South West Monsoon (SWM) to start withdrawal

The SWM withdrawal is on the cards and is seen drying up the North and NE states. A trough, in the form of line of Wind discontinuity, extends from  Interior Telangana into South Karnataka and is bringing ideal conditions for Thunderstorm development over South Interior Karnataka & Rayalaseema. These conditions will also trigger heavy thundershowers over parts of Interior Karnataka, Kerala and Interior TN.

Interior TN especially Vellore, Salem, Perambalur, Ariyalur, Trichy, Madurai, Tiruvannamalai and the delta districts of Tiruvarur & Tanjore can expect evening thunderstorms.


Chennai: Max temp expected to stay close to 34-35C with good chance of rains in the evening.

Vellore: Day temperature could peak at 36C paving way to evening thunderstorms

Coimbatore: Another day of warm conditions

with temp settling close to 33C with fair chance of thunderstorm activities.

Madurai: A Hot day could be followed by couple of rain spells. Max temp may climb up to 37-38C during the day followed by couple of rain spells in the evening.

Trichy: Mercury could scale 37C during the day. The Rockfort city can expect evening thunderstorms.

680 thoughts on “South West Monsoon (SWM) to start withdrawal

  1. strong circulation between 7000 feet to 15000 feet above sea level over andaman sea….

    centre lowest pressure=1002mb

    will start movement according to pressure dynamics ,when the pressure less than 999 mb….

    steering winds supporting the depreesion to move towards east coast….

    No chance of becoming a tropical cyclone like hudhud and phailin…

    This will retain moisture in south bay and tamil nadu and helps in rainfall activity during NEM..

    other factors like


    ONI index also becoming a slight favour…..

    this NEM going to be conventional NEM….latent heat absorption good in TN……

    I am expecting a normal NEM …..with south TN getting 20-25% above normal rain.

    Next year due to lateral inversion of SST’s a extreme lanina event expected and we can enjoy cyclone systems around TN…

    Keep going guys!!!! we should get satisfied with what we have…..nature is well matured than us. It knows what to do and what not to do…..

    From now i may not hear deficient and deficit words in this blog for 2 years !!!

  2. Good mrning guys! ๐Ÿ™‚
    Reached bangalore yesterday afternoon.
    Temperature was really good within 32 degree.
    Massive rains started overnight nd now derrizles continuing with a temperature of 22 degree.

  3. August team wishes September team good luck for today. For the sake of water starved Chennai residents we hope all places in Chennai record good rain in coming days.

  4. Yesterday Rain was a miss eventhough North and Western Suburbs of Chennai received Moderate Rains. Today looks Good Chances for TS. North & Central Tamilnadu will get bulk of Rains tonight and good chances for Chennai as well. Some places of South Interior Tamilnadu will get moderate TS

  5. Many places reported good rains in tiruvallur vellore districts expect double fig in tn.. Pallipatu in tiruvallur dist 55.5mm 52.5 in an hour
    Walajapet also over 60mm (data need to b validated)

  6. Massive rains at sholingar!(from 2 00 am)
    Thundery night ….lightning’s and thunder swere very severe for an hour!although the rains are not so more lightning’s and thunders made the Me rock!

  7. Heavy rains in drought areas of kurnool Anantapur….
    Rain fall till 8 am…
    Rayadurg – 127 mm
    marutur – 102 mm
    Kalvatla – 99mm
    muddanur – 99 mm
    uyyalawada – 93 mm
    Nandyal kurnool – 87 mm
    maddur – 86 mm
    pqnyam kurnol – 80 mm

  8. Monsoon Reversal: Rainfall regime to shift towards Peninsular India – See more at:

    We have entered the fag end of September and the withdrawal phase of Southwest Monsoon. Conditions are favourable for the withdrawal of Monsoon from rest of North and Central India within next 2 to 3 days.

    The first half of October is the overlapping period for retreat of Southwest Monsoon and incursion of Northeast Monsoon in the Southern Peninsula. The stage gets set and change is mainly brought about by weather systems originating in the Indian seas.

    You may also like:



    In the northern parts of the country we generally see the establishment of anti-cyclone over Rajasthan. This brings about the reversal of wind pattern and accentuates the withdrawal process of Southwest Monsoon from North and Central India.

