For Wednessday, Mumbai had frequent heavy spells, yes. But not 60 mms. Colaba and S,cruz recorded 11 mms.each. Why ? Well, the rains missed Mumbai "by a whisker", if it can be said. This rainfall map shows the actual rain during the 6 hr. period on Wednessday, from 9.00 a.m.

The rain area is just off Mumbai, in the sea. And, it seems Gujarat coast, and interior Mahatshtra got a good bout of rain instead. IMD reports 292 mms of rain in Veraval, south Gujarat during the day today. Some other interesting heavy rain figures for Wednessday morning for places around Mumbai in cms: Mahabaleshwar-41, Matheran-31, Karjat-30, Santacruz-27, Dharavi, Mahad-25 each, Poladpur, Panvel-23

Rains had totally surrounded Mumbai. And spared it for the day ?

And, the low in the bay has now slipped inland and is over Orissa now. strong westerlies are still prevelent.

On the movement of the low inland, Mumbai should also have got heavy rains, as one reader mentioned. But, good or bad, the rains just by passed the city today.

For the night, I still think, looking at the situation, Mumbai can recieve at least 35 mms , to catch up on my predicted total. :) Some heavy showers during the night can bring the required amount of rain.

For tomorrow, let us study the behaviour and weakness of the erratic low during the next 12 hrs.

Special for Mumbai :
Shall try my hand at forecasting and in a way helping citizens to cope with the rains, or rather with the weather. Not too good at it, so help me out if I go wrong.
For Wednessday: It seems the low, at 992 mb. in the bay, is quite concentrated enough to continue pulling moisture from the Arabian Sea, and bring rains to Mumbai, and almost all of Maharashtra on Wednessday. The map in the previous blog illustrates this.
I will try to estimate rains quantum, for that will give a clear picture of assumption and one can get a clearer picture.
Mumbai, city, should expect around 60 -70 mms of rain today ( between 8.30 a.m. and 8.30 p.m.). Suburbs can expect 10% more, that is around 80 mms.
Showers will be frequent, with some rather heavy spells during the day.
Water logging possible during afternoon.

Shall update at night.

The much awaited, much forecasted and much needed low in the bay has finally formed. That too a dya ahead of the predicted date.The first system to form in the bay after 'Aila", the cyclone.

Today, 14th. evening, the system was as a well marked low pressure area over coastal areas of Orissa and adjoining northwest Bay of Bengal.

Now, quite unexpectedly, I admit, strong winds from the Arabian Sea got pulled towards the system and brought moisture, and heavy rain to Mumbai, and to many a regions of interior Maharashtra. The attached streamline map shows the winds directed towards the low. Normally, these winds would start when a system, specially a depression, crosses the east coast and travels inland.

Mumbai had heavy rains on Monday (120 mm in Colaba and 150 mm at S'cruz).On Tuesday, in 9hrs ending 5.30, Colaba recieved 44 mm while S,cruz got 166 mms ! Several other stations in Maharashtra too recieved heavy rains on Monday. Dharavi recorded 350 mms, Bhira got 166 mms and Koyna recieved 220 mms. In Chattisgarh, Arang got 340 mms, Raipur had 275 mms.

Now, with the inward movement of the system all of Maharashtra, M.P. and then Gujarat can start recieveing rains. For, if the system moves north-west, the parched regions of north-west India can get the much required rainfall.

On Wednessday, I feel mumbai should get around 75 mms of rain with rain intensity increasing in the night.

Like mentioned previously, the Arabian Sea low prospects have diminished.

Its getting into the act now ! El Nino seems to be developing faster than expected.

US scientists say that the El Nino warming trend of the Pacific Ocean waters has returned, bringing with it almost certain changes in weather patterns around the world.
The El Nino climatological effect - the periodic warming of central and eastern tropical Pacific waters - occurs on average every two to five years and typically lasts about 12 months.
The US National Oceanic and Atmospheric Administration said the current El Nino was likely to develop further during the next several months, with additional strengthening possible and is expected to last through early 2010.

For us, in the sub continent, it is a certain El-Nino when the SOI, ( a difference in the pressures at Tahiti and Darwin) is -10. The latest figure has reched to -5.

The reason I am stressing on this now, is because, since the last 30 days, I see no proper system coming/developing for the Indian Sub Continent ( in the Bay, specially), in spite of several reputed forecasting agencies prophecising the same.

Today, 11th July, and yesterday, Rajasthan and parts of Punjab saw some rain. But, this was due to the interaction of the mentioned Easterlies with the Upper Air Circulation, now over M.P./Rajasthan. What I mean is , to get real Monsoon rains, meaningfull rains, we need a full scale system like a depression, at least. Till then how can such a big rain deficit (of the north/central/west) be wiped out ?

As of now, I do see any such system coming "in-situ" in the Bay till the 15th. The attached 825 hPa map shows the "UAC" in the west, another weak "UAC" over Bengal in the east, and the axis of the monsoon "line " joining the two. Rains are today seen along this axis line. With the fizzling out of the western UAC, I see the axis line shifting nortwards again. And diminishing the rains over the northern/central regions.
And the Arabian Sea low, seems to be a difficult proposition now. And if at all, it will too away to have any effect on India.

Mumbaites, my 4/5 days rain estimate will be over by Sunday evening. Expect less rains for next 4 days ( maybe 15-20 mms /day). And for Maharashtra, the winds rushing towards the Eastern Low, brought some rains (see map) last 2 days. Maybe lessening of precipitation next few days.
Gujarat, a day more of some rain, till the western low fizzles out. Maybe scanty rains next few days.

