Monday, May 27, 2013

Monsoon LIKELY TO BE STALLED after entering Kerala

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

METD WEATHER's Indian Monsoon Forecast ( IndiMO) is already out! Check the monsoon forecast for your region here  (PUBLIC VERSION)

The monsoon has already arrived in Andaman and Nicobar Is and may be at the doorstep of India but the wait should be more as was expected and mentioned in the forecast.

As per the latest guidance from 00z, 28th May 2013 GFS, a low pressure system is mingling offshore Yemen-Oman as can be seen from this IMD IR imagery


One can clearly see the system just touching Yemen-Oman in the Arabian Sea region which is still having intense convection as being suggested by the two dense reflectivity (compact white regions)... If one believes the track of this system, the system will have a very strange and mingling motion in the Arabian Sea as it will move now south then again intensify head ENE then again WNW as a low pressure system prominently.. Convergence is doubtful with it as the GFS precipitation forecast does show many rain bands around the system and hence not consolidating as a Tropical Depression/Cyclone in the coming days. 

The forecast says that the system will move towards Oman ( Muscat ) as an insignificant system around 3/4th June 2013 and will likely bring rains there. We will update that on our facebook page as it comes in the Short range forecast panel. Some light clouds will continue in Muscat occasionally due to the system apart from rainfall in the shore of Oman-Yemen ( facing Arabian Sea)

However, this system will cause a big problem as feared! Lets have a look at the 850mb map showing the moisture. 



The top-most image is of the the present conditions ( 00z,28th May 2013) where this system can be noticed as anti-clockwise circulation region offshore Yemen-Oman. We can clearly see that the moisture at that level is being spread over Arabian Sea into West of India ( As the Somali Current has intensified allowing this to happen). However when one looks at the bottom image of the forecasted conditions on 2/3rd June 2013, one can clearly see the system gaining size ( hence strength) and pulling moisture in it. As a result, the amount of moisture in the Arabian Sea will decrease and subsequently the monsoon advance will get stalled for India ( Excluding the Bay Bengal branch)

In fact, NE India will see the monsoon advancing on time and hence eastern NE India states like Mizoram etc will witness the onset ON TIME AS MENTIONED BY METD WEATHER i.e around 1-3rd June 2013

The SW monsoon also will hit Kerala, some parts of Tamil Nadu that tenure itself but then as the system dominates, the advance is likely going to be affected.. We will wait for more details to come but the chance of happening this looks high as of now.

The monsoon will revive after a 5-6 day gap and hence advance into Karnataka-Andhra Pradesh by 10th June 2013 ( As per METD WEATHER's forecast).

II Bay System

Rains are being reported in Orissa and subsequent East India as a low pressure system continues to churn in the Bay of Bengal sending pulses towards India. Heavy rainfall ( accumulation over 100mm) is likely in Odisha in the next 48hrs ( prominently between Bhuvaneshwar-Kolkata geographical wise). That system will then move North and bring heavy rains in Western West Bengal,Jharkhand and southern Bihar by 1st June or so. 

People of Odisha and West Bengal coast must be attentive due to this system's movement and the rainfall due to it. 


Sunday, May 26, 2013

IMPORTANT- METD WEATHER'S MONSOON FORECAST HAS BEEN USED WITHOUT PERMISSION





MONDAY, 27TH MAY 2013
0100HRS, IST 
NAGPUR

METD WEATHER'S INDIAN MONSOON FORECAST ( INDIMO)  USED BY A FEW WITHOUT PERMISSION 

Shortly after the Indian Monsoon Forecast ( IndiMO) was issued on the blog and facebook,a facebook page called "Moods of Monsoon" copied the same image of METD WEATHER AND DELETED OUR COPYRIGHT MARK. THEY ALSO ADDED THEIR OWN COPYRIGHT as (c) moods of monsoon to that image and shared on their facebook page. 

Upon being noticed, METD WEATHER immediately took an action by informing the readers on our facebook page and by asking them to write absurd comments on that page forcing them to take down that image or shut that page permanently. The page "Moods of Monsoon" wrote a very strange reply justifying that someone had hacked their page and did this act of imposing a copyright of their own brand on METD WEATHER's background image. 

Here is what Moods of Monsoon had done.I personally obtained this image from that page. PLEASE NOTE THAT THE FORECAST BELOW STANDS CANCELLED AND HENCE THERE IS NO POINT IN COPYING THIS IMAGE FURTHER . 


One can clearly see the (c) moods of monsoon sign on the top right. The background image is of METD WEATHER which I can confirm from the name of METD WEATHER written at the top i.e *Based on METD WEATHER's monsoon onset norms*... How can moods of monsoon use METD WEATHER norms????

The reason of hacking isn't acceptable as the page barely had 7-8 likes and no one will hack that page. Upon being forced to delete the page, shortly after this incident, readers of METD WEATHER confirmed that the page WAS DELETED

As a result of this malpractices, we have revised out forecast.. plus the new images have bigger and more copyright marks which won't allow others to steal them. 

