Co Authors: GSB, Shreyas Dhavale, Pradeep John, Dr. Vineet Singh, Gokul

Tuesday, June 16, 2009

Monsoon 2009: We had earliar termed the initial early start as a "false star." Now, I think we will have to call it a " ceased start" altogether !


No positive indications seem to be be buiding up as on today.


The ECMRWF does show a low in the bay around the 19th. Subsequently, as per them, it becomes a depression crosses the Andhra coast around the 24th. If this prediction holds on, then, we can witness a revival of the monsoon all along the "subdued" regions from the 19th.


The interiors of the central and southern Peninsula will get rains and the central regions, upto M.P. and south Gujarat can get rains between the 20th. and 25th. On the formation of this predicted low, the west coast, and north Konkan, can see a progress of the monsoon, which can then reach Mumbai by the 20th.


But, before counting our "chickens before they are hatched", I will wait till the low actually forms ( looking at the current behaviour of the monsoon).


And, the negative point ! A German forecast model, COLA, the NCMRWF (Noida) and at least 1 other International Model, show no signs of any low forming in the Bay around this date !!


The above models do not show any rains progressing, that is there is no monsoon progress as per them, till the 21st.from the current position.( Mumbai and Mah./Gujarat included).

In this case, then, the current monsoon regions will continue with weak rains.


Of- course, the Arabian Sea is devoid of any system forming till the last week of June.


For the SW Monsoon, very little advance is made since the last week in May. What had been a 1/2 week early advance has now become and retreated to 1/2 weeks behind schedule.
A question on everyone's mind, WHY? why have the rains halted their advance?


As mentioned in the last blog, the warming of the ses in the central Pacific, and the trend going towards an El-Nino phase could be one resaon.

Another factor is the still continuing W.Ds. As Jim puts it "`stubbornness` of the Westerlies to yield ground over the Pakistan and north India''. For the northern subcontinent region, due to the W.D.s, dry air from the west continues (even today), and sporadic rains, specially in Sindh and Rajasthan areas, have dipped the minimum temperatures to "undesirably" low levels. ( The deep blue tongue of extreme low in the map shows the sharp dip).

And the core pressure at the centre of the monsoon low has now risen to 1000 mb.


Now what ? Wait, and observe, day by day, the developments, and non developments, and as indicated, I will blog my observation on a day to day observation basis.





Sunday, June 14, 2009

We might just retain he first para. of my last blog, and reproduce it with the dates changed. The dates menioned, could just be pushed another 3 days ahead to 18th./19th ( for Mumbai included).

Can't help it !The conditions, or lack of it, are just the same.

The weak off shore trough off the Karnataka/Kerala coast will coninue to precipitate rains along that coast line. Sporadic local thundershowers will bring heavy downpours in the interior Karnataka/A.P./Orissa regions.(Due to the increasing heat).

But for the rest of the country, north of the current monsoon line, the wait continues.

No international weather forecasting model shows the rains, or monsoon, progressing northwards before the 19th. IMD announced the monsoon to be subdued till the 18th. And NCMRWF, Noida, shows the rains creeping into north Konkan (including Mumbai) on the 19th.
Interiors of Maharashtra and Gujarat can expect the monsoon to progress not before 21st., at least.

The main factor for the further delay is the fall in the pressure gradiant. The core pressure seen in the map is now at 1002 mb. Definitely it will be at least 3/4 days, if the reverse process starts now, before it recovers back to the 994mb level.

A heat wave in northern India only can "hasten " this in todays scenario.

As, the situation requires minute observation, we shall have another review in a couple of days.

kapadias@gmail.com



Friday, June 12, 2009



And the wait continues.


No fresh sign of any developing low or systems either side of the Indian Peninsula in the next 4 days, meaning the subdued monsoon conditions are likely to continue , as on today, till the 15th./16th. at least. (Mumbai, wait at least till 15/16, Gujarat/inland Mah. till 20th.).




