SW Monsoon Retreat Countdown starts

keaweather 2015, KEA Blog, SWM-2015

Dry air dominance persists over NW India. As the Western Disturbance also remains weak, the dry air is strengthened and is getting pushed into central parts of the country. Due to this reason, South West Monsoon withdrawal is likely to begin from NW India in the next few days and will rapidly approach North and Central parts of the country. This is likely to increase the deficit of monsoon rains. Monsoon Axis is likely to come down in latitude and merge with the secondary branch and run through Uttar Pradesh and thence South Eastwards to East-Central Bay of Bengal. Heavy rainfall likely to continue at many places in NE States, West Bengal, Odisha, North Coastal Andhra Pradesh in the next 24 hours.

A trough running from Rayalaseema to Gulf of Mannar at 1.5 km above mean sea level persists. Under this influence heavy rainfall is forecasted in isolated places over Tamil Nadu, Puducherry, Kerala, Coastal and South Interior Karnataka and in one or two places over Rayalaseema.
02. INSAT
Chennai will see a day temp around 36 C. Rain or Thundershowers possible towards evening or night.

Coimbatore’s max temp will be around 32 C with a possibility of rain / thunderstorm.

Madurai will stay hot with a recording of 37 C. Rain or Thundershowers possible towards evening or night.

1,063 thoughts on “SW Monsoon Retreat Countdown starts”

  1. We had enforced a strict rule a few months ago that no Kea blogger will be allowed to post in any other Chennai weather blog. I can see that the rule is being misused by some bloggers. If any blogger is found to post in other chennai weather blog, he/she will be automatically banned for 1 month.

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  3. Winds have turned to South and today seems to be slightly Cooler than last few days due to Southerly winds and lot of Cumulus Clouds already present in the sky

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  5. wow!!!!

    http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=ind&pkg=mslp_uv850&runtime=2015090318&fh=336&xpos=0&ypos=428

    http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=ind&pkg=mslp_uv850&runtime=2015090318&fh=360&xpos=0&ypos=342

    http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=ind&pkg=mslp_uv850&runtime=2015090318&fh=372&xpos=0&ypos=342

    http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=ind&pkg=mslp_uv850&runtime=2015090318&fh=384&xpos=0&ypos=342

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      • ha..ha..but those regions (including Kankan, Goa and Mumbai, peninsular India), which are mostly suffered due to scanty rains so far will be pounded by heavy rains due to upcoming BOB-Depression that forming at west-central BOB. This means SWM-2015 may not leave any single region in India in complete drought. Moreover the cumulative SWM-index will climb up above 90% before end of the season. This is the specialty of Elnino-2015 🙂

      • oh…need to pick another region “Indian ocean” and select animation to see the upcoming Depression at WC-BOB neat CAP coast.

  6. At last things are working in favor of peaking Elnino as SSTA near Chile/Peru coasts (A red-circle) started increasing with simultaneous warming at north Atlantic (B red-circle). Moreover the cold patch at Niño 1+2 will warm up in coming days due to surfacing EKW.

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  7. If the upcoming MISO (going to mimic just like June-rainfall scenario by setting a depression at west-central BOB) materializes by mid-September, then IMD’s forecast in the following articles may become wrong. SWM-2015 cumulative index may climb again above 90% before completion of this SWM season.

    article 1: http://economictimes.indiatimes.com/news/economy/indicators/monsoon-likely-to-be-below-prior-forecast-says-imd-chief/articleshow/48774558.cms

    article 2: http://www.ndtv.com/india-news/our-monsoon-forecast-correct-says-met-department-1213981

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  12. Guys, one sincere request, do not throw negativity into the discussion. no rains for chennai…or so…be happy some rain is falling around chennai…and let us pray we need a bountiful rain this year from this moment onwards…as you must be aware. chennai reserviors are like play grounds now almost…in 2 weeks time, they can just dry out with no trace of rain and we cannot even think of that situation. If not like 2005 NEM rains, we need rains close to it…So let us have a positive discussion.

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  17. From today….Rains gonna begin in many places of South India…
    Hopefully I should see developments over Raichur Dharward Tumkur koppal kolar by afternoon…which subsequently move into west AP and Telangana

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  24. Just for info, no need to analyse.

    Latest Update Suggests that a system is forming SE bay on 15th October, may be the trigger for NEM, then system move towards TN till 18th and then move away towards North bay of bengal by 20th. This is just an initial report, nothing to clarify or debate.

