Wednesday, June 30, 2010

This write up is updated on 2nd. July @ Due to server difficulty, the blog is unable to post new updates directly in current dates. Hence it appears in the last blog dated 30th. June. I will update in this date, with a note till the difficulty is rectified.

The Upper Air Circulation which formed over the bay, has now, as an UAC, started moving inland. As seen in the clouding imagery, the system now seems to  be over the Chattisgarh/Vidharbh region. I am unable to locate this system as a low at MSLP.

TheThai MSLP map (as of Friday evening), nor the latest IMD map show anything in terms of the system coming to sea level as a low.

This (UAC) may move westwards across Central India, i.e. North Maharashtra and thence to Gujarat. Observing the moisture attracting capacity of this, we can expect very  good rainfall activity  from Friday thru Sunday over areas from Vidharbh to North Maharashtra, Gujarat and rest of central India.In fact regions of the Maharashtra section have recieved rains ranging from 30-80 mms.

On its path, i foresee an incursion of moisture from the Arabian Sea into Gujarat and onto the west coast north of Mumbai.South Coastal Gujarat regions, areas from Surat to Porbunder and the gulf of Cambay, could recieve rainfall upto 200-250 mms Saturday thru Sunday.
Good, heavy rains upto 100-125 mms, could be expected elsewhere in east Gujarat and Saurashtra, and in North madhya Maharastra and Marathwada regions.
A deficit Saurashtra could get good relief from this rainfall.

Mumbai, should get heavy rains on Saturday, as the UAC moves westwards. On Saturday, the city can expect rainfall at regular intervals, with some very heavy falls, throughout the day, with rainfall amounting to around 70-80 mms.Observing the movement of the circulation, I feel Mumbai rainfall will decrease from Sunday evening, about 25-35 mms on Sunday, as the system moves west, and weakens.

Just to mention, there have been 2/3 previous occasions in the last 9 years, when an upper air circulation at 850 hpa has been reported to stay put in Gujarat region for upto 5 days. Due to a sudden burst of moisture from the Arabian Sea, it maintained its strenght, and even continued to pour heavy rains in Gujarat and coastal regions.

However, advancement of monsoon beyond East Uttar Pradesh, even with the help of a predicted cyclonic circulation is doubtful.This system is short lived, and is expected to whizz past the central and western areas fast, within 3 days.

Highest, all India Rainfall from 1st.June-30th. June with deviations:

Cherrapunji: 3340 mm (+546)
Harnai: 1117 mm (+430)
Khozikode: 1016 mm
Passighat : 1014 mm (+165)
Lakhimpur: 1010 mm(+351)
Agumbe: 1093 mm
Goa: 981 mm (+112)
Mumbai Colaba: 947 mm (+396)
Mumbai S'Cruz: 712 mm (+168)
Mahableshwar: 577 (-289)*
* given bcoz it is supposed to be among the highs normally.

June 2010 is over and done with. The story of the Monsoon till end June is vague and haphazard. A stunted progress, and a completely distorted movement.
The monsoon set in over Kerala on May 31 and reached Mumbai on 11 June. A day early, and a date late to the normal dates.

It  covered the northeastern states slightly earlier than the normal time, but reached Kolkata only on June 13, about a week later than normal.

As of Tuesday, the monsoon has reached up to central and east India, as per the Monsoon limit line in the IMD map.
Rainfall activity  being reported from most of the areas covered are not too uniform, and are sporadic and scanty in the Gujarat region. (Shall put up the monsoon performance map/report till end June as soon as it is published by IMD).
Maharashtra is still on the "pre-monsoon " stage, with thundershowers developing, specially over North Mah. region, every afternoon,but pouring heavy rains in very isolated pockets, and clearing by the the morning.

Else, the rain accumalation map shows some precipitation along west coast, and in patches elsewhere.

But things do not differ much than what has been mentioned in my blog dated 22nd. June, from which I reproduce - "If, after this week, the axis of the monsoon shifts further north towards the Himalayas, and deepens,then the entire peninsula region is in for an unwanted "break". This may delay the monsoon progress into the Northern regions and subsequently into the North-West corner". Mentioned also in my footnote of the blog of 20th.
"The "interfering" monsoon axis has always been my main concern of worry, and has proved that it can create a sort of break monsoon.
My worst fears were that the monsoon would halt, and it sure did !  From the18th, its been stationary,  there has not been any advance of the monsoon over new areas since then.
There were many forecasts and "hopes" of the monsoon advancing, but as mentioned in "Vagaries", the MJO has been consistently negative for further advance since the last 12 days.Readers must have checked this point on the link provided in my blog dated the 22nd.