ITS VERY DISAPPOINTING AND ANNOYING TO NOTE SUCH INCIDENCES. PEOPLE OF INDIA ARE SPOILING THE NAME OF OUR OWN COUNTRY BY DOING SUCH MALPRACTICES ESPECIALLY THE ACT OF :MOODS OF MONSOON:

HENCE I WISH TO BRING IT TO YOUR NOTICE THAT METD WEATHER HAS FULL RIGHTS OF THE IMAGES, TEXT. ANY USE OF IT WITHOUT PERMISSION OR CITATION WILL BE A MALPRACTICE AND METD WEATHER WON'T TAKE THE RESPONSIBILITY OF IT. 

IF YOU COME ACROSS MORE OF SUCH MORPHED METD WEATHER FORECAST MAPS, PLEASE REPORT BY SENDING A MESSAGE TO YOUR FACEBOOK. YOUR IDENTITY WON'T BE DISCLOSED AND WE WILL TAKE AN ACTION ON THE PAGE RESPONSIBLE

AKSHAY DEORAS
METD WEATHER






2013 INDIAN MONSOON FORECAST ( PUBLIC VERSION)



Dear Readers, 

Greetings! 

As a part of the annual forecast of the Indian Monsoon (IndiMO) since 2010, METD WEATHER brings the 2013 Indian Monsoon Forecast ( IndiMO ). The Summer Monsoon forecast is prepared using multiple parameters which include the Indian Ocean Dipole ( IOD), Madden Julian Oscillation (MJO),El Nino Southern Oscillation (ENSO) and their inter relation. Its widely observed that the Indian Summer Monsoon is largely affected by the atmospheric patterns such as the Madden Julian Oscillation which is directly linked to the El Nino Southern Oscillation. The Indian Ocean Dipole also plays some role in the strength of the monsoon current and subsequently affects the quantum of the monsoon rainfall. We will be using the IOD-MJO inter-relation parameter which was derived in 2012 Indian Monsoon Forecast (IndiMO 1) this year. 

To give a better idea about the monsoon, a portion from the 2011,2012 IndiMO Part 1 is being added. To help more in understanding, the forecast will be issued in two versions which includes a technical version and a public version. Public version is all about the conclusions explained in simple words for the readers. 

METD WEATHER has all the rights reserved for this forecast and the matter is (C) 2013 METD WEATHER. 

Apologies for the delay!

A.Deoras







REGION WISE FORECAST


1) SOUTHERN INDIA 
The IOD which is expected to be more towards weakly negative will lead to dry phase development which may reduce the rainfall amount in this area. However, due to favoured conditions, monsoon will follow the dates. The rainfall amounts shall increase from July. 
Region will witness " DEFICIENT" Rainfall with around 85% NORMAL RAIN.

2) Western India
The same conditions shall apply for Western India also as if the MJO activity remains less, monsoon winds shall be weak in this region.Also the arabian sea low pressure system will shape up which will cause the monsoon to be slightly delayed here leading to a less June month rainfall (as compared against the normal). However, it has been observed that the monsoon current as well as the quantum intensifies in later July/August which ultimately balances the deficit. 
The region will witness "SLIGHTLY DEFICIENT" rainfall around 85% of normal rainfall.

3) Northern India
The region can expect good rainfall unlike the other areas. The primary reason seems to be the wind patterns expected. The region will receive some rains from the Disturbances which may have a southernly dip than normal. This factor was observed in April month also when greater than normal thunderstorm activity was reported across North-East India as the trough dug more southward and brought rains. 
Aperiodic rainfall shall be there with 85% NORMAL and 15% DEFICIENT CONDITIONS

4) North East India
NE India will witness EXCESS Monsoon with the primary reason expected to be the less effective Bay of Bengal current.
Expected 100-105% OF THE NORMAL RAINS 
5) East India
Region shall witness NORMAL TO SLIGHTLY EXCESS MONSOON CONDITION. 
Expected 95% NORMAL
6) Central India
If one assumes the weak monsoon current due to negative IOD and dry MJO, Central India will have a less than normal rains but the rainfall due to low pressure systems will balance the deficit hence the resultant will be NORMAL RAINFALL 
rainfall will be 90% NORMAL and 10% DEFICIENT. 

7) Andaman and Nicobar Is. 
Normal rainfall is expected in this region around 95% of the normal rainfall. 
8) Lakshadweep and surrounding
Considering the expected strength of Monsoon current and Ekman Drift this region will witness deficient rainfall 

80% NORMAL

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MONSOON ONSET DATES (as per METD WEATHER'S NORMS)

