Tuesday, August 31, 2010

Mumbai measured 108 mms at Colaba, and 76 mms at S'cruz in the 12 hrs ended 8.30 pm.

Season's total from 1st. June at Colaba now stands at 3004 mms, and 3075 mms at S'Cruz.
Replying to a comment received, I'll clarify that Upper Vaitarna and Bhatsa are still to overflow. As on Tuesday evening, I have got this feedback from reliable sources.
Bhatsa water has been discharged as a precautionary measure. It is still below overflow mark.

I would not go by media's blown up and "we told you first" reports !
As at 3 pm, Tuesday, rains still continue in Mumbai. Heavy showers with regular frequency have been lashing the city and suburbs throughout the day. Rainfall varying at different centres from 50-80 mms have been recorded in Mumbai from 8.30 am till 2.30 pm. Vagaries estimate of 40 mms in the day has been "tossed away" :)
nt, you are partly right i think. Partly because basically the vortex, or UAC was in the upper atmosphere. Winds do affect the ground level, but to a lesser extent. But yes, the winds, which were stormy till morning, have "sobered down" to a greater extent.

But the rain intensity is still heavy. The current pressure position is generally available only after a few hours, but presuming the trend, the vortex is expected to move away or fizzle out within 12 hrs of formation.
Latest position of vortex and 500 hpa chart seen here: http://www.wunderground.com/wundermap/

Rain intensity should decrease from late evening in Mumbai.

Mumbai this year has been battered and pounded by very heavy rains. The total rainfall is racing ahead, and could touch an all time high. Or will it ?
It would be realistic now, to change the poll, and get our reader's view on this.( poll for Mumbai Colaba).
We can conclude the result once the monsoon is over as normally the post monsoon rain in Mumbai is negligible.
Would appreciate your guess/estimate on this.

Some facts:
Rain at Colaba till 31st. Aug: 2896 mms
Normal rain for September: 259 mms
Highest ever annual total: 3482 mms (1954)
Highest ever in September: 1245 mms (1949)
Lowest ever in September: 41 mms (1896)
Shortfall for record as on today:586 mms

Unfortunately, we'll have to cut short the current poll for this. The current poll has 58% showing the possibility of a cyclone from the Bay, and 8% showing it coming from the Arabian Sea.

Meanwhile, all the lakes supplying water to the city have received heavy rain in the last 2 days. The storage of all the lakes combined now stands at 11.59 lmlitres, against a full storage required of 13.0 lmlitres.

Heavy rains have battered Mumbai last night and continuing in the day on Tuesday. With 113 mms at Colaba, as on Tuesday morning, the 3 day total from Sunday is now 170 mms. And with 98 mms at S'Cruz, the same total, for last 3 days is now at 240 mms.
The rain intensity was over the rate of 80 mms/hour at 3 am on Tuesday morning.

The reason ? The vortex mentioned yesterday has slid downwards off Mumbai. This bubbling of the voretex up and down is causing the very heavy downpours in Mumbai. Initially, if we recall, it was mentioned in the vagaries that the vortex would remain North of Mumbai. But its sliding down is the cause of moisture incursion. Not totally surprising, but un- expected, specially after 2 days of lingering off the coast, when it was time to "move on".
Normally, it would hold this position for a maximum of 12 hrs.
Still i expect the rains to taper off by evening.

Next follow up at 4 pm. Will Mumbai create a new record ? Vagaries Poll change suggested .

Monday, August 30, 2010

Rains were heavy yesterday (sunday), especially in the Konkan and ghat regions. And the corrected rainfall figures for Mah. in cms:
28 Bhira
22 Karjat, Navsari
20 Matheran
19 Thane
18 Pali, Daman
16 Roha
15 Mahabaleshwar, Bhiwandi, Umargaon
14 Santacruz
13 Kalyan, Ulhasnagar, Mulsi, Jalalpur
12 Khalapur, Mahad, Vapi
11 Talasari, Murbad, Ambarnath, Uran, Panvel, Velhe, Mahudha
10 Vasai, Mangaon, Harij, Madhuban
9 TBI, Sahapur, Vikramgad, Pen, Maval, Radhanpur

Tamini 38, Dawdi 35 , Shirgaon 32 , Dungerwadi 31 , Bhira 28, Ambone23 , Lonavala (T) 20 , Lonavala(O) ,Walvan 17 each, Khopoli 14, Shirota, Bhivpuri 11 each, Khand 10, Thakurwadi, Wangaon 8 each, Koyna(N), Koyna(P) 6 each

Gujarat heavy rainfall figures (Sunday):
Navsari 220 mms, Upleta 214 mms, Umergam 154 mms, Kutiana 150 mms, Bardoli 140 mms, Jamjodhpur 133 mms, Doraji 130 mms,s, Jalapor 127 mms.

As per the ranfall pattern, in the coastal and ghats region heavy rains were due to
the "activated" off shore trough,embedded with 2 UACs. Rainfall map of Monday shows the rainfed regions.
The incursion of strong moisture laden winds, gave rise to violent thunderstorms in the interiors of the 2 states (Mah. and Guj.).

