this is another reason for chennai or coastal areas of TN and SAP not getting good rainfall even there is a dip in trough.

  2. Met predicts rain in Maharashtra after September 18
    “Presently, there are no signs of withdrawal of monsoons from the state,’’ said the Met.
    With a low pressure in West-central and adjoining North-west Bay of Bengal, the Met officials have forecast fairly widespread rainfall in the coming week .We have forecast good rains after September 18. Presently, there are no signs of withdrawal of monsoons from the state,’’ said the Met.Central India and the state will get good rainfall,’’ he added.
    The overall deficiency has reduced in all divisions. On Monday, Konkan and Goa registered a deficiency of 34 per cent, Maharashtra registered 38 per cent, Marathwada — 44 per cent, and Vidarbha — 19 per cent.
    There will be widespread rainfall along the Konkan and Goa coast, fairly widespread rainfall in the central parts of the state and good rains in Marathwada and Vidarbha regions in the coming week.
    http://indianexpress.com/article/cities/pune/met-predicts-rain-in-maharashtra-after-september-18/

  3. Good rain hope in monsoon withdrawal delay hint
    A scientist from the Indian Institute of Tropical Meteorology (IITM) said there are chances of rain in parts of northwest India even after September 22. “The extended range forecast shows the possibility of some rain in northwest India from September 24 to 28,” he said.
    The monsoon normally completes its withdrawal from northwest India, including Delhi, between September 15 and 21.
    The scientist said Maharashtra will receive heavy rains around September 17 to 19. After this, another system, which is currently over the Philippine sea, is expected to move to the Bay of Bengal and may bring rains to central and northeast India till September 26. These rainfall spells are expected to impact the monsoon withdrawal from the rest of northwest India.
    An India Meteorological Department (IMD) expert said the recent surge in monsoon activity has caused some rainfall in east Rajasthan, leading to moisture in the air. “This rain spell may continue for another five days, and the withdrawal from the rest of the northwest India may begin only after this,” he said, adding that a five-day delay in withdrawal is normal.
    http://timesofindia.indiatimes.com/city/pune/Good-rain-hope-in-monsoon-withdrawal-delay-hint/articleshow/48964625.cms

    • this clearly shows that IMD is not confident of this present MISO and declared SWM-withdrawal due to evolving strong Elnino. Irony is that direct rains will be there from this LPA in later this week in those SWM-withdrawal pointed regions. So if any rains happens then it must of the SWM (related system)-only in that already SWM-withdrawal regions.

      • from day 1, you are confident that this year monsoon will defy predictions, happy your prediction becomes reality to some extent,

      • by recalling your prediction from last month, you are so much confident that maharashtra will receive rains before monsoon ends, and now this becomes reality, kudos

  4. Invest 99B by JTWC: http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/ab/abiosair.jpg

    AN AREA OF CONVECTION HAS PERSISTED NEAR 18.0N 86.1E,
    APPROXIMATELY 160NM EAST OF VISAKHAPATNAM, INDIA. RECENT ANIMATED
    INFRARED SATELLITE IMAGERY SHOWS PATCHY DEEP CONVECTION DEVELOPING
    ALONG THE WESTERN PERIPHERY OF A BROAD LOW LEVEL CIRCULATION CENTER
    (LLCC). EVIDENT IN A 141500Z ASCAT PASS. THIS DISTURBANCE LIES
    EQUATORWARD ON AN UPPER-LEVEL RIDGE AXIS, IN AN AREA OF MODERATE
    EASTERLY VERTICAL WIND SHEAR AND WESTWARD AND EQUATORWARD DIFFLUENCE
    ALOFT. NUMERICAL GUIDANCE INDICATES LIMITED DEVELOPMENT OF THIS
    SYSTEM OVER THE NEXT FEW DAYS BEFORE THE LLCC MOVES OVER LAND.
    MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
    MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 999 MB. BECAUSE
    THE LLCC IS WEAK AND UPPER-LEVEL FLOW IS LESS THAN OPTIMAL, THE
    POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
    WITHIN THE NEXT 24 HOURS IS LOW.

  5. Why more dry spells seem inevitable
    Simple physics tells you that rainfall will increase as global average temperatures increase. A warmer atmosphere will hold more moisture, and this moisture has to come down as rain.
    Will the major agriculture regions of the country get enough rainfall, spread out over the season, year on year over the next few decades? There is no clear answer to this question, but there are a few pointers.

    There are over 40 models that include the Indian monsoon, and they all show that temperatures would increase relentlessly over the sub-continent. However, they do not agree with each other on rainfall.
    Rajendran, scientist at the Fourth Paradigm Institute in Bengaluru. took one of these models, from the Japan Meteorological Agency and Meteorological Research Institute,and simulated the monsoon over the next few decades at very high resolution. He and his colleagues made a surprising finding.

    While rainfall increased in most parts of the country, it showed a decrease in the western coast from the southern tip of Kerala to Goa. This trend has been going on for about half a century, and is supposed to accelerate according to the models.

    The culprit is pollution in terms of aerosol particles emitted by vehicles and burning of solid waste. These particles cool the atmosphere and reduce the temperature over land. This reduces the difference in temperature between land and sea, which is the main reason why monsoon winds blow. So although the models show increase of rainfall, pollution reduces the strength of the monsoon winds.

