Wednesday, April 24, 2019

Posted Friday 26th Morning>>>

BB-2 is a well marked Low Pressure. Core wind speed estimated at 35 kmph.

Likely with favorable conditions to deepen into a Depression and possible (2) tracks shown.

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Chances of CYCLONE FANI  FORMing IN Southern BAY OF BENGAL

Today, a cyclogenisis initial  stage is seen as cyclonic circulation over extreme Southeast Bay of Bengal and adjoining Equatorial Indian Ocean.
A Low is likely to form in the Southern Bay South East of Sri Lanka, around 5N and 90E,  by 25th April. 
That is BB-2 ...Models are indicating that the system would be initially moving in northwest direction. It is likely to get more marked during the next 24 hours from 25th and would be inducing a low pressure area by April 25. 
BB-2 is to intensify into a Depression and track North West. Favourable atmospheric conditions would be further enhancing the strength of the depression.
1. Sea Surface Temperatures: Currently in favourable SST at 30c, but can go into cooler waters after 15N.
2. Vertical wind shear helping the system initially.
3. MJO (Madden–Julian oscillation): It is another key factor as movement of MJO through Indian Ocean at this time would lead to enhanced conditions for sustenance and rapid deepening of BB-2
This may turn into a deep depression and finally into a tropical storm in the subsequent three days i.e. April 29.
Season’s first cyclonic storm  is most likely to be formed and be active.
When BB-2 strengthens into a cyclonic storm, it would be named as ‘Fani’ 

Though it is early to talk about the track of the likely storm, but we can see that there is no consensus among the numerical weather models. Two possible tracks as per Vagaries. System fizzles out at the end of the track...Due to STR resistance

Tuesday, April 23, 2019


Posted Tuesday 23rd April....

A gradual rise in day temperatures from Thursday will be seen in Mumbai. Interior North Konkan already seeing 40c+ from today!

Temperatures will rise in Madhya MH, Marathwada and Vidarbha region of Maharashtra.





Mumbai: At Mumbai Scruz, a gradual rise will see the mercury rising (from the present 34c) to 37-38c by Friday, 36c on Thursday 25th and 38c on Friday 26th and Saturday. During the peak heat on Friday/Saturday, Colaba can touch 36c.

Nights will also rise to warmer temperatures in Scruz to around 26c.

A change of winds to N/NE, and expecting a delay in the sea breeze will shoot the mercury up to these levels.


Eastern Mumbai suburbs from Powai-Vikhroli will cross 40c+ mark temp and Outer townships like Navi Mumbai, Panvel, Thane, Badlapur and Kalyan-Dombivli will experience heat wave with daily 40c+ will continue till Sunday. Friday/Saturday may witness hottest day of season with temp may shoot up to 43c mark.



Pune & Nashik: Warming up from Tuesday may see daily 40c+ temp till Sunday, with the Friday/Saturday/Sunday mercury rising to 41c and possibly chances reaching till 42c in same period.


Aurangabad: Warming up from Tuesday may see daily 40c+ temp till Sunday, with the Saturday/Sunday mercury rising to 42c and possibly chances reaching till 43c in same period.


Nagpur: Warming up from Tuesday may see daily 42c+ temp till Sunday, with the Saturday/Sunday mercury rising to 44c and possibly chances reaching till 45c in same period.



For those wanting to escape this heat...Hill Stations like Lonavala (38-39c) and Mahableshwar (36-37c) will be hot this weekend. 


Heat likely to subside after Monday 29th.

Wednesday, April 17, 2019

Wednesday, April 17, 2019


Monsoon Watch - 2...2019 ....17th April
Further Analysis of the parameters as discussed in MW-1... 

Position as on 17th April :
1.Cross Equatorial Winds:
Let me explain, that the winds on crossing the equator break into 2 branches. i) gushing into the Arabian Sea, and ii) moving into the Bay of Bengal. 
Normal April Winds



Current Winds



During Monsoon Watch 1 , the cross equatorial flow was not at all organised.
+i) The cross equatorial wind flow, has yet to organise  up in the Western sector Southern Hemisphere. Winds, have not yet in the required SE direction off the East African Coast. Winds from South East direction as required, are just below the Trough along the 7S line. Above 7S, the winds are Westerlies. The Northwards movement of the ITCZ will surely hasten and strengthen the winds.

ii) In the eastern sector, in the Bay Branch, the Cross equatorial winds are not organised Westwards towards the Sumatra Coast.  "Low" at  5S  below the Equator between 80E and 90E are keeping the cross flow winds dis organised. The winds hitting Sumatra coast are not Westerly (as required), and also need to gather strength soon.