-***  NICOBAR ISLANDS  AND ANDAMAN ISLANDS ( INCLUDING LITTLE NICOBAR,GREAT NICOBAR,KATCHAL,NANCOWRY ISLANDS AND VICINITY) - MONSOON HAS SET
** PRE MONSOON RAINS WILL INITIATE ACROSS SRI LANKA, SOUTHERN,WESTERN KERALA,TAMIL NADU AROUND THIS MONTH END
*** MONSOON WILL REACH SRI LANKA AROUND 1-2ND JUNE 2013
*** MONSOON WILL REACH SOUTHERN INDIA LIKE KERALA, TAMIL NADU AND SOUTHERN MIZORAM AROUND 1-3RD JUNE 2013 
*** LAKSHADWEEP BY 6-7TH JUNE 2013
*** MONSOON WILL COVER NORTH EAST INDIA ( 7 SISTER STATES) BY 10TH JUNE 2013
*** MONSOON WILL REACH CENTRAL KARNATAKA AND MOST OF ANDHRA PRADESH  AROUND 10TH JUNE 2013
*** MONSOON WILL REACH SOUTHERN,CENTRAL,WESTERN MAHARASHTRA AROUND 15-17 JUNE 2013
*** IT SHALL COVER MUMBAI BY 16/17TH JUNE 2013
***NORTHERN MAHARASHTRA,SOUTHERN  MADHYA PRADESH, CENTRAL GUJARAT,CHATTISGARH ( ALMOST ENTIRE) AND VICINITY BY 21ST JUNE 2013
MONSOON WILL ARRIVE IN NAGPUR ON 19/20TH JUNE 2013 (MEANINGFUL RAINS IN JULY HOWEVER)
*** NORTH INDIA PORTIONS TILL NEW DELHI BY 29TH JUNE 2013 AND PUNJAB AND FURTHER NORTH INDIA AFTERWARDS ( AROUND 3RD JULY OR SO)
*** IT ALL DEPENDS ON THE ARABIAN SEA LOW PRESSURE SYSTEM I.E ITS POSITION AND INTENSITY 
*** FORECAST CAN CHANGE DEPENDING ON CONDITIONS. SO PEOPLE MUST FOLLOW UPDATES***

 Inference 

* METD WEATHER ESTIMATES THAT THE SUMMER MONSOON FOR INDIA IN 2013 (01ST JUNE - 30TH SEPTEMBER) WILL BE AROUND 90% NORMAL AND 10% DEFICIENT (IMD VALUE MAY REACH TO 95% NORMAL I.E DEPARTURE OF -5%)
* THE SUMMER MONSOON 2013 RAINFALL AMOUNT WILL BE ALMOST EQUIVALENT TO 2012 YEAR'S MONSOON
* NEUTRAL EL NINO SOUTHERN OSCILLATION, NEGATIVE INDIAN OCEAN 
DIPOLE AND LACK OF MADDEN JULIAN OSCILLATION (WITH MORE DRY PHASE) SHALL REDUCE THE RAINFALL.
* SOUTHERN AND WESTERN,NORTHERN INDIA SHALL GET MORE DEFICIENT RAIN AS COMPARED TO OTHER PARTS. THE LOWEST MAY BE EXPECTED IN LAKSHADWEEP ISLANDS AND AROUND.
* NORTH EAST INDIA WILL GET EXCESS RAINFALL ALONG WITH EAST INDIA GETTING NORMAL OR SLIGHTLY EXCESS RAINFALL.
*MONSOON WILL BE WEAK IN JUNE
* LESSER LOW PRESSURE SYSTEMS SHALL AFFECT THIS YEAR PARTICULARLY IN ARABIAN SEA. 
* INDIAN OCEAN DIPOLE (IOD) SHALL REMAIN NEGATIVE ( MONTH WISE) THROUGHOUT THE SEASON. 
* ENSO IS EXPECTED TO REMAIN NEUTRAL THROUGHOUT THE PERIOD
* MJO INTERFERENCE SHALL BE WEAK IN BOTH THE PHASES. MORE DRY EVENTS EXPECTED

2013 Indian Monsoon Forecast (IndiMO) TECHNICAL VERSION


Dear Readers, 
Greetings! 

As a part of the annual forecast of the Indian Monsoon (IndiMO) since 2010, METD WEATHER brings the 2013 Indian Monsoon Forecast ( IndiMO ). The Summer Monsoon forecast is prepared using multiple parameters which include the Indian Ocean Dipole ( IOD), Madden Julian Oscillation (MJO),El Nino Southern Oscillation (ENSO) and their inter relation. Its widely observed that the Indian Summer Monsoon is largely affected by the atmospheric patterns such as the Madden Julian Oscillation which is directly linked to the El Nino Southern Oscillation. The Indian Ocean Dipole also plays some role in the strength of the monsoon current and subsequently affects the quantum of the monsoon rainfall. We will be using the IOD-MJO inter-relation parameter which was derived in 2012 Indian Monsoon Forecast (IndiMO 1) this year. 

To give a better idea about the monsoon, a portion from the 2011,2012 IndiMO Part 1 is being added. To help more in understanding, the forecast will be issued in two versions which includes a technical version and a public version. Public version is all about the conclusions explained in simple words for the readers. 

METD WEATHER has all the rights reserved for this forecast and the matter is (C) 2013 METD WEATHER. 

Apologies for the delay!

