Friday, May 05, 2017

Monsoon Watch – 3 (part 1)...2017 .....4th May
Further Analysis of the parameters as discussed in MW-1,MW-2.
Position as on 4th May :

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. 
wind flow on 4th May 2017

i) In the Western sector Southern Hemisphere, winds are just picking up speed and hitting the East African coast, but no proper re-curving is seen. To get a defined Somali Current, we need a proper re-curving Northwards/North-East of the winds, on the Kenyan coast. The current SST off the Somali Coast is 26 c (above normal),while the required SST in first week of June is 19/20c. (Required to form masses of Monsoon clouds in the warm central Arabian Sea).

ii) In the eastern sector, in the Bay Branch, the cross equatorial winds are currently haphazard and disorganised. In the Bay along India coast , the winds turn Southerly, due to a weak High Pressure in the Bay.
The winds hitting Sumatra coast are not Westerly (as required), and also need to gather strength soon.
We prefer the Bay Branch to be better organised, as the normal date for SWM to hit the South Andaman Sea is 15th May.

Mascarene high
 pressure zone in the South Indian Ocean.
Main High reading of 1025 mb and other highs of 1021/1022 mb are currently observed between Madagascar and Australia.

The "Power House" of the Monsoon winds is lower in strength (should be 1032 mb), for this time of the season.


 2. Seasonal Low: 

The NW plains heating picked up initially, and laxed again, as WDs started streaming in.
After the early summer onslaught, the heat decreased considerably over the North and west subcontinent between MW-2 and MW-3 period.

Over Northwest India, the max and min temps fell by 5 -10 c from the levels seen during MW-2 (averaging max 46 c / min 30 c ).
After recording first ever 50 c temp in April(19th) in Asia, Larkana (Sindh) is currently hovering at 41.5 c.

Past 7 days anomaly -
North ,west ,central India was in the normal range.

                    Min temp was in the normal range.

The seasonal Low, as a result has weakened considerably. Had shown good progress during MW 2 when it was 998/1000 mb.

The pressure in the core region (Thar Desert / Sindh) is just touching 1006 mb. (In 2014 was 1004 mb, 2015 was 1000/1002 mb , 2016 it was at 1002 mb during this time). 

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

 After a lull, the core low formation region (Thar desert) has started to heat up again. Barmer recorded 42.8 c on 3rd May 2017.Delhi AP recorded 41.1 c.

The highest max temperature (45.2 c) over the subcontinent on 3rd May 2017 was recorded at Banda (UP) and the highest min temperature (30.6 c) on 4th May 2017 was recorded at Barmer (Raj).
After a lull, the minimum temperatures have also increased over the subcontinent and have just started touching the 30 c mark .

3. ENSO: This year also, like last year, we also base our observations on the Multivariate ENSO Index (MEI).  An attempt is made to monitor ENSO by basing the Multivariate ENSO Index (MEI) on the six main observed variables over the tropical Pacific. 

These six variables are: sea-level pressure (P), zonal (U) and meridional (V) components of the surface wind, sea surface temperature (S), surface air temperature (A), and total cloudiness fraction of the sky (C). (Negative values of the MEI represent the cold ENSO phase, a.k.a.La Niña, while positive MEI values represent the warm ENSO phase (El Niño).The MEI is computed separately for each of twelve sliding bi-monthly seasons (Dec/Jan, Jan/Feb,..., Nov/Dec). 

Negative values of the MEI represent the cold ENSO phase, a.k.a.La Niña, while positive MEI values represent the warm ENSO phase (El Niño).

The updated (Feb-Mar) MEI is at -0.08 (in Jan-Feb was -0.056), for a slightly decreased ranking.

30 day SOI has fallen further after MW2 and is now at  -5.8.
90 day value is -0.3 ( sustained 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 has increased marginally after MW2 and latest value is 0.1 .
( ONI of -0.5 to 0.5 is neutral. Above 0.5 is El Nino, and below -0.5 is La Nina).

Indicator: ENSO Neutral (should be watched for El Nino development in August/September).

4. The Bay had hosted a pre-monsoon low during mid April. 
As discussed, we should normally see a low sometime after the 15th of April.
But there has been no development after that. As on today, this region still maintains a luke warm response to the formation of a quick low. The pressure is anything but low, and currently a weak high is observed. 

What is needed now is a pulse from the Far East. But,currently there is no storm or low pressure in the Philippines’ Seas.

A strong MJO would hasten the favourable formations and lows, with enhanced precipitation.
The propagation of the MJO to the Indian ocean is uncertain over the next two weeks.

