Tropical Storm "Lehar" threatens India!

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

With just over a month from the landfall of disastrous Category 5 cyclone Phailin  and just a few days after Tropical Storm Helen , the Bay of Bengal is all set to host another Tropical Cyclone which will be soon officially called as "Cyclone Lehar".. At METD WEATHER, Saffir Simpson Scale is followed and hence we have already named the area of deeply organised convection about 1560km SE of Vizag,Andhra Pradesh as Tropical Storm Lehar given the estimated maximum sustained winds of 35kt as of today morning. This Tropical Storm which at present lies in the periphery of land, The Andaman and Nicobar Islands is all set to pass dangerously between Little Andaman Island and Port Blair between late tonight, 24th Nov and morning of tomorrow,25th Nov 2013 as a "Tropical Storm category" with max winds reaching upto 100Km/hr accompanied by strong rains and storm surge likely upto 10ft.... Lets have a look at the dynamics of Tropical Storm Lehar in the Bay of Bengal-

Shown above is a composite view of Tropical Storm Lehar. The topmost simple Infrared view (top left) and IR-BD view (Top Right) clearly shows almost circular convection centre with cloud tops reaching upto -70C which is an indicator of organising convection and intensification of the system. Interesting thing to note in the lower images is the organising of outer bands- rain bands- banding feature around the LLCC (Low level circular centre) as can be inferred in the NRL images. The lack of symmetry is being attributed to the periphery of the land which isn't allowing the system to undergo rapid intensification stage as it churns in the sea having temperature of 29C...

A look at the wind profiles & dynamics show that Tropical Storm Lehar is being troubled by moderate wind shear of 30kt to the north and south of the centre and 20kt to its East disabling it to intensify robustly. Over the past 12hrs, convergence at the lower atmospheric profile has decreased slightly along with the poleward outflow which now stands to be 40kt peak as against 60kt peak 12hrs ago...

As the system steers North West slowly ( at present with a velocity of 17km/hr), after the encounter with Andaman and Nicobar Islands, the system shall get a clearance from land to intensify.

Shown above is the Sea Surface Temperature view via CIMSS.. Here Red colour represents Sea Surface Temperature of 30C, Orange shows 29C, yellow shows 27-28C. Thus the sea coupled with the moisture content will be favourable for intensification. But the question arises, will Tropical Storm Lehar reach a Category 5 status like Tropical Cyclone Phailin ??

The answer at the moment seems- NO

Here is the reason,

This is CIMSS view of the wind shear in knots across Bay of Bengal.. Here solid white lines indicate an increasing shear tendency: unfavourable for storm intensification. Over the Bay of Bengal, it seems the wind shears will remain considerably higher than they were during Phailin's time as a result this factor will always try to reduce the intensity but with other factors favourable, Tropical Storm Lehar shall intensify to atleast Category 2 although JTWC says it can go upto Category 3. As the sea few hundred kilometers offshore Odisha and Andhra Pradesh is slightly cooler, intensification may not be that high and hence for now, people shouldn't panic or compare this cyclone with Phailin or Supercyclone of 1999 or with the US hurricane like Katrina.

Where will it head ?

This is always a million dollar question. At the moment, the sub tropical ridge seems to be steering the system towards Indian coast but the area in North Bay of Bengal is being monitored for the development of high pressure at the lower levels (850mb or say 5000 ft AGL). If the high pressure forms in that region, the cyclone shall not move much North in its NW journey and in that case its region of landfall shall be south of Vizag in Andhra Pradesh on the morning of 28th Nov 2013, Thursday.. 

However as GFS 00z is showing, if the high pressure doesn't form, system under the influence of sub-tropical jet stream of India will curve a bit north and make a landfall near Brahmapur,Odisha- apparently at the same place like Cyclone Phailin on the morning of 28th Nov 2013, Thursday

Where ever it shall head, people living along the coastal line from Kakinada,AP till Brahmapur,Odisha shall pay attention towards the development of this system which will be covered on METD WEATHER's facebook page (www.facebook.com/deorasakshay) and on this blog also

Once the forecast becomes more clear, an alert map will be issued by METD WEATHER

*** Preparation*** 

Rough Sea of Bay of Bengal will start now onwards and will continue till Thursday,28th Nov. Fisherman are requested not to venture with their ships/boats.. 

