The June rain figures are out, and as expected, the country as a whole is in deficit of -46%. Quite a huge deficit, considering the fact that June is the main month of rain and gets around 25% of the season's amount.
The figures are:Actual: 92.6 mm, Normal: 171.2 mm and Departure: -46%.

The sub-divisionwise weekly and seasonal rainfall distribution is presented in enclosed map. This shows only 1 region in the mainland as +, that is Rayalseema, and + in Lakshdweep Islands. Huge areas are seen in deficit or scanty shades.

The June of the last 5 years has been much better off. The June percentages from 2004 to 2009 were:-2%, -20%, -21%, +20%, +21%, and -46% this year !!

In Maharashtra, specially the inland regions, the deficit is alarming. -60% in Marathwada, and -50% in rest of the regions including Konkan. Rains in Mumbai are at 50% of the normal,( S'cruz at 40% of normal), and Mahableshwar( a key area for the catchment of 5 rivers) has recieved only 20% of its normal. In fact, the total for June in Mahableshwar was only 166mm (normal is 800mms). This is the lowest ever June total for this hill station, the previous being 194 mm way back in 1891 !

I have just recieved rainfall for June from Cmdr. Potey for Lonavala (hill station 100kms from Mumbai). June rain: 2009 =175mm( -85%). 2008= 1187mm. Normal= 1200mm.( my estimate). Thanks Cmdr.

In fact, in my previous blog, I had anticipated a low rainfall for Mumbai this week, Monday thru Thursday. I imagined the city would recieve 20-25mm per day. But, on these 4 days, Mumbai got an average of 10 mm only. Diagram shows the measly rain per day.

Now what? There is some positive and bright news. IMD, and some international forecasting models predict a definite Low in the bay, and the Arabian Sea around the 6th. of July. I feel, if this happens, and in all likelyhood it will, it will boost up rains in most of the deficit regions.
Strong wind flows from the Arabian Sea and the Bay of Bengal are expected to originate with the formation of the low-pressure areas around this date.
The Bay ‘low’ is forecasted to move west over land towards central India and most likely to merge with the system in the Arabian Sea, raining heavily all the way.
Entire central India, north peninsular India, Madhya Maharashtra, west coast,M.P. and Gujarat can recieve good rains along the path.

On Wednesday, the Australian Bureau said " more evidence of a developing El Nino event has emerged, and that computer forecasts show there’s very little chance of the development stalling or reversing.
The Pacific Ocean sea surface is currently significantly warmer than the long-term average across most of the tropical Pacific."

But, I feel, it may not affect our monsoon, not till August end, at least. An interaction of westerlies and easterlies around the Bihar/East U.P. region is precipitating heavy thundershowers. But these are short lived, and not expected to cause much damage.Once the lows from the peninsula seas get "in line", the easterlies will slide south towards central India along with the monsoon trough.
An eastward-bound MJO wave is already impacting the monsoon. It has "livened up" the coastal trough, as seen in the sudden surge of heavy rainfall events over the west coast. Hence hopes of quick revival, that is around the 6th. is more likely now.

The last 8 days has suddenly made all the difference and changed the total weather scenario, in the Indian region. The Monsoon, has moved, or jumped, northwestward by covering the states of Mah, Gujarat, Chattisgarh, M.P .Bihar and U.P. Delhi and parts of Punjab within with the last week. Thus, the northern limit of the Monsoon has achieved near normal levels after having lagged well behind in time and place by almost 15-20 days.

But now, onset/advance needs to be converted into normal rainfall, and as Jim from Accuweather puts it " for the details of atmospheric behavior under the setting of Monsoon are critical."

The June rain totals in almost all regions are below normal, that too to a large extent in regions of Mah, Karnatak to name a few. Details of the quatum of rain and deficit will be put up on this blog in a few days after the release of the details.
Now, this is predominantly due to be the lack depressions, the last was Tropical Cyclone Aila in the bay, and one depression in the Arabian Sea, fizzling out in 1 day over Gujarat.
After moving into Delhi today, mainly due to the Upper Air Circulation over the U.P. region, the monsoon may slow down for a few days. This can be due to the upper Air Circulation fizzling out due to lack of sufficient support from the bay.