The 200 level jet streams are still stuck at 20N, and will allow the monsoon to progress only when it shifts Northwards.

Now, any further progress will be halted till the formation of a monsoon low pressure area/depressions over the Bay of Bengal.
Interestingly, the COLA has estimated an UAC to form over NorthMaharashtra/South 2nd, and the circulation is projected to move west. If so, then good and much needed rains could commence in Saurashtra on the weekend, as COLA estimates rainfall upto 100 mms in the region.
I will cautiously monitor the forming of the UAC.

Strong westerly flows, due to the axix position, over most parts of northwest/ central India and frequent western disturbances have disturbed the monsoon's smooth advance. And the W.D's are making "hay" due to the total absence of any systems from the bay. These are the days for the bay to dominate, not the W.D's.
Now, IMD has said in a special bulletin on Tuesday "that monsoon is unlikely to advance into the remaining parts of east and central India during the next four days.the remaining parts of central and east India are expected to be covered by the end of first week of July and the entire country by the middle of July".
Like i mentioned, nothing on the horizon till 5th. July at least. We preview and monitor again for any good developments each day.

Mumbai June report tomorrow.

Monday, June 28, 2010

An  IMD update said on Sunday that the offshore trough extending from south Gujarat coast to coastal Karnataka coast persists.
According to international forecasts,the west coast and, can expect  heavy to very heavy rainfall from around July 1 (Thursday).
Now thats the forecast estimate, but will the forecast sustain?? I really don't know !! 
I have given the reasons in my blogs for my doubts, of the monsoon current picking up by the 1st. I do not see any "low"or system developing either side,before the 2/3 July. And, the MJO shows no positive signs till the 5th. July.
A real meaningfull momentum to the off shore trough in the west will be only after an active MJO, or a low in the bay draws the winds from the sea onto the land.
To add to the negatives,a feeble western disturbance would be moving over northwest India for the next 3 days. This would prevent the monsoon from moving further into the region.
(These are my personal judgements, and I think prevailing upon estimates given by proffesional meteorologists would be a better reliance for commercial use).

The "huge" convective thunder clouds forming last 2 days in the North Maharashtra regions are basically rising "heat thermals" and I don't think realted to any organised system anywhere. Its just a lot of on land moisture rising to great heights. And precipitating heavy "evening thundershowers', nevertheless. Organised or not, useful rain nevertheless !
Great Britain to see Warmest of 2010 today
Central London likely to near 90 this afternoon
Special Story
By Mark Vogan

As of 9am GMT, Sunday, it was an already balmy 72 degrees (22C) at Charlwood in Surrey and after the same location within Greater London just fell shy of the UK's warmest reading so far of 2010 which was 84 degrees at Heathrow Airport yesterday with a high Saturday of 83 degree (28.6C) reading, it looks set that somewhere within the Greater London area will see the warmest reading of the year so far, today with Mark Vogan predicting a high of 88-90 degrees (31-32C) between 3-5pm GMT.

It's all about a "building of heat" which has been the case since Thursday, gradual warming often sees a "peaking in daytime highs" which is likely today (Sunday). When conditions are right and high pressure stands strong in one given area, highs gradually warm day after day and more importantly, nights fail to cool. When you've reached that threshold of minimal nighttime cooling, that allows the day to start off warmer than the previous, so a warmer base allows that rising sun to heat the air faster and easier. For example, Charlwood's 9am reading of 72 is the warmest so early in this current warm spell. As that sun rises throughout the morning, the air is ALREADY WARM so it doesn't take as much work from the sun to further heat the air. When conditions are right, when you look back at the previous day and it's a degree or two warmer than the same time the previous 24 hours, it's more than likely the actual peak temperature will be warmer, therefore a good indicator and often for meteorologists a good indicator at just where that high will peak at... that of course is given the winds remain relatively light and there is minimal clouds to abstruct the sun's rays to the surface. Sometimes a breeze will kick in, often due to heating, or a thunderstorm will blow up, these two factors often prematurely cut off the daytime heating process and therefore the high doesn't reach the anticipated level. That isn't likely to be the case. The atmosphere is reasonably "capped" over southern England, therefore cloud formation should't be an issue. The core of high pressure is fairly closely over southeast England, therefore winds should remain light, thus all indications are that it's going to reach forecasted levels this afternoon.
Pressures are lower across the north and with a closer distance to an area of LOW pressure to the northwest of Scotland, surface warming this afternoon should still allow 70s for central Scotland, the energy of a frontal boundary across the northwest may spark of afternoon thunderstorms across central Scotland as surface readings warm and helps ignite energy aloft. 