However, the ECMRWF forecasts the formation of a low, a monsoon forming low, in the bay around the 20th. of June.( Too lata, if true). The map from the ECMRWF site shows it. And the COLA map reveals it properly. Rain in forecasted week 12th.-19th, is along the southern coast, and in the subsequent week 20th. -28th, moving north into the central regions and the projected low forming along the east coast.

For the moment, minimal rainfall will be restricted to the coastal regions of Karnataka/Kerala for the next 2 days only. This is due to a weak off shore trough along this region.
Otherwise, very scattered localised thunderstorms will be prevailing in the interior Maharashtra/M.P. and northern peninsula regions next couple of days. This is mainly due to the local convection.

Thru my blogs, I am reviewing and observing the situation on a day to day basis. Today, with the monsoon stuck in a "half Monsoon " position, the synoptic situation can be very fragile, and could go in for a dramatic change, either way within 24/36 hrs. ( At very short notice !).

Another major, and unexpected, development is the forming of the El-Nino.
The waters of the central and eastern Pacific Ocean have started warming up. It seems to be heading towards the formation of El-Nino conditions within 2/3 months, according to some forecasts.
Now, I am far from being an expert on the El-Nino scene.. But I do believe that the sudden rise in sea-surface temperature anomaly occuring since the last March is--and will continue to cause the weather, and our monsoon, to behave differently than it normal pattern. Jim (Accuweather) feels this could be a reason for the "sputtering SW Monsoon?" Maybe. My thinking is that there may be a link too.

Tuesday, June 09, 2009

An exceptionally quiet day of weather on the Subcontinent.

What we were apprenhensive of, has actually happened !

We discussed in one of my blogs, a few days ago, about the monsoon actually "retracting" after the onset.
And , now , I feel, after seting in along the west coast upto Ratnagiri, it has almost become dormant in all of coastal Karnataka, Goa and south Konkan (the area mentioned as Monsoon Set).

Why ? Already discussed yesterday.

Whats there to look ahead now ? Without any "technical" elaborations, in brief, I would say, a continuation of the present conditions in the west coast, except Kerala, till at least the 14th.

Because, I see no system developing till the 14th. either side of the Indian Peninsula.

Quite clearly seen and justified in the COLA forecast for the next 15 days. The first 8 days are devoid of any meaningfull rains north of the Kerala coast, and inland into the interiors of central and western India. Also, forecasts of the MJO show the dry phase dominating for another week or so.

Mumbai, expect very light passing drizzles till the 14th. Infact, only a total accumalated rainfall of only 5 mms is estimated in Mumbai till the 14th. Normal for this period should be at least 55 mms. Gujarat and other regions north of Mumbai will have to wait even beyond the 15th.



Monday, June 08, 2009

After the fizzling out of the low from the bay, I obsereve something 'surprising", or rather something "unwarranted" at this stage of the advancing season !

The MSLP map and streamlines map from the IMD show a clear shifting of the yet unformed monsoon trough away from the normal east-west postion at 15N. We see a weak trough along the line south of the Himalayas, across Haryana thru the state of U.P.


The result of this is the upper air 200hpa jet streams, which should normally be east-west below the 20N line, are now in the direction mentioned below the 15N line. Pushed down for a few days by the "static" situation created.


Though this may,( and should) , change within 2 days, it is uncalled for at this stage. This development will "halt " the monsoon advance (again), and "subdue" it as per the IMD.

The advance of the monsoon along the west coast upwards from Ratnagiri will become tardy again for 2/3 days, thus lenghtening the wait for Mumbai.


Meanwhile, i would like to mention the unusually big "jerk" with which this "weak monsoon current" has moved into Goa and south Konkan. A weak current though, the monsoon movement northwards into Goa was with a whopping 43 cms of rain in Sanguem and 20 cms in Panaji, and 17 cms in Ratnagiri and 17 cms in Canacona (Goa). So, in a small stretch of about 75 kms along the west coast, massive amounts of heavy rain s have been recorded in 24hr periods.