And that is exactly where the start should be for the SWM to arrive at the Andamans. 

We prefer the Bay Branch to be better organised, as the SW Monsoon is normally expected there in less than a month.

Mascarene high pressure zones in the South Indian Ocean. Main High reading now 1027 mb and another two at 1022 mb has been observed between Madagascar and Australia.


The "Power House" of the Monsoon winds is slightly behind schedule, for this time of the season. But it is expected to strengthen fast with no tropical storms around.Hence would hasten the Cross Equatorial Wind flow.
Indicator : -ve

2. Seasonal Low: 
 Heat wave is currently observed in the Central Regions of Sub Continent. By Heat waves, we mean temperatures over 5-7c above normal..not the normal heat.



2019: The core low formation region(Thar desert/Sindh) has heated up normally this summer . The highest in the region of Thar /Sindh has been around 46c, and Central India (M.P.)  just about touched 45.5c . 
Nights are cooler than last few years, and 30c minimum is no where near yet.
See the 14 days Max temperature anomaly 


In 2017Barmer had approached 46 c and recorded min temp above 30 c. April heat records had tumbled at many locations in the subcontinent. On 19th April 2017, first ever 50 c temperature in April in Asia has been recorded at Larkana (Sindh).
Temperatures of more than 45 c had already been recorded in many states of India . Even at Srinagar (Kashmir),Shimla (Himachal) temperatures  approached around 29 c in April 2017 . Delhi AP was 44.9 c on 20th April 2017.

In 2017,  Most of India was in the 4-7c above normal range and pockets shooting to 15 c above normal ...

Earlier than normal,the night temperatures had also crossed the 30c mark ! Barmer in Rajasthan recorded 30.4c as minimum on 15th April ,Kurnool (Andhra) saw a low of 31 c on 19th morning and Jhansi (UP) saw a low of 31.6 c on 21st morning.
Jaipur,Kota,Bundi,Alwar,Bikaner,Churu,Pilani (Rajasthan), Cuddapah(Andhra) saw lows of/above 30 c on 21st April 2017 morning.

Comparison with previous years shows the difference this year. In 2010, the first 45c touched on 10th. April, and on the same day Nagpur was 44c, Delhi 42.8c. Soon on 15 th April 2010,  Nawabshah (Pakistan) soared to 47c, Simla to 28.2c on 16th, Ganganagar, Akola and Hissar to to 46c. 

But, in 2011, 2012, 2013 and 2014, till date, temperatures were  yet to reach 45c anywhere in the Sub-Continent . 

2015...Into the 3rd. week of April , we had seen 48c in Pakistan on 19th April in Larkana,and 46.5c in Moen Jo Daro. In India had just topped 44.6c in Barmer on 19th April.

2016....touched 46c in Bankura on 16th April...and was constantly hot in Eastern region with almost daily ,a place touching 46c.. Bhubaneshwar and Titlagarh in India and Dadu in Pakistan had touched 46c. Several large regions in Vidharbh, Telengana and MP were in the 44/43c range.

The seasonal Low, as a result of nominal heating, is shaping up "casually". It has shown slow progress after MW 1 when it was 1008 mb.
Strengthening of the seasonal low over NW India is not seen , and a weak Core formation at 1008 mb is seen ...general area covered is 1010 mb.


2018: The lowest pressure, in the core (Thar Desert) region was at 1006 mb.( 2017 was  998/1000 mb). (In 2011/2014 was 1006 mb, 2010/2012 was at 1002 mb this time. 2015/2016 it was at 1000-1002 mb). 
IMD Chart:


As mentioned, it normally should reach a low nadir of 994 mb in June in the Thar Desert, and with 1008mb in the South Arabian Sea, a perfect gradient is created to attract the south -west winds towards the coast.

Thunderstorm activity in Southern Tibet is seen to be picking up. 


The trough/wind discontinuity from south Madhya Maharashtra to Comorin area across interior Karnataka & interior Tamilnadu at 0.9 km above mean sea level persists. 
The Line of Wind Discontinuity should normally stabilise around Central India perpendicular down into the Southern Peninsula by mid April. 

This enhances the speed of the Seasonal Low formation. Normally is required to start taking shape for the monsoon by the second week of April.