VIA BOM,Australia (People of Andhra Pradesh-Odisha Coast must note) 

When a cyclone watch is issued

• Re-check your property for any loose material and tie down (or fill with water) all large, relatively light items such as boats and rubbish bins.
• Fill vehicles' fuel tanks. Check your emergency kit and fill water containers.
• Ensure household members know which is the strongest part of the house and what to do in the event of a cyclone warning or an evacuation.
• Tune to your local radio/TV for further information and warnings.
• Check that neighbours are aware of the situation and are preparing.

Cyclone Phailin makes a landfall near Gopalpur,Odisha

METD WEATHER
AKSHAY DEORAS
SEVERE WEATHER FORECASTER

Powerful Cyclone Phailin has made a landfall near Gopalpur,Odisha at around 0730-0800PM IST ((1400-1430hrs UTC) with estimated max sustained wind of around 220km/hr, air pressure at the core of around 930mb. Above is the RAMMB image of 15z (0830PM) showing the movement of the system over land : close to Gopalpur- Brahmapur in Odisha!

FOR MORE DETAILS- FOLLOW METD WEATHER ON FACEBOOK 

Meanwhile, I had the opportunity of getting featured in the news article of the magazine DTE (Down To Earth) regarding Cyclone Phailin. Here is the URL of the news article ( http://www.downtoearth.org.in/content/phailin-s-wind-speed-exceeds-1999-super-cyclone) OR CLICK HERE 

Down to Earth is an Indian science and environment fortnightly, established by the Society for Environmental Communications in May 1992. Over the years the magazine has informed and inspired people about environmental threats facing India and the world—a dimension underplayed in mainstream media. DTE has become a reading habit in 400 of about 500 districts of the country—more than any other Indian newspaper or magazine. DTE’s sphere of influence is not limited to India. Numerous readers across the world rely on the magazine for a comprehensive view from South Asia on the most critical issues of human existence

CATEGORY 5 CYCLONE PHAILIN TO IMPACT ODISHA TODAY,EXTENSIVE DAMAGE EXPECTED

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

*** CATEGORY 5 CYCLONE PHAILIN HEADING TOWARDS ODISHA, BIG DAMAGE EXPECTED FROM TODAY*** 

Beating all the expectations, Cyclone Phailin yesterday (11th Oct) morning intensified to a Category 4 cyclone and had a peak winds of 135 kt as per JTWC which gusted even above 150 kt during the morning hours. The estimated air pressure at the core too had dropped to around 925mb-930mb. Morning images clearly showed an eyewall surrounding the eye and Phailin was all set to replace its existing eye with the eyewall- a process common in such high intensity cyclones which is called as "Eyewall Replacement Cycle". The maximum winds in such a high intensity cyclone are in the

eyewall and as it moves inwards towards the eye, the cyclone typically weakens which is usually indicated by the increase in the air pressure of the core and decrease in the wind speed. Although with Phailin, we couldn't avail sufficient data to demonstrate how much the wind speed decreased or air pressure increased.

(Image at Right obtained in the late afternoon showed the completion of eyewall replacement cycle)






As soon as the new eye got stabilised, Category 4 cyclone Phailin re-intensified to a powerful Category 5 cyclone and at the moment continues to be a category 5 cyclone with estimated max sustained winds of around 146kt (around 270km/hr),gusting to over 320km/hr and an air pressure of around 915mb at the core as per NRL. Over the past few hours, Tropical Cyclone Phailin has become faster as it moved North-West with a speed of around 17km/hr from the previous 10km/hr which was yesterday morning. The latest attached imagery (the top image) clearly shows a stable eye and a CDO feature (Central Dense Overcast : a feature in which large band of thunderstorms in various shapes, here circular surround the eye) and typically the Dvorak intensity decreases
(say T ~5).