Now, I anticipate the UAC to move west, towards the Dwarka area of Gujarat,
hence 1 more day of heavy rains of this spell for Gujarat. As the UAC
moves, it should weaken the off shore trough, or in other words "take the steam off" the trough, and bring it back to a "normal'' trough strenght.
For rest of western Mah. region, a decrease in rain from Wednesday, as the moisture level drops due to the vanishing of the UACs.

As yet, I do not foresee any bay low forming till 3rd Sept at least.Possibility on 4th. However, the monsoon axis remains in its normal position.
Due to vanishing of the off shore trough in the east, a sudden decrease in rainfall for the states of T.N./Karnatak and A.P. from Tuesday, till the 3rd.

In fact rains could be very isolated rains in these regions. Chennai can get some convective rains in the afternoon/evening on Tuesday, and clearing up next 3 days.For Bangalore, just some drizzles till 3rd.Sept.
Northern region will also have subdued rains, next 3/4 days.

Sunday/Monday has measured up 200 mms at S'Cruz and 100 mms at Colaba, including 38 mms (Colaba) and 63 mms (S'Cruz) on Monday. Vagaries had estimated average 130 mms for Sunday thru Tuesday.
Lakes supplying Mumbai too had heavy rainfall: Tulsi 21, Vihar 15, Tansa 11,Vaitarna 8, U.Vaitarna 7, Bhatsa 6

From Tuesday, Mumbai rains will decrease, and drop to 15 mms range per day from Wednesday.
Tuesday should guage up about 40 mms of rain in Mumbai,with decrease in intensity towards evening.

The Vortex position. We see the original UAC in the Gulf and an additional elongated UAC south of Gujarat peninsula, stretching upto Mumbai. Now, that's an added UAC system, a bonus to the original one.

Resulted in good rainfall in Gujarat and North coastal Mah.

Some prominent Mah. rains as on today morning:Thane received 163 mms, S'Cruz 138 mms, Karjat 158 mms and Bhira 292 mms.
Intermittent rains continue in Mumbai today.
Detailed report of Gujarat rainfall and Mah. figures will be put up at 8 pm tonite.

Sunday, August 29, 2010

Summarising 28th August rainfall:

Mostly around the active vortex (UAC), and vigorous in Gujarat.
Some of the heaviest falls in cms.in Gujarat, West Mah. region as on 29th. morning:
Belapur (Thane) 12.7, Roha, Mahabaleshwar 11.9, Sidhpur 8.2, Harnai 8.0, Alibag 7.0, Panvel, Soegaon - 11 each, Srirampur, Kalyan, Vaduj - 10 each, Mahad, Tala, Harnai, Mandangad, Ulhasnagar - 8 each, Alibag, Bhira, Mangaon, Pali, Mhasala, Lanja, Thane, Ambarnath - 7 each.

Now, the current UAC, may linger around the North Mah.coast/South Gujarat coast till Tuesday. With this, I see rainfall continuing around this areas till Tuesday. Heaviest falls will be in the core of the UAC. So, in a way, I feel some heaviest rains could be expected in the Saurashtra areas and North Mah.coasts, but north of Mumbai.
South Gujarat shoulds get heavy rains on Monday and Tuesday.Maybe some heavy rain in
Bharuch on Monday/Tuesday.

For a brief look at the MJO situation, I directly quote from the Australian Buraeu: ""The MJO has displayed generally erratic behaviour, and has had perhaps the greatest influence on weather across southern Asia. Longer term, one would expect to see redevelopment of the MJ
O in the western Indian Ocean around early to mid-September. If this scenario were to play out, we would expect the increased risk of a reinvigoration of the Indian Monsoon, and increased potential for tropical cyclone development in the region".
Monsoon is in active phase as can be seen from the Indian Monsoon Index in the chart which shows above normal activity for the next two weeks:

ECMWRF forecasts another fresh UAC forming North of Mumbai on the 1st. of September,
tracking Northwards into Saurashtra coast, and fizzling out the very next day (2nd.Sept).
IMD sees a low in the bay by the 31st. I am not too optimistic on this low, not around this d
ate at least. Maybe a bit later, after the 4th. Sept. That's my reading of events.
I trust this Map of NCEP/GFS forecast to show the accumalated rainfall till 3rd. Sept.

With steady moderate day long rains in and around Mumbai, Sunday was a rainy and grey, with about 45 mms at Colaba and S'Cruz.(till 8 pm).
The lakes guaged up good rains on Saturday night/Sunday morning.In cms. they were:
Upp. Vaitarna - 13, Vihar - 7, Tulsi - 6, Vaitarna - 4, Tansa - 1.

As the UAC "activity" area is scheduled to be North of Mumbai, I see the heaviest rainfall from it avoiding Mumbai.
Monday/Tuesday will be frequented with periods of showers, some heavy and thundery. Windy during rain showers.Around 75 mms acccumalated for the 2 days.Decreasing precipitation after Tuesday night.

There's the estimated vortex in the Northern Arabian Sea !
Though estimated a bit North of Mumbai, it is in the upper air, almost over S.Gujarat.
Possibility for the UAC to slide a bit southwards by Sunday evening, or Monday.

