Wednesday, June 13, 2012



Mumbai Lake Levels on Mumbai Page....


Monsoon Watch -8  (Periodical Progress and Current Status). 



Much has happened after the last Monsoon Watch put up on Vagaries. MW-7 pushed the Monsoon into Maldives and Andamans. 


Current Position Explanation till 13th June:


All through this year's previous MWs articles, we have been mentioning, and explaining that the Arabian Sea sector of the Monsoon has been weak, and lagging. It was either a weak cross equtorial flow or a weak Somali effect or not enough momentumin the Arabian Sea due to low SSTs.
While, the Bay branch, has been normal and was always on schedule.


We saw the SWM advance into the Bay Islands almost on schedule by the 19th of May. Progressed well, though a little behind date into the Andaman Sea and had covered the Islands by the 25th of May. The Arabian Sea branch covered the Maldives around the 25th/26th of May.


The Bay current and momentum was kept active by strong cross flows from the South, and with a pulse from the Thai mainland, the SWM moved into the NE states by the 3rd of June. 
Cherrapunji announced the arrival with 400 mms of rain in a day !


The Arabian Branch had always been without proper support and energy. All the supporting factors here were lagging, and "letting down" the SWM. Still. a weak and lame SWM crept into Kerala, and the Indian mainland was hit on 5th June.
The off shore trough here along the west coast responded fast, and its formation led to the advance along the coast into coastal Karnatak and Goa by the 6th of June, and into South Konkan by the 10th.


Interior Karnataka and TN did not get the required benefits of Monsoon rains as the sole initator of the SWM advance along the west coast was a "lame" trough. 
But, all the other parameters for Monsoon advance like OLR, Upper Winds, UTH and 200 hp jet streams were favourable in S.I.Karnataka and TN, but without proper precipitation.
Vagaries had moved in the SWM in these regions on 10th due to these factors. IMD has moved the SWM in on the 13th.


For the Eastern sector, the sector which gets the SWM from the Bay, resistance came from 3 WDs, J1,J2 and now J3. The back to back WDs in June kept the pulses and any system from the Bay from forming in the Northern Bay areas, and prevented any form of Monsoon advance moving into the mainland all along from TN to the NE states. 


The Eastwards moving WDs pulled the seasonal low into an elongated low across the plains of N.India. In early June, the first 10/11 days of June, we see a long elongated region of 998 mb low stretching from around Delhi to Bihar. 


This is in effect a similar condition to a "break monsoon" situation. Though not actually a break monsoon scene, as the Monsoon has halted advance well South of the Peninsula.
The actual area under Monsoon as on 13th is very small and comparatively much less than normal coverage.


For Chennai, Strong Westerly winds prevented and blocked the East sea breeze from setting in last 2/3 days, and resulted in the days shooting up again to 40c and above.


Due to lack of cooler and moist air, prevented from flowing in land, Orissa, Chattisgarh and Coastal AP bore the brunt of a severe heat wave, which broke several all time records. In fact it was one of the longest lasting heat waves in terms of days in Orissa. 
Bhubaneshwar broke its all time high record. Vagaries has been mentioning these high temperatures in its daily blogs.


Meanwhile, a "brave' vortex maneged to creep into Coastal AP yesterday (Tuesday,12th June), and bring some relief rains along the coastal regions. Tuni and Vizag recieved 24 mms. Other hotspots like Vijaywada and Narsapur were lucky to get some soothing showers.


Between the 10th and the 13th of June, there was a favourable "chance" for the Monsoon to move into North Konkan due to the formation of a UAC in the off shore trough. An ideal influencing factor for monsoon advance. The UAC was critically located just off the Mumbai coast. 


But the clouding associated with the system was restricted to the SW of the system. By the 13th, the UAC, though still present, has moved NW, and tilted the Northern end of the trough away from the coast, westwards


Resultantly, instead of Konkan, we see heavy thundershowers in Saurastra, parts of Kutch and Eastern Gujarat on Wednesday. Heavy rainfall ranging from 15 mms - 70 mms are reported fom Gujarat. 
Askokbhai mentions Rajkot getting 44 mms in 90 minutes on Wednesday afternoon, with maximum rain rate around 3.30pm at 150 mms/hour ! 


Thundershowers will linger around for another day due to superb moisture incursion. Bharuch and Baroda regions to get maximum rains on Thursday.


