Dangerous Cyclone Mahasen gathering strength in the Bay of Bengal

By: Dr. Jeff Masters , 4:25 PM GMT on May 11, 2013

Dangerous Tropical Cyclone Mahasen is gathering strength over the Indian Ocean's Bay of Bengal, and is a potential major threat to Bangladesh and Myanmar. The 11 am EDT Saturday advisory from the Joint Typhoon Warning Center put Mahasen's top sustained winds at 55 mph, with a motion northwest at 19 mph into the center of the Bay of Bengal. Satellite loops show that Mahasen has a large area of intense thunderstorms with very cold cloud tops that reach high into the atmosphere. The cloud pattern is not well-organized, with little spiral banding. However, the cyclone has developed respectable upper-level outflow channels to the north and east, which are ventilating the storm by carrying away air converging to the center near the surface. High wind shear of 20 - 25 knots is affecting the storm, which is keeping the system disorganized. However, wind shear has declined about 5 knots since Friday, and is predicted to fall to the moderate range, 10 - 20 knots, by Sunday. This should allow organization into a Category 1 storm on Sunday. Aiding this process will be Mahasen's motion away from the Equator, which will help the cyclone leverage the Earth's spin to get itself spinning faster. Also aiding the intensification process will be ocean waters that are an exceptionally warm 31°C (88°F). This is about 1°C warmer than average for this time of year.


Figure 1. Latest satellite image of Tropical Cyclone Mahasen gathering strength over the Indian Ocean's Bay of Bengal.

Forecast for Mahasen
The official forecast brings Mahasen to Category 1 strength before landfall occurs in Bangladesh near the Myanmar border on Wednesday. Comparative model forecasts of Mahasen from the GFS, ECMWF, UKMET, GEM, NAVGEM, and FIM models show wide disagreement on the future intensity and speed of the storm, though. It is possible that wind shear will keep the storm disorganized and below hurricane strength until landfall, as suggested by the GFS and ECMWF models. The 06 UTC forecast from the HWRF model brings Mahasen to Category 3 strength on Monday, but weakens the storm to tropical storm strength at landfall. The model predicts that the storm will dump a significant area of heavy rains of 32 cm (12.6") over Maynmar and Bangladesh. The storm surge, high winds, and heavy rains of Mahasen are a huge concern for the thousands of Myanmar refugees living near the coast in makeshift camps, as reported by the New York Times.


Figure 2. Double trouble: Tropical Cyclone Jamala (lower) and Tropical Cyclone Mahasen (upper storm) spin on opposite sides of the Equator in this in this MODIS image taken at 04:25 UTC May 10, 2013. Mahasen is the name of a King of Sri Lanka from the 3rd century. Image credit: NASA.

MJO pulse that spawned Mahasen headed towards the Atlantic
Mahasen spun up in response to an active phase of the Madden Julian Oscillation (MJO) that has been moving through the Indian Ocean during the past week. The MJO is a pattern of increased thunderstorm activity near the Equator that moves around the globe in 30 - 60 days. The strong MJO pulse coincided with a convectively coupled atmospheric Kelvin wave (CCKW), a wave of increased heat and moisture propagating along the Equator, which helped increase thunderstorm activity. The active pulse of the Madden Julian Oscillation is expected to reach the Western Caribbean sometime May 22 - 26, and there will be a heightened chance of an early-season tropical storm forming in the Eastern Pacific and Western Caribbean during that time period.

There is a small disturbance a few hundred miles north of Puerto Rico today that has developed some spin and a bit of heavy thunderstorm activity. This system is over cool waters of 77 - 79°F, and will likely be torn apart by high wind shear on Sunday.

Resources
Comparative model forecasts of Mahasen from the GFS, ECMWF, UKMET, GEM, NAVGEM, and FIM models

India Meteorological Department's tropical cyclone page

Bangladesh Meteorological Department Warning

Myanmar Dept. of Meteorology and Hydrology Warning

Tutorial on Equatorial Waves in the COMET program's Introduction to Tropical Meteorology, plus their case exercise built around the May 2002 "twin twins" case, for use in a tropical synoptic course.

Jeff Masters

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Quoting AussieStorm:

Where does it develop the "system"? Does that mean in 10 days the shear will drop down 70kts??

The southwestern Caribbean.