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  25. Action shifting to central interior ,north interior Tamilnadu and s.interior karnataka.. Dharmapuri,erode ,salem & surrounding may see the strongest storm activity.. few places in theni,madurai also may surprise

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  26. The country is heading for a shortage of water for irrigation and drinking as water level in 91 major reservoirs has dipped 16% below normal, and is expected to deplete further with the monsoon on the verge of withdrawal.
    Officials say the situation is particularly disturbing in western and southern regions although central Indian reservoirs have adequate water. The situation in the north is also better due to heavy downpours in the Himalayan states.
    “By September 7-8, we expect all condition of withdrawal from west Rajasthan to be met,” DS Pai, head of the long range forecast at IMD, said.
    The monsoon deficit has affected reservoir levels in Jharkhand, Odisha, Maharashtra, Chhattisgarh, Uttar Pradesh, Andhra Pradesh, Telangana, Karnataka, Kerala and Tamil Nadu. This could affect crop planting in the country, which is in the last phase.
    Reservoirs in Himachal Pradesh, Punjab, Rajasthan, West Bengal, Tripura, Gujarat, Uttarakhand and Madhya Pradesh had better water levels than a year earlier.

    Read more at:
    http://economictimes.indiatimes.com/articleshow/48796798.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst

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  29. Good humid morning, Little cloudy, looks some ridge effect there today for Chennai, medium rains possible.

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  33. Only hope for September Mid MJO fading away.

    Latest updates are downgrading the strength upcoming MJO by mid of the month. Day by Day the strength is getting reduced, now it has completely weakened. More negative vorticity expected across the state.

    Rain so far in state has been -7% below normal.

    Click to access hydro.pdf

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  38. countdown for SWM withdrawal started in last week of august itself. It is just we are not in the mood to accept it.

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      • one anticyclone needs to get established at lower level..rest of the upper level and relative humidity criteria’s hav been satisfied

      • acc will develop later, the point is, there may re emergence of SWM might happen, this event happened in 2013.

        for example – yesterday morning we had dry air till Maharashtra, if you see today, it has gone back up to gujarat, hence the moist air at lower latitudes pushing upwards, hence IMD is waiting.

      • moisture content,wind flow direction, future lpa &its movement would all b into consideration.. significant reduction in moisture for the period of 4 to 5 days is one best indication along with nw winds.. anyhow WD is not part of monsoon circulation.so its almost ready

  39. Quite interesting…………

    The Bay of Bengal cyclone of 18-28 October, 1963 has been studied by Mathur and Sikka (1965), Anjaneyulu, Sikka and Gurunadham (1965) and by Mukherjee, Mooley and Natarajan (1966) as it was singular in that after entering inland near Cuddalore and weakening into a depression, it curved to northeast and moved into the north Bay where it again intensified into a cyclone which struck the Chittagong-Arakan coast. According to these studies, the depression formed on the 18th as a result of the influence of a trough in the westerlies at 200 mb on the surface disturbed conditions near l0 N, 92 E. While the feeding moist current at that time was from E to SE, SWly moist current in the depression field, was also present. The depression intensified into a cyclone on the 20th when it lay in the southwestern periphery of a upper tropospheric
    anticylone. After entering inland it weakened and curved to northeast around “the 300 mb anticyclone ahead of a trough in the westerlies which pushed the anticyclone southwards. The depression intensified into a cyclone again in the north Bay under the influence of the eastern portion of the anticyclone in the rear of the trough in the westerlies. There were definite evidences of (1) the continental drier air being replaced by the Ely to SEly moist air over Visakhapatnam as the cyclone approached the coast, (2) the moist air being replaced by drier . air for a day when the cyclone after entering in~land, moved away from the station and (3) the drier air being replaced by Wly to SWly mo ist air as the depression curving towards northeast approached the station; the moist air was again replaced by the drier air as the cyclone in the north Bay moved
    away northeastwards. There were also evidences of an up glide surface of warm front type and associated rain. In the rainfall distribution there were two maxima one near the disturbance due to cyclonic convergence, the other on the Andhra coast largely due to the orographic lifting of the moist air on the coast as a result of the Eastern Ghats and also to some extent on account of the divergence associated with an upper tropospheric anticyclone and the forward portion of the trough in the westerlies in its rear mentioned above. A third rain belt had also developed to the northeast of the disturbance during its recurvatur, ~der the conditions mentioned above. Between 22nd and 24th The ~~ ~, to SEly moist current was replaced
    by the SWly to Wly moist curr~nt; such a Change in the moist current also occurred in the 1945 October cyclone in the Bay which had “curved to northeast (DEtsai ‘and Rho, 1954 -2). Thus ,’the change in the direction “of the’ feeding current coincided with re-curvature which was al”so affect”e:d by the ‘;up’per ·tropospheric patterns as ,mentioned above. During the ‘:first fortnight of May ; 1930, a cyclone;from the south Bay'”entered inland, weakened into a: depression which moved to near the west coast’ and curved to northeast ‘and after passing out into the north ‘Bay, intensified again into a cyclone and struck the Arakan coast near Akyab; , the change i’n the direction ‘ of movement of the disturbance was associated with a change in the direction of the feeding moist ” current from ;Ely-:-SEly to SWly – Wly ‘ and started earlier for the recurving pre monsoon ,and winter cyclones. Wi th the influx ‘ o’f ‘ SE’ly to :Sly air over the Peninsula, wide”‘; spread convective thunderstorms a~d shows occur there at times.The troughs in the westerlies begin to move in a more southerly)altitude and weather northwest India gets ·at·, ·times affected in association with that passage east to northeastwards

