Mumbai, Konkan Faces Deluge On September 24, 2016

SEPTEMBER 15, 2016, THURSDAY 

Coastal Maharashtra and the city of Mumbai are in for extremely heavy rains around September 24, 2016. Some forecast models suggest about 25 inches of rain in these places by the end of the month. 

The rest of Maharashtra, south Gujarat, some districts of Saurashtra and north, central Gujarat may also receive 2-5 inches of rain at that time.

This is going to happen because a Bay of Bengal cyclonic circulation will clamber over peninsular India, emerge near the Konkan coast in the Arabian Sea around September 24 and intensify into a well marked low pressure area.

Where will the low pressure system go after that? Hard to say now. Some forecast models say it will weaken and move into northern Maharashtra-western Madhya Pradesh. But this is not certain.

It might well decide to take a stroll in the Arabian Sea.

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"Latest GFS forecast says the Arabian Sea low pressure system will hit northern Oman on September 29, 2016 with heavy rains."

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Things are going to happen in the coming days in the Indian west coast. Mumbai. Prepare for floods. The GFS model says heavy showers in Konkan, Mumbai will start much before September 24. In the next few days. Heavy rains are expected in Maharashtra on September 17-18.

Very heavy rains are possible in Mumbai in next 72 hours. This will be just a precursor to the expected deluge on September 24.

Forecast models are predicting a sudden explosion of monsoon activity with two strong low pressure systems developing, one each in the Arabian Sea and Bay of Bengal around September 24, 2016. That day seems to be D-Day. Deluge day.

Situation presently is fluid. So it is hard to say where the rain systems will go. One thing is certain. Some places in South/West Asia are in for a lot of rains in the coming days.

Arabian Sea Depression May Hit Oman With Rains On September 25, 2016

SEPTEMBER 10, 2016, SATURDAY 

Forecast models are hinting at the formation of an Arabian Sea low pressure area/depression in the coming days. The American GFS model expects it to form off the Mumbai-Konkan coast on September 19, 2016.

This system may intensify into a deep depression as it nudges the Saurashtra coast and head straight west towards northern Oman, reaching it on around September 24, 2016. 

The GFS only says it will be a depression. But there are still 10-15 days to go and a tropical cyclone cannot be ruled out. 

Other forecast models confirm a low pressure area on Maharashtra on September 19. But they do not attest to the GFS prediction of an Arabian Sea storm. We have to wait a few days for the confirmation. This system will come over from the Bay of Bengal. This is the same cyclonic circulation which is dancing around the eastern coast of India. This is expected to intensify into a low pressure area and move to Maharashtra on September 19-20 via Andhra Pradesh and Telangana.

Meanwhile a depression will move through Vietnam, Laos, northern Thailand and reach southern Myanmar on September 16. But it may fizzle out after that.

The reasons for the disappointing South Asia monsoon this year are 3-fold. 

>The Indian Ocean Dipole, IOD, is negative. 

>La Niña still continues with her nakhras and refuses to come. Conditions are ENSO neutral.

>The storm maker Madden Julian Oscillation, MJO, had gone for a walk in the Pacific Ocean, so central Pacific Ocean is throwing numerous hurricanes. Though chances are a weak MJO may arrive in the Indian Ocean soon. But this is not confirmed. (See MJO diagram below).

UPDATE, SEPTEMBER 11, 2016

The GFS in its later forecasts now rules out an Arabian Sea depression. But there is a good chance of very heavy precipitation in Konkan, Goa and Mumbai around September 25, 2016. We are talking of 10-20 inches of rain in 2-3 days.

Something is going to happen in the Arabian Sea in the coming days. When forecast models give highly erratic predictions for an area, it rings an alarm bell somewhere.

The different phases of MJO. When it is phase 2,3 the North Indian Ocean throws out tropical cyclones.

Monsoon To Intensify From June 18, 2016

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JUNE 13, 2016

Monsoon has been quite dormant after the push into Kerala, Karnataka and parts of Andhra Pradesh a few days back. Nothing dramatic is expected in the next 2-3 days except that it may move into Goa and some parts of North East India. Even the Goa part seems doubtful at present.

The Center of attraction is the Indian north east. Assam, Meghalaya, Arunachal Pradesh, Tripura, Mizoram, Manipur and Nagaland. It is going to rain cats and dogs here for at least the next three days. I guess it is monsoon entering in the area.

But from June 18, things are going to change elsewhere too. It will because of two circulations. One off Goa in the Arabian Sea. The second in the Bay of Bengal at the Andhra Pradesh coast.