CYCLONE PHAILIN NOW IS STRONGER THAN THE 1999 SUPERCYCLONE OF ODISHA

Right- The latest CIMSS image of SST (Sea Surface Temp) of Bay of Bengal shows a pool of unusually warmer sea offshore Odisha,Andhra Pradesh having SST of 30C as against 29C where Phailin's heat engine (the core) is at the moment. Thus its likely that as Phailin moves NW further towards the coast for a landfall, its intensification will continue given this support. Phailin has enjoyed light sheared environment of just 5-10 Kt that has hardly spoilt its intensity (apart from broken symmetry to its SW spiral arms around yesterday when they were in a moderate shear region of 25-30Kt).

The air dynamics too have been favourable for this system with the upper air divergence now better than the yesterday morning : during the eyewall replacement when it had dropped to 30 kt. Although it continues to be numerically the same, a drop (cooling) of cloud tops are indicating a better southward radial outflow and a better symmetrical structure thanks to the assisted 40 kt lower air convergence which too had dropped to 30 kt for a while leading to a kind of fragmented spiral arms of the system leading to the broken symmetry today (short before it being declared as a category 5)

TPW (Total Precipitable Water) continues to be very impressive with a numerical value of over 65mm suggesting a very high flooding threat for coastal,interior Odisha apart from significant

rainfall in Eastern India (see METD WEATHER map for details) which covers states like Jharkhand,Bihar,West Bengal prominently.

(Right- CIMSS TPW image showing high PW)


So it looks like Tropical Cyclone Phailin will continue to move NW towards Odisha coast with more or less the same intensity till the landfall (although some models indicate it to be a higher end of Category 4 cyclone at the landfall). The reason being attributed to this is the proximity of land and subsequent interaction with the dry air just before the landfall.

The area of landfall should be around Brahmapur in Odisha rather Gopalpur (which comes more close to the sea than the former). The region of landfall like conditions should bounce between Srikakular,AP to Puri,Odisha with the highest chances towards Brahmapur region and the landfall (eye crossing the land) will be towards today evening (ALTHOUGH LANDFALL LIKE CONDITIONS WILL BEGIN FROM THE LATE MORNING TO AFTERNOON ONWARDS) 

POTENTIAL IMPACTS TODAY

* As the cyclone approaches the coast, there will be an increase in the sea waves height as the storm surge (movement of wall of sea water towards the land as the cyclone moves inward). 

*Rainfall along with wind speed will gradually increase in Odisha state including bordering states like coastal Andhra Pradesh, coastal West Bengal. Big cities like Puri,Cuttack,Bhubaneshwar etc will witness high velocity winds,rains in the day and conditions turning worst from the afternoon onwards. 

* Due to increased rainfall and wind, the first damage will be to the weak settlements like huts etc and breaking of trees (uprooting too) with damage to powerlines will start.

* During the landfall, the coastal areas of Odisha and areas around Srikakulam,AP will witness strong tides of height upto 20ft and wind having velocity of around 230km/hr and above (gusting more than that). Interior areas too will start witnessing such conditions along with heavy rains.

* Widespread disruptions to rail,road and air traffic in the state are likely from today. Due to flood in many areas due to the rains, villages etc will get cut off from nearby cities/towns. Severe waterlogging too will be witnessed in big cities like Bhubaneshwar and around. 

SAFETY MEASURES (Via Ready.gov)

• Listen to the radio or TV for information.
• Secure your home, close storm shutters and secure outdoor objects or bring them indoors.
• Turn off utilities if instructed to do so. Otherwise, turn the refrigerator thermostat to its coldest setting and keep its doors closed.
• Turn off propane tanks
• Avoid using the phone, except for serious emergencies.
• Moor your boat if time permits.
• Ensure a supply of water for sanitary purpose such as cleaning and flushing toilets. Fill the bathtub and other larger containers with water.
• Find out how to keep food safe during and after and emergency.

You should evacuate under the following conditions:

If you are directed by local authorities to do so. Be sure to follow their instructions.

• If you live in a mobile home or temporary structure – such shelter are particularly hazardous during hurricane no matter how well fastened to the ground.
• If you live in a high-rise building – hurricane winds are stronger at higher elevations.
• If you live on the coast, on a floodplain, near a river, or on an island waterway.

