Thursday, July 31, 2008

After last week's rain, the "yellow" patch over Marathwada has vanished, the" scanty" region is now in the "deficient" zone. Marathwada is still "red", but slightly better, and the konkan belt has gone in the "green" zone. Overall India deficient is still at -2%.
The system bringing this much needed relief has now moved westward, and is now as a weak system over the Arabian region. Some cloudyness and light rain could be expected on Friday in Oman, Dubai and east Arabian Peneinsula.

Now, for some unexpected change of scene. The heat wave in the Central Asian region has produced a W.D., in the upper air, and a line of wind discontinuity over Pakistan.
Map shows a weak sea level low over central India. The monsoon trough line is right thru central India, and runs from the 22N region almost horizontal (seen joining the 2 lows).

Result forecast for next 2/3 days(1st week Aug): Increased rain in the northwest and north Indian regions and rain shifting back to north Pakistan. Since the trough is at 22N, and the south west current as seen in the map is strong, "normal" rains will occur in the states of M.P.,Gujarat, Maharashtra, Karnataka, and subdued over T.N. and Kerala. Lonavala and Mahableshwar will get "normal" showers in the first week, not exceeding 20-50mms/day. Rains in India have shifted north from today (31st).

Resultantly, the bay low is again pushed off, and can form after the moving away of the W.D.

Monday, July 28, 2008

At last the parched regions of south Pakistan are scheduled to get some rain in the next two days from monday.
The "God sent"upper air circulation has moved across the border into the sindh area. Though short lived, this will surely introduce the first rains into the region (Karachi included). As the monsoon trough will now remain south at its normal position, with its western end into sindh, the south/central Pakistan areas will continue to get cloudy weather with fair showers into the first week of August.
The upper air circulation forming over M.P. on Thursday (25th), rapidly moved across westwards, and at the time of writing, on Monday evening, lies on the Gujarat/sindh border.
In India, the much needed dry regions of Gujarat, Maharashtra and north A.P. got the required relief by way of fairly good showers on the weekend. Though the interiors of Maharashtra required much more than the 20-25mms of rain it got per day on Saturday/Sunday (26th./27th.), it was a matter of the rains actually "starting" for the season in areas of marathwada and south Maharashtra.
The north Maharashtra coast recieved good rains, with Mumbai getting a drenching with about 470mms in 3 days upto Monday evening. Roha was highest with 370mms in 24hrs. ended Monday morning.
In the northern regions of the sub continent, it remained fairly devoid of rains as expected.
The suddenly formed upper air system, at 500-700hpa, may have delayed the formation of the low in the bay by a couple of days.
It can now be expected to form in the bay by the 31st. ,and move westwards into the states of central India. The system could be expected to get to some intensity, as this year, the bay has not produced a seasonal depression since the 18th. of June, and June/July are normally expected to throw up at least 2 per month.
First week of August will see the precipitation of good rains in Orissa, M.P.,Maharashtra and Gujarat.

Thursday, July 24, 2008

The western coast of India has got some revived rains today,Thursady. Mumbai had 65mm during the day, and many stations along the coast 30-50mms. The off shore trough, a result of the monsoon trough surely shifting southwards, is the cause of this revival.
Another sign of the trough going southwards is the decrease in rains in the foothills ,and a rise in temperatures in north India.(Gangapur was 42c today).
Rains in northern Pakistan too will lessen and as the trough's western end moves down, some rains may come to central regions. For the south of Pakistan, the rains will arrive with the westerly movement of the bay low, or a sudden dip in the western end of the monsoon trough.
Now, as per our last assessment, the next stage should be the immediate formation of a low in the bay. IMD has estimaed this to form by the 27th. Once this is in place, the complete central region and northern peninsula states should get good rainfall. Yesterday, a heartening feature was a solid 102mm of rain in "rain starved " Solapur.

The rain map as on 23rd.July defines the "north/south" divide mentioned earliar. The diagonal line division of the excess/normal/deficient regions is clear in the map. The overall rain in the country has now slipped into the negative, -2 %.
It is now hoped the deficient areas get some rain with the current wave of rain coming.

Monday, July 21, 2008

In my last blog, the elusive system from the bay was discussed, and I had thought, it could be expected to form in the begining of this week(monday21st.). well, it is still elusive, as on today,21st. The monsoon trough today has its western end in north Pakistan, runs along U.P., then thru west Bengal runs thru Nagaland with its its eastern end in the north-eastern states.
As a result, we have rains continuing in north Pakistan. But the rains are yet to begin in the south of Pakistan, with Karachi having got only traces of rain for the season as of today.
Rains today are good in U.P. Bengal and the north-eastern states of India.
However, the rains still play truant in the rain starved states south of M.P./Rajasthan level.
Now, for some hope of positive developments.
According to the international forecast models, A system could form in the central bay, around 15N, by this weekend, around 25th, and progress towards the Orissa/A.P. coast. It may not strenghten enough to move inland. But, I think it can bring and pull the monsoon trough southwards towards its normal position, that is across central India.
Consequently, as the low forms in the bay, by Friday,25th. we can expect increased rainfall along the west coast, specially the Karnataka/Maharashtra coast and in Mahableshwar and Lonavala.
On the trough taking its normal position, rains can resume in central India and the interior regions of Maharashtra and the southern /central peninsula from Sunday/Monday (27th./28th.).
Hence, after the 25th.,and before the month end, it is possible to see a revival of the monsoon in the effected states of Gujarat,Maharashtra, A.P., Karnataka and to some extent Kerala.
As the western end of the trough will be over south Pakistan by the 28th. of this month, sindh and Karachi can expect its first rains by then.