These very warm readings SO FAR of low 80s have failed to reach Mark's criteria of "HOT", so far it's fallen into the "Very Warm" category but if it reaches the expected 88 degrees or higher, then for the first time in 2010, southern England will enter the "Hot" category...
Mark Vogan fears a Summer of 2003 repeat
The increasingly drier soils, particularly over the Lake District but also throughout much of the UK with exceptions of northern and far western Scotland, this is already aiding in strengthening high pressure over us. The dry weather shows no signs of change and as we appreoach the hottest portion of the year, the signs are there for what could be a scorcher of a July and August. Remember the hottest air of the year during the record sdummer of 2003 didn't hit until early August! Right now it appears that July will see a much warmer and drier than normal pattern and highs which push into the 90s for the south and 80s for the north. 

Saturday, June 26, 2010

We are still concerned,again, with the erratic behaviour of the seasonal trough, the Monsoon axis.
This trough is currently north of its normal position. It has been so, and concern for the same has been regularly mentioned in previous blogs.This position allows  westerlies to flow south of the trough.
Meanwhile, a again moving thru north-west India, bringing partly cloudy sky conditions and isolated thunderstorms.With this, at least the severe heat wave is a thing of the past for now,though days are still slightly above normal.
The low-pressure area off Orissa coast  moved inland and is now an Upper air Circulation. Hovering over Madhya Pradesh and adjoining areas, it may precipitate pockets of heavy rains in parts of M.P.and Chattisgarh Monday thru Thursday.

I do not see any international model showing formation of a low, or any system in the bay till 2nd. July. and without this, a major thrust of monsoon rains in the peninsula regions will be absent. This will leave the lone off shore trough along the west coast to hang on, which will result in some 'decent rains" along the west coast. 
Due to lack of suitable "waves",I surely see the east coast, south of Orissa, totally dry till Friday next(2nd. July).
A monsoon progress into Gujarat and M.P.could be ruled out till the 2nd. at least. 
Delhi, could get the isolated thunder squall produced by the moving W.D.

Today's (Saturday) rainfall map shows very  isolated, un-monsoon like rainfall. The rainfall regions could be "hand-picked". The west coast, due to the trough, the eastern sector in patches, due to the UAC, and few regions in the north, due to the W.D. No widespread rains seen anywhere.

Mumbai, like I said, will get diminshed rainfall over the weekend, maybe 15-20mms/day.A couple of short duration heavy falls could be expected,especially during the night. 
Some quantum increase in rains, to about 35-40 mms/day, could be expected on Tuesday and Wednesday, due to the off shore trough lingering on.
Mumbai may be rejoicing with the very heavy rainfall recieved this June,but,as mentioned, the rains are very sporadic, and though Colaba recieved an extremely good amount of 920 mms, Santa Cruz totalled only 650mms. and where it matters the most, the lakes,the rains were measely in comparison. The highest amongst the lakes to get the rains is Bhatsa, with 492 mms,Tansa recieved 263 mms,  Vaitarna 236mms and upper Vaitarna 231mms. 
Not really impressive, these figures ! 

Friday, June 25, 2010

Mumbai seems to have gone past both the the wettest spots of the country this year,as of today, barring ,of-course Cherrapunji.
The rainfall for this month, till date, 25th, for various places,
Mahableshwar: 492 mms(-88),  Agumbe: 887 mms,  Mumbai Colaba: 910 mms(+494),  Harnai:1037 mms(+532),  Cherrapunji:2468 mms(+160).