    Northeast Monsoon

    Unlike the Southwest Monsoon, Northeast Monsoon does not have any specific date of commencement. It mainly affects five sub-divisions of South India, namely Tamil Nadu, Kerala, Coastal Andhra Pradesh, Rayalaseema and South Interior Karnataka.

    With the commencement of the Northeast Monsoon season, total reversal of winds take place from the Indian seas and Peninsular India.

    Northeast Monsoon Forecast

    At there is a weather system brewing up in the Andaman Sea. It could most likely become a significant one, developing first into a depression and further into a deep depression. Another system will come up in the Lakshadweep region very soon. Both these systems will take about a fortnight to complete the sea travel and finally be instrumental in the commencement of Northeast Monsoon.

    Another pre-requisite is a good burst of widespread rainfall over Tamil Nadu and Coastal Andhra Pradesh. Skymet will keenly follow the transition from Southwest to Northeast Monsoon.

    Image courtesy – The Hindu

    – See more at:

  9. How many of know this I dont know. Tamil nadu boundary strikingly resembles human face. No wonder this land is having ancient human civilization of millions of years

  10. Monsoon may retreat from state in two days: IITM forecast

    Do not expect any rejuvenating rains in the remaining days of September. Rainfall during the week was 68% above the long period average (LPA) over the country but the remaining part of September may witness subdued rainfall, a fresh extended range forecast by the Indian Institute of Tropical Meteorology (IITM) has said.

    With the two monsoon systems which were to provide rainfall to the country gone, the withdrawal of the southwest monsoon will now begin from the rest of northwest India, and may even be faster from western and central India. The monsoon may withdraw from parts of central India as well as Maharashtra in the next couple of days, the model’s forecast shows.

    An India Meteorological Department (IMD) official said that chances of rain-bearing systems over northwest India are now slim, indicating the withdrawal of the monsoon.

    In fact, with the formation of a low pressure system in the southern Bay of Bengal, the northeast monsoon is expected to start in the first week of October. The period from October to December is referred to as the northeast monsoon season over peninsular India. Earlier, this period was also referred to as “post-monsoon season” or “retreating southwest monsoon season”.

    The northeast monsoon season is the major period of rainfall activity over the south peninsula, particularly in the eastern half comprising the meteorological subdivisions of coastal Andhra Pradesh, Rayalaseema and Tamil Nadu-Pondicherry.

    An IITM scientist told TOI that with the two systems dissipating after giving above normal rainfall in parts of the country, the monsoon withdrawal will soon start once again. The monsoon usually withdraws from central India and parts of Maharashtra from October 1.

    The scientist said the northeast monsoon’s performance during the first week of October looks promising. “The models are showing a system over the southern tip of the peninsula which may give good rainfall over the peninsula during the first week of October,” he added.

    Meanwhile, met department officials said that during the week from September 17 to 23, 64% sub-divisions received excess rainfall and 17% normal rainfall. All the four homogeneous regions of India – northwest India, central India, south peninsula and east and northeast India – received above normal rainfall during the week, except south peninsula, where the rainfall was 38% below the LPA.

    However, cumulative rainfall for India as a whole during the southwest monsoon from June 1 till September 23 has been 12% below the LPA. Rainfall activity was less than normal in all four homogeneous regions of the country during this period, met department officials said.

    Pune’s total rainfall since June 1 stands at 471.6mm, around -56.9mm below normal. In the next few days too, the city may only see one or two spells of rain and partly cloudy skies.

  11. IMD to Inspect Rain Gauges to Clear Cloud Over Rainfall Data

    BHUBANESWAR:With accurate rainfall data from districts not reaching the State Government from the block headquarters, the Special Relief Commissioner (SRC)โ€™s office has requested the India Meteorological Department (IMD) to carry out an on-field assessment of rain gauge systems across the districts.

    The weather office is preparing a plan under which it will constitute a technical team which will visit the blocks and make a verification of the rainfall measurement systems in place.

    Even as prolonged dry spells led to a drought-like situation in many parts of the State, SRC office received conflicting reports on real-time rainfall from several districts prompting it to take a corrective course of action, sources said.

    At present, the IMD collects its rainfall data from 58 rain gauge stations which are in proper functional state. However, the State Government is dependent on systems installed at its 314 blocks headquarters but all are not in proper working condition.