But the forecasts for Mumbai are holding good. Thunder Rains from Saturday night, as expected into Sunday. Will wait and see if the amount is anywhere near the figure projected by "vagaries".
Sunday is already forecasted as a rainy day, and the same for Monday.Same, no change from earlier forecast.
Rainfall, from 8.30 till noon, between 20-40 mms at various places in Mumbai.

For S.Gujarat, rain showers will continue on Sunday, with some heavier spells on Monday,north of Surat coast.

Detailed Mumbai/South Gujarat (on request) and India forecast and position of UAC, and the new low projected in the bay, will be put up here at 8 pm today.

Friday, August 27, 2010

Vortex of -40 over South Gujarat/N.Mah. coasts, and interior Mah..

The Northern suburbs of Mumbai recieved heavy thunder showers on Friday afternoon. Some of our readers have confirmed heavy afternoon rains at Chembur and Deonar. Mk informs of heavy rain from 2pm at Panvel.
The showers were patchy, but heavy in certain areas. The Southern city was dry, with no rain.
Some parts, like Dindoshi (Aarey) recieved 88 mms of rain within a two and a half hour time period, 3 pm to 5.30 pm, and 123 mms in the 12 hr period upto 9 pm.
Other areas with rain were: Chincholi 61 mms, Malad 49 mms, Deonar 40 mms, Airport 25 mms, Kandivali 22 mms.

A brief progress report on yesterday's Forecast blog:

1. The Bay low has behaved and "obeyed" the NGP forecast put up in "vagaries". It is now, today, over land in the Orissa area. At 1002 mb, i would hardly call it a system, and is as good as over and out.

2.The 850 UAC mentioned in "vagaries" yesterday, a pulse from the system, is well on its way westwards. (Thai map).

3. The Northern and Southern areas, including the Metros, are clearing, and rains have decreased.

4. The west coast off shore trough has "livened" up. (as seen in morning's satellite image).

5. Now, if our schedule is adhered to, a low, or vortex is the next "happening" off the west coast (northern areas ), maybe tomorrow.
Mumbai Lakes and Water position:

As on Wednesday, Modak Sagar, Tansa, Vihar and Tulsi lakes are full to the brim, and overflowing.
The 2 major lakes, Upper Vaitarna is 95% full, and Bhatsa is 90% full.

Against the full required storage capacity of all the lakes, which is 13.2 lmlitres, the overall storage of all the lakes combined is 11.01 lmlitres.That is 85%, storage.

Therefore calculating at the FULL supply to Mumbai, without cut, which is .035 lmlitres/day, we have today 314 days supply. That is as on today.
About 10 months, and enough to last till 25th. June.

Rainfall ( upto Thursday) at Colaba: 2681 mms (+1010)
S'Cruz: 2669 (+799).

Thursday, August 26, 2010

Rains decreasing in T.N. and North, increasing in West:

The system, low, in the bay, is now persisting in the area, off the A.P. coast, and as anticipated, is lingering in the region. Having moved a bit North, and at 100
0 mb (as per IMD) today, it should now cross the coast (on the 26th.) and move inland into Rayalseema and M.P. areas.

The monsoon axis is now forked, one branch towards the north-east, and one towards the centre of the bay low.The system will move along th
e axis corridor.

The best possible estimate of its track and strength,I feel,is shown in the NGP forecast, and will move, and fizzle out approximately as per the diagram put up.

Now onwards, I can safely visualise a decrease in rains in the drenched Northern belt, including Delhi and Haryana, already reeling under the swollen Yamuna. A major relief for the hill states of H.P.and Utteranchal which have witnessed very heavy rains and landslides last week.
As the low fizzles out, by the 28th, a decrease in precipitation may also be seen in the central regions.

And, a clearing up of the T.N. and south coastal A.P. is seen from 28th, with almost clear skies for Chennai, as the pressure at MSL increases forming a vertical velocity of +10 in the region.

Then onwards, it will be the interior Maharashtra, coastal Karnataka, Goa, Konkan and eastern areas of Gujarat which will get an increased precipitation. From Saturday, it may be possible that rains will increase in these regions, and last till Monday. This enhancement in rains will be a result of an upper air low at 850 hpa, which will travel west as a pulse and get embedded (vortex) by Sunday, in the "livened up" off shore trough.
From Saturday thru Tuesday, good rains ranging from 50-150 mms could be expected in coastal Karnataka/Goa/Konkan and south coastal Gujarat.

Early next week, from 1st to 3rd. September, I estimate light rainfall travelling the south Sindh coast, with not much threat inland.

Mumbai: Rains Coming back by Saturday/Sunday. Friday: Cloudy with heavy showers sparsed in the day, with day's rainfall around 20-25 mms. (Average rain on Wednesday was 30 mms). Same intensity on Saturday, but heavier falls on late night Saturday. As a vortex forms, an increase in rain intensity from Sunday thru Tuesday, with around 130 mms of rain accumalating on these 3 days. Monday/Tuesday, of the days will be particularly heavy, and windy. A reminder that monsoon is still very much there, and an answer to FAQs.

Wednesday, August 25, 2010

A Change in this Blog.