Current Pre Monsoon Thunder Showers



Pre –monsoon thunderstorm activity was seen in Interior Mah, Int  Karnataka and Kerala. Some activity seen in patches along Coastal A.P. and Odisha…..after  MW 1 release.

In reality, this LWD ( full formed) remains till June, in variable phases, and finally merges with the Monsoon trough (axis)/ITCZ  when the ICTZ moves towards the Sub Continent.
Indicator: -ve

3. ENSO

Although sea surface temperatures in the tropical Pacific Ocean are still close to El Niño thresholds, the atmosphere is yet to show a consistent El Niño–like response. The Southern Oscillation Index, which typically drops when an El Niño pressure pattern develops across the equatorial Pacific, remains neutral and trade winds are currently close to normal strength near the equator.
A weak El Niño is likely to continue through the Northern Hemisphere summer 2019 (65% chance) and possibly fall (50-55% chance).

SOI rises Sharply from = -13.5 in February to -6.8 in March.
The SOI for the 30 days ending 14 April was −2.0, so rising ! 
( SOI of -7 to 7 is neutral. Above 7 is La Nina, and below -7 is El Nino ).

The Oceanic Nino Index (ONI) is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO.
 ONI latest is 0.8... ( ONI of -0.5 to 0.5 is neutral. Above 0.5 is El Nino, and below -0.5 is La Nina).
Indicator: heading towards El Nino.


4. The Bay has yet to host a pre monsoon low during  April. 
As discussed, we should normally see a low sometime after the 15th of April. The high pressure region in the Bay, at sea level, no longer prevails. 

A strong MJO would hasten the favourable formations and lows, with enhanced precipitation. A slight strengthening of te MJO is seen in the next 6-10 days...hopeful of a low after 8/10 days in the Bay. 


Another factor, which helps the winds gain strength, and bring more moisture into the Indian landmass, is the sea temperatures on both sides of the Peninsula. Optimum (warm) temperatures will hasten and create more clouds, and help in faster forming of the lows from the Bay. Currently , the sea temperatures on both sides of the Peninsula are normal/below normal.





We prefer the Bay parameters to show progress faster , as the SW Monsoon is expected there in less than a month…
Indicator: -ve

5. To bring the existing SE winds above the equator (as SW), the ITCZ should move northwards. Around 1st. of May, this should cross the equator. The ITCZ should now come back to its Northward position, as the effective "Lows" created by the Rossby Wave are reducing. 
ITCZ is just south of the equator (1 s).
Indicator: Normal

So, overall, we can summarise as:
Parameter:    1) -ve   2) -ve  3) El Nino  4) -ve   5) Normal.

Summary : Three parameters is -ve as of today . Parameters have not improved compared to MW 1 .
We will put up the estimated date of arrival for Andamans and Kerala in the MW-3.

But, situations can change fast, and by the time we discuss the next MW, some factors can suddenly become +ve or -ve. So, MW discusses and follows the developments as they emerge, and discuss the parameters as is where is. 

No model can commit  today when the Monsoon can arrive. 
Quantum of rain forecasting in April for June right through September is an impossible task. Things get clearer by last week of April. Vagaries' (in MW) normally remains true to estimates around early May. 

Next MW up on 1st May with Dates of Monsoon Arrival.

Monday, April 15, 2019

Sunday, April 14, 2019

Posted Sunday 14th Afternoon:

Western disturbance A-1 is approaching the sub Continent. It has the distinct Upper Level Trough dropping down south into the Arabian Sea. As a result, we may get rains from the system in Rajasthan, Southern Gujarat and North Konkan and Interior Maharashtra on Monday/Tuesday.

Mumbai: Sunday will be warm and hot, with high humidity levels. 
Monday will see a partly cloudy morning with thundery developments in the East skies. Light rains likely in parts of Mumbai on Monday.
Warm and high humidity in the day will bring the Real  Feel Effect to around 37/38c.

Pune will get evening Thunder showers on Sunday and Monday. Will be accompanied with squall and hail.Days will be hot around 38/39c, but Night time temperatures will show a variation by dropping to around 18/19c.
Expecting rain and thunder showers in Marathwada (Aurangabad) and Madhya Maharashtra.
Mahableshwar: Thundershowers on Monday and Tuesday. During the showers, the mercury will drop to 17/18c.

Surat : Hot Sunday will be cooled by a thunder shower on Monday. Will bring down the temperatures during rains.

Karachi: As the system A-1 moves it will bring rains and thunder showers to Karachi on Monday. Some parts, locally will get medium heavy rains. Will bring down the day temperatures.
Expect rains in coastal Sindh and SE Sindh regions.