    โ€œWe would like the rain gauge stations to be inspected by the IMD so that they give us proper feedback on how to improve the systems for accurate rainfall record which is key for agriculture as well as flood and drought information management in the State,โ€ the sources added.

    The rain gauge systems use simple equipment but location of the systems and time of rainfall recording are equally important.

    The IMD, on its part, sends teams to make random inspection of the rain gauge stations and suggests improvement but the SRC office has requested a complete inspection of the stations in a phased manner.

    This year, the State has received 1032 mm rain since June 1, beginning of the monsoon season. It is eight per cent less than the normal rainfall record. At least four districts have recorded deficient rainfall although the number of blocks which have received less showers is high.

  12. IMD hits bull’s eye for the first time with prediction of drought year

    NEW DELHI: In April this year, the Indian Meteorological Department had stuck its neck out and warned the country of a second straight drought this year. It was IMD’s bleakest monsoon forecast, the first time it had predicted a rain shortfall of more than 10 per cent. As it turned out, IMD was spot on.

    As on September 24, the monsoon deficit for the season was 13 per cent, as against the department’s forecast of 12 per cent. With less than a week to go for the end of the monsoon seaso ..

    Our forecast had an error margin of 4 per cent on either side. The actual monsoon performance is likely to fall within a margin of 2 per cent,” said B P Yadav, director, IMD.

    IMD calls a countrywide monsoon shortfall of 10 per cent or more as ‘deficient monsoon’. Popularly, it is known as a drought year – a term previously used by the department but later discontinued because, as an official put it, the entire country never faces a drought.

    Although last year too, IMD had pare ..

    Read more at:

  13. Average rainfall for state rises from 55 to 62 per cent: IMD

    Following fresh spells of rainfall in the last two weeks, the Indian Meteorological Department, along with the state government, has announced that the average rainfall had risen from 55 per cent to 62 per cent this season.

    Earlier this month, the IMD along with the chief ministerโ€™s office (CMO) had announced deficiency in rainfall with the average rainfall standing at 55 per cent in the state for this monsoon. The declaration was made soon after the announcement of withdrawal of monsoon winds was made by the IMD. Though water deficiency still looms ahead, fresh spells of rainfall are believed to have favored the conditions. The average rainfall in the state has been recorded at 677 mm. Rainfall has been deficient in Konkan, north Maharashtra, western Maharashtra, parts of Vidarbha and Marathwada, which have received average rainfall between 55 per cent to 76 per cent.

    The earlier estimate for these regions was 55 per cent to 71 per cent according to a release by the CMO. Other district of Nashik, Ahmednagar, Solapur, Kolhapur, Beed, Latur, Osmanabad, Nanded, Parbhani, Yavatmal received less than 50 per cent rainfall.

    The CMO also said that a total of 1,638 villages and 3,082 wadis were being supplied drinking water through 2,300 water tankers. During this period last year, only 48 tankers were deployed to supply drinking water to areas facing drinking-water scarcity.

    The release revealed that out of the 49 per cent of water stored in Maharashtraโ€™s reservoirs, only eight per cent of water got stored in the Marathwada region.

    According to the IMD, the city is still deficient in water by 250 to 300 mm. The pattern of heavy rainfall after the announcement of withdrawal of monsoon is being noticed for the last 10 years in the state.

  14. Ecmwf changed the depression lf point to machili.. Another Fresh one moving into gulf of siam,watchout that may be the monster

  15. The weather pattern from late September into early October typically features the jet stream diving southward across United States and bringing shots of much cooler air from Canada into the United States. Meanwhile, the warm waters of the Gulf of Mexico and off the southeastern United States continue to be a threat to produce tropical systems.

  16. all Banks gave some Ks (may be int free loan) to female a/c holders, may continue on Monday – any idea about this

  17. Rain havoc in Anantapur district

    Damage details

    Railway tracks in guntakal vajrakarur have been damaged a lot
    2 lorries have been sweeped into the penneru stream
    Remaining crops that stood against severe drought were damaged by floods
    non stop heavy rain in central areas
    poultry faced a great loss

  18. Models are suffering which clearly indicates , the present knowledge is still not able to understand the genesis of Tropical systems. They are best only after they form ..

      • Not only a case with last year, it has been the same since the early days of modern meteorology.Understandings in Tropical Meteorology is still a good distance away from Mid latitudes understanding.