    Read more at:
    http://economictimes.indiatimes.com/articleshow/48964592.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst

  6. Why there was less convection over South and SW quadrant. There is a positive anomaly of 850 HPA wind over TN, starting from 08th September and Easterly wind anomaly increased over East Indian Ocean and diminished over SW and South Bay. This has suppressed the moisture over SW Bay of Bengal upto South AP latitude. This is due to Positive IOD development. The cooling off SST over East EQ IO has increased the easterly wind anomaly over Eastern IO and Westerly anomaly over SW and South Bay. This is bringing more dry air from TN land to Bay. Due to this the LOW formed over West Central Bay does not have convectivity over Southern quadrant, instead it has cloud cover over SE and Northern Quadrant.

    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf

  7. For hyderabad is the IMD reading the only ones available? The ones in IMD website shows AP reading? It shows only 9mm.. I am not able to find more local data as we can get for bengaluru..

  8. Top 15 rainfall of SWM 1st June – 12th September, 2015
    =================================
    Min 4000 mm

    1.Mawsynaram, Meghalaya – 10550
    2.Cherrapunji, Meghalaya – 9143
    3.Cherrapunji RKM, Meghalaya – N.A.
    4.Hulikal, Karnataka – 4980
    5.Mastikatte, Karnataka – 4791
    6.Agumbe, Karnataka – 4624
    7.Lamaj, Maharashtra – 4507
    8.Yadur, Karnataka – 4473
    9.Shiragaon, Maharashtra – 4319
    10.Talacauvery, Karnataka – 4257
    11.Mani, Karnataka – 4212
    12.Kerekatte, Karnataka- 4100
    13.Mulshi, Maharashtra – 4004
    14.Cogar, Karnataka – 4000
    15.Kuttiyadi, Kerala ~ 4000

    http://tamilnaduweatherman.blogspot.in/

  9. rammb.cira.colostate.edu/products/tc_realtime/products/storms/2015IO99/MIIWVRGB/2015IO99_MIIWVRGB_201509150310.jpg

    CC centered In orissa border

  10. Partha sir, Mumbai radar is worse than Machili and I’ve mentioned it thousand times. White (35-40 dBz) spots dump very heavy rains in this

  11. Todays DC forecast after some adjustments in format. Please do check and give comments. Is there anyway we can improve this further?

  12. Tropical cyclone activity eases across Pacific Ocean
    – Tropical cyclone activity over the Pacific Ocean has eased significantly during the last week
    – Tropical storm Vamco makes landfall on Vietnamese coast, expected to generate widespread flooding over region
    – Tropical storm Etau caused significant damage to Japan

    Madden–Julian Oscillation (MJO) remains weak
    – For the last several weeks the MJO has been weak
    – Some international models forecast the MJO to strengthen slightly and move over the Maritime Continent and western Pacific Ocean

    El Niño strengthens further with a record, warm Indian Ocean
    – El Niño is continuing to strengthen and is expected to peak towards the end of the year
    – Sea surface temperatures and atmospheric indicators may reach or exceed values observed during the 1997–98 El Niño
    – Indian Ocean remains warmer than average with sea surface temperatures in the southern Indian Ocean the highest on record for winter
    – Positive Indian Ocean Dipole is likely

  13. Latest OLR Map too shows that NEM likely to set by October 23rd or 24th. Lets not take it as final one, we will wait for some more time. As we go into October 1, things will changed drastically, from then on the forecast will be clear.

  14. we are almost crossing mid sep.. lets have a look back on the chennai forecast given by models for first half of sep. First 4 to 6 days of sep was shown as NEM kind of rainfall sweeping chennai in gfs,jma charts & touted as 6 to 7cm of rainfall. then 7th to 10th sep was projected to get 3 to 5 cm.. on a whole GEFS was showing 10-15cm of rainfall for first fortnight

  15. Upcoming Australia bangla series is gonna be interesting.. Aus r not in a good position bangladesh lions have fighting spirit 10 times than india..gonna be a toughie for oz

  16. Flash
    please send all of ur res. address
    jeetu sponsoring kfc bucket to all by home deleivery…
    for his new dp ….
    come on…dont miss anyone….

  17. Sea breeze front forms a bit offshore and it appears as if strong surface winds imparting dynamics on the regular thermal contrast to make it unusual.

  18. @ krishnan…
    pity u didnt see above 19cm…..u have to see all the stations for north tamilnadu during nem..above 20 cm is very common during nem in some places…arakku valley got today,tommorrow it may be nunga or cuddalore or pondy

  19. Sea brezze struggling to enter. As GTS pointed out. Westerlies are too strong. But this is ideal case for rains with trough dipping and eventually when sea breeze enters the city its going to trigger lot of pop-ups.

  20. Ensemble models are expecting a rise in day time temperatures for Chennai over the next few days starting 17th for about 4 days. The expected rise is around + 2 degree C.

  21. Just for the info, there must be at least a 10F difference between land and above sea temp for a sea breeze to set in. I was watching that for the past few days sea breeze setting very very late in the evening as the day temp over land is around 34C, above sea was around 31-32C. Today it might pull up the sea breeze, as the land temp exceeds 36C, but it will take time.

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