Wednesday, July 16, 2008

The above 2 diagrams show the severity of the rain deficiency in the interiors of Maharashtra. It will not be possible to show many cities, but the 2 which I have repeatedly mentioned are shown, that is Aurangabad and Sholapur. Aurangabad shows only 2 really "rainy" days,with another 3/4 days of very little rain (1-3mms), in the last 30 days. The other diagram of Solapur shows only 2 days of rain,that too less than 5mms, in the last 1 month. The entire Marathwada and south madhya Maharashtra are heavily deficient.
The overall map of India in this aspect will be out tomorrow, when the IMD issues the weekly report.

Kerala too is in the red. This diagram of the rain in Trivandrum depicts the large shaded area as deficient.

Meanwhile, the situation as now is a bit more positive. A trough along the Karnataka/Kerala coast has formed, and is likely to remain intact for the next few days. Thus, the regions of coastal Karnataka/Kerala is likely to get rain for a couple of days.
Some models predict a low in the bay by the 18th. As per forecasts, this system is expected to cross the heartland of India thru Orissa,M.P.,Gujarat during the ensuing two days.19th./20th. If it is strong enough, this system can move into south coastal Pakistan subsequent to crossing thru India.
On the forming of a low, it will benefit the the regions of M.P.and Gujarat along with north Maharashtra with the much needed rains (hill stations of the western ghats too can hope for a reveval with this). Can provide some relief the rain deficit areas of Maharashtra.
But, the actual low has to first form. Not all models are in uniformity with this forecast. I am not too sure of a low forming by so soon. Wind developments show, according to me, of a low at a slightly later date, maybe by next week.(around 21st./22nd.).
With this low, the monsoon trough will move southwards to its normal position, thus it can change the entire rain pattern prevailing now.

Monday, July 14, 2008

1. The monsoon trough has now "snuggled" into the Himalayan foothills. The eastern end runs thru Bangladesh into the north-east states. Ridge of high pressure seen in south-east Arabian Sea.
2. The rain will therefore be restricted to the states of Punjab, U.P.,Jharkhand,Bihar,Bengal and north-east. Flooding danger in east U.P.
3. Remaining south/central regions will be comparitively dry.
4. Deficit has spread to the west coast south of konkan,extreme deficit seen in Marathwada,adjoining A.P.,Kerala.
5. No emerging low seen in the bay till Friday,at least. Hence no change in rainfall pattern in affected areas till Friday/Saturday. Warmer conditions expected in Maharashtra/Gujarat, Karnataka and interior A.P. on Tuesday/Wednesday (15th./16th.).
6. As western end of the trough runs into northPakistan, rain to continue in northern regions of Pakistan. Central and south may remain dry thru this week.
7. Abnormally long period of break condition due to inactive bay. Resultant of dull west Pacific typhoon season and active W.D. season in the northern most regions.

Friday, July 11, 2008

Yesterday, a low coming in from the eastern M.P. region moved in fast and poured heavy rain in scattered pockets all along the regions of M.P,Gujarat and Rajasthan. Regions of normally sparce rainfall like Jaipur, Chittorgarh and Jodhpur in Rajashtan got heavy rains from 90-220 mms. It has advanced the monsoon into the remaining parts of the country and moved the monsoon into east Pakistan region. The remains of the system may give some rain now to the sindh region, including Karachi.

But, just as fast it came, the low is fizzling out in the deserts of west Rajasthan and Sindh. It has brought some relief to the regions going towards deficiency.

The rain map on 9th. July shows the area south of M.P. as deficient, with a pocket in central Maharashtra as extremely deficient, and the western states as normal. The entire northern belt is excessive in rain. The rainfall pattern is moving towards a "north-south" divide.

I quote from the latest report of the MF Global Weather Inc.
“Weather over
the next ten days to two weeks looks to be drier than
usual across much of southern and western India and that
will perpetuate the drier bias further delaying some
summer planting. Early seeded crops have likely not
established well and the next few weeks will be critical for
getting significant rain into the region to avoid noticeable
cuts in production potential”
• Further, World Weather Inc opines that “The combination
of sea surface temperature anomalies and lingering La
Nina will result in lighter than usual July rainfall in Tamil
Nadu, Andhra Pradesh, southernmost Maharashtra, Kerala
and Karnataka – basically the same southern crop areas
that were drier than usual in June will be dry again during july."