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 only sort of +ve sign is the above normal temps (30 c) of the seas surrounding the peninsula. But sea temps (29 c) near the South Andaman Sea have fallen below normal currently.

We prefer the Bay parameters to show fast progress, as the normal date for SWM to hit the South Andaman Sea is 15th May.
 Sea Temp Anomaly

Indicator: -ve

5. ITCZ / LWD :
To bring the existing SE winds above the equator (as SW) , the ITCZ should move northwards. Currently it is near the equator. During late April , it oscillated between equator to 5N.
A LWD in the central peninsula region "looks after" the moisture content in the interior areas, and prepares the atmosphere with the humidity required. In reality, this LWD remains till June, in variable phases, and finally merges with the Monsoon trough (axis)/ITCZ  when the ITCZ moves towards the Sub Continent.

Currently, the line of wind dis-continuity is located as a trough, through the peninsula, from Madhya Maharashtra towards Kerala. It is giving adequate precipitation in the peninsular regions. Outbreaks of pre- monsoon thunder showers which are expected normally in the southern states and South Maharashtra, are taking place.

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

Indicator: Normal

6.Jet Streams :
The 200 hpa Jet streams over the subcontinent is the additional parameter to be watched from MW-3 .
The jet streams are to be followed as the westerly jet core shifts to the north and easterly jet stream is formed, over the course of late summer, progressively from south to north of the subcontinent , heralding the progress of south-west monsoon over the subcontinent.

Currently are weak south-easterly, south of 8 N latitude.
They are required to strengthen to easterlies at those latitudes in the coming days, for heralding the SWM to the South Andaman Sea.

During late April, westerly jet core was located between Lat. 21°N & Lat. 26°N with the wind speed varying from 65 - 100 kts around 200 hPa. The highest wind speed of 100 kts was recorded over Lucknow at 292 hPa on 26th April. 

The westerly jet core shifts north of the Himalayas during the southwest monsoon season, as the jet streams turn easterly over the subcontinent.

Indicator: Normal

So, overall, we can summarize as:
MW-3 (1)
1) Cross Eq.Winds
2) Seasonal Low
4) Bay Low
6) Jet Streams
Slightly -ve

*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 are.
Monsoon Watch should not be used/depended upon commercially or otherwise. Monsoon Watch Series may differ from other models.)

Looking at the current parameters, there seems slight delay in the South West Monsoon arrival dates for Andaman and Kerala as of now. 

But would like to wait for another 4 days to see any changes in parameters, so MW-3 Part 2 will be published then (Brief write up with estimated dates of SWM arrival).

The quantum of rainfall expected will be analysed in the subsequent MW-4, which will be ready for publication on 16th May.

Special Thanks to Vagarian Rohit Aroskar for his contribution to this article.


Conceptual Persistence said...

Can you let us know what is the source of the data for wind flows ?

Hrishikesh said...

Any change in mumbai weather?

Rajesh said...

Wind flow map is from Yo Surfer

Comment from Nilay: Thanks Rajesh sir for keeping update on factors and Rohit for his contribution thereon. Lets hope negativity is outcasted by positivity soon

Vijith Menon said...

Rajesh sir - is the threat of el nino real enough to affect the monsoon - Australian Bureau shows 50% chance of el Nino.

Is the IOD likely to be positive as forecasted and expected to negate the El Nino effect on the Indian monsoon.

Appreciate your view ob above.


sset said...

Mumbai/MAHA rains are well known over the world! Financial capital (Mumbai) with 1000mm in 24hrs is known for its torrential downpours - all eyes over the sky praying hard for rains to stop. Today Navi Mumbai is dense cloudy - rains around the corner?

Karan Kumbhar said...

Observed something very similar to mammatus type of clouds in Pune today !!

NilaY Wankawala said...


By News Nation Bureau  |  Updated On : May 08, 2017 03:00 PM

New Delhi :  

Amid the Arctic sea losing glaciers at a rapid pace due to global warming, a new study has warned that it will be free of ice 2040, 20 years before the previous estimate of 2070. Over the past three decades, the Arctic sea is dangerously melting away, which is resulting in the falling of the ice by more than half, a new research has said.

The study has been carried out by the Arctic Monitoring and Assessment Programme that comprises more than 90 scientists. It has been found that the projections for the melting of the Arctic sea have been “underestimated”.

The report found that for the past 50 years, the region had been warming twice as fast as the rest of the world. Also, a significant fall in the snow cover in the Arctic regions has been witnessed, according to the report.