The  low-pressure area formed over the Bay of Bengal is sort of "blowing hot and blowing cold". From showing no signs of deepening on Wednesday, it suddenly became 99B on Thursday, raising hopes of becoming "well marked".(Sounds familiar, heard this before :))
 In sympathy, the western trough off the coast suddenly shot into action, and precipitated heavy rains along the Konkan/Goa coast on Thursday (24th.), wiping out the fears of reducing rainfall there due to the "break Monsoon" scare. And, the monsoon axis, as if in obeyance, has retreated its threatening stand, by forming a core of 992 mb far away from the Indian land mass,deep into the Sindh desert. The correct place for the western end of a typical axis.

The low in the bay is likely to become ‘well marked' soon.That's the repeated expectation since the last 24hrs,but as and when it does, it should travel west into India, and merge into a W.D. approaching from the northwest, and set up rains over the Gangetic plains, and rain in some places in the North, bringing some respite from the severe heat.
But as estimated, the interiors of the peninsula region are relatively drier. Rainfall figures of interior Maharashtra and peninsula cities are still wanting, and rains are badly needed there. And may remain so for the next 2/3 days.

Mumbai has got more than its a fair share of drenching. With Colaba recieving 210 mms of rain in the last 24 hrs, ended Friday morning, the June total has leaped to 909 mms. Now thats a whopping  495 mms above the noraml, or +54%, for this time of the year. The all time high for June is 1280 mms.

But the all India average is -11%, a big  improvement from last year, after the disastrous 54 per cent deficit recorded up to June 25 last season. The year 2009  had witnessed the worst drought in three decades.
The +ve regions are the areas where the monsoon has not yet arrived. Like Rajasthan, with+214%. But mainly due to the interaction of the remant of Phet with a W.D. over the region. -ve is in the East.

One of our readers has rightly commented today, that Mumbai is recieving very good rains in spite of no system or active MJO, either from the bay or the Arabian Sea. Defying forecasts, the off shore trough along the west coast, a permanent feature during the monsoon, has shown "its strenght" in the last 4 days and produced very good rainfall along the Konkan and specially off the Mumbai coast.
You see, the trough has been "going on and off" very frequently. It formed a embedded vortex, which suddenly disappeared, without crossing the coast. But still precipitated rains off the Mumbai area (see previous blog). Now today, its Northern end has abruptly moved North to the Saurashtra coast. While observing the trough. I had judged about 100 mms of rain for Mumbai Thursday/Friday, but Thursday itself brought 210mms in Colaba, but 120 mms in the suburbs.Sporadic and differentiating.Santa Cruz total till today is 643 mms !

Ahead,I see the rains lessening a bit in Mumbai during the weekend, only to pick up slightly from Monday.

Further Monsoon movement will depend on the behaviour of the low in the bay. Dont see much prospects of the low picking up till Monday.Hence, rainfall in the interiors of Maharashtra, Karnatak,and eastern plains of Northern India will be restricted. But rainfall can be expected, next 2 days,in Chattisgarh and Eastern M.P. due to the weak low persisting.
Do not see rains advancing much into Saurashtra too.
From Our Partner Blog:
It appears the warmth is continuing to build across the southern half of Britain.. After a dreary, dull and showery day, though we didn't recieve much rainfall, enough to sprinkle on the ground as a frontal system tries to push southeast from the outer Hebrides into the central belt of Scotland. It's drizzling as I type this.
Down south of the border it was all about the sunshine and warming temps. Highs are very likely to warm towards the highest of 2010 so far either tomorrow or Friday and if London tops 30C or 86 degrees, this would mark the warmest in the UK so far in 2010! We shall see, stay tuned for more updates on the heat in Britain.
Note to Scots and Irish: We will see the return to sunshine within the next day or so, highs in the mid-70s?  ...And lots more on the Americas, for those interested....on Mark's blog.

Wednesday, June 23, 2010

The positive point of todays blog is the fixation and firm position of the monsoon axis,along the Punjab,North M.P.and Jharkhand route.The mere refusal of the axis to shift North is a very encouraging sign, and could allow the formation of a low in the Bay, and allow it to travel along its "line".
Thankfully, we can forget about the "break Monsoon" in that case.