(I reproduce a section of my blog of 29th. May:"Also seeing the current situation, the fast vanishing La-nina, and the "slipping" SOI index, it may be difficult, in certain areas, for the monsoon rains to be normal this year. There may be some delay and below normal rains in June/early July. Hence the initial period of June/July will have to be watched and followed closely for regions in western and central India.)

This report needs a lot to think over and take effective remedial steps at this stage for crops, power and water planning, seciaqlly in Kerala,Maharashtra,Gujarat and Karnatak.

The situation, as per almost all weather models show no signs of any low or system forming in the next week, that is upto 18th.July. The monsoon rains in the next week will be confined to the northern/eastern states and coastal Orissa. Now, with the soil already saturated, the threat of flooding in these states will be more in July than June.

Hence, I quote from the MF report in conclusion:"
A close monitoring of weather in to south Maharashtra into
Andhra Pradesh and Karnataka over the next two weeks will
be warranted, especially since computer forecasts are still
downplaying rain potentials during the next two weeks.
• Portions of Gujarat and far western Madhya Pradesh have
had their bouts of below average rainfall, too, this summer
and they are about to enter another period without much
rain. Recent rain has improved soil moisture in these two
areas and that will help provide adequate crop development
potential until a better period of rain evolves later this month."
Thanks to Ashokbhai for sending the report.

Monday, July 07, 2008

There is nothing much to write between my last blog of 4th. and this. If one reads thru the previous blog, the situation is almost the same ,and we have to wait till around the 11th.,as discussed then, for the much elusive Bay low. The low today over the Bangladesh coast is still too weak and much of it over the land area to actually prove effective.
Yes, and the deficit is growing in all the peninsula states, Gujarat, and the central region. (Aurangabad in Marathwada has reached a deficit of 75%).
Excess rain still holds good in the line along the trough, that is, Punjab, U.P.,Delhi, Bihar and Jharkhand.
Today,heavy rains held on to the western end of the trough, with Islamabad (Pakistan) getting 270mms in the last 2 days, and Jammu recieving 99mms today. The map shows how scanty the rains have been in the rest of the sub continent today. (The map shows rain from 5.30 a.m. till 5.30 p.m. on 7th.).
Also, its time now the western end of the monsoon trough pushes its way westwards into west Rajasthan and Sindh,Pakistan, to precipitate the much needed monsoon rains there.

Friday, July 04, 2008

The Hong Kong Observatory has declared June 2008 its wettest month ever on record, with records dating back to 1884. Up to midday on Monday June 30th, the total rainfall recorded at the Hong Kong Observatory was 1,346.1mm (53 inches) breaking the previous record set in May 1889. The previous rainfall record was 1,241.1mm (49 inches).
This record was in spite of the fact that there was only 1 typhoon in June. Most of the rains was due to strong south-westerlies.
With no typhoon still in sight, a high pressure has set in over the HK area, thus a let up in rain.

But with the above scenario, the sub continent will be bereft of lows, at least for the next 8 days. Hence no organised system in sight from the bay for the next 8 days till the 11th. July.The image alongside shows the scanty rain during the day on the 4th. in the sub continent, baring the north-east.

The result, W.D.'s are forming in a row, and keeping the monsoon trough far north than its normal position. In fact, today, the IMD has stated the eastern of the trough has moved northwards from the bay position towards Shillong. The result for the next week: moderate rains for the states of U.P.,Bihar ,H.P. and north Bengal regions.And, increased rain in the north-eastern states. All these along the monsoon trough line.
Subdued rains will prevail in M.P.,Gujarat, Maharashtra,Karnatak,Kerala and most of the peninsula regions. Hence deficit regions may cover a wider area this week over last week (right).

Vinson (Business Line) has explained the revival of the MJO over the Indian Ocean,and the Indian Peninsula, from the 10th. of July. If this occurs, it could give the much needed revival to the central and southern peninsula regions. These developments have to be watched.

Wednesday, July 02, 2008

The ray of hope for Gujarat did "shine" (meaning rain). Gujarat got good amounts of rain from the upper air circulation over the north Arabian Sea yesterday, about 100-200mms /day for the two days from 30th. June. And as forecasted, the system is dying out fast, and may not last another day.
North Konkan, Mumbai, and north maharashtra too did get 2 days of good rains. It held out hopes of more rain to come in the hearts of the people of Mumbai, but , as was expected, the rains widhdrew from the evening of the 1st. itself.
Now, there is no system on the horizon in the bay or elsewhere for another 3/4 days ay least. What we should see is some subdued rain along the west coast and ghats and subdued rain in the north/nort-west regions of India till the 6th.Recent formation of an upper air W.D. over north Pakistan may also prevent an initial low in the bay from materialising.Eastern states may get some rain due to the eastern end of the monsoon trough carrying an embedded lcirculation in it.
The heating of the middle east is also slowing down after the start last week. The average highs in Arabian peninsula are around 46c today. May delay the formation of the western end of the monsoon low drifting west.
Hence, it seems, subdued rainfall till the 5th./6th. overall.

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