What Next ?:








This UAC in the Arabian Sea is expected to persist for a day more, but more towards the west. On dissolving, we may have the off shore trough shifting back near the west coast again.


The revival of the monsoon gets another chance, if/when the trough moves towards the coast, and hosts another UAC within. 
Synoptic situation indicates formation of an embedded low by Saturday, 16th/Sunday, 17th. 
But current scenario shows shows sustaining and retention strength of the "to-be" UAC is poor, and may dissolve within 36 hrs. of forming. (Chances for Monsoon advance up the west coast is almost "touch and Go".)


But, even this factor is cosmetic. It will move up the SWM along the coast, but the interiors of Mah region will devoid of monsoon rains till a proper low emerges from the Bay. 

With the Bay clear of any resistance (from WDs), it should getting active from Sunday, 17th June, onwards. A pulse/UAC can travel into AP and move towards Vid and adjoining Mah areas. 
Possibility of Monsoon advance into Vid and Chattisgarh regions and East MP by the 20th of June. 
Simultaniously, monsoon rains will move westwards from the Bay into W Bengal (Kolkata) and remaining Bangladesh.


A weak MJO phase enters our seas from 15th June, and could prevail till 27th June at least. The 30 day SOI value is also not very favourable at -7.8.
Hence, Monsoon remains overall weak in June even after advance. 


Interior Peninsula, NW India may see a June deficit, alongwith some regions of East MP, Rajasthan and Southern Interior Peninsula.


Presently, the ENSO condition is neutral. Many international models forecast the El-Nino to develop by September. 


I would not currently worry about the El-Nino for our Monsoon. Let us be more concerned with the current weak MJO phase, which might push the SWM into a "break" phase immiedietly on setting in  !


Mumbai
June rainfall can still reach around 550 mms. 


Thursday 14th: Partly cloudy with Thunder heads in the evening sky. Chances of some rains in some parts Rain < 5 mms


Friday, 15th: Thunderclouds forming could precipitate rains in some parts of the city. expect the odd heavy shower somewhere. Rain amount 10 mms.


Saturday, 16th: Increasing cloudiness and a few showers and thunder shower by evening. Rain Amount 15-20 mms. 


Monsoon could advance into Mumbai by Sunday, 17th.
(Mumbai Wednesday ,13th, clear sky Sunset pic on Mumbai Page)

23 comments:

RK said...

@Rajesh, Eagerly Waiting for your next monsoon watch. What is the current state of ENSO and how it will be for the monsoon period? I hope there is no El Nino.

After last week's soothing rains, the temperature is back to low forties here in Delhi.

Anonymous said...

Hi Rajesh,
considering your blog audience is varied, i request you to publish concise and detailed version.

Thank you
Regards, Ananth

Ron said...

i agree with ananth..we don't mind it if it is detailed...

junaid said...

i agree wid ron nd ananth we get to know many things about meteroelogy from detailing

Shitij said...

Please Rajesh sir give detailed explanation.Because of your detailed explanation I have gained lot of knowledge about meterology.

Anonymous said...

Yeah detailed weather report is the only thing i enjoy reading without getting bored ... so rajesh please publish the detailed version :)

sset said...

Seems again Gujarat/Rajisthan are likely to hit target, dense clouds giving rain to Gujarat - monsoon ahead of time. Last 5 years Gujarat/Rajisthan receiving more/excess rains. Next low over Arabian sea may move north and again bring bountiful rains to Guj/Raj/Mah?

What is happening to south interior peninsula? Absolutely no rain. Forcast of rain to interiors and AP is null.

Thanks

Ron said...

so the el nino won't be that big a factor then...thanks for the update...fingers crossed for the monsoon to reach mumbai on sunday

Rajan Alexander said...

Hi Rajesh. All elements of a non-linear chaotic system of weather are there to see.

The IOD turned positive from negative two months ago. Most models have to eat their words.

The El Nino international models from predicting very probable, now says 50-50 most probably ENSO neutral! Here too, there is a climb down. With a negative PDO and post 2 year La Nina, it maybe too much to expect a strong El Nino, in fact any El Nino at all. It may need another two weeks for a confirmation where ENSO is heading.

The clouds are La Nina like - a any big positive

So that leaves the MJO as you rightly concluded as the wild card.My knowledge of MJO's impact on monsoon is poor. What I learnt from you is that it moderates the breaks. When does the MJO expected to flip back?