Heavy Rains in Nepal. Plane Crashes.(Have been mentioning Nepal consistantlyin blog).

Freak hailstorm hits northern Poland

Leh got 240mm in 24 hrs on the fateful day - GSI

Tuesday, August 24, 2010

The low in the bay finally appeared today,24th. August, and, is off the North T.N./ A.P. coast. At 1000 mb, it is persisiting, and lingering in the region since the last 24 hrs.From tomorrow, 25th.it should strenghten and move towards the A.P. coast. I estimate the system to cross the coast by the 26th, and at 998 mb pressure.
The WD25, mentioned in the "vagaries" has entered India from the west, as expected, and aligned itself with the monsoon axis. Resultantly, the Northern regions continued to
recieve heavy rains from the 23rd. and today's satellite image shows excessive clouding in
the U.P. and Bihar regions.

Today,the WD having moved away, now may not impact the direction of the bay low.The bay system should now take the axis corridor. The axis has now joined into the low as its eastern end. On crossing land, moving across A.P. and into M.P, it should precipitate rains along its path, and thru Vidharbha, and Northern Maharashtra, on 26th/27th August.

By the 27th.,it should fizzle out. BUT, a pulse emerging from the system, at 700/850 hpa,
should move ahead, and culminate into a vortex, or maybe a low, off the North Maharashtra/Gujarat coast around the 28th. Simultaneously, the off shore trough off the west coast will "liven up". Most models are in agreement.
Consequently, a much heavier rainfall regime should commence along the west co
ast. The rainfall areas will be from Karnataka coast/ Konkan and South Gujarat coast.
Some models are showing a very deep vortex, within the trough, and linked to the projected low which may form off the Gujarat/North Maharashtra coast. If it materialises, North Maharashtra coast (North of Mumbai) and Gujarat coast could recieve extremely heavy rains, upto 300/350 mms, around 28th. Saturday/ 29th. Sunday. The affected region, as of estimates now, would be North of Mumbai.Its a bit early to forecast t
oday, and we shall monitor this on daily basis.

To summarise, I would estimate precipitation as per these 2 weekly accumalated weekly rainfall maps of the next 2 weeks from NCEP/GFS. Of all the various models and estimates, I feel, these m
aps summarises the system's most probable rainfall track.


Mumbai: On reading the above, I feel, Mumbai should start with rains again f
rom Friday/Saturday
Friday: Frequent showers. Cloudy and overcast. Rainfall upto 20 mms.
*Saturday: Rainy condtions, and by evening frequency of rains increasing. Squally weather, with about 50 mms of rain, more at night.
*Sunday: Overcast. Windy and rainy. Heavy showers, with flooding. Rainfall on Sunday could be upto 100 mms.
*Saturday and Sunday forecast are subject to revision. Depends on the exact location of the Arabian Sea low, and the vortex, to be formed. As mentioned above, will be monitored daily, as important for Mumbai weather.

Sunday, August 22, 2010

91B has come and gone !
Remnants of an erstwhile low, presently at 1004 mb in the southern Bay, hangs around, embedded in an off shore trough line along the Eastern coast south of A.P. With clouding along the trough, we have seen rains in T.N. in the last couple of days.In fact very good rains all over the state have raised hopes , after a weak SWM. Almost reminding the state of the NEM.
Bangalore was drenched with good rains from Thursday/Friday. After rains on Sunday evening, the rains may decrease in the city.

I would expect this low, to deepen and sort of re-form in the same region by 22nd/23rd. But would not expect very heavy rains at this stage.

Now, almost all models indicate the low to linger in the same region, in the sea, till 26th. Around that date, it may enter inland, as a 1000 mb low.
Where ? Normally I would say the A.P.coast. But, as a W.D. (I name it 25W), is crossing the northern region, we could expect the low to be pulled away from the east coast, and move Northerly, and then maybe cross near the Orissa/Bengal coast.
T.N. rains wll decrease , and the persisting low, will result in cloudy weather, but lesser rains in the interiors of the states of T.N. and Karnataka, next 3 days. Thence, all depends on the course of the low.But, I would expect precipitation in pockets to continue in the southern peninsula throughout next week.
See a small vortex, inland forming north of Bangalore on Monday/Tuesday. Maybe some rain in Bangalore on Monday night/early Tuesday.

The same 25W is sure to inter act with the axis, by then in a firm position along the Himalayan foothills, and produce heavy rains from H.P.thru Utteranchal and west U.P. and Nepal. We can expect very heavy downpours along the hills as the axix itself is also at a pressure of 1000 mb.The western end of the axis is saddled in Balochistan, at 998 mb.and will remain firm till the TD off the Vietnam coast survives. Indicating no signs of the monsoon withdrawal from there as yet.
This coming week, more rains for Delhi area after the 25th.

The western coast off shore trough remains weak next week. Normal rains of upto 10/15 mms per day could be expected.

Mumbai: Another few days of less rain.
Monday: Partly cloudy, with sunny intervals. A couple of brief heavy showers.
Tuesday:Partly cloudy, with sunny intervals. A couple of brief heavy showers, especially in the night.
Wednesday: Cloudy with some showers. Stuffy at night.
All days rains will measure upto 10/12 mms per day.