A.Deoras
-------------------------------------------------------------------------------------------------------------------------------------

CHAPTERS-

1) The Summer Monsoon mechanism
2) Gist of the Summer Monsoon activity
3) Interseasonal Oscillation,IOD
4) IOD-MJO Interaction
5) Discussion on the present conditions
6) 2013 Summer Monsoon Forecast
7) Inference
8) References

I- The Summer Monsoon mechanism 




Indian Summer monsoon is an annual phenomena happening briefly in the Indian Ocean,Arabian Sea and the Bay of Bengal. The summer monsoon is characterized by the development of monsoon current or a band of South West Winds carrying moisture lash the mainland bringing torrential rains.
The summer monsoon has two category on the basis of its splitting at Southernmost India

The Arabian Sea Branch
The Bay of Bengal Branch

This Monsoon current sets up because of differential heating of continental and sea air mass.
As the air over mainland gets heated more in summer period as the sun apparently migrates Northwards of Equator, rising warm air causes a decrease in air pressure over the Northern regions of India. As the Sea air mass has comparatively less cooling, a system of winds from South West develops which carries moisture with it.


The Somali Current plays a very important role in monsoon . The somali current generates the SW Monsoonal flow and the current typically resides in the 10-15N in Arabian Sea during the monsoonal period bending in and then entering bay of bengal.
The Ekman drift comes in effect in Arabian Sea when the ocean waters are directed at an angle of 45 degrees to the wind stress in the region. This arrangement directs the SW Monsoon winds towards mainland of India.

Right
The IMD GFS Forecast map of 925mb ( Surface Winds) indicating well developed SW Winds as valid for 12UTC 22/05/11

The dark blue region indicate amplified winds pulling in moisture and regarded as SW Monsoon current.
This current originates from the Somali current

** The Inter-Tropical Convergence Zone or ITCZ which is an area of strong convective activity and rainfall can be seen as a region of converging winds as shown South of Sri Lanka.

ITCZ migrates North with torrential heating during summers and is over India during the Monsoon period.

(B)-



Left, The GFS map of 850mb winds Valid 00z Fri,13th May shows Broad Anticyclonic circulation in Arabian Sea offshore India.
This circulation is regarded at "The Great Whirl"
and is present during summer in this region.
You can also see enhanced moisture SW of the Whirl which is the Somali Current developing.

THE GREAT WHIRL MOVEMENT CONTROLS THE DIRECTION OF MONSOON CURRENT AS IT ACTS LIKE A BLOCKING HIGH PRESSURE RESPONSIBLE FOR INCREASE IN HEATING OVER CENTRAL INDIA,WESTERN INDIA. ITS DISAPPEARANCE IMMEDIATELY REGULATES THE MONSOON CURRENT.
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II- GIST OF SUMMER MONSOON ACTIVITY

The summer monsoon activity formation requires following key factors-

1) Ample heating of Northern Plains of India and surrounding regions leading to formation of low pressure area due to land air mass lifting
2) No interference of Tropical Cyclones ( Which mostly forms within Monsoon trough) and limit the Monsoon wind amplification and disturbs the flow
3) An Enhanced Convection phase of Madden Jullian Oscillation ( Inter-Seasonal Variational Wind flowing Eastwards)
4) Reduction in intensity of North-East winds ( Trade Winds) permitting the flow.
5) Positive phase of the Indian Ocean Dipole ( for more than average rainfall).



*The second parameter of Tropical Activity has been a major concern which had disrupted the Monsoonal Winds since many years.

III- Interseasonal Oscillation(MJO),IOD

Madden Julian Oscillation

MJO or Madden Julian Oscillation is a moving variation ( Travelling Variation) in the Tropical Atmosphere having a period of roughly 30-60 days.
This cycle moves Eastwards and is of the form of Enhanced or Suppressed Convection region depending on the Surface temperature of segment of Sea infront of them and behind them geometrically.
For higher latitudes, Jet Stream plays an important role in deciding the weather pattern. However for tropics, interseasonal variations are the deciding factor for the weather.

MJO can be determined studying the Outgoing Longwave Radiation OLR depicting Cloud tops temperature and thus forecasting the location of the phase.

The year 2009 turned to be a major rainfall deficiency year for India because of the absence of Enhanced Convection phase of the MJO. In addition to this years where strong deficiency or rainfall was seen in India, MJO wet phase was absent.


Right-
The 2009 plot showing the MJO. On Y-axis, period is plotted i.e months. On X axis, longitudes are mentioned.

Check the vertical column above 70-100E region.
In the map, Orange-Yellow shading indicates suppressed region of rains while the blue shows wet phase of MJO
For the entire year of 2009, there was a remarkable absence of Wet phase of MJO leading to depreciation in the quantum of rainfall


Above-
Two phase of Madden Julian Oscillation in progress. The top image is of 14th May 2011 of the Outgoing Longwave Radiation showing a suppressed phase over India and South East Asia ( Depicted by the brown region in the right side of image)

Bottom image shows the Enhanced phase of MJO depicted by the precipitation region and green blue area over SE Asia. At the same time, the opposite phase can be seen near Atlantic Ocean.