And no "low" is forecasted yet in the bay, not till the 5th. of July .at least.
Rains may yet be subdued again in the states of Mah. Gujarat, M.P. Karnataka and the central/northwest regions of India. May not be a "break monsoon", but surely the easterly winds needed to bring in the bay moisture into central India will be missing till the 5th./6th.
But W.Bengal and the north-east may continue to recieve moderate rains, at times heavy, as the northern bay will be springing up a low in the next 5/6 days, and the moisture inflow into the W.B. coast may continue.

Normally, depressions deliver widespread rains in the main heartland of India. this year, the late onset and the absence of rain-making systems from the bay, is the reason for the deficit.
For the next 5 days, there is no indication of is any depressions.

A well defined trough along the west coast, with the recent depression at its "head", has resulted in some fairly good rains in nirth Konkan, and Mumbai on Thursday night/Friday (25th/26th). Along this region, Dahanu recived 65mms and Harnai 61mms, with Mumbai (colaba) getting 58mms, all as on Friday morning.

But, as I have been mentioning, the inland regions of Mah./Karnatak and M.P. are still dry.
The IMD now, as of June 24/26, has moved the nothern limit of the monsoon up the west coast into Gujarat and into interior Mah..
In the Eastern region, it is still the same, more or less. Onset regions as of the 24th june was two or more weeks behind schedule over central region, and eastern India, with little or no advance during last four weeks.

Hence, the overall rain as on 24th. June, shows a massive deficit of 54% ! Only 2 areas ( and Kashmir), in the IMD map, show a surplus, and vast regions in the central and coastal regions show scanty to below normal rains. Situation, as of the 24th, is surely not comfortable for the agriculture, hydro and overall economic scene.

A slowing down of the Westerlies into the northern Subcontinent has taken place during the last 2 days ( IMD streamline map below shows this). This should be seen as favorable,for a surge in and advance of the SW Monsoon in the next 2/3 days.

What is lacking are the usual Bay depressions. Systems from the bay are always instrumental in widespread rain into the central/western and northern regions of India. Depressions usually follow (by about one week) a western Pacific storm. This, I had mentioned, and anticipated last week itself for the typhoon "Linfa", but, there was no evidence from the storm. The bay now has to be watched again early next week in aftermath of" Nangka", now near Philippines.
Hence, the inland peninsula regions, will continue to be almost dry till first week of July. Along the west coast, the existing trough is expected to slide down , and linger off the Karnatak/Kerala coast from Monday onwards. Meaning, the rains in Konkan will reduce, to some extent, after the week- end.
Mumbai can get about 80 to 100mms on Sat/Sun. Thereafter, from Monday, it should get around 25mms/day for the next few days.

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The low pressure which established south of Gujarat, rather suddenly and unforecasted, became defined on Tuesday, and became a depression, moving northeastward into the Gujarat landmass. Some very heavy rains,between 100 to 150 mms were recorded in the southern coast of Gujarat. As of Monday night, it made landfall near Diu.
Wind shear had earliar stifled its east cloud band and whirl.

Satellite imagery shows a marked northward spread of clouds, directly a result of the depression weakening on moving on land. Anyway,it is beneficial that this weather system has pulled the Monsoon northward following almost 18-20 days of stagnancy.

And, the IMD has ,on 24th. June, advanced the monsoon into Mumbai.
Mumbai was just one day behind the all time "last date" of monsoon advance, 25th. June in 1959. The advanced area now covers south Gujarat, parts of Kutch and Madhya Mah. Inland Mah. still remains out of the monsoon reach. The monsoon progress map is available on the IMD site.
Moisture flowing from the northbound lsystem will, for about the next two days, bring precipitation, though scatterred, into Rajasthan. These are pre monsoon rains, and not rains brought by the a "Western Disturbance".