IMD predicts that "an upper air cyclonic circulation may form over west-central and adjoining coastal areas of north Andhra Pradesh and south Orissa".
The system could transform into a low-pressure area over central Bay by as early as Thursday. The system would head westward along the axis line, over land and might inter act with a prevailing W.D. coming Eastwards from Thursday. The actual interaction region would definitely see good precipitations and advancement of the Monsoon,and go on to set up clouds over further northwest, 
The low, on crossing land (could be by Friday), will, in all probibilities, form a North-south trough from the centre of the low thru maharashtra Southwards upto the interiors of Karnataka.Northern peninsula could possibly experaiance widespread rainfall till Monday.
But,the CPC sees the revival of the monsoon covering the entire peninsula,during the week ending June 28.

The existing trough off the west coast is precipitating rains,in its limited capacity.All this due to the stubborn mosoon axis in the North not allowing yesterday's UAC to cross the land. 

As discussed in yesterday's blog, the rainfall amounts along the West coast, were much less than originally estimated, save and except the Mumbai coastal regions,which recieved heavy rains.In the Konkan region, only the  the Mumbai coast region,has recorded the highest rains.Thane Belapur 17cms,Thane 13cms,Mumbai Colaba 12cms,Dharavi 11cms and Uran 9cms.Even the ghats did not recieve much rains, just between 2-4cms.

Mumbai: Yesterday's revised rain estimates of reduced rains in the Konkan proved correct, but Mumbai turned out to an exceptional "iso;lated wet spot". 
As an exception for Mumbai, Vagaries of the Weather original forecast for Wednesday, the forecast published on 20th.June blog,was accurate, with the rain intensity increasing from Tuesday night. Wednesday was a rainy day, with 60 mms at Colaba and 44 mms at Santa Cruz of rain in the day.On revision, the estimate was scaled down to 30mms yesterday.
Overnight Tuesday rain was 123mms in Colaba and 87 mms in Santa Cruz.
Heavy showers, some prolonged, will continue into thursday morning, with rains decreasing in frequency later after friday.Thursday thru Friday should total upto 100 mms of rain for the 2 days.
Seems as of now, weekend rains will reduce to 25-30mms per day, with sunny patches.

Hot Night: Gwalior recorded a minimum temperature of 36.4c yesterday night(22nd. June). One of the hottest on record anywhere, I suppose.The nearest i know is the 38c recorded as the minimum at Sibi(pakistan) a few years back. The hottest night, in my record books, was at Khandwa. the lowest the mercury could go down to was 40c !!

Tuesday, June 22, 2010

Starting with the developments aliong the West coast of India,we see the UAC (Upper Air Circulation) in the trough has become less marked.
Now, this development means that there is no UAC present to cross the coast near Mumai as estimated earlier, and as a result, I would scale down the quantum of rainfall estimated earlier.

Since the coastal trough still hangs on (see IMD map),we can expect rains on a lesser scale to continue along the coast North of Karnataka this week.
As mentioned yesterday, I personally think that the Monsoon axis trough running west-east along the Northern plains of India, has had some role to play in the vanishing of the UAC. I have always been sceptical when this axis shifts northwards, as it heralds a "break" period for the peninsula regions, and can weaken the trough, or any embedded low in it.
With the trough intact, as it will be till Friday 25th. at least,rainfall to some extent will continue along the coast and in the interior areas of Maharashtra and Karnataka thru this week.

If, after this week, the axis of the monsoon shifts further north towards the Himalayas, and deepens,then the entire peninsula region is in for an unwanted "break". This may delay the monsoon progress into the Northern regions and subsequently into the North-West corner.
Though nobody wants a break now, the MJO forecast (see this link) shows the "unwanted negative" MJO waves during the next 15 days. When positive, it creates the "lows" and the depressions, and the rain bearing systems into the monsoon currents. When forecasts show a negativity, it reads as less systems in the regions.It is one of the few aspects of the weather that can be skilfully predicted beyond about 2 weeks into the future.
But, I really hope that things change for the better, and Nature eventually ridicules man's forecasting. We will keep our observations updated and monitor the same.

Meanwhile, the extreme in the Northern belt continues with a special mention of a minimum of 33.8c at Gwalior last night, and 32.6c as the low at New Delhi.