If you are unable to evacuate, go to your wind-safe room. If you do not have one, follow these guidelines:

• Stay indoors during the hurricane and away from windows and glass doors.
• Close all interior doors – secure and brace external doors.
• Keep curtains and blinds closed. Do not be fooled if there is a lull; it could be the eye of the storm – winds will pick up again.
• Take refuge in a small interior room, closet or hallway on the lowest level.
• Lie on the floor under a table or another sturdy object.
• Avoid elevators.

Cyclone Phailin undergoes rapid intensification, now a Category 3 cyclone!

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

TROPICAL CYCLONE PHAILIN POSSES AN INCREASED THREAT FOR ODISHA AND BORDERING ANDHRA PRADESH COAST


Surpassing all the anticipations, Tropical Cyclone Phailin has undergone (and continues to undergo) a rapid intensification due to which in a very short time it has intensified to a powerful Category 3 Cyclone with maximum winds of around 100Kt (around 185km/hr) gusting to around 125Kt and cloud top temperature over -70C with a clearer eyewall!!!!

The above image of Cyclone Phailin from NRL clearly shows a stable eye and possibly the associated eyewall close to 16N,90E as Phailin continues to move NW towards the Odisha coast.

The major reason of this rapid intensification of Cyclone Phailin is the absence of the conditions (on high magnitude) (like dry air, cooler sea surface temperature,high vertical wind shear etc). Such conditions often interfere with the strength of a cyclone leading to its weakening. With Tropical Cyclone Phailin, the conditions have been supporting for it to intensify since the beginning.

Upper Air conditions continue to indicate that Tropical Cyclone Phailin is getting a very favourable southern outflow ranging over 30 Kt assisting the convection process whereas its being "gripped/tightened" due to the extremely favourable convergence ~30Kt at its base to the south of non CDO (Central Dense Overcast) eye. Wind shears to continue to be relaxed just 5-10Kt near the LLCC (Low level circulation centre) and continue to be moderate to the SW (seen from the broken fragments) although it is not affecting the cyclone's strength. The CIMSS wind shear tendency continues to show that Phalin will continue to enjoy a light sheared environment enroute to Odisha coast thereby nailing down its chance to weaken significantly.

The above multi sensitivity image from NRL (refer bottom two) clearly show the symmetrical rainbands (pointed by yellow arrows) around the eye and the stable eyewall circulating the eye. Hence one can't expect an eyewall replacement cycle soon in Phailin. The temperature of the eye of Phailin has risen to 0C also (Courtesy-Rajesh Kapadia/Vagaries of Weather) which is a usual feature with such high intensity cyclones which happens when the air in the eye gets adiabatically compressed (during its sinking stage) leading to a rise in the temperature. The MSLP in eye area is anticipated to be around 950mb!

As Phailin continues to churn in a warm (29C) SST of Bay of Bengal, not even the dry air (encircled in red in the above image) offshore West Bengal will affect its intensity as the inflow isn't from northern direction.

Considering all the parameters, Tropical Cyclone Phailin is now expected to intensify (JTWC estimate) to a Category 4 Cyclone shortly before it hits Odisha coast : Near Brahmapur on Saturday (12th Oct 2013) afternoon period (Although landfall like conditions will emerge from the evening/night of Friday,11th Oct ONLY) 

It looks like max sustained wind of this cyclone at the landfall on Saturday will be around 110kt (around 200km/hr) which will be categorised as a high end Category 3 Cyclone (Although on Friday,11th Oct its likely to intensify to Category 4). As it approaches Odisha (although landfall like conditions will happen in Odisha bordering Andhra Pradesh coast like Srikakulam), the outer convection bands will encounter with the land and so there should be a decreasing intensity (A degradation from Category 4 to Category 3) but be it Category 3 or 4, Tropical Cyclone Phailin posses a MAJOR threat for Odisha which includes widespread damage to life,property

Jharkhand,Western West Bengal also posses heavy rainfall threat due to it along with Odisha on Saturday,Sunday chiefly. 

* The big city coming in this threat will be Bhubaneshwar in Odisha where high velocity winds (gusting possibly upto 200km/hr ) with heavy rains will be witnessed during the landfall.