High temperatures over Sindh, Western India, NW India will ease for a few days next week.

Monday, April 08, 2019


Monsoon Watch - 1... 2019...8th April 2019


These reports are my personal views, study and observations. Estimates and forecasts are also my own calculations and views, and may/may not tally with any other estimates. This may not be used for commercial purposes. The author is not responsible for any commercial loss from this article, or this series of articles.


The Monsoon developments, as they unfold, will be analysed and discussed and explained in Vagaries. 


The South West Monsoon is just about 35 days away from its normal date of arrival from the shores of India ! Yes ! its just 35 days from the First touch of shores...Southern most point of India on the South Andaman Islands, Indira Point, where the normal arrival date is 15th May.

And its about time we start the follow up of its progress and monitor its developments. 

The Sub-Continent is eagerly awaiting its share of 2019 monsoon rains !


This annual series is a follow up and chasing of the South-West Monsoon.


 Every article in this series explains the synoptic situation as it actually is, and based on the day's position, the date and quantum of rains as on THIS SITUATION.


It is very important to firstly estimate the date of arrival of the South West Monsoon, as year to year, variations in dates of onset of the monsoon can occur and there have been several occasions in the past when the monsoon arrived over certain parts of the country about a fortnight earlier or later than the normal dates. The SWM has the  weatherman tearing at his hair for the exact date or time, extent and progress. This is never 100 per cent sure though various weather models are used to calculate this event.


Initially, in the first few parts, of this series will be chasing and closely following up the actual developments of the monsoon parameters, and analysing its progress regionally for calculating and estimating the arrival date. 

We are not yet contemplating the quantum of rains or the monsoon strength as yet. 

There are 2 parts to this article:

A)-This is the Ideal Conditions  During SWM Onset in Early June. 
and 
B)below indicates the actual situation of the parameters situation today (9th April).

A)

Very very briefly, let  us first understand, that the "power house" of our SWM is actually based far away in the southern Hemisphere. The main "generating factory" is the Mascarene Highs, between SE of the Madagascar coast and Australia. The SWM is born down South, 4000 kms from the Indian Mainland !
The proper formation of these "High" regions,(1032/1034 mb at least) will boost and create proper South East winds to lash the East African Coast near the Equator, and then turn perpendicular to South West in the Northern Hemisphere. 
And the formation of the "Tibetan High" is another factor. An anti-cyclone in the upper atmosphere over the Tibetan Plateau. During the formation stages, there will be thunderstorm activity in the SE parts of Tibet during the months of April and May.

To generate a powerful SW wind, the cross equatorial flow must be strong and gusty. SW winds (ultimately upto 600 mb levels) then are capable of riding on the warmer Arabian Sea waters (Arabian Sea Branch of SWM) and bring cloud masses towards the West Coast of India. In the Bay, similar SW winds are generated (Bay branch of SWM), but from SE winds below the equator, just below Sri Lanka.


And to attract the SW winds, again, we need a good proper "seasonal low" to develop in the Sub-Continent. This seasonal low, normally should start forming around Barmer, Rajasthan, by mid April, and at its peak stretch upto Arabia. Seasonal low at its peak, in early June, should normally be around 994 mb, and the ridge around Kerala should be 1008/1010 mb. This enables a good gradient to pull the SWM Northwards along the coast and inland.


B)-In this initial stage, we will observe the basic root and foundation, the initial 4 parameters only, and the initial seed of the monsoon. From these parameters, later a few more develop.

1. Cross Equatorial Winds from Southern Hemisphere.
2. Seasonal Low over India/Pakistan.
3. ENSO Status.
4. Pre Monsoon Low in the Bay.

Position today:

1. Cross Equatorial Winds:
The Mascarene Highs are the main "Power House" of the South -West Monsoons. This generates the South -East winds, which after gaining strength, cross the equator and become south west. For a proper High to form in the South Indian Ocean, the cyclone season (Low pressures) should completely die down from that region.

As on date today, the Mascarene Highs is yet to form in the required region.



But things are unorganised  below the Equator.( Wind Chart Below)

Cross Equatorial Winds should start forming, and taking shape from mid -April, especially in the South Indian ocean region. 
Initial forming of SE winds off the East African Coast has not started from below the equator. Weak SW flow below Sri Lanka (in the Southern Hemisphere) can be see, though a bit dis-organised. High pressure in the Arabian Sea has reversed the flow in the Sea.