Mumbai: Will continue to get the passing showers on Tuesday, with about 10 mms of rain. Wednesday's forecast may have to be scaled down due to the reasons discussed. City can expect a few more showers, with rainfall during the day totaling 20mms. Thru Friday, Mumbai can get passing thunder rain, and with the rainfall scaled down, city may just about recieve 25-30mms till Friday.

Monday, June 21, 2010

The Return of the Sub-Continent heat wave !
Highest in Asia: Mecca and Jeddah (S.Arabia), Sibi (Pakistan): 50c
Highest in India: Dholpur 48.8c, Ganganagar 48.7c, Hissar 47.8c

Some met. reports are now hinting at a small break in the Monsoon advance.
Quoting Meteorologist Ashok Patel from Rajkot:
"Monsoon is not expected to progress further for next five days. However, weather over Saurashtra is expected to improve under the mild influence of the Monsoon trough along Konkan and the Cyclonic Circulation over East Arabian Sea. Light Rainfall is expected over Saurashtra mostly South of Rajkot. Rajkot could get rain on Thursday/Friday.
"There is a Cyclonic Circulation over Arabian Sea West of Maharashtra Coast. Monsoon trough along the Konkan Coast and the Cyclonic Circulation will combine to give Heavy Rainfall for Goa to Konkan and also some parts of South Gujarat. Rainfall estimates for Goa, Konkan and nearby South areas will be posted soon".

Sunday, June 20, 2010

The heat is back in the Sub-Continent ! 
"Vagaries of the Weather"  mentions today (afternoon write up) of the possibility of a heat wave returning to the region. But before "the ink could dry",we have it on us !
Today's highest in Asia reading returns back to Pakistan, with Larkana and Sibi notching 51c.Followed by 50c at Al Ahsa Airport in Saudi Arabia.
Bhawalnagar(Pakistan) was next with 49c
In India, it was Ganganagar as usual with a high of 48.1c. (Information from smaller towns not yet in). 

Delhi airport has jumped to 46.7c today.The list of 47s and 46s are long, so putting up a map of the highs today would be better.
Monday could see higher temperatures in the region...

On Sunday, Mumbai had a high of 32.2c at Colaba and 32.6c at S'Cruz, with 2.2 mms of rain (Colaba) and 9.4 mms at S'Cruz. (Prediction for Sunday in this blog was 32c and 15mms of rain.)

From our Partner Blog:
....and if you  want to know how the summer's going to be in the U.K. read Mark's superb analysis here.

The off-shore trough at mean sea level from south Maharashtra coast to Kerala coast persists. The Upper Air cyclonic circulation (UAC) over eastern Arabian sea and adjoining Maharashtra-Goa coast persists and now is at lowers levels.
For the west coast of India, this is the trough we have been observing. The embedded UAC which was expected to form off Mumbai, and now going by our estimate, should strenghten to some extent, and cross the coast south of Mumbai by Tuesday evening.
Resultantly, the entire west coast North of Karnataka (included) should get enhanced rainfall from Tuesday thru Friday. The brunt of very heavy rains, on Wednesday/Thursday will be taken by the Konkan region and the adjoining western ghat stations.
I do not expect the UAC to go to great strenghts, but still could pour some extreme rainfall of +250 mms on Wednesday/Thursday in extreme cases along the Konkan coast or ghat stations.
The rain spell will be restricted mainly along the coast, and may not venture much into the interior of the peninsula regions. The much needed parched regions of interior Maharashtra and adjoining Karnataka, M.P.will get scanty rainfall, in pockets, during the week, not exceeding 10-15mms /day.Vidharbh could get some good rain on Wednesday.

The push into Gujarat will be after Wednesday. From then we see the rain areas pushing into Saurastra, with rain in almost all the regions of Saurashtra from Wednesday thru the week.
But the Monsoon throughout this week, till the 25th. at least, will refuse to move further.On 22nd,It will just about enter Gujarat region, barring the Northern Kutch and adjoining Rajasthan region. 
Till the 25th, it will remain stationary in the eastern sector, without moving towards east U.P. That's the gateway to the Northern plains including Delhi. No formation of any low is seen in the head bay till the 25th, which makes me conclude the stationary monsoon prediction in this sector.Even the 200 hpa jet streams do not "fall in place" before that.
That translates to a continuation of the heat wave in Rajasthan, Punjab/Haryana and delhi.With a mainly clear sky, the maximum temperature would hover at around 44c in Delhi. And the desert state could see 47/48c next few days.On saturday, Phalodi in Rajasthan sizzled at 46.5c and Kota registered 46.3c.