Monday: Cloudy day, with drizzle. More Rain at night, with thunder. Rain upto 15 mms.
Tuesday: Rains in the a.m. Later cloudy and cool. Rains measuring upto 10 mms mms.
Wednesday: Cloudy with drizzle. rains will measure about 5 mms.

All India Rainfall Toppers From 1st. Jan - 21st.August 2010: (From Pradeep)

Cherrapunji (Meghalaya) - 1140 cm (Annual around 1100)
Agumbe (Karnataka) - 488 cm (Annual over 750)
Gaganbawada (Maharashtra) - 432 cm (Annual over 600)
Shirali (Karnataka) - 351 cm (Annual over 400)
Coochbehar (West Bengal) - 342 cm (Annual around 350)
Passighat (Arunachal Pradesh) - 331 cm (Annual around 450)
Mahabaleshwar (Maharashtra) - 321 cm (Annual over 600)
Silchar (Assam) - 308 cm (Annual around 350)
Honavar (Karnataka) - 307 (Annual over 350)
Ratnagiri (Maharashtra) - 307 cm (Annual around 300)
Buxa (West Bengal) - 302 cm (Annual around 550)
Piravom (Kerala) - 302 cm (Annual around ??)
North Lakhimpur (Assam) - 298 cm (Annual around 350)
Panambur (Karnataka) - 293 cm (Annual over 350)
Mangalore AP (Karnataka) - 292 cm (Annual around 400)
Bhagamandala (Karnataka) - 291 cm (Annual over 600)
Vadakara (Kerala) - 287 cm (Annual around ??)
Karwar (Karnataka) - 282 cm (Annual around 400)
Gangtok (Sikkim) - 280 cm (Annual over 350)
Panjim (Goa) - 273 cm (Annual around 300)
Jalpaiguri (West Bengal) - 268 cm (Annual around 350)
Kottigehara (Karnataka) - 263 cm (Annual around ??)
Harnai (Maharashtra) - 263 cm (Annual around 250)
Mumbai Colaba (Maharashtra) - 263 cm (Annual around 200)
Mumbai Santa Cruz (Maharashtra) - 262 cm (Annual around 250)
Peermade (Kerala) - 256 cm (Annual around 500)
Chinnakallar (Tamilnadu) - 253 cm (Annual around 500)
Kannur (Kerala) - 248cm ( Annual around ??)
Itanagar (Arunachal Pradesh) - 245 cm (Annual around 350)
Matheran (Maharashtra) - 232 cm (Annual around 550)
Kozhikode (Kerala) - 232cm ( Annual around ??)
Kochi AP (Kerala) - 229cm ( Annual around ??)
Dibrugarh (Assam) - 228 cm (Annual around 300)
Valparai (Tamilnadu) - 222 cm (Annual around 350)
Dahanu (Mah.) - 215 cm (Annual around 250)
Kottayam (Kerala) - 206cm ( Annual around ??)
Devala (Tamilnadu) - 202 cm (Annual over 400)

Saturday, August 21, 2010

Some Cool News from the Antartica:
One site in East Antarctica did set a record lowest temperature this month.
Concordia station registered -84.7 C, which is -120.5 F.

This is getting near that all-time world low of -89.2C, or -129.6 F, tallied at the Vostok Antarctic station.
At Vostok, lowest this year has been -81.8 C, or -115 F.

Both Concordia and Vostok lie on the interior ice sheet above 3,200 meters.

Across the globe, this week's hottest temperature was 49.4c at Death Valley, California.
The week's coldest temperature -76.3c, at Russia's Vostok Antarctic research station.

Giant Iceberg Breaks off Growing – Growing! - Greenland Glacier:
We've seen those articles on the internet/press shouting that an iceberg four times the size of Manhattan broke off from one of Greenland's main glaciers, the biggest such event in the Arctic in since 1962.

Many of those articles are trying to blame (so-called) global warming. But before we swallow that story, let's just be aware that Petermann Glacier has been advancing for years.The Petermann Glacier had been growing in size for seven or eight years. Nobody can claim this was caused by global warming.

The new ice island will eventually float into the Nares Strait, about 620 miles south of the North Pole between Greenland and Canada, said Muenchow. It could fuse to land, break up into smaller pieces, or slowly move south where it could block shipping,--- Remember the Titanic?

Latest Update: On the 21st, the projected low in the bay has formed...91B is created. Presently at 9.6N and 85E, at 1006 mb, it is set to deepen and grow as it is expected over sea till at least 26th....more reports later as and when.