II- MJO Formation

The air flows out from the suppressed convection region due to the absence of primary lifting required for convection. This air progresses towards the Enhanced convection region.
The circulating air carries moisture with it. When it reaches the area of Enhanced Convection,the development of cyclonic circulation at lower troposphere layers ( Around 850mb) leads to convergence of moist air. The moist air rises inside a convection region and hence a Wet phase of MJO develops.

The dry phase of MJO is a region having Cyclonic spin at the 200mb ( In contrast to wet phase mentioned above having an anticyclonic spin at 200mb) while dry phase has anticyclonic or clockwise spin in lower profiles.
This is a textbook description why a broad region ( The Great Whirl mentioned above) is seen during dry MJO in Arabian Sea.

Indian Ocean Dipole 

The Indian Ocean Dipole (IOD) is another major contributor in the summer monsoon. The previous years monsoon forecast hadn't mentioned this Dipole but from IndiMO of 2012, IOD will be considered. 

The Indian Ocean Dipole also referred as IOD is a variation in the SST ( Sea Surface Temp) in the Indian Ocean. The variations are seen across the Western and Eastern Indian Ocean where above average or below average sea surface temperatures are recorded. Its an aperiodic variation i.e not of a specific duration or is known to repeat after a specific duration. The IOD is a phenomena similar to ENSO ( El Nino Southern Oscillation) in the Pacific Ocean where there is an interaction of the atmosphere and the ocean. Just like the ENSO, IOD has three phases briefly Positive,Neutral,Negative phase. 

Positive Phase- 
The Positive Phase happens when the SST across the Western Indian Ocean are above normal (Warmer) and the SST across the Eastern Indian Ocean are below normal (Colder). Due to favored SST, strong convection and cyclogenesis take place across the Western Indian Ocean. The rate of this convection activity is often greater than the normal levels for Western Indian Ocean which impacts areas like India,North Africa and Madagascar as shown in the below image of schematic Positive Dipole Mode..

Positive IOD event

Negative Phase-
In a negative phase, the scenario is exactly the opposite as during the Positive phase. The SST across Western Pacific is less (cooler) than the SST across Eastern Pacific which is warmer than the normal. As this happens, the convection shifts towards the Eastern Pacific Ocean with more rainfall across Indonesia and vicinity,Australia and some parts of Japan.

The phases are determined from the DMI ( Dipole Mode Index). Below is the schematic diagram of the conditions during the Negative Dipole Mode.

Negative IOD event

The third stage is a neutral one which will not be discussed. We shall also not discuss the IOD formation.
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4) Relation of Madden Jullian Oscillation with the ENSO

As discussed above, inter-seasonal variation plays a great role in deciding the quantum of monsoon rainfall in India.

However, it has been noted that there is a relation between ENSO and MJO

ENSO refers to the oscillational transition taking place in the Equatorial Central Pacific due to changes in the Sea Surface Temperatures which is attributed to variations in the intensity of trade winds.
ENSO has two phases -
El Nino and La Nina



Above- During a La Nina period in June-August, regions of SE Asia experience Wet and Cool weather.
The Reason is not known why there is such anomaly during La Nina in SE Asia



The Warm Phase of ENSO i.e El Nino
During El Nino,Trade winds weaken leading to accumulation of Sea waters near Indonesia due to which temperature rises ( SST).
During El Nino, there is deficient rainfall in India as shown above.

Relation of the MJO with ENSO-

Considering the ENSO,MJO events since 1978-2010

El Nino Years- ( After 1978) ( S for Strong,M for Moderate,W for Weak)
1982 ( S)
1983 first half (S),
1987(M),
1991(S),
1992(M)
2002(M)
2004,2006 (W)
2009(S)

The MJO was mostly positive (+1.5 to 2) all these years especially during the Summer Monsoon period i.e June-Sept
clearly depicting its direct relation.
All related data can be availed here

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_mjo_index/pentad.shtml

La Nina years
Brief year 1988(S)
1998,1999 (M)
2010(M)

It can be seen that during this period, the MJO phase was mostly Wet or Negative ( Anomaly of -1 to -2)

For images click above

III -
Neutral Phase-
1978-1982 ( Neut)
and some more years like Mid 2012

It has been observed that the MJO wave has a nature depending on the intensity of Neutral.
During the period 1978-1982 when the SST was showing weak negative anomaly,
those years witnessed more number of wet phase of mjo than the dry


4) IOD-MJO Interaction 

The Madden Julian Oscillation is observed widely across the Indian Ocean and Pacific Ocean.

As discussed in the above MJO section, conditions favorable for convection lead to the development of "wet phase" of MJO while those areas where strong convection is not possible the dry phase develops.
It can be noted that the MJO formation across the Indian Ocean is much marked than the Pacific Ocean

The animation of the OLR for a period between 19th Nov-19th Dec 2009 can be seen here at the top panel.


http://www.esrl.noaa.gov/psd/map/clim/olr_modes/mapanim2.html






As seen in the image, a blue shade area which is represented by a "Red Circle" ( Positive phase of the MJO) is forming across East Central Africa while a developed orange-yellow shade ( Negative phase of MJO) is sweeping across Indonesia.
We now have a look at the DMI ( Dipole Mode Index) for the period of Nov-Dec 2009.