ITCZ:This Seasonal trough passes from the South  Arabian Sea to Andaman sea after the withdrawal of SWM in Oct. Shifts further south in Dec. Moves North during SWM

Now near the equator.

Today, the winds  North of the Equator revolve round a High in the Arabian Sea (normal).

As the Monsoon strikes the Andaman Sea by mid May, developing wind currents ( Westerly) are required to be observed initially near the Eastern side of the Southern Indian Ocean, and this is weakly forming as of today, Southerly flows are striking Sumatra. Winds are from the East in the Southern Andaman Sea.
Indicator: Normal

2. Seasonal Low: Now, this year, the heating in the sub continent has started from March end , with  Heat Waves in Gujarat, Central India and parts of NW India.. The above normal heating in many parts continues in April.  

On an average, March has registered normal temperature (average day and night) in North, and above normal in Central ad South.
The above normal heating in many parts continues in April. The first 45c 0f the Sub Continent was at Nawabshah on 3rd April.  





Below normal rainfall...17.2 mms received against the normal required of 27.1 mms (-36%)..

These are a points in the formation, or a quicker formation of one of the important pre monsoon weather requirement, the seasonal low.(RAINFALL MAP)

In June,the seasonal low, which stretches to Arabia from India, normally starts forming in the Barmer and adjoining regions in the second week of April. 

Today, the MSL is around 1008 mb in the North Rajasthan/Sindh region. There is a isobar of 1008/1010 mb covering almost the entire Indian region. In the "core seed" area, it 1008 mb. (The ultimate low in the core, in June when ready, should be 994mb.). This progress is bit tardy.

The current Line of Wind Discontinuity should stabilise around Central India perpendicular down into the Southern Peninsula. This enhances the speed of the Seasonal Low formation. Normally is required to start taking shape for the monsoon by the second week of April. 
Indicator: +ve

3. ENSO is on way to a El Nino Stage. 

El Niño conditions are present.*
Equatorial sea surface temperatures (SSTs) are above average across most of
the Pacific Ocean.
The pattern of anomalous convection and winds are consistent with El Niño.
During the last four weeks, above-average
SSTs have persisted across most of the
equatorial Pacific Ocean.
Weak El Nino conditions are likely to continue through the Northern
Hemisphere spring 2019 (~80% chance) and summer (~60% chance).

SOI is rising, and is now at - 6.8 ...Now "coming into the Neutral range"..
30 days ago It was -13.5. 
Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña. Values between +7 and −7 generally indicate neutral conditions.

The Oceanic Nino Index (ONI) is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO. The last 3 overlapping seasons show towards establishment of a neutral event. ONI latest is 0.8... Just marginal, could get higher in the coming months...But at this stage, it cannot be surely mentioned, that an El Nino stage could fully develop by June, the onset time of our South West Monsoon.( 0.5 - -0.5 is neutral. Above 0.5 is El Nino, and below -0.5 is La Nina).


Indicator: Heading towards EL Nino.


4. Another pre monsoon seasonal normal requirement is the creation of a low in the Bay by the second week of April. This is necessary to trigger off the flow and formation of lows from the bay.

Progress this year is bad, as the Bay shows no signs today. No forecast of any low as of now. (in 2009,a low formed by the 12th. of April, and later it intensified into cyclone "Bijli", 2010 had no low till 3rd week of april).
Today, we have East winds. The required SW winds may not yet form at least for the next 3/4 days, as a High is likely to form later this week off Odisha Coast.

Indicator: -ve


Summary for arrival Date: Parameter 1). Normal.  Parameter 2). +ve,  Parameter 3). Towards El Nino, Parameter 4). -ve.

Summary: Tilted towards the normal, as of 10th April. Parameters analysed as of now show normal progress for Monsoon Advance on time.


New Readers, please note, These initial Parameters are normally (every year) considered in MW Series to gauge and estimate the arrival date of SWM, not strength. Time of arrival normally indicated in MW-3, and strength after 27th April. There are more parameters are to be considered, as and when they are developed and to be taken into consideration.

MW-2 on 22nd.April.

http://rajesh26.blogspot.in/2012/03/importance-of-monsoon-forecast-for.html....March 19th 2012

http://devconsultancygroup.blogspot.in/2012/04/normal-monsoon-forecast-indian-ocean.html

Posted Friday 26th Morning>>> BB-2 is a well marked Low Pressure. Core wind speed estimated at 35 kmph. Likely with favorable...