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      • Yeah quite unique and that it is the reason the reanalysis was being given a special attention in a paper

      • The situation was specially created for this storm. The pattern of October upper level wind is clearly shown in the movement track of the storm. It always had moisture and dry air support from SE Bay to North Bay travel. It is clearly driven by 200 HPA in sea and in land 300 hpa level wind direction.

  42. Temperature very much reduced across tamilnadu….dont call it as veppa salanam rains again
    pondhicherry- 31c
    cuddalore-31c
    madurai- 35c
    trichy-34c
    vellore-33c
    parangipettai-31c
    nagapattinam-32c

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    • What is the link between reduced temp And vs rains? Vs rains occurs when temp shoots up… Actually I feel you still didn’t understand the vs concept, poorly blabbering

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  46. OMG !!!

    The observations of IMD on possible scenarios underwhich a cyclone can develop in Bay is very interesting ….

    one such case…….

    With the waves in the easterlies, deep easterly warm moist air moves into the Bay and at the triple point i.e. the meeting place of the northeasterly colder and drier air, the easterly warmer and moist air and the southwesterly to westerly moist air (Roy, 1946),depressions or cyclones form, an upglide surface getting established between the NEly and Ely to SEly air and their occurs warm front type rain (Ramanathan and Narayana Iyer, 1930; Mal and Desai, 1931; Desai and Rao, 1954 -1). Later studies (Mathnr and Sikka, 1965) have shown that intensification of incipient disturbances was preceded by incidence of strengthening of easterly wind circulation in the lower levels, Further, they observed that in some storms the mid-tropospheric cyclonic circulation was ahead of the lower system. Once the moist feeding current weakens ·or withdraws, the disturbance fills up.

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  47. Popups started to form in interiors to the NW of Tirupati. Interior Tamilnadu & Kerala might see heavy Thunderstorms

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  48. IMD Rainfall update

    Vedasandur (Dindigul Dist)

    7

    Aravakurichi (Karur Dist)

    6

    Dharapuram (Tiruppur Dist)

    5

    Coonoor pto (Nilgiris Dist)

    4

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  58. @ storm n chennai
    So how sure are you in trusting such long range forecast regarding arb early Oct system? Is it trustworthy

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  62. NAO turned Negative. The Prospect of NEM.

    Iceland LOW has become Weak, and HPA over sub tropical region started to weaken, more moist weather likely over SW part of Europe and Dry weather over Northern part of Europe and East American Coast likely in the next one month time. Negative NAO with Positive ENSO and Negative SOI then Weak Positive IOD in September is good for NEM. We must at least get Normal Rainfall this season in both Chennai as well as Tamil Nadu. I have enclosed picture with this combo based on 2015 values. There were 3 years before 1997, 2002 & 2009. We need to exclude 2002, since it was a ELNINO-MODOKI. We have got Normal to Excess rainfall during NEM in those years. Hence Tamil Nadu and Chennai will get minimum Normal NEM this time, Excess category we leave it to Nature.

    NAO value in July was -3.18, August yet to be released.

    Monsoon over West African Coast has begun, this is making South Atlantic Ocean dry, hence SST Anomaly over South Atlantic likely to become Negative. ACC developed over South Coast of South Africa and another ACC developed over South Indian Ocean and it is strengthening.

    NAO Forecast, CPC forecasts Negative and Macritchies forecast Negative in September.
    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

    http://earth.nullschool.net/#current/wind/surface/level/overlay=relative_humidity/orthographic=-20.07,48.09,394

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  68. NAO turned Negative. The Prospect of NEM.

    Iceland LOW has become Weak, and HPA over sub tropical region started to weaken, more moist weather likely over SW part of Europe and Dry weather over Northern part of Europe and East American Coast likely in the next one month time. Negative NAO with Positive ENSO and Negative SOI then Weak Positive IOD in September is good for NEM. We must at least get Normal Rainfall this season in both Chennai as well as Tamil Nadu. I have enclosed picture with this combo based on 2015 values. There were 3 years before 1997, 2002 & 2009. We need to exclude 2002, since it was a ELNINO-MODOKI. We have got Normal to Excess rainfall during NEM in those years. Hence Tamil Nadu and Chennai will get minimum Normal NEM this time, Excess category we leave it to Nature.