       DATE           DMI

2009:11:11:0 -0.0511759
2009:11:18:0 -0.199991
2009:11:25:0  -0.0942584
2009:12:2:0    0.152676
2009:12:9:0    0.535976
2009:12:16:0   0.571879
2009:12:23:0  -0.0290021


Here, negative DMI indicates Negative phase of the Indian Ocean Dipole (IOD) where Warmer water (SST) is present across the Eastern Indian Ocean and Cooler water is present across Western Indian Ocean.
Negative IOD event
 The Eastern Indian Ocean during a Negative phase has greater convection activity going on which supports the formation of a Wet Phase of the MJO while across the Western Pacific, a Positive ( DRY) phase of MJO develops. 
We consider some more examples of a significant MJO event across the region. 
OLR Anomaly March 2010-May end 2010
2

For the Western Indian Ocean, one can note that there is a blue shade region ( Blue shade= greater than normal rain/clouding which is the enhanced phase of MJO). An orange shade is noted across the Eastern Indian Ocean ( orange=lesser clouding i.e dry phase of the MJO). 

Here is the DMI for the period

  DATE         DMI
2010:3:3:0   -0.0212098
2010:3:10:0  0.275377
2010:3:17:0  0.378245
2010:3:24:0  0.201978
2010:3:31:0  0.515495
2010:4:7:0   0.712007
2010:4:14:0  0.447102
2010:4:21:0  0.234534

Here, the DMI values are positive ( Positive Indian Ocean Dipole) from 10th March-April end 2010
Thus the Enhanced ( WET) phase of MJO coincides with the Positive IOD. 
2) OLR Anomaly (Oct 2010-Dec 2010)

A significant DRY PHASE of MJO seems over the Western Indian Ocean. Lets see the DMI now 

    DATE         DMI
2010:10:6:0   -0.918562
2010:10:13:0  -0.948848
2010:10:20:0  -0.968341
2010:10:27:0  -0.581541
2010:11:3:0   -0.497689
2010:11:10:0  -0.546642
2010:11:17:0   0.0580557
2010:11:24:0  -0.0620495
2010:12:1:0   -0.119381
2010:12:8:0   -0.297918
2010:12:15:0  -0.0470014
2010:12:22:0  -0.493268
2010:12:29:0  -0.0990546

Here, a significant negative DMI event ( Negative IOD) is in place which is responsible for the DRY PHASE OF MJO
More analysis of MJO events with DMI can be done comparing the two links
http://www.bom.gov.au/climate/mjo/ ( OLR ANOMALY MJO)
http://www.jamstec.go.jp/frcgc/research/d1/iod/DATA/dmi.weekly.ascii ( DMI=IOD)
THUS ONE INFERS THAT THE MJO DRY PHASE DEVELOPS WHEN THE NEGATIVE INDIAN OCEAN DIPOLE IS IN PROGRESS WHERAS ENHANCED MJO DEVELOPS WHEN THE POSITIVE OCEAN DIPOLE IS IN PROGRESS FOR WESTERN INDIAN OCEAN. VICE VERSA FOR EAST INDIAN OCEAN
Reason- 
As explained in the MJO,IOD section, a positive IOD will support stronger convection and hence Enhanced MJO across the Western Indian Ocean whereas a negative IOD will support suppressed convection and hence a dry phase of the MJO. 


The IOD-ENSO relation is still being studied and shall be mentioned in a separate article- 

5) Discussion on the present condition 

ENSO:
ENSO Neutral conditions are continuing in the Pacific Ocean. After a weak La Nina event in the year 2011 which continued in the 2012 beginning, conditions turned to ENSO Neutral in the Equatorial Pacific Ocean. The latest weekly departure ( Temp.anomaly) from the Equatorial Central Pacific Ocean and surroundings indicate a well defined ENSO Neutral which is persisting!  


NINO REGIONS IN THE PACIFIC OCEAN
LATEST WEEKLY DEPARTURE ( As of 20th May 2013)

The latest weekly SST departures are: 

Niño 4       -0.2ºC
Niño 3.4    -0.4ºC
Niño 3       -0.6ºC
Niño 1+2   -1.1ºC 

Above- The SST Anomaly shows positive anomaly regions offshore South America, Australia- Indonesia prominently. However the positive anomaly isn't that significant so as to be considered as El Nino event (prominent departure of -0.4C in Nino 3.4

II ..MJO

As seen from the above index, a negative MJO was persistent during the early to mid may 2013 however, a dry phase is approaching (and now set over 70-100E) region. 