Friday, August 20, 2010

(Sorry for the delayed Postings).
Its been a day of mixed re-actions. weather-in-Mumbai wise.
Started of with the potential of good, heavy rains, with a big cloud mass forming overnite, and threatening the city with torrential rains. The satellite images put up, in the morning were indicative enough.
Then, during the day, it was yes and no.
Yes in South and Central Mumbai. Heavy, very heavy, rains lashed Central Mumbai right thru noon to evening hours. Flooding was the scene !
Colaba saw 55 mms till evening, while it was more in Central areas.
On the other hand, for some unanswerable reason, suburbs in the North had hardly any rains ! S'cruz recorded just 9 mms in the same period ! 9 mms, when conditions were very favourable for it to pour, and with dark overcast skies all day.( Maybe wanted to hold on to "vagaries" original forecast of yesterday -:)

No. I do not understand the differentiating. In fact, Colaba has been favoured throughout this season :)
I see the rains easing out in South Mumbai,(will have to bifurcate North n South now), and surely lessening, and back to heavy shorter duration showers, with around 15 mms of rain on Saturday, and sunny intervals with 15-20 mms on Sunday.Monday forecast will be put up tomorrow night.
As long as the trough along the west coast holds on, the possibility of vortice formations are always there. The trough has now shrunk, and runs from Karnataka to South Gujarat coast.

Now, there is a distinct possibility of a low forming in the bay, by the 23rd.
Forming at 100 mb,may go deep to 998 mb, before crossing the A.P. coast around the 26th. This is as per the NGP forecast model. (Which I feel may hold good).
ECMWRF estimates no system at all for around this date!

There is a dim possibility, maybe 20% chance, for this new low to move Northwards instead, and cross straight into North Orissa coast.I say this,as the time of approaching the East coast, there is a strongish W.D. approaching, which may alter the track of the system.

Rain and track, will discuss as the low forms.

Rains have also eased off along the T.N. coast, with chances of a push again from the 24th.
By the way, Delhi recieved its heavy rains (forecasted in "vagaries"), with almost 200 mms in 2 days. Thats quite a lot, what with Parliament House roof leaking !
The axis has moved North, and estimates of very heavy rains in U.P. and Nepal holds good for the next 2/3 days.

A vortex has culminated from the UAC, inland of Mumbai, due East. Not very strong, but still pouring rains in Mumbai. Worst affected is the South/Central areas.

I expect the vortex to fizzle out very soon, say by late night.

Heavy downpours are lashing South/Central Mumbai since the late morning, more so after 1 pm. . Some areas like Worli (45 mm) and Haji Ali areas are lashed by very heavy rains. Road flooding seen at Grant Road, Race course area and some parts of Worli. Byculla and Mumbai Central areas see some flooding due to very heavy showers.
Some really very heavy rains are measured at Colaba and Girgaum areas in South Mumbai.
But areas North of Bandra, have not seen much rain, in fact very much less in comparison to the areas south of it.

Rainfall is sparse in the far flung Northern suburbs.

Next report with rain amounts and situation at 8.30 pm
In a very sudden development, an UAC formed overnite over Eastern Maharashtra, and became well marked at 500 hpa. As nt, our reader pointed out correctly, it was sudden and unexpected.

During the night, I monitored the cloud mass, and observed it moving westwards. At 9.30, saw it approaching Mumbai at "super speed". A 4.30 IST rain map s
hows its proximity to Mumbai at that hour.
Cloud tops are at -50c, and could form 2 level thunder clouds.
A sudden burst of rain became inevitable for Mumbai.

All forecasts thrown away ! No model could forecast this rain spell !

As, we do not know when an unexpected guest will leave, unlike a planned guest who tells us his programme, we do not know the duration of this spell.

Big Cloud Mass nearing Mumbai. Monitoring the Cloud for Unexpected Change in Mumbai Weather.
Could lead to Heavy Rains. (Posted @ 10 am)

Thursday, August 19, 2010

Mumbai Reaches 100" Mark:

Mumbai Colaba and S'Cruz, both have reached the 100" mark, for this year's rainfall.
Within a few hours between them , both the official IMD stations in Mumbai touched the 2500 mms ( 100" ) mark, on 18th. August.

I have no records or data to verify this, but I feel this could be the earliest date ever, for Mumbai to touch 2500 mms.

As on 19th. morning, Colaba totalled 2553 mms, and S'cruz 2582 mms.
On Wednesday, Colaba recieved 51 mms and S'Cruz 90 mms. against the "vagaries estimate of 55 mms (average).
This also means, both stations are above their individual annual quota.

Tuesday, August 17, 2010

The forecasted low in the bay, which did not form, just got converted into a "mini" off shore trough along the T.N.coast. The result was good rains from feeder Southerly winds into the trough vortex, and precipitating good rains for T.N.including Chennai getting thunder showers.
The southeast coast may see rains tapering off by Friday.

The monsoon axis is now due to shift North again. Hopefully, for the regions directly under the rainfall areas, it would stay there for a week.
Consequently, IRI has forecast extremely heavy rains for parts of West Nepal and adjoining Himalayan foothills along Uttar Pradesh.
The systems, ones active over India today are the monsoon trough and the upper air circulation over North-West Rajasthan, and the re-activated off shore trough along the West coast.

Now, rest of the week till Sunday:
North: Heavy rains in Utterakhand, U.P. and parts of Bihar. heavy falls in West Nepal.Heavy rainfall in North M.P. and Delhi regions on Friday.
South: Rains along South East coast decreasing from Thursday. Rest southern Peninsula with very meagre rains.
West: Off shore trough, though weakened, will precipitate some rainfall along the karnataka/Konkan coast. Though not heavy or prolonged.Maybe around 2
0 mms /day.
Gujarat will see scattered rains in pockets.
East: Increasing rains in the North-Eastern states due to the eastern end of the trough spreading in the region.