Mumbai: Well, we had our hot day on Sunday,with just about 5 mms of rain. Expect some passing showers on Monday, rainfall upto 15 mms.
Tuesday will be overcast, and by evening,   an increase in rainfall can be expected. 
Wednesday thru Friday, will be days of heavy rains, with flooding in vulnerable areas. Rains on Wednesday could be around 50mms, And 80-100mms on Thursday/Friday.

The trough of low at mean sea level passes through Churu, Gwalior, Rewa, Gaya, Asansol, Kolkata and thence southeastwards to eastcentral Bay of Bengal. 

Now,something has got me thinking.The forecast prediction for this trough is a bit confusing. IMD's GFS maps show this monsoon trough, along the Northern plains,dropping pressure to 994 mb, with a core of 992 mb, by the 24th. Frankly, if that were to happen,I would fear a Break Monsoon condition. Now that's quite scary ! A Break Monsoon is the last thing we need now!I am not predicting this,I am just putting up my point of view. It may not happen, and I hope not, but a low trough of 992 mb in the East-West axis is certainly not the ideal situation during, or even before the monsoon has set in !

Saturday, June 19, 2010

98A formed at 72.5E and 17.5N. Expected to stay embedded in trough and move west as estimated today morning. Its terminology is changed, and is the vortex mentioned earliar.
Readings as on 19th. June:
Hottest in Asia:Al Ahsa Airport (Saudi Arabia)  50c, and Al Khaisumah Airport (Saudi Arabia)  50c.
Hottest places in Sub-Continent: Larkana (Pakistan) 49c, Kota (India) 46.3c.
Hottest Night in Al Khaisumah Airport 34c, and Kota recorded 32c last night.Heaviest Rain yesterday: Harnai (maharashtra) got 421 mms in the last 24 hrs.

125mms of Rain in 90 Minutes ! 
What Mumbai experianced on Friday afternoon was a virtual cloudburst.
I personally could not witness the rainstorm,as was in Goa,in fact waiting for the aircraft clearance at Goa airport from 3pm to 9pm. Thats till our aircraft got the go-ahaed to proceed to Mumbai.
Even though it was the aftermath of the storm,fortunately,I was able to observe the towering cumulo- nimbus thunder heads at eye-level from the airplane whilst approaching Mumbai. The route taken from Goa was initially North along the coast, but about 150kms before Mumbai, the aircraft turned towards the North-West, and flew over the sea, to approach Mumbai from the west, and it had flown a good 50-60 kms due west off Mumbai. Since the aircraft took the sea route while approaching Mumbai, I observed the maximum cumulo-nimbus clouds, thick and threatening, about 40kms off the city coast, due west.The cloud height observed then could have easily been  35000 feet above MSL, with the outside cloud temperature showing -30c on the passenger information screen. Even though it was night, a keen observer could locate and study the towering thunder heads at close quarters, infact flying through  massive storm clouds at times.

With 125mms of rain in just 90minutes, it was a massive cloudburst, and could be due to a formation of a local vortex within the off shore trough. The local heat during the day, it was 32c on Friday, added fuel, and convection pushed up the vertical cone to heights of maybe 45000 ft during the storm. Cloud tops were observed at -55c in the weather maps.

As seen in the satellite image, a vortex is seen hanging around off the North Konkan coast even today, with enhanced cloud cover.
Now, as per the forecast models, this cloud cover will remain in the same stationary position till Tuesday, off the Maharashtra coast, and on Tuesday move towards Mumbai, and precipitate heavy rain along the Mumbai-North Konkan coast on Tuesday/Wednesday.
Since there is a possibility of an active MJO enhancing Monsoon prospects along the west coast, I would prescribe to this forecast, but for this to happen, there could be some mild heating again along the "forecasted "region on Sunday/Monday.
That is when I would presume an upper air circulation to form over south Gujarat, and precipitation could resume in strenght along Saurashtra from Tuesday.
Rain is seen pushing into interior Maharshtra this weekend. Some favourable rains could be expected in Madhya Maharashtra, Marathwada and Vidharbh this weekend.