III Indian Ocean Dipole 


IOD had a strange trend. It remained high (positive) last year from July onwards returning to the mean later on in early 2013 and now having a sharp negative value (-0.61)

IV Somali Current



The above IMD 925mb map showing Somali Jet (current) has established offshore Somali in the Arabian Sea. As the forecast has been late this year, Somali Jet has established (unlike IndiMO 2012 when it wasn't established) 

Above is a projection (+7 days) showing amplification of the Somali Jet ( Current). This is an impressive feature which suggests that the monsoon will be approaching ( i.e it doesn't look like a case of stalled monsoon at this level) 

V- Low pressure in Arabian Sea

The above parameters look to be normal. However, the short range GFS shows a possibility of development of a low pressure system in the Arabia Sea. This low pressure shall form offshore Yemen coast i.e exactly in the centre of the Somali Jet. 
As can be seen from the situation of 30th May/1st June, the system shall be right in between the somali jet and the Indian west coast. This means that if this system intensifies or become more marked, the moisture from the somali jet will be pulled by this system and hence monsoon arrival can get delayed for subsequent west India and Central India also by a few days. 


6) 2013 INDIAN MONSOON FORECAST

Its very important to have a look at the ENSO forecast for the Summer monsoon period. Here is the IRI/CPC outlook on the ENSO



IRI Probabilistic ENSO Prediction for NINO3.4 Region
SeasonLa NiñaNeutralEl Niño
MJJ 201321%77%2%
JJA 201326%67%7%
JAS 201327%60%13%
ASO 201328%58%14%
SON 201328%58%14%
OND 201326%60%14%
NDJ 201423%63%14%
DJF 201422%65%13%
JFM 201421%65%14%

As can be seen from the forecast, ENSO Neutral is likely going to continue throughout the monsoon period! The probability of this more than 50%.. 

So we conclude that ENSO Neutral conditions will continue in Indian Monsoon

2) Indian Ocean Dipole 

WE WILL STRICTLY REFER BOM MODELS/DATA

The Australian Bureau of Meteorology ( BOM) is showing that the IOD will have a mean negative ( negative anomaly) trend during the key monsoon period.. IOD keeps swinging every week ( DMI Values).. However, when a mean is calculated, either a positive or negative value comes in the form of results. 

So unlike last year, it looks like IOD will be slightly influencing the monsoon. 

MJO 

Above is the CPC MJO forecast for June and early July (40 day forecast, base 00z 25th May 2013). The persisting dry phase shall get over around Mid June allowing a wet phase to drive in which will help the progress of the monsoon ( AFTER THE LOW PRESSURE SYSTEM IN ARABIAN SEA AS MENTIONED ABOVE DISSIPATES).  

However as IOD is forecasted be to more towards the negative, it looks like a dry phase will be taking up in July. Hence the June 2013 month will witness normal rainfall ( for most of the parts of India) 

Conclusion- Neutral ENSO coupled with negative IOD will be dominant in the Indian Summer Monsoon. As a result of negative IOD, MJO might have less wet phases in the season. However it won't bring a large scale deficiency in the net quantum of the rainfall over India! 



REGION WISE FORECAST
1) SOUTHERN INDIA 
The IOD which is expected to be more towards weakly negative will lead to dry phase development which may reduce the rainfall amount in this area. However, due to favoured conditions, monsoon will follow the dates. The rainfall amounts shall increase from July. 
Region will witness " DEFICIENT" Rainfall with around 85% NORMAL RAIN.

2) Western India
The same conditions shall apply for Western India also as if the MJO activity remains less, monsoon winds shall be weak in this region.Also the arabian sea low pressure system will shape up which will cause the monsoon to be slightly delayed here leading to a less June month rainfall (as compared against the normal). However, it has been observed that the monsoon current as well as the quantum intensifies in later July/August which ultimately balances the deficit. 
The region will witness "SLIGHTLY DEFICIENT" rainfall around 85% of normal rainfall.

3) Northern India
The region can expect good rainfall unlike the other areas. The primary reason seems to be the wind patterns expected. The region will receive some rains from the Disturbances which may have a southernly dip than normal. This factor was observed in April month also when greater than normal thunderstorm activity was reported across North-East India as the trough dug more southward and brought rains. 
Aperiodic rainfall shall be there with 85% NORMAL and 15% DEFICIENT CONDITIONS

4) North East India
NE India will witness EXCESS Monsoon with the primary reason expected to be the less effective Bay of Bengal current.
Expected 100-105% OF THE NORMAL RAINS 
5) East India
Region shall witness NORMAL TO SLIGHTLY EXCESS MONSOON CONDITION. 
Expected 95% NORMAL
6) Central India
If one assumes the weak monsoon current due to negative IOD and dry MJO, Central India will have a less than normal rains but the rainfall due to low pressure systems will balance the deficit hence the resultant will be NORMAL RAINFALL 
rainfall will be 90% NORMAL and 10% DEFICIENT. 