Still, I do not yet see any well formed system,such as a Bay depression moving across the heart of India to bring widespread heavy rain in the regions the monsoon is yet to cover
The Arabian Sea system may also "pull" away rain clouds from approaching the Konkan and Goa coast, at least for the next 2/3 days.
Meaning, Mumbai will get only "passing showers', and the real monsoon may not yet pick up till 27th. June in Mumbai.

And yes. The IMD updated forecast of the monsoon season , as a whole over India , shows a deficient monsoon. To the extent of 93%. But, I would wait and observe the development of the Ell-Nino, in the next 30 days. There is a 60% possibility of it gaining in the next month or so.

A low pressure area formed over east central Arabian sea on Sunday evening, and on Monday lies over east centralArabian sea.Subsequently, the cyclonic circulation over east central Arabian sea off Goa-Karnataka coasts has merged with the above system. The trough at sea level from Karantaka coast to Lakshadweep area now extendsfrom the centre of the low pressure area to Lakshadweep area.
As a result, daily clouding with thundershowers are seen and experianced in the Saurashtra regions, and some moisture incursion in interior Maharshtra also occured.

But, as on Monday, the Monsoon has moved only upto Alibag, south of Mumbai, and is just off Mumbai now.It covers southern region of Mah. south of Pune. With the existing off shore trough and the low pressure in the Arabian Sea, the monsoon can move northwards within 24 hrs.

But, as discussed in my previous blogs, it may remain weak for a few days after advancing. Again, it all depends now on the low in the Arabian Sea. If it moves away from the Indian shores, the advanced monsoon will definitely get weak. But its moving towards the coast of Gujarat, will surely give an overall boost to the monsoon current. Effective heavy rains will be from Maharashtra to M.P.
Further north movement, is still hazy and uncertain timewise.
Heat wave conditions have re-appeared in west Rajasthan and adjoining Sindh. 46c at Ganganagar was the highest day temperature on Monday.

Continuation/Development from yesterday's blog.....
1. I would give importance to the Tropical Storm "Lnfa", in the South China Sea. The pulses from this storm are likely to travel westwards, and create a low in the Bay. By estimates, and observations of previous years, a low can appear in the Bay, from a system in the South China Sea, in this case as a result of "Linfa", after 5/6 days . That is around 22/23 June. This can help the monsoon intensify in the heartland of India.
2. The off shore trough, till yesterday holding on from Karnataka to Kerala, has now intensified a bit, and extends from Konkan to Kerala. Thus, the monsoon gaining strenght along west caost in 2 days seems likely. Thick convective clouds are seen off the Karnataka coast as a result.

A low pressure appeared on the 17th. and fizzled out equally fast in the Bay. Within 24hrs, the much awaited low vanished as fast as it appeared.
But, today, the IMD has forecasted a further progress of the monsoon into north Konkan, and Mumbai by the 21/22 June.
This may be as a result of a surge, or a burst of thick clouding being forecasted to bring heavy rains, along the west coast of india. But, as per the COLA estimates, the heavy rainfall pattern is restricted to the region south of Ratnagiri (mostly to Kerala/Karnataka coast). The north Konkan- Mumbai region shows a very nominal rain of 5-10 mms in the week begining from 20th. June.
If the monsoon is advanced over the north Konkan by the 21st. it will most likely be as a weak current !
I feel, for Mumbai, it can still go beyond this date by a day . Anyway, the interiors of the states of Maharashtra ,M.P. and Gujarat will be looking out for the monsoon till the 1st. week of July.

By the way, the last date the monsoon has ever advanced over Mumbai, in its 130 years history is 25th. June. Never beyond that date.
And, the rainfall, monsoon figure, as on 17th. June shows a rain deficit of 45%, overall throughout the country.