You must not be familiar with early season development in the region.
Member Since: December 31, 1969 Posts: Comments:
Happy Mother's Day to all of the Mother's who blog on here. Really nice weather along the SE & Gulf today so I hope your Son's & Hubby's hook you up today. No excuse not to grill or barbeque on such a beautiful day if that is the plan.
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Won't be getting any relief from the marine layer here today.

Happy Mothers Day to ALL......
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Quoting AussieStorm:

Go ahead and post 1000hrs out, But don't say oh, it will likely happen. Even I post the CFS for laughs, and that's all it can be posted for.


I do believe I posted the CFS the last week and gave credit to VR about how it was still showing the May 15-17 storm and you corrected me stating you posted the model first..just for laughs huh..sound like you wanted credit for posting a long range model run..cant have it both ways Aussie:)..let people post what they want..Im sure it has been stated here plenty of times especially by me about our responsibility here in relaying information and what could happen..there are other things that could be discussed here if we didnt have long range model runs and we all know how that goes..
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If you see at 192 hours,a low pressure center is already forming in the region, so, we are in less than a couple days to see the consensus with the other models..
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Quoting TropicalAnalystwx13:

You realize it begins developing the storm at day 10, 240 hours...?

Where does it develop the "system"? Does that mean in 10 days the shear will drop down 70kts??
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Quoting VR46L:
Only just noticed something ... Oh well

Anyway


Even in rainbow ,the blob people were wanting to call an invest, doesn't look impressive




Not all the blob people. :)
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564. JRRP
Member Since: December 31, 1969 Posts: Comments:
Quoting AussieStorm:

LOL, you seriously think what the GFS is showing 380+hrs out will come true? Crazy

You realize it begins developing the storm at day 10, 240 hours...?
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Quoting ncstorm:


you are on a weather blog and you are asking people to stop posting weather model long range runs??..you going to hate me then because I post the CFS and that goes out to a 1000 hours..the long range on these models are out there for a reason..if you are tired of seeing them, then perhaps you might be on the wrong blog?..

oh and Good Morning to all and happy mothers day!!


Go ahead and post 1000hrs out, But don't say oh, it will likely happen. Even I post the CFS for laughs, and that's all it can be posted for.
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Quoting SFLWeatherman:
GFS


Thanks SFL..
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Quoting AussieStorm:
Can we give it a break on posting what the models are saying 380 hrs out. 240hrs is 10 days, and we know how bad the models are that far out. times that by 1000 and your close to how bad they are. Wait til they show maybe 240hrs then we have to start watching but posting 240hrs and it's dreaming.


you are on a weather blog and you are asking people to stop posting weather model long range runs??..you going to hate me then because I post the CFS and that goes out to a 1000 hours..the long range on these models are out there for a reason..if you are tired of seeing them, then perhaps you might be on the wrong blog?..

oh and Good Morning to all and happy mothers day!!

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558. VR46L
Quoting pcola57:


Sorry,I think you were referring to this one..
More coffee please..Lol.. :)





Pcola..... lol yeah the one north of the Islands ...

Cant see the images
Member Since: December 31, 1969 Posts: Comments:
557. VR46L
Quoting pcola57:


I agree..
Models are models..
Your weather is sloppy/cloudy again..









Can you just cruise to the beach in the auto and check it out?
Or are you too absorbed by the football?


I am only about 500 yards from the beach ... Might go for a walk in a little while ...
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Member Since: December 31, 1969 Posts: Comments:
http://weathercurrents.com/riverside/ArchivePrecipi tation.do

Riverside (Canyon Crest), California Precipitation Summary

Normal season: July 1 through June 30

Average seasonal precipitation: 7.76"(197.1 mm)1
Season Precipitation
2005-2006 4.69" (119.1 mm) *
2006-2007 2.15" (54.6 mm)
2007-2008 7.35" (186.6 mm)
2008-2009 6.68" (169.6 mm)
2009-2010 10.21" (259.3 mm)
2010-2011 14.55" (369.5 mm)
2011-2012 5.62" (142.7 mm)
2012-2013 4.62" (117.3 mm)

* Actual season start date: January 21, 2006

1Average precipitation does not include incomplete rain seasons or the current rain season.

This is closer to the southeast part of the city up in the hills by the 215 freeway
Member Since: December 31, 1969 Posts: Comments:
Quoting TropicalAnalystwx13:

That's their issue. It's been stated here countless times that though the system is still in the long range, and though it has a good possibility of eventually panning out, we still need to watch for better consistency between other models and the GFS, and even between those models and their ensembles.