Despite the poor start, I still maintain a normal 99-104 LPA forecast. Plan to review in two weeks time.

Pradeep said...

Dear Rajesh,

I agree with what Rajan Alexander said and MJO forecasts looks very scary. All MJO models forecast dry phase of MJO till first week of July.

And it looks damm bleak even for monsoon bounty states such as Maharashtra, Karnataka and Kerala They will also get below normal rainfall in june. And May be deficient too.

So lets all wait till Super July where bountiful monsoon rains are expected.


And this statement of IMD

http://economictimes.indiatimes.com/news/economy/indicators/imd-expects-monsoon-advancing-vigorously-from-june-17/articleshow/14105680.cms

of monsoon monsoon after 17 June may be true, but it will be weak monsoon wave.

Pradeep said...

And Mumbai rainfall ....hmmm.... Rajesh....it will be hard for mumbai to get to 550 mm mark in june. Anything above 300-400 is bonus for mumbai in june.

rajesh said...

Ron: El-Nino may not worry us now..for the time being..but cant say about the MJO ..
Rajan/Pradeep: Yes, Pradeep/Rajan, really worried and concerned about the MJO..indirectly we have already had a "break Monsoon from 5-15th June..like i mentioned in vagaries..and dont see really meaningfull rains in the west coast after the coming UAC fades away..-:
RK: yes these high temps were expected again in Delhi..dont see relief soon..

rajesh said...

Pavan: when I did not have the computers, and other fast forecasting methods, even Sat images were rare, and could get them 1 day late, I managed and forecasted the weather then by visual observations. I am talking of the early 70s, 40 years back.
A deep blue sky, with sharp outlined clouds means good moisture in the atmos, and less dust particles. Generally observed during an approaching low or depression, or in case of a "front"
generally indicating approaching rains, specially if clouds are alto cumulus (dotted). But a faded light blue sky, where the clouds are not prominently seen or hazed, means no moisture and rains fading away, (munmbai today on Thursday).
A sunset showing deep red colouring heralds unstable weather while a plain sunset with a dull orange on the horizon shows fair weather.
Yellow sunset means storm.
This is brief..can make a seperate note later if required.

Pavan said...

Thnx sir really a good information, in days 2 come u can publish books on meterolgy for common man, hope u considr my suggestion

Ron said...

wow..this is interesting..didn't know about these cloud patterns..Could you tell us more in brief pls rajesh sir??

rajesh said...

sure ron/pavan: I'll write a short note on visual obseravtions (crude method as per todays std) tom.
shall put it by night on inter active page...

GSB said...

A huge cloud formation moving towards Mumbai. Will it rain tomorrow (Fri the 15th)?.

Excellent analysis @Rajesh saar!! Feel like a kid waiting to see Harry Potter for a few years and the theatre doors are finally open.....

rajesh said...

CA NILAY RAJNIKANT WANKAWALA/GSB : Thanks for the kind words and your encouragement.
Welcome to Vagaries' family, and i do hope to receive your comments and views to give a wider outlook to Vagaries.
Monsoon is sluggish, and with the MJO factor worrying us now, we have to wait and see...

GSB said...

Oops! Should have said moving towards Mumbai from the NE. Some thing similar happened in gujrat yesterday.. giving them good rains.. (Guj 124% and SAUKUTCH 331% above normal!!)

Ron said...

now even the imd is predicting a low pressure in NW BOB...so hopefully good rains in Central India..

emkay said...

A bleak situation as far as the Arabian Sea wing of SWM goes !! But I was hoping for a better start to the Bay wing considering the fact that last year too Bay did not really host many lows. Over all if you look at it tendency of things to move eastwards - Burma/ NEast. Even Pacific storms are veering North Eastwards.
Praying this tendency gets arrested and tropical storms move westwards sending pulse into the Bay. If El-Nino sets in, we should be seeing series of storms in the China Sea. Am I right Rajesh ?

Returning to West coast of the country, wondering why IMD has not rung the alarm bell !! BMC has start immediate water cuts in Mumbai. Heard from Kerala that Idukki Dam has just 10 days of water left.

Overall Monsoon adding to the overall cynicism in the Nation.

junaid said...

after a hiatus of 4 days monsoon clouds r back at panvel!!!!so rleived to see the grey low clouds coming from south west and spreading their magic!!!!i guess offshore trough must be realigning!!!

Shitij said...

Whether forecasted low pressure in NW BOB can give rainfall in Gujarat?