SAFETY TIPS- (Via Ready.gov)

Before a Cyclone (Hurricane)

To prepare for a hurricane, you should take the following measures:

• To begin preparing, you should build an emergency kit and make a family communications plan.
• Know your surroundings.
• Learn the elevation level of your property and whether the land is flood-prone. This will help you know how your property will be affected when storm surge or tidal flooding are forecasted.
• Identify levees and dams in your area and determine whether they pose a hazard to you.
• Learn community hurricane evacuation routes and how to find higher ground. Determine where you would go and how you would get there if you needed to evacuate.
• Make plans to secure your property:
• Cover all of your home’s windows. Permanent storm shutters offer the best protection for windows. A second option is to board up windows with 5/8” marine plywood, cut to fit and ready to install. Tape does not prevent windows from breaking.
• Install straps or additional clips to securely fasten your roof to the frame structure. This will reduce roof damage.
• Be sure trees and shrubs around your home are well trimmed so they are more wind resistant.
• Clear loose and clogged rain gutters and downspouts.
• Reinforce your garage doors; if wind enters a garage it can cause dangerous and expensive structural damage.
• Plan to bring in all outdoor furniture, decorations, garbage cans and anything else that is not tied down.
• Determine how and where to secure your boat.
• Install a generator for emergencies.
• If in a high-rise building, be prepared to take shelter on or below the 10th floor.
• Consider building a safe room.

During a cyclone (hurricane)

If a hurricane is likely in your area, you should:

• Listen to the radio or TV for information.
• Secure your home, close storm shutters and secure outdoor objects or bring them indoors.
• Turn off utilities if instructed to do so. Otherwise, turn the refrigerator thermostat to its coldest setting and keep its doors closed.
• Turn off propane tanks
• Avoid using the phone, except for serious emergencies.
• Moor your boat if time permits.
• Ensure a supply of water for sanitary purpose such as cleaning and flushing toilets. Fill the bathtub and other larger containers with water.
• Find out how to keep food safe during and after and emergency.

You should evacuate under the following conditions:

If you are directed by local authorities to do so. Be sure to follow their instructions.

• If you live in a mobile home or temporary structure – such shelter are particularly hazardous during hurricane no matter how well fastened to the ground.
• If you live in a high-rise building – hurricane winds are stronger at higher elevations.
• If you live on the coast, on a floodplain, near a river, or on an island waterway.

 If you are unable to evacuate, go to your wind-safe room. If you do not have one, follow these guidelines:

• Stay indoors during the hurricane and away from windows and glass doors.
• Close all interior doors – secure and brace external doors.
• Keep curtains and blinds closed. Do not be fooled if there is a lull; it could be the eye of the storm – winds will pick up again.
• Take refuge in a small interior room, closet or hallway on the lowest level.
• Lie on the floor under a table or another sturdy object.
• Avoid elevators.

TROPICAL CYCLONE WARNING FOR EAST INDIA- ODISHA UNDER THE THREAT

METD WEATHER
AKSHAY DEORAS
SEVERE WEATHER FORECASTER

JOIN METD WEATHER FACEBOOK FOR LATEST DETAILS- facebook.com/deorasakshay

The second part of 2013 North Indian Ocean Cyclone Season has started with a bang with a new Tropical Storm (we call it 02B as per JTWC) already born in the Bay of Bengal. This new Tropical Storm 02B in North Andaman Sea near 13N,93.5E approximately 1200km east-south east of Visakhapatnam already has wind of 35KT (and hence already lies in the Tropical Storm Category of the Saffir Simpson Scale) 

Seen above is the latest IR-NHC imagery of the Tropical Storm 02B via CIMSS showing the system as Invest (I). Distinct banding features are visible west of the low pressure as the LLCC (Low Level Circulation Centre) is trying to organise in the warm Bay of Bengal having SST of ~29C. LLCC is also becoming more exposed and consolidating also. At the surface level too, the system continues to enjoy lower southern convergence of ~30kt and the convection continues to boost up given the excellent upper air divergence to the south of the system as the system is tracking along the southern periphery of the Subtropical Ridge although its experiencing moderately sheared environment to its south-west.