    • Actually this one from ecmwf and the other GFS analysis show different snap shots of the present conditions. With deviations in initial conditions much higher in magnitude, it is still a bit confusing as to who reads the present atmosphere correctly.

  19. Arakonam (Vellore Dist)


    Thathiengrpet (Trichy Dist), Kalavai AWS (Vellore Dist)

    7 each

    Cholavaram (Tiruvallur Dist), Gudiyatham (Vellore Dist), Vellore (Vellore Dist)

    6 each

    Ponneri (Tiruvallur Dist), Ambur (Vellore Dist), Thuckalay (Kanyakumari Dist), Gudalur (Theni Dist)

    5 each

  20. Tamilnadu Rainfall ending 8.30am today (26.09.2015) in (mm)

    Arakkonam – 90
    Thuckalay (Kumari) – 70
    Walajapet Agro – 68
    Kalavai (Vellore) – 65
    Vellore – 57
    Pallipet – 55
    Pernampattu (Vellore) – 51
    Killiyoor (Kumari) – 48
    Anaicut (Vellore) – 45
    Madhanur (Vellore) – 40
    Kadaiyampatty (Salem) – 39
    Vaniyambadi – 38
    Tiruvallur – 37
    Krishnagiri Agro – 37
    Hosur – 34
    Neyyoor – 34
    Chengam (Tiruvannamalai) – 33
    Valparai – 32
    Pennagaram – 32
    Tiruttani – 30
    Keelapavoor ((Tirunelveli) – 30
    Vaiyampatty (Trichy) – 28
    Poonamallee Agro – 28
    Kottampatti – 27
    Hosur Agro – 27
    Munchirai (Kumari) – 25
    Vellore Agro – 25
    Vadipatti – 24
    Mecheri (Salem) – 23
    K.V.Kuppam( Vellore) – 22
    Pudupalayam ( Tiruvannamalai) – 22
    Kamudhi – 21
    Palacode – 21
    Melaneelithanallur (Tirunelveli) – 19
    Kaniyambadi (Vellore) – 19
    Kuruvikulam (Tirunelveli) – 18
    Tirukkalukundram (Kanchipuram) – 18
    Chinnasalem (Villupuram) – 18
    Tirupparangundram (Madurai) – 17
    Andipatti – 16
    Vembakkam (Tiruvannamalai) – 16
    Kambam – 15
    Kalasapakkam (Tiruvannamalai) – 15
    Karimangalam (Dharmapuri) – 14
    Ennore – 14
    Arani – 13
    Dharmapuri – 12
    Nilakkottai – 12
    Minjur – 12
    Kodaikanal – 11.2
    Natrampalli (Vellore) – 11
    Vadamadurai (Dindugal) – 11
    Theni – 11
    Erumaipatti (Namakkal) – 11
    HVF Avadi – 11
    Peddanaickenpalayam (Salem) – 11
    Puzhal – 10


    Arakonam (Vellore Dist)

    Thathiengrpet (Trichy Dist), Kalavai AWS (Vellore Dist)
    7 each

    Cholavaram (Tiruvallur Dist), Gudiyatham (Vellore Dist), Vellore (Vellore Dist)
    6 each

    Ponneri (Tiruvallur Dist), Ambur (Vellore Dist), Thuckalay (Kanyakumari Dist), Gudalur (Theni Dist)
    5 each

    Thamaraipakkam (Tiruvallur Dist), Vaniaymbadi (Vellore Dist), Melalathur (Vellore Dist), Periyakulam (Theni Dist), Kaveripakkam (Vellore Dist)
    4 each

    Aranmanaipudur (Theni Dist), Polur (Tiruvannamalai Dist), Colachel (Kanyakumari Dist), Alangayam (Vellore Dist), Valparai pto (Coimbatore Dist), Mettur (Salem Dist), Marandahalli (Dharmapuri Dist), Sholavandan (Madurai Dist), Chengam (Tiruvannamalai Dist), Hosur (Krishnagiri Dist), Mettupatti (Madurai Dist), Valparai taluk office (Coimbatore Dist), Vadipatti (Madurai Dist), Wallajah (Vellore Dist)
    3 each