LOL, you seriously think what the GFS is showing 380+hrs out will come true? Crazy
Member Since: December 31, 1969 Posts: Comments:
Quoting VR46L:
Only just noticed something ... Oh well

Anyway


Even in rainbow ,the blob people were wanting to call an invest, doesn't look impressive




I thinking EastPac will absorb it as it's getting ripe there now..
(Looking at the South Carrib..)
Member Since: December 31, 1969 Posts: Comments:
GFS
Member Since: December 31, 1969 Posts: Comments:
551. VR46L
1:29 PM GMT on May 12, 2013
Only just noticed something ... Oh well

Anyway


Even in rainbow ,the blob people were wanting to call an invest, doesn't look impressive


Member Since: December 31, 1969 Posts: Comments:
550. SFLWeatherman
1:28 PM GMT on May 12, 2013
240HR out cmc
Member Since: December 31, 1969 Posts: Comments:
549. pcola57
1:27 PM GMT on May 12, 2013
Quoting PedleyCA:

2.31 since Jan 1, 2013


That seems a little low Ped..
Is that normal for ya?
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548. pcola57
1:25 PM GMT on May 12, 2013
Quoting VR46L:


Na nothing special ... its not Mothers day here !cant even go down to the beach for a walk only 50°F and raining :( Just watching the racing and some soccer .

Yeah I know , I am a bit like that .. but I take models with a pinch of salt unless it continues showing it and moves up the the timeframe !


I agree..
Models are models..
Your weather is sloppy/cloudy again..









Can you just cruise to the beach in the auto and check it out?
Or are you too absorbed by the football?
Member Since: December 31, 1969 Posts: Comments:
547. PedleyCA
1:23 PM GMT on May 12, 2013
Quoting pcola57:


Wow Ped..
Morning to you too..
Your warming up quite nicely now..
How are you in the rain catagory?

2.31 since Jan 1, 2013
Member Since: December 31, 1969 Posts: Comments:
546. PedleyCA
1:18 PM GMT on May 12, 2013
Good Monday Aussie...
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545. pcola57
1:17 PM GMT on May 12, 2013
Quoting PedleyCA:
Good Morning, pcola57, and Good Afternoon VR46L, 65.0 here this morning, was 93.8 here yesterday, 99 at the Airport. Should be HOT again today.


Wow Ped..
Morning to you too..
Your warming up quite nicely now..
How are you in the rain catagory?
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544. TropicalAnalystwx13
1:15 PM GMT on May 12, 2013
Quoting AussieStorm:

Yeah, there is fun then there is saying... oh I think it will happen. Come on Give me a break. If a noob came in here and saw us talking about a fictitious system, they might believe us and freak out.

That's their issue. It's been stated here countless times that though the system is still in the long range, and though it has a good possibility of eventually panning out, we still need to watch for better consistency between other models and the GFS, and even between those models and their ensembles.
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543. VR46L
1:14 PM GMT on May 12, 2013
Hiya Ped ! Good Morning to ya to!!
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542. PedleyCA
1:13 PM GMT on May 12, 2013
Good Morning, pcola57, and Good Afternoon VR46L, 65.0 here this morning, was 93.8 here yesterday, 99 at the Airport. Should be HOT again today.
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541. AussieStorm
1:11 PM GMT on May 12, 2013
Quoting MAweatherboy1:

You're probably right, but that doesn't mean we can't have some fun with it. What else can we do at this time of year besides post long range model runs?

Yeah, there is fun then there is saying... oh I think it will happen. Come on Give me a break. If a noob came in here and saw us talking about a fictitious system, they might believe us and freak out.
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540. VR46L
1:09 PM GMT on May 12, 2013
Quoting pcola57:


Good Morning/Afternoon to you VR46L..
Some are just reacting naturally to a long and,to them, boring off season..
I don't blame them..
But I've learned to take this time of year with a grain of salt..

Doing anything special today?


Na nothing special ... its not Mothers day here !cant even go down to the beach for a walk only 50°F and raining :( Just watching the racing and some soccer .

Yeah I know , I am a bit like that .. but I take models with a pinch of salt unless it continues showing it and moves up the the timeframe !
Member Since: December 31, 1969 Posts: Comments:
539. pcola57
1:06 PM GMT on May 12, 2013
Once again Good Mornig All..
68 degrees with 78%rh and dew at 61..
Winds 7 from NNE..
Clear blue skies..