The next day , the amounts of rain were almost negligible !


Saturday, June 06, 2009

Monsoon Watch-17


Something positive, to some extent, at last !


1. The pressure at the core of the seasonal monsoon low, which was at 996mb, as mentioned in MW-16, is now finally at the required normal 994mb. And the Arabian Sea is at 1008 mb. Enough differance to now make this sluggish monsoon edge up a bit. The IMD maps produced show a clear illustration of it all.


2. The central regions of India are also heating up to required temperatures again. Though not to any severe heat wave levels. Sindh had a high of 47c yesterday at Nawabshah. A sign of more heat coming into north-west/central India.


3. The south-west streamlines are very strong and appropriate below 15N, but still a bit weak above, that is north of Goa. Indicates a slow, but definite movement of the monsoon current north along the coast.




4. The much "dreaded" W.D. has moved away too far north to have any substantial effect on the proress of the monsoon.The 500hpa map shows this clearly.


5. After all this if we see nothing, Then all I can say is: "Its the Vagaries of The Weather" !!



Today, the feeble low in the north bay is half inland (into W.Bengal) and half over the sea (seen in the streamlines). The low, at most is an indication or "helping hand" for the monsoon to move a little northwards.

Why "little" northwards ? Because, I do not see the monsoon moving far beyond Mumbai, in the next 5 days from today.


No concrete signs of the monsoon getting a good push into Gujarat before 11th. are seen.

As mentioned before, the monsoon might still restrict itself to the coast of Maharashtra, (interior Karnataka can be covered by the monsoon due to the current low in the bay), and the interiors of Maharashtra may still have to wait till after the 12th. for a proper monsoon. This includes the Pune/Mahableshwar/Marathwada regions.


Mumbaiites, a couple of days more of sweltering heat !









Wednesday, June 03, 2009

Monsoon Watch-16
Monsoon Watch, Yes. I have been only watching the monsoon, and observeing its dormant state, and non advance !
What I feel about the state of the South West Monsoon as 3rd. of June is it seems to me that the SW monsoon commenced this year only to back off after an eventful start over Kerala. I have been mentioning a lull, but this is beyond my expectations.
Persistence influence of W.D.s, over the north of the Subcontinent is, perhaps, the reason behind the halting, or slow advance of the Monsoon for at least the last week. . Since the dissipation of Aila, my take is that rainfall within the regions where the monsoon has advanced, is been patchy and scattered.
Now, as per consistent forecasts, is shown to a northward spread of rain along the west coast as it should should be normally.
Except for the W.D.s, I fail to understand the reluctance of the rains to move north along the west coast ! The pressure gradient may not be strong enough, as the low is at 998mb., but the off shore trough along the west coast should bring rains along the west coast at least !
My forecast was for the movement of pre monsoon showers upto Mumbai by Wednessday, but I do not see any substantial cloud developments in the Arabian Sea as on today. The streamlines are ready, the Somali current is strong and the south west winds are "in form". Then why no pre monsoon movements? Your guess is as good as mine !
Only reason I see is the fall in day and night temperaures in the entire subcontinent northern and central regions since 31st. May, till date. See map and observe the "fall" in the subcontinent highs from 51c to 45c, as on today.
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The forecast of Madden-Julian Oscillation -- MJO -- looking forward 40 days shows a setting to favor the suppression of convective rain for about the next fortnight.
Now what ? Coastal rains can resume "any day" but the interiors will stay devoid of real rains till the 12th. at least . Penetration of monsoon inland into Karnataka, Maharashtra, and upto Gujarat remains elusive till the 12th. of June, at least.
ECMRWF shows no upcoming low in the bay till the 12th. June.



FINAL MONSOON REPORT 2026

X-axis represents years with monsoon rainfall, lowest of 697.4mm in 1972 (extreme left) to the highest of 1124.2 mm in 1917 (extreme right)....