Meanwhile, with the strenghening of the off shore trough with the help of a vortex embedded, places around Mumbai got heavy rains. The vortex, s
een isolated over Mumbai, as the cloud tops reach -40c, resulted in thunder/lightening over Mumbai. I had put up a possibility of thunder as a vortex this deep can produce lightening,
"Vageries ' estimate (in the last write up) of a voretx was misplaced from east of Mumbai to just around Mumbai.
Recordings of heavy rain (in cms) around
Mumbai, all of it on Tuesday (17th. )morning: Santcruz 16, Dharavi 15, Uran 14. Lakes:Vihar – 5,Tulsi - 4
And rainfall on Tuesday, (morning to evening): Bandra 98 mms, Worli 90 mms,Colaba 77 mms.Got heavy rains on Tuesday with thunder/lightening.
Wednesday, will get heavy showers, with lesser duration in comparison to Tuesday's rains. The vortex is vanishing. Day time rains of around 75 mms around Mumbai on Tuesday, will drop to around 55 mms on wednesday.
Thursday, a sudden diminishing in the rains. Cloudy weather, with sunny intervals. Till Sunday, Mumbai will get little rain,or passing short duration showers, with the rain guage reading about 10 mms/day.

Sunday, August 15, 2010

The rain spell from the previous low is all but over !
However, showers/thundershowers along the monsoon axis will continue.

We will now catch up, or rather chase up the other developments estimated in "vagaries", on the 13th.

A new low in the bay on the 17th ? Well, CMC says yes, it will form and move inland from the 18th.
ECMWRF and GFS say nothing is on the horizon ! two diverse views.
So, now lets wait and watch, it's a matter of 2 days. Bay of Bengal is putting up surprises !

Then, the next was the MJO push in the Arabian Sea. Yes, that's at least on stream. It has shown good clouding, and is heading towards the kerala coast.
Of-course lots of rain on the Kerala coast, and Karnataka coast. A little bit of rain creeping in the interiors of Karnataka is possible on Monday/Tuesday.
But its for a day only. Rain patch can move up along the west coast to hit the Maharashtra coast, that is around Thursday but I see it weakening by then.
On Tuesday/Wednesday (17th/18th), a local vortex is likely to form, for a day, just around the region east of Mumbai. So, some rain inland ,in the madhya Maharashtra region.

Mumbai: Slight change in the forecast put up on 13th. Monday, passing rains, sunny with 10 mms of rain. Rain intensity will increase for a day on Tuesday/Wednesday.Thursday, a sudden drop in the frequency of showers.Warm, or should I put hot ?
Reproduced from Kaneyen's post. Very interesting, so must share.

"I attended a lecture given by one of the eminent environmental enthusiasts in Tirunelveli. He is of the view that warming in the upper atmosphere especially between 850 to 700 hPa is responsible for relatively lesser rainfall in the Wyanad, interior parts of Karnataka including Bengaluru. The usual monsoon trough or depression are NOT forming at sea level in Bay of Bengal.

Leh the elevation of which is 11500ft [approximately 3.5km]receives usually lesser rainfall. A small portion of moist warmed upper air orographic-ally rose and burst into sudden rain over a small area. The intensity of rainfall is such that it triggers immediately mud slides.
[As happened in Ketty, Nilgiri district in Tamilnadu during NEM 2009, when 82 cms fell in a day]
This can not be tied to global warming effects, but it is warming of upper air.

The volcanic eruption in Iceland during this Summer 2010 and the tectonic sub surface ocean floor was warmer due to vent in the floor and made Artic ocean warmer. This leads the ice in the Artic melt. The ocean is the culprit. Not the atmosphere".

World feeling the heat- 2010 is becoming the year of Heat waves ... part 2

In response to previous post... World Feeling the Heat

What you have reasoned for the prevailing high temperatures in Russia and northern parts of Europe [Azores High and Ridge etc] may be one of the reasons. But as pointed out by one of environmentalist, perhaps, the volcano eruption in Iceland and the subsequent ocean sub surface temperature increase in the near by sea,due to vents in the tectonic floor in Arctic ocean may be another reason for warmer Russia and Europe.
The La Nina conditions in long run will bring colder current in western Pacific too and as a result the NEM may fail. AS our Director pointed out in 1932 the same situation prevailed. The warmer western Pacific [west of 180 W /International Date Time]may cause flooding and land slide in China i.e NE parts from Pakistan to China [whenever SWM is active in Aug]

a second part to my blog posted by Kaneyen.