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The monsoon will get very vigorous over Goa and northern Karnataka from June 18-19. Very heavy precipitation is expected in these regions. The rains will then move into the rest of Andhra Pradesh, Telangana and parts of Maharashtra.

After that it is possible the monsoon may enter Mumbai, touch Gujarat and Madhya Pradesh.

There is a strong possibility of a low pressure area developing near the Goa coast on June 18-19. This system will have a lot of rain to throw. But present indications are that instead of moving north to Mumbai it will wander off in the sea. Where it goes is to be seen. Gujarat? Pakistan? Or head west towards Oman?

Rainfall activity to be vigorous over Karnataka, Goa coast in coming days

Image credit: Political Indian 

JUNE 4, 2016

The progress of the monsoon in 2016 will be undramatic this year. No drenching depression or tropical cyclone that will propel it into India. Just slow incremental progress. A tortoise not a hare.

Update, June 6: NOAA says MJO, Madden Julian Oscillation, will become active in Indian Ocean from June 8, hence monsoon will become vigorous soon. It also says possibility of a tropical cyclone in South China Sea is receding. 

Numerical weather prediction, NWP, models have been giving out erratic, inconsistent predictions. Just yesterday the European model hinted at a depression or a tropical cyclone in the Bay of Bengal. In today's data, there is none.

After analysing data from various models we have some insight into what is going to happen on the monsoon front in the coming days.

Rainfall activity after a few days will fizzle out on the eastern coast states like Andhra Pradesh and Odisha. Though the northeastern states will remain wet. Monsoon should enter there in a few days.

Though some models see a different future for Andhra Pradesh. According to them rainfall will remain over the state till June 10 when a low pressure area may form off the coast. The system will move through the Bay of Bengal and drench northern Myanmar/Chittagong area after a couple of days.

But this scenario is not supported by the multi-model ensemble forecast. The rainfall forecast map valid till June 9 shows significant precipitation only in Karnataka, Kerala and Indian north eastern states.

The focus of attention will be the Arabian Sea coast of India. Karnataka is going to be pounded by rains for days. Coastal Karnataka and Goa will see increasing rainfall activity. This will slowly spread to Konkan and then Mumbai.

Monsoon may knock on its door on June 13-14 along with rest of Maharashtra. Gujarat on June 18-20.

Looking at rainfall forecast maps issued by NOAA's model we can say that by June 20, the rainy season will have started in Bihar, Jharkhand, Chattisgarh, Maharashtra and Gujarat. We are talking here of the northern limit of monsoon's progress.

Rain-Maker Depression To Deluge Andhra, Maharashtra, Mumbai By September 20, 2015

We had predicted a low pressure/depression in the Bay of Bengal and Arabian Sea almost a week ago. The system will form on September 14, 2015 near the Andhra coast.

The Bay of Bengal is already showing increased storm activity in preparation of the birth of the rain maker weather system.

The low pressure area will form off the eastern coast of India near Andhra Pradesh and hover around for the next two days till September 18 bringing heavy rainfall in Andhra Pradesh.

It will then cross the coast and move through Andhra, Telangana, Northern Karnataka, Maharashtra onto Mumbai.

Very heavy rains are expected in Mumbai on September 20.

The low pressure area will then intensify again in the warm waters of the Arabian Sea into a depression/deep depression (Forecasts rule out a tropical cyclone presently, but 10 days is a long long time in weather forecasting. Anything can happen).

The depression is expected to move along the Saurashtra coast into the open sea and reach the coast of central Oman on September 23, 2015. Though the European model believes it will move into Gujarat on September 20. We have to wait awhile before the picture becomes clearer.

In a nutshell the low pressure area is going to bring very heavy rains to Andhra to Mumbai from September 14.

 A SECOND DEPRESSION IN THE BAY OF BENGAL?

A forecast model predicts a depression moving into Odisha on September 21, 2015, but this is yet to be confirmed by other models. It appears that the present low pressure area in the South China Sea is going to do a lot of travelling over Vietnam, Thailand and Myanmar and then hop over into the Bay of Bengal on September 19. This will then gain strength and become a deep depression and hit Odisha as we have said earlier. Chances are this predicted system has the makings of another tropical cyclone. As there are  10 more days to go and forecasts have the habit of changing in these many days.

The European Model predicts this low in the South China Sea will hit Odisha on September 21, 2015

Cyclone CHAPALA to from off Konkan coast on September 20, 2015?

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The depression as seen on September 21, 2015, moving away from the Indian coast off Mumbai.