The Bay seems to remain devoid of a low till Tuesdat at least. The East-West trough is seen along the plains of North and Northeast India, but bluntly cutting off in the east. Hence local pulses will bring rains along the Orissa/West Bengal coast this weekend , and at least till Tuesday, I do not see any meaningful rain in T.N. and A.P.
As per the 200 hpa jet streams, I would still stay put the Monsoon at 22N. After,the 23rd, when the active MJO gets into action, we could expect a further advance of the monsoon, in the eastern and western regions.Monsoon may push into U.P. and M.P.after 23rd.

Mumbai Forecast: 
Mumbai Colaba has recieved 478mms of rain in the 18 days of this month. This is much better than the 266mms recieved in the whole of June last year. A good and bountiful beginning for a thirsty city.
Santa Cruz has recieved 333mms of rain till date this month, against 216mms recieved in June last year.
I see a slight let up in the rains for the weekend, say about 20-25mms per day, with with a chance of a thunder shower in some areas. Day temperature may go up to 32c on Sunday.
Rainfall will increase from Tuesday,22nd, thru Wednesday23rd. For Tuesday/Wednesday, I would put the accumalated rainfall at 120/150mms. Again,check up local areas for flooding on Wednesday,23rd.

If you would like to estimate in the poll, the overall India performance of the Monsoon till 16th. June is at -5%.

Wednesday, June 16, 2010

The pieces have fallen well in place,with the trough off the western coast of India, embedded with a vortex off North Maharashtra coast,producing the heavy rains predicted, and moving the monsoon northwards into south Gujarat and all of Maharashtra.The limit of the monsoon is seen in the 200jet stream map.Easterlies indicate the monsoon limit normally.

Some of the heavy rainfall figures of rain recorded on tuesday(day n night) for Konkan coast are (in cms):
Mahableshwar 14cms, Dahanu 11cms,Ratnagiri 10cms, Mumbai S'cruz 9cms and colaba 8cms
The lakes of Mumbai too recieved very good rainfall on Tuesday, a boon to the city:Vihar-16, Bhatsa-7, Upper Vaitarna-5, Tansa-4, Tulsi-3,Vaitarna-2.

For Mumbai,heavy rains were predicted on this blog,,Monday thru Wednesday,At least a week in advance."Vagaries of the Weather" had estimated 23cms of rain Monday thru Wednesday for the city, and the actual rain recorded was20cms at colaba and 18cms at S'Cruz,till Wednesday evening.

And flooding and water logging and gusty winds was anticipated.The tall claims of the authorities have fallen like a pack of cards,in spite of the fact that flooding was expected.More than 20 low lying areas in the city were flooded knee deep, and Walls have collapsed.Landslides in Thane have led to much damage, and importantly,loss of lives.
Same old story!Forget the hoodwinking of the Shanghai story!Better would be a Venice promise,it will be easier !

The off shore trough will hang on, but the vortex off Mumbai, I expect, will cross inland. The result should be some torrential rains in North Madhya Maharashtra on Thursday. 
Konkan rains will linger on till Saturday, though reduced. 
Mumbai will see the rains gradually reducing from Thursdsay, and the weekend should be comparitively drier, with about 25-30mms of rain/day.
The rest of the west coast areas will continue to get moderate rains, around 35mms/day till Sunday.

All eyes on the Northern head of the Bay now. An unusual monsoon trough of low (for this time of the season) runs along the Northern plains of india, with the eastern end dipping in the Bay. Now this "dip", is the centre of all attention, and should form into a low. 
With this formation, the monsoon's eastern branch should move along the axis of the trough, and bring the rains into Bihar and East U.P.on its way into Delhi.
Also,the south-west flow from the Arabian Sea onto the Karnataka and Konkan coasts will get a boost from this formation.

With the advancing monsoon spreading a cloud cover over the peninsula,and a W.D.covering the North/Northwest,the highest day temperatures have reduced to around the 40c levels.
On Wednesday,
Highest in Asia:Basrah(Iraq):50c
Highest in India:Patna:42c

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