Already heavy rains have been reported in Andaman and Nicobar Is. Entire Andaman and Nicobar Is will continue to get heavy rains today with high velocity winds as the Tropical Storm intensifies close to the area. After the Tropical Storm moves NW tomorrow (10th Oct) onwards, there will be a decline in the rainfall in this area. 

The Tropical Storm 02B shall be curving to NW as it steers in a moisture rich,higher sea temperature of Bay of Bengal considering the available TPW (Total Precipitable Water). Atmospheric conditions also are expected to be conducive for this Tropical Storm to intensify to Category 1 (say with peak winds of around 80KT) around tomorrow,10th Oct afternoon or so and amidst produce "Rough Sea" in the Bay of Bengal in the highlighted region of METD WEATHER alert. Models are converging for landfall of this system along the Odisha coast on Saturday,12th Oct 2013 (Although landfall like conditions shall start from afternoon-evening of Friday,11th Oct 2013). 

The approximate landfall of this system seems to be around Brahmapur in Odisha however landfall like conditions (which includes heavy rains, gusty winds prominently) will be widely experienced along the entire Odisha coast even stretching upto North East coast of Andhra Pradesh which is bordering Odisha around Friday-Saturday. 

In the forecast map, METD WEATHER has issued a Tropical Cyclone Warning for East India Coast that prominently includes Odisha and Andhra Pradesh and heavy rainfall extension in Jharkhand also (May stretch upto Bihar on 13/14th Oct 2013). 

IMPACTS- 

*Damage to boats,ships in the "Rough Sea" or in the ports of Odisha (Rough Sea starts now and shall continue till 14th Oct 2013. Fisherman are also advised now to enter the Bay of Bengal till 13/14th Oct 2013. 

* Considering the fact that as of now the Tropical Storm will intensify to Category 1, widespread damage is likely along Odisha coast initially and later on moving into interior (particularly near the landfall area). Damage shall start from afternoon/evening of Friday,11th Oct 2013.

* Extensive damage to huts,trees and weak settlements is likely during the landfall and there exists a high flood threat for Odisha coast and interior as the weakened system (Tropical Depression will bring heavy rains).

* Disruptions of rail,air,road traffic is possible around the capital Bhubaneshwar. 

PRECAUTIONS (Via BOM: Bureau of Meteorology, Australia) 

When a cyclone watch is issued (Extended for North East AP and areas in orange colour in the alert map) 

• Re-check your property for any loose material and tie down (or fill with water) all large, relatively light items such as boats and rubbish bins.
• Fill vehicles' fuel tanks. Check your emergency kit and fill water containers.
• Ensure household members know which is the strongest part of the house and what to do in the event of a cyclone warning or an evacuation.
• Tune to your local radio/TV for further information and warnings.
• Check that neighbours are aware of the situation and are preparing.

When a cyclone warning is issued (Odisha coast) 

Depending on official advice provided by your local authorities as the event evolves; the following actions may be warranted.

• If requested by local authorities, collect children from school or childcare centre and go home.
• Park vehicles under solid shelter (hand brake on and in gear).
• Put wooden or plastic outdoor furniture in your pool or inside with other loose items.
• Close shutters or board-up or heavily tape all windows. Draw curtains and lock doors.
• Pack an evacuation kit of warm clothes, essential medications, baby formula, nappies,
  valuables, important papers, photos and mementos in waterproof bags to be taken with
  your emergency kit. Large/heavy valuables could be protected in a strong cupboard.
• Remain indoors (with your pets). Stay tuned to your local radio/TV for further information.
• DON'T TRAVEL TO COASTAL AREAS TO SEE THE TROPICAL CYCLONE

Dry phase of the monsoon to begin very soon

METD WEATHER
Akshay Deoras
Severe Weather Forecaster

SW Monsoon has been very active in some parts of the nation in recent but the conditions are going to change very soon.

The above image from CPC shows the propagation of the MJO ( Madden Julian Oscillation). As can be seen, a region having orange, red-orange color will be approaching over India from 20th June 2013. This is a textbook dry-phase of the MJO where the precipitation will be suppressed in India ( which at the moment is enhanced). As a result of this, the rainfall amount in India from 19-20th June will go down considerable. Break-monsoon conditions are very likely due to the same effect. 