No doubt these two beach areas will be packed later..



Member Since: December 31, 1969 Posts: Comments:
538. Tropicsweatherpr
1:06 PM GMT on May 12, 2013
Quoting nrtiwlnvragn:
The system the GFS is forecasting must be marginal, and the lower performance of the 00Z cycle in the tropics may be hinting at that, thus dropping it for that cycle.


A Comparison of Forecast Skills among GFS Four Cycles in the Past Ten Years








Very interesting.
Member Since: December 31, 1969 Posts: Comments:
537. JRRP
12:59 PM GMT on May 12, 2013
Joe Bastardi ‏@BigJoeBastardi 2min

GFS spinning up TS for Memorial day in w carib. Think this is because its too fast on MJO.. probably will happen, but later ( June)
Member Since: December 31, 1969 Posts: Comments:
536. CybrTeddy
12:58 PM GMT on May 12, 2013
Unreal. It's predicted to get into the lower 50s and upper 40s throughout Florida.. in nearly mid-May!
Member Since: December 31, 1969 Posts: Comments:
535. pcola57
12:57 PM GMT on May 12, 2013
Quoting barbamz:
Very different topic, but a very eery video as well!

Ice sheet creeps ashore on Minnesota lake

12 May 2013 Last updated at 10:08 GMT Help

A creeping wave of ice has come ashore on the banks of Lake Mille Lacs in Minnesota.

Strong winds pushed floes towards the water's edge creating cascades of ice crystals which have pushed up against trees and houses.

No one has been injured by the ice, but one home has reportedly suffered mild damage.


Thats one cool video barb..
Thanks for sharing.. :)
Member Since: December 31, 1969 Posts: Comments:
534. MAweatherboy1
12:57 PM GMT on May 12, 2013
Quoting AussieStorm:

It's seeing a ghost storm. Does it every year

You're probably right, but that doesn't mean we can't have some fun with it. What else can we do at this time of year besides post long range model runs?
Member Since: December 31, 1969 Posts: Comments:
533. pcola57
12:56 PM GMT on May 12, 2013
Quoting VR46L:


Aw Aussie ! they are like watching a film a source of entertainment ... sometimes its a comedy , thriller or horror ! and folks reactions are interesting . but thats just my opinion but I do believe the GFS program is seeing something @ 300hr just its not sure what yet !


Good Morning/Afternoon to you VR46L..
Some are just reacting naturally to a long and,to them, boring off season..
I don't blame them..
But I've learned to take this time of year with a grain of salt..

Doing anything special today?
Member Since: December 31, 1969 Posts: Comments:
532. barbamz
12:56 PM GMT on May 12, 2013
Very different topic, but a very eery video as well!

Ice sheet creeps ashore on Minnesota lake

12 May 2013 Last updated at 10:08 GMT Help

A creeping wave of ice has come ashore on the banks of Lake Mille Lacs in Minnesota.

Strong winds pushed floes towards the water's edge creating cascades of ice crystals which have pushed up against trees and houses.

No one has been injured by the ice, but one home has reportedly suffered mild damage.
Member Since: December 31, 1969 Posts: Comments:
531. WxLogic
12:52 PM GMT on May 12, 2013
Morning... and Happy Mother's day.
Member Since: December 31, 1969 Posts: Comments:
530. TropicalAnalystwx13
12:52 PM GMT on May 12, 2013
The 6z GFS full resolution shows a weak tropical storm headed for southwestern Florida at the end of its run, after beginning to develop south of Jamaica well before that.

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529. AussieStorm
12:50 PM GMT on May 12, 2013
Quoting VR46L:


Aw Aussie ! they are like watching a film a source of entertainment ... sometimes its a comedy , thriller or horror ! and folks reactions are interesting . but thats just my opinion but I do believe the GFS program is seeing something @+300hr just its not sure what yet !

It's seeing a ghost storm. Does it every year
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528. AGWcreationists
12:50 PM GMT on May 12, 2013
Quoting CaicosRetiredSailor:
In the history of U.S. military research, there’s never been a project with such a combination of big science, high sleaze, and pure conspiratorial strangeness. Yet somehow, some way, the story of the High Frequency Active Auroral Research Program, or HAARP, just got sleazier and stranger — all thanks to an elderly physicist named Alfred Wong.