    NAO value in July was -3.18, August yet to be released.

    Monsoon over West African Coast has begun, this is making South Atlantic Ocean dry, hence SST Anomaly over South Atlantic likely to become Negative. ACC developed over South Coast of South Africa and another ACC developed over South Indian Ocean and it is strengthening. Hence Positive IOD will develop for sure this month.

    NAO Forecast, CPC forecasts Negative and Macritchies forecast Negative in September.
    http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

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  69. FLASH

    The Southwest Monsoon has withdrawn from western parts of Rajasthan. The withdrawal line passes through
    Anupgarh, Nagaur, Jodhpur and Barmer.

    Conditions are favourable for further withdrawal of Southwest Monsoon from some more parts of northwest India
    during next 3-­4 days

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  73. Novak, this UAC in SE bay is now in Comrin Sea as it shifts further away our chances are superb and from tomorrow we can see some action. As of now wind directtion is weird. Very difficult to track the movement of TS.

    Else TS has to form overhead for it to rain.

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    • Pradeep, I’m purely going by the current conditions , which is very oppressive ( humid, sticky. Hot, and what not) .I also observe and feel some cool breeze in between these unbearable conditions. Plus, yesterday evening, late night sultry n sweaty conditions I guess are a perfect build up for some real action tonight or may be even earlier. Lets see how things unfold.

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  78. I sincerely pray we should have good rains this year. We should be self sufficient and all our framers also should get water.

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  81. Horrible climate in Hyderabad…feeling like April may…
    Temperatures soaring at 38 degrees by 1 pm itself
    Chilakalaguda (Hyderabad) – 38.1 degrees
    Narayanaguda (Hyderabad) – 37.6 degrees

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  85. Temperature of Hyderabad today stands at 8 degrees above normal….Really abnormal
    Yesterday it was 6 degrees above normal in imd hyderabad

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  88. The European Centre for Medium-Range Weather Forecasts on Thursday seemed to discount the possibility a low-pressure area developing in the Bay of Bengal any time soon. Instead, it said typhoon Kilo in the North-west Pacific will have the upper hand over the weakened South Asian/Indian monsoon. Kilo will keep the monsoon under a spell until it hits Japanese coast early next week.
    The Climate Prediction Centre of the US now says South India may dry up during the week beginning September 12.
    Some rain will migrate from the peninsula briefly into west Madhya Pradesh and adjoining south-east Rajasthan from where the monsoon has all but exited currently.
    http://www.thehindubusinessline.com/economy/agri-business/rains-in-south-saves-the-blushes-deficit-stays-at-12/article7611994.ece

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  89. As the UAC shifts from Comrin sea to Arabian Sea. Watch out for Nilgiris (Coonoor / Kethi). It may get massive rains today.

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  93. Please confirm it, it comes on 6th….no more hot days please, we are done for year !! God show us mercy !! We love to get wet !!

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    • Satish, got to bear these hot conditions at least till October 1st week or may be up to 10th October. For us the breathing period is only from the onset of NEM till March 20th..When easterlies are in full flow.

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    • u cant separate heat from Chennai..even oct will be superhot until winds r easterly..Chennai history therinchum,ingae vaazhnthum aen northies maadhri makkal polamburaanga

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      • I agree to you. I am born and brought up in chennai. But there is drastic change. Being hot is ok but too sultry and uncomfortable dog days..especially this year, it was just ridiculous. May and June were reasonably ok while July – first 10 days, when schools open, it was just mad…then that rain until first week of August. Too many changes to tough to predict…what next

    • Chennai will experience 6 months hot from april to september and cool and comfortable days from oct to march. So equal to both

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  94. The UAC started to move to arab sea..i hope the westerlies will back from tomorrow noon or even.. Interiors r getting gud rains..Much needed one for them to stop the heat over there..TS forming today near madurai & trichy..

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  97. BENGALURU:In what could be a challenge to the state, hit by drought and farmer suicides, the weather department has predicted a worryingly dry September.
    According to the Indian Meteorological Department, rainfall could be below normal for September, expected to compound the problems associated with agriculture and water supply.
    Former director of the centre B Puttanna observed that the prevalence of a surface trough over the interior parts of Karnataka and Tamil Nadu might result in thundershowers.
    “Surface trough is generally observed in May during the pre-monsoon season. The trough during the fag end of the monsoon season is quite surprising,” he said.
    There might be respite for South Interior Karnataka as several districts in the region receive good showers in September, he said.

    http://www.newindianexpress.com/states/karnataka/Weather-Department-Predicts-Worryingly-Dry-in-Karnataka/2015/09/04/article3009875.ece

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  99. Storms near madanapalle & its stretch are getting severe..Popups r forming like anything over south int AP..

    Reply

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