    Uttamapalayam (Theni Dist), Mahabalipuram (Kancheepuram Dist), Palacode (Dharmapuri Dist), Red hills (Tiruvallur Dist), Tiruvallur (Tiruvallur Dist), Poonamallee (Tiruvallur Dist), Sathanur Dam (Tiruvannamalai Dist), Shoolagiri (Krishnagiri Dist), Kadavur (Karur Dist), Rayakottah (Krishnagiri Dist), Thiruvalangadu (Tiruvallur Dist), Sholingur (Vellore Dist)
    2 each

    Sankarankoil (Tirunelveli Dist), Pallipattu (Tiruvallur Dist), Ennore AWS (Tiruvallur Dist), Arani (Tiruvannamalai Dist), Nilakottai (Dindigul Dist), Denkanikottai (Krishnagiri Dist), Dharmapuri pto (Dharmapuri Dist), Kodaikanal (Dindigul Dist), Tirupattur (Vellore Dist), Hvf avadi arg (Tiruvallur Dist), Bhoothapandy (Kanyakumari Dist), Krishnagiri (Krishnagiri Dist), Anjatti (Krishnagiri Dist), (Tiruvallur Dist), Tirumangalam (Madurai Dist), Peraiyur (Madurai Dist), Tirupathur pto (Vellore Dist), Pechiparai (Kanyakumari Dist), Hogenekal (Dharmapuri Dist), Natham (Dindigul Dist), Eraniel (Kanyakumari Dist)
    1 each

  22. Lake level rains mm

    Cholavaram 61
    Redhills 22
    Tamaraipakkam 44
    Puzhal 3

    Unfortunately chembarambakkam, puzhal missed out also redhills low, redspot got stuck jst north

  23. I assured you guys that I will post my Rameswaram, dhanushkodi visit pictures for your interest. Here are those. Hope you guys enjoy it.

    1) famous rameswaram temple gopuram from a tourist ship
    2) Dilapidated Dhanushkodi church which explains the power of 1960s dhanushkodi cyclone
    3) Trawler ship
    4) Ramar theertham pond
    5) sand dunes visible from highest point from a temple
    6) Dhanushkodi end. from here, ramar paalam starts
    7) view from famous pamban paalam.

  24. Actually, Tropical system’s formation is understood by many in several ways. One study says, their genesis arises from organisation of mesoscale clusters, and the resulting pressure drop leads to further organisation of convective clusters, followed by latent release heating of mid tropo. This is something which involves initially the first order conditional instability and later second order instability comes into place. But this can better be correlated to the ones that get birth from African easterly waves , as they have been almost associated with land based convective systems at cloud cluster scale. Whereas, some arise from cyclonic vorticity above boundary layer followed by frictional boundary layer convergence and further development and organisation of deep convection that takes place as a secondary development. This is something like an UAC beginning the action. The third identified case is a development from advection of low to mid tropo warm air parcel type concentration which develops from the resulting pressure drop underneath the areas which it passes over, something like our equatorially trapped atmospheric waves. Sometimes, there are cases like Potential vorticity at upper levels triggering action in ground levels.

    • I remember Sel saying about a possible correlation between a TY landfall in Chinese coast and a system genesis in Bay happening in close time periods. This one reminds me that.

      • Yea, the pulse from that never fails.. One reason I believe is the southward extension of a trough from all typhoons, possibly due to interaction of winds with the mountainous regions of Taiwan and Philippines

      • Yeah , he used to say about the east west running isobar from India all the way up to South China Sea , that happens in the presence of a TY there. Also, I’ve read somewhere, that the easterly shear transfers some energy packet in the upper levels and it triggers some action in Bay.

      • Hmm yes, I remember your comment yesterday regarding the energy transfer :p Infact the model charts show the enhanced vorticity, with winds bending around the mountainous regions… Indha NEM idhayum observe panna veendiyathu thaan.

        Here is the ECMWF chart showing the mountain vorticity

  25. IMD
    โ™ฆ The trough/wind discontinuity from Telangana to South Interior Karnataka now runs from Telangana to south Tamilnadu across South Interior Karnataka and extends upto 1.5 km above mean sea level.
    โ™ฆ The upper air cyclonic circulation over Comorin area now lies over Lakshadweep and neighbourhood between 3.1 & 4.5 km above mean sea level.

  26. The atmospheric mean flow is still not seen around for the system to take shape. Possibly by tomorrow morning.things will be clear …

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