A fresh review, in a couple of days, may pop up some sudden surprises, hopefully.

Actual: 151.0 mm, Normal: 234.7 mm and Departure: -36%.
This is the position of the monsoon deficiency as on 8th. July. Much is being talked about the poor rainfall, and the scanty conditions Surely is a cause for concern.

The map shows the all India position. Broadly speaking, the south is now normal, and the rest of the country, west, east, north and central still" below." The overall Negative has come down, from the last figure in my blog of last week, from -56% to -36%.

Now, continuing from the last blog, the sequence of events seems to be taking shape.
I reproduce a paragraph from my prevoius blog, just to continue from there-:" But for north Konkan, and Mumbai,the inflow of substantial moisture bearing rain clouds could start "rushing into" the coastal regions from Wednessday evening itself. Heavy rains could once again start in from Wednesday /Thursday , and could, as a result of the system moving westwards,continue for the next 4/5 days.." Holds true today also. The land based low has moved west from Jharkhand, and the rains in the mentioned regions have commenced. The IMD streamline map (of 10th.) shows the monsoon trough also sliding south. The trough is now the "line" joining the 3 lows from Sindh to south rajasthan to West Bengal. And aptly demonstrated by the easterlies above the trough.
Now as discussed, these easterlies must bring in the moisture to the northern belt. But, only after the 2nd. projected low forms in the bay around the 12th. Now, 2 lows are awaited. 1 in the bay, and 1 in the northern Arabian Sea. Both predicted to appear around the 12th. On this happening, the full course of the rain path mentioned my blog dated 7th. could materialise.
Only one important change has occured (not occured). The Arabian Sea low may not become into a deprssion and head towards Oman as mentioned and projected.

(I am sorry to make frequent referances to my blog of 7th. But, this write up is almost like a continuation).

So, let us hope, and pray, that these 2 weather systems do form, and bring the much required rains in central/northern/western regions of the country.

In the absence of rains in the initial week of July, the temperatures in Gujarat, Rajasthan, Punjab,Delhi and Sindh regions shot up to markedly above normal figures. Ahmadabad had an all time high for July, recording 42.8c on the 4th. The days were at 43-44c in Rajasthan, and the night temperature in Bikaner was 33c. Also, 49c at Sibbi, was the highest across the border yesteday.
Due to this heatwave, isolated pockets in Gujarat recieved extremely heavy convective rains in the week. Unofficial reports from Bharuch mention of 82 mms of rain in 55 minutes on the 2nd, with a wind speed of 120 Kmph ! Baroda got 110 mms in 1 hr. 30 mins with strong gusty winds.

kapadias@gmail.com

A land-based low-pressure area has formed over Jharkhand and neighbourhood on Monday.

This is now forecasted by a few international models to precipitate monsoon rains, initially,over central India during the rest of the week.
Model forecasts also estimate that this land based ‘low’ will take a westward course to move into central India, giving the much required rains in Chhattisgarh, north coastal Andhra Pradesh, Vidarbha, Marathwada and madhya Maharashtra.

Consequently, northwest India could also get get some rains as the westerlies along the monsoon trough interact with the easterly flows associated with the land-based ‘low’.
During this week, the system would attract moisture-laden southwesterlies winds, with rain clouds, from the Arabian Sea and is likely to commence a rain spell over western Maharashtra, north Konkan including Mumbai and south Gujarat.
But for north Konkan, and Mumbai,the inflow of substantial moisture bearing rain clouds could start "rushing into" the coastal regions from Wednessday evening itself. Heavy rains could once again start in from Wednesday /Thursday , and could, as a result of the system moving westwards,continue for the next 4/5 days..

Now, this land-based system, will be be chased by a second low from the bay, off the Orissa coast by Monday (13th. July). If true, this can make sure of that the wet spell started by the first low, continues for a further 6-7 days, in central India, as this would bring in substantial moisture from the bay. This, low, is forecasted by the IMD, and the European Centre for Medium-Range Weather.
The movement, and direction of the bay low is not forecasted or indicated by the models.
The ECMRWF also forecasts the formation of a low in the Arabian Sea by the 11th. But, this is estimated to move westwards, and "hit" the Oman coast around the 14th. as a depression.

Now, this day to day, step by step, activity and precipitation, is on the estimated and forecasted basis. I have seen, things go awry several times in the last 1 month.

Like, we have been waiting for forecasted lows from the bay for the last 21 days now. And, one suddenly shows up, un-announced. on land !

Estimates have either been delayed, by a few days, or a week, many a times this year, and I do not want to stick to fix days and dates this time. Not pessimistic, but realistic !.

Maharashtra Special:
Due to the expected formation of a "vortex" of low pressure over the North Konkan Coast by Saturday evening, heavy rains can be expected in Mumbai, and Konkan from Saturday thru Sunday and Monday. On Saturday, Mumbai could recieve about 75mm of rain, 120mm on Sunday/Monday. Some stations in Konkan can get upto 200 mms per day.
Mahableshwar can also see the commencement of "real" heavy rains from Sunday thru Thursday, at least.
The rain are likely to move eastwards towards interior Maharashtra from Monday. Yet another low pressure circulation is forecasted in the Vidharbha/Madhya Maharashtra region from Tuesday. Hence, very good rains are expected in Maharashtra from Monday/Tuesday.
Madhya Maharashtra regions may recieve 50-60mms of rain per day from Monday for a couple of days.( Mahableshwar may get upto 400 mms in these 2 days).