Scientists have said that the only thing that could help ease the predicted impacts of climate change on the Arctic sea and the rest of the world is the efforts to cut greenhouse gas emissions. They also said that the point of no return for the ice in Arctic sea has passed.
Droughts, floods and heat waves are some of the incidents caused by the melting away of the glaciers in the Arctic sea.

The ocean currents and the winds which affect the monsoon across the world are affected by the warming in the Arctic. This further affects the food production and cropping patterns. This also results in the rise in sea level, which affects the coastal cities.

According to scientists, in order to reduce global warming, the production of carbon dioxide must also be reduced as it heats up the environment.

Meanwhile, according to NASA, between 1976 and 1996, the sea ice loss in the Arctic sea was on average 8,300 square miles per year, as compared to 19,500 square miles per year between 1996 and 2013. These figures clearly show that it had more than doubled in that period.

$500 billion plan to make more ice in the Arctic sea

A massive scheme to add more ice to the Arctic has been proposed by a planetary scientist at Arizona State University. He says this may help in slowing down the rising global temperature. But the proposed cost will cost taxpayers $500 billion over 10 years.

Author Sid Perkins in an article published in May 2017 edition of Science News Magazine has explained that the logic behind ASU professor Steven Desch’s plan to save the world.

Desch said that the thicker ice in the Arctic would trap more heat and this can help in cutting down the global temperature.

Explaining Desch’s theory, Perkins wrote, “Ice is a good insulator, says Steven Desch, a planetary scientist at Arizona State University in Tempe. That’s why moons such as Jupiter’s Europa and Saturn’s Enceladus, among others, may be able to maintain liquid oceans beneath their thick icy surfaces. On Earth, sea ice is much thinner, but the physics is the same. Ice grows on the bottom surface of floating floes. As the water freezes, it releases heat that must make its way up through the ice before escaping into the air. The thicker the ice, the more heat gets trapped, which slows down ice formation. That’s bad news for the Arctic, where ice helps keep the planet cool but global warming is causing ice to melt faster than it can be replaced.”

How humans can make the ice thicker in the Arctic?

“Suck up near-freezing water from under the ice and pump it directly onto the ice’s surface during the long polar winter,” Perkins wrote, citing Desch. “There, the water would freeze more quickly than underneath the ice, where it usually forms.”

According to Desch’s estimates, the machines would work like windmills and would cost about $50,000 each. Perkins notes, “Over a decade, covering 10 percent of the Arctic Ocean with buoys would cost about $50 billion per year.”

First Published: Monday, May 08, 2017 01:44 PM

Vijayanand said...


NilaY Wankawala said...

Credit Australian government Bureau of meteorology

Latest ENSO Wrap-Up issued 9 May 2017

The latest ENSO Wrap-Up and Climate Model Summary are now available on the Bureau's website.

Models reduce likelihood of El Niño for 2017 but tropical Pacific Ocean warmer than average

The tropical Pacific is currently El Niño-Southern Oscillation (ENSO) neutral. Despite the likelihood for El Niño easing in some models, an event in 2017 cannot be ruled out. The Bureau's ENSO Outlook remains at El Niño WATCH, meaning there is around a 50% chance that El Niño may develop in the coming months.

Sea surface temperatures in the tropical Pacific Ocean have warmed since the start of the year, but remain below El Niño thresholds. Some atmospheric indicators have shifted over the past fortnight, but also remain below El Niño levels.

Some international climate models have reduced the likelihood of El Niño this year. However, five of eight models still indicate the tropical Pacific Ocean may exceed El Niño thresholds during the second half of 2017. It should be noted that models have lower accuracy forecasting El Niño through the autumn months.

El Niño is often, but not always, associated with a drier than average winter-spring over eastern Australia. Of the 27 El Niño events since 1900, 18 have resulted in at least some areas of significantly dry conditions for Australia.

The Indian Ocean Dipole (IOD) remains neutral. Four out of six climate models suggest a positive IOD is likely to develop during winter. Generally, when a positive IOD coincides with El Niño, the pattern of below average rainfall extends further west than it typically would under El Niño alone. 

Next update expected on 23 May 2017

sset said...

Vijay it is not question of MAHA vs KAR it is question regarding respect for environment (like local lakes conservation, tree plantations, no dependency on cauvery, protecting farmers against droughts..) which KAR Govt lacks more corrupt (even though I am from KAR). MAHA has taken lots of steps to improve this area. Few people/groups from KAR are fighting for this but without govt support this will not succeed. I only hope rains will be better for entire south this year.

Rajesh said...

Nilay: Nice article shared by you

NilaY Wankawala said...

Thanks Rajesh sir. Whenever i come across such things the first thing that strucks my mind while reading the matter or article is vagaries of weather.

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