All IndiaTop Rainfalls, over a limit of 2200mms, from 1st. June to 15th. August 2010.
Cherrapunji: 5787 mms (435)
Agumbe: 4409 mms
Shirali: 3672 mms
Mahableshwar: 3037 mms (-1200)
Honavar: 2826 mms
Ratnagiri: 2823 mms (+698)
Mangalore: 2644 mms
Karwar: 2500 mms
Goa Pnjm: 2493 mms (+382)
Mumbai Clb: 2312 mms (+778)
Mumbai Scz: 2219 mms (+512)

Pradeep, please fill in the missing ones :)

Saturday, August 14, 2010

Views of Extreme Weather From our Partner Blog
Weather Talk
By Mark Vogan


I blame the extremes we have seen across the world as NATURAL VARIABILITY and the the stage the ocean and atmosphere's current cycle in in.... Have a warm and cold ocean at the same time and you drive weather weather... Like two widely contrasting air masses produce supercell thunderstorms and when you have a very warm, moist lower atmosphere and a very cold air mass aloft, that as well as other things provide the high octane fuel to power hurricanes.. So have a warm Atlantic and a rapidly cooling Equatorial Pacific, surely that will create feedback? Also, we just saw one of the stongest El Nino's on record right? Drought in many areas which commenced all the way back to winter, so doesn't take a rocket scientist to work out that those drought areas may in fact see a warm summer. Drought and a powerful El Nino doesn't mix well and sure enough we have seen tremendous heat in Russia, my argument is this.... is this the only time in "earth's" history that this has happened?

Indeed, my reasoning for the Pakistan and Chinese floods is simple... have that much heat to the west in the perfect place, this will have to reajust the atmosphere surrounding.. to the east and south is of course the region home to one of the greatest seasonal weather shift on earth, the monsoon, when does all the heat occur over Russia? The heart of the monsoon season, drive the atmosphere's turbo of fuel (jet stream) down over the monsoon region and bingo, you've got added fuel to an alrready charged atmosphere...

The the meantime, there are places seeing cold, in fact South America has seen one of it's coldest winter's in decades so let's not get too easily laid astray by the hype of the media. REMEMBER, OUR "REAL AND TRUE" MEASUREMENTS ONLY DATE BACK TO 1970... I believe a heck of a lot of "extreme weather" happened by that, dating way way back thousands of years. Only difference today is we're here, recording and documenting stuff that wasn't before!
Full Blog Here.
Mumbai Lake levels at 80.6%.
As on yesterday,13th.August, the lakes supplying water to Mumbai, all included, had an overall storage stock of 10.48 lmlitres, against a full storage capacity of 13.0 mllitres. That is, the overall storage is now at 80.6%.
Last year, on this date the storage was 7.30 mllitres. Working out to 56.3%.

Normally, Mumbai needs to be supplied, requires, 4300 mlitres/day. ( 0.04 mllitres, comparing with the above units). But even in normal times, the supply was restricted to 3450 mlitres (0.35 mllitres), as full supply.
The city, in the initial stages of the 2010 monsoon, in June, got 2900 mlitres (0.029 mllitres). Then it was raised to 3000 mlitres (0.03 mllitres), and yesterday, it was decided to further raise the supply to 3100 mlitres (0.031 mllitres).

Friday, August 13, 2010

Continuing from Wednesday's blog, the axis of the monsoon did slip Northwards , albiet for a few days in the initial days of this week. the result:
A weakened monsoon monsoon with -26 % rainfall during the week ending Wednesday. Now, as anticipated, with the southern peninsula and adjoining east India posting significant deficit.

As expected...the North also did get its heavy rains (read about the Delhi flooding, with Delhi Ridge recording 104 mms in 12 hrs), and Northern
Bihar recieving heavy rains yesterday. Isolated thundershowers kept the central/northern peninsula wet. Map of actual rain on 12th.

And "lo" (pun intented), the axis is dragged down again.
As if a "kill joy", a fresh low appeared, and moved inland to reach Maharashtra's eastern end within a day, by Friday.The low, even though only at 1002 mb. is aptly supported aloft by stronger lows, precipitated good rains in its Eastern Quadrant. Remember, this low has clouding in its Eastern Quadrant.
This low, weakening,is expected to move north initially, and then a short distances north-west before fizzling out. And, simultaneously, the Eastern "block" of clouds ,will move accordingly. But, the movement will be fast, judging by the current speed, by the time you have read this, it must be over Rajasthan !
Rains will be moving out from North Maharashtra into East Gujarat into South Rajasthan.

But a new low is forecast in the bay around the 17th. Like the current low, its
movement/direction seems to be identical. At least seems so from this CMC
And the MJO is pushing in a fresh burst of south-westerlies into the west coast from around the 17th. of this month. South-Westerliy winds will bring rain onto the Kerala/Karnataka coast from the 17th. onwards for a couple of days. This rain will move up northwards along the coast, not inland !

Mumbai: Sharp rain showers , between sunny intervals, remind the citizens that the monsoon is not over and done with. In line with the "vagaries" estimate,Wednesday thru Friday, Mumbai had an average of 10-15 mms/day. And as stated above, the current low might just by-pass Mumbai of the heaviest rains.I would just about the Weekend forecast to a little increase in rain, maybe to about 25 -30 mms/day. Rain spells were short during the week, may be a bit longer during the weekend. The intensity may increase Monday onwards.The thunder ? Maybe ?

 19th Night Hottest Weather in North India Persisting relentlessly.... New Delhi witnessed on 19th morning, the worst Night temperature ( mi...