Wong was an early proponent of HAARP, who used the facility in his studies of the ionosphere, the electrically-charged portion of the atmosphere. He also was something of a serial con man, according to a federal plea agreement provided to Danger Room. (.pdf) On Thursday, Wong agreed to pay nearly $1.7 million in damages for falsely billing Darpa and the Interior Department. He also plead guilty to a host of fraud charges.

HAARP was originally pitched back in the Cold War as a way for plasma physicists to study the ionosphere by blasting it with radio frequency emissions. If you build this series of RF antennas in remote Alaska, the scientists told the Pentagon, HAARP wound not only advance our understanding of this crucial field. It could also be used to fry incoming Soviet missiles and spy on underground bunkers. One physicist working for the Arco oil-and-gas conglomerate even suggested that HAARP could be used to weaponize hurricanes — that is, if Arco’s natural gas fields were used to power the thing.

Well, knock me over with a feather. Someone misrepresented a project and mis-used federal pork for personal uses. Talk about a dog bites man story.
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527. pcola57
12:49 PM GMT on May 12, 2013
Happy Mothers Day for all our mothers out there.. :)

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526. islander101010
12:49 PM GMT on May 12, 2013
big bend area of fl. seems to be a magnet for these early atlantic season storms.
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525. VR46L
12:49 PM GMT on May 12, 2013
BTW Good Morning Folks !
Member Since: December 31, 1969 Posts: Comments:
524. barbamz
12:48 PM GMT on May 12, 2013
Cyclone Mahasen losing steam as it tracks across Bay
Thiruvananthapuram, May 12:

The Regional Specialised Meteorological Centre (RSMC) at New Delhi has hinted that tropical cyclone Mahasen in the Bay of Bengal may have started weakening this morning.

It cited satellite imageries to deduce that the cloud system packing into the storm structure has disorganised, weakening it.

LANDFALL AREA

Mahasen moved northwestwards and lay centered 600 km west-southwest of Car Nicobar; 700 km northeast of Trincomalee (Sri Lanka); 850 km southeast of Chennai; and 1,450 km south-southwest of Chittagong in Bangladesh.

It would initially move northwestwards during the next 36 hours and re-curve thereafter northeastwards towards the Bangladesh-Myanmar coast.

But the US Navy’s Joint Typhoon Warning Centre (JTWC) has recalibrated the expected point of landfall as just north of Chittagong in Bangladesh by Wednesday.

The RSMC estimated the sustained maximum surface wind speed at about 74 km/hr gusting to 93 km/hr this morning.

TEMPORARY PHASE

The weakening trend of Mahasen could be temporary, it observed. Prevailing ocean and atmosphere factors support the case for its strengthening as a severe cyclonic storm.

A similar outlook has come in from the US Navy’s JTWC. In its latest update issued at 8.30 a.m. it too noted that the large and densely overcast feature in the system centre has broken up.

Convection (evaporation and moisture-building) has become fragmented, but feeder cloud bands have wrapped tighter into the storm centre.

Mahasen could slow down before it turns northeastward in response to an approaching western disturbance from Northwest India.

VARYING OUTLOOK

But the storm may continue to intensify to clock a peak of 157 km/hr in a couple of days as it makes landfall just north of Chittagong as a moderate cyclone.

Other models are also in better agreement with the re-curve scenario towards Bangladesh but with varying track speeds over the period leading up to landfall.

The European Centre for Medium-Term Weather Forecasts and the UK Met Office do not see scope for intensification; rather they expect Mahasen to weaken after re-curving. vinson.kurian@thehindu.co.in


Source
Member Since: December 31, 1969 Posts: Comments:
523. VR46L
12:48 PM GMT on May 12, 2013
Quoting AussieStorm:
Can we give it a break on posting what the models are saying 380+hrs out. 240hrs is 10 days, and we know how bad the models are that far out. times that by 1000 and your close to how bad they are. Wait til they show maybe 240hrs then we have to start watching but posting + 240hrs and it's dreaming.


Aw Aussie ! they are like watching a film a source of entertainment ... sometimes its a comedy , thriller or horror ! and folks reactions are interesting . but thats just my opinion but I do believe the GFS program is seeing something @+300hr just its not sure what yet !
Member Since: December 31, 1969 Posts: Comments:
522. pcola57
12:47 PM GMT on May 12, 2013
Quoting Dakster:


It ONLY takes ONE to wreck your day.


Or year..
Good Morning Dak..
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