It looks like another enhanced convection/rainfall phase will arrive over India from Mid July 2013. 

*** Heavy rains are likely in a wide area in North India stretching from Himachal Pradesh, Uttaranchal, Western Nepal, Western Uttar Pradesh,Central Uttar Pradesh, Haryana and around and Southern, South-Eastern, Eastern Gujarat and around till 19th June 2013 

Light rains are also expected in Delhi-NCR in the tenure. 

Rainfall will be relaxing in Central India from tomorrow/day after tomorrow onwards. 

Monsoon arrives in Bangalore, heads slowly towards Goa

METD WEATHER
AKSHAY DEORAS
SEVERE WEATHER FORECASTER

Based on METD WEATHER's norms ( See here for details- http://www.facebook.com/notes/metd-weather/norms-for-the-onset-of-sw-monsoon-metd-weather/216135871743180)

SW Monsoon arrived in Karnataka yesterday i.e 4th June 2013 covering a northern limit of Mangalore-Bangalore.

However, there hasn't been any significant rainfall in Tamil Nadu particularly Chennai ( excluding the thunderstorm related rainfall on 2nd June 2013) and hence the primary criterion of rainfall as per the norms is missing due to which METD WEATHER isn't considering the SW Monsoon onset in Tamil Nadu. However more analysis will be done on it today,5th June 2013.

However, IMD advanced the SW Monsoon as north as Southern Maharsahtra, North Central Andhra Pradesh.. Their onset norms are very unclear and hence its being suspected that they violated the norms which includes rainfall, wind direction as not so major rainfall was reported in the regions since June 1st 2013 nor there is an appreciable wind structure blowing from West/South West direction in all the layers of atmosphere till 600mb. Infact, the wind at lower atmospheric profiles ( like 700mb etc) is blowing from the East/South East instead of West/South West in the further lower profile like 850,925mb etc.

Here is a GFS meteogram of Panaji for the next few days

One can note that the 2m RH plot showing the surface relative humidity is still dropping to a minimum of around 50% whereas as per METD WEATHER's norms, it should be atleast/above 60% for 48hrs. Hence METD WEATHER doesn't agree with IMD's advancement

However, it can be seen from 9th June 2013 that the conditions are changing. Its very clear that all the factors are coming together including the wind direction,speed,rainfall amounts,RH etc.

As a result of which, SW Monsoon will advance into Goa during 11-12th June 2013. Before that, it will reach south of Goa i.e north of Karnataka ON TIME AS PER METD WEATHER's forecast of 8-10 June

SW Monsoon will also arrive in Chennai and subsequent Tamil Nadu around 11th June as the conditions come together

The next destination will be Pune ( As I don't see major rainfall for Hyderabad and Andhra Pradesh as the bay branch is inactive at the moment just like Chennai is not getting rains).

Parameters like wind,pressure, rains will start stabilising around 12/13 June 2013 and hence SW Monsoon will be reaching Pune on 15/16th June 2013. See the meteogram here ( http://monsoondata.org/wx/punegfs.png)

Next will be Mumbai! SW Monsoon will reach Mumbai in a day or so after reaching Pune. Hence the onset will likely be around 17/18th June 2013.

SW Monsoon will be arriving in Nagpur on 19/20th June as per the present situation.

Worrying factor -

The Madden Julian Oscillation (MJO) had a wet phase till now due to which there was enhanced rainfall in west coast of India. Heavy pre-monsoon/ system influenced rainfall will likelyinitiate in these areas after around 10th June 2013 and then the dry phase of MJO will take over. Due to this dry phase, its very likely that the monsoon's speed will be a bit slow and also will be the rainfall amounts. Hence the monsoon will taking so much time to reach the areas . 

The Arabian Sea low pressure will fizz away vey soon. It already did what one had feared off i.e pulling moist ladend winds and clouds. However IMD went forward and declared the monsoon to everyone's surprise in Southern Maharashtra! 

Central India will be getting the first heavy pre monsoon showers around 7-9th June 2013.