7) Andaman and Nicobar Is. 
Normal rainfall is expected in this region around 95% of the normal rainfall. 
8) Lakshadweep and surrounding
Considering the expected strength of Monsoon current and Ekman Drift this region will witness deficient rainfall 

80% NORMAL

2013 MONSOON ARRIVAL DATES

REFER THE MONSOON ONSET NORMS HERE
MONSOON ONSET DATES
-***  NICOBAR ISLANDS  AND ANDAMAN ISLANDS ( INCLUDING LITTLE NICOBAR,GREAT NICOBAR,KATCHAL,NANCOWRY ISLANDS AND VICINITY) - MONSOON HAS SET
** PRE MONSOON RAINS WILL INITIATE ACROSS SRI LANKA, SOUTHERN,WESTERN KERALA,TAMIL NADU AROUND THIS MONTH END
*** MONSOON WILL REACH SRI LANKA AROUND 1-2ND JUNE 2013
*** MONSOON WILL REACH SOUTHERN INDIA LIKE KERALA, TAMIL NADU AND SOUTHERN MIZORAM AROUND 1-3RD JUNE 2013 
*** LAKSHADWEEP BY 6-7TH JUNE 2013
*** MONSOON WILL COVER NORTH EAST INDIA ( 7 SISTER STATES) BY 10TH JUNE 2013
*** MONSOON WILL REACH CENTRAL KARNATAKA AND MOST OF ANDHRA PRADESH  AROUND 10TH JUNE 2013
*** MONSOON WILL REACH SOUTHERN,CENTRAL,WESTERN MAHARASHTRA AROUND 15-17 JUNE 2013
*** IT SHALL COVER MUMBAI BY 16/17TH JUNE 2013
***NORTHERN MAHARASHTRA,SOUTHERN  MADHYA PRADESH, CENTRAL GUJARAT,CHATTISGARH ( ALMOST ENTIRE) AND VICINITY BY 21ST JUNE 2013
MONSOON WILL ARRIVE IN NAGPUR ON 19/20TH JUNE 2013 (MEANINGFUL RAINS IN JULY HOWEVER)
*** NORTH INDIA PORTIONS TILL NEW DELHI BY 29TH JUNE 2013 AND PUNJAB AND FURTHER NORTH INDIA AFTERWARDS ( AROUND 3RD JULY OR SO)
*** IT ALL DEPENDS ON THE ARABIAN SEA LOW PRESSURE SYSTEM I.E ITS POSITION AND INTENSITY 
*** FORECAST CAN CHANGE DEPENDING ON CONDITIONS. SO PEOPLE MUST FOLLOW UPDATES***
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7) Inference 

* METD WEATHER ESTIMATES THAT THE SUMMER MONSOON FOR INDIA IN 2013 (01ST JUNE - 30TH SEPTEMBER) WILL BE AROUND 90% NORMAL AND 10% DEFICIENT (IMD VALUE MAY REACH TO 95% NORMAL I.E DEPARTURE OF -5%)
* THE SUMMER MONSOON 2013 RAINFALL AMOUNT WILL BE ALMOST EQUIVALENT TO 2012 YEAR'S MONSOON
* NEUTRAL EL NINO SOUTHERN OSCILLATION, NEGATIVE INDIAN OCEAN 
DIPOLE AND LACK OF MADDEN JULIAN OSCILLATION (WITH MORE DRY PHASE) SHALL REDUCE THE RAINFALL.
* SOUTHERN AND WESTERN,NORTHERN INDIA SHALL GET MORE DEFICIENT RAIN AS COMPARED TO OTHER PARTS. THE LOWEST MAY BE EXPECTED IN LAKSHADWEEP ISLANDS AND AROUND.
* NORTH EAST INDIA WILL GET EXCESS RAINFALL ALONG WITH EAST INDIA GETTING NORMAL OR SLIGHTLY EXCESS RAINFALL.
*MONSOON WILL BE WEAK IN JUNE
* LESSER LOW PRESSURE SYSTEMS SHALL AFFECT THIS YEAR PARTICULARLY IN ARABIAN SEA. 
* INDIAN OCEAN DIPOLE (IOD) SHALL REMAIN NEGATIVE ( MONTH WISE) THROUGHOUT THE SEASON. 
* ENSO IS EXPECTED TO REMAIN NEUTRAL THROUGHOUT THE PERIOD
* MJO INTERFERENCE SHALL BE WEAK IN BOTH THE PHASES. MORE DRY EVENTS EXPECTED

8) References 

1) METD WEATHER - 2011 IndiMO Part I
http://metdweather.blogspot.com/2011/05/indimo-2011-part-i-indian-monsoon.html
2) INDIA METEOROLOGICAL DEPARTMENT- MAPS RELATED TO SOMALI CURRENT
http://www.imd.gov.in/section/nhac/dynamic/nwp/welcome.htm
3) NCEP COLA GFS FOR 850MB MAPS
http://wxmaps.org/pix/casia.fcst.html
4) CLIMATE PREDICTION CENTER FOR MJO RELATED IMAGES
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml
5) JAMSTEC for Indian Ocean Dipole 
http://www.jamstec.go.jp/frsgc/research/d1/iod/iod_home.html.var
http://www.jamstec.go.jp/frcgc/research/d1/iod/DATA/dmi.weekly.ascii
6) BUREAU OF METEOROLOGY,AUSTRALIA FOR OLR MAPS
http://www.bom.gov.au/climate/mjo/
7) http://ggweather.com/enso/oni.htm
8) WIKIPEDIA.ORG FOR ENSO RELATED IMAGES
http://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillation
9) METD WEATHER INDIMO 2012
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