New Caribbean disturbance 93L a major concern; flooding in Asia kills over 200

By: Dr. Jeff Masters , 2:50 PM GMT on June 21, 2010

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A concentrated region of intense thunderstorms associated with a tropical wave has developed in the central Caribbean, a few hundred miles south of Puerto Rico. This disturbance was designated Invest 93L by NHC this morning, and has the best chance to become Tropical Storm Alex of any system we've seen so far this year. The disturbance is located near Buoy 42059, and this buoy has been reporting winds of 5 - 15 knots this morning. So far, pressures are not falling. Water vapor satellite loops show that 93L is embedded in a large region of moist air. Some dry continental air from North America is over the western Caribbean, but this dry air is too far away to interfere with development today and Tuesday. Wind shear is a low 5 - 10 knots. The high wind shear associated with the strong winds of the subtropical jet stream are over the northern Caribbean, too far north to interfere with development. Sea Surface Temperatures are plenty warm, a record 29 - 30°C. The Madden-Julian oscillation currently favors upward motion over the Caribbean, which will act to increase the chances of tropical storm formation this week. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased. The only negative for 93L would seem to be the lack of spin; the University of Wisconsin 850 mb relative vorticity analysis is showing only meager amounts of spin at 850 mb (roughly 5,000 feet in altitude.)


Figure 1. Morning visible satellite image of the central Caribbean disturbance 93L.

Forecast for 93L
NHC is giving 93L a 20% chance of developing into a tropical depression by Wednesday morning, which is a reasonable forecast. With wind shear expected to drop to low values less than 10 knots over the central and western Caribbean this week (Figure 2), I don't see any major impediments to the storm becoming a tropical depression by Friday. The ECMWF model is the most aggressive in developing this system, taking it into the Gulf of Mexico as a hurricane next week. The NOGAPS model keeps the storm weak and farther south, predicting that 93L will bring heavy rains to northern Honduras as a tropical disturbance or tropical depression on Friday and Saturday. The GFS model does not develop 93L. Expect 93L to bring flooding rains of 3 - 6 inches to Jamaica, eastern Cuba, and extreme southwestern Haiti on Wednesday. These rains will spread to the Cayman Islands and central Cuba by Thursday.


Figure 2. Predicted wind shear for Friday, June 25, as forecast by this morning's 2am EDT run of the GFS model. Shear is given in meters per second; multiply by about two to convert to knots. Low wind shear values less than 6 m/s (12 knots) are predicted for much of the Western Caribbean this week.

Elsewhere in the tropics
The tropical wave (92L) that brought heavy rains of 2 - 5 inches to Puerto Rico on Saturday has weakened and is no longer a threat to bring flooding rains to the Caribbean.

Floods in China and Burma kill over 200
The deadliest and most destructive weather-related disaster on the planet so far this year is occurring in southern China and northern Burma, where a week of heavy rains has caused flooding that has claimed over 200 lives. The death toll stands at 175 in China and 63 in Burma, with more than 100 people still missing in China. Damage so far in China has been estimated at $4.3 billion.


Figure 3. Tree branches hung on a bridge at Taining County, southeast China's Fujian Province, June 19, 2010. Taining recorded 225 mm (9 inches) of rain in six hours on Friday. Image credit: Xinhua/Jiang Kehong.

Montana tornado rips roof off entertainment complex
A EF-2 tornado with winds of at least 100 mph ripped the roof of an entertainment complex in Billings, Montana on Sunday, causing up to $15 million in damage. No injuries were reported. It was the strongest tornado to hit the Billings area since 1958.


Figure 4. Video of the Billings tornado shows an impressive debris cloud (and a few expletives not deleted!) The clear slot on the right of the tornado is likely associated with the parent thunderstorm's rear flank downdraft.

Wind and ocean current forecast for the BP oil disaster
Southeast to east winds less than 10 knots will blow in the northern Gulf of Mexico today through Friday, according to the latest marine forecast from NOAA. The resulting weak ocean currents should cause little motion of the oil slick, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The long range outlook is uncertain, as the tropical wave over the central Caribbean could enter the Gulf of Mexico early next week and develop into a tropical storm.

Resources for the BP oil disaster
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool allows one to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Jeff Masters

Billings, MT tornado (StormTeam)
Photo taken from approx. 5-6 miles east. Video here: http://www.youtube.com/watch?v=8429C0-LSlo
Billings, MT tornado

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2578. Grothar
Quoting futuremet:


It still seems to be an inverted trough. I see no significant west winds at the southern side.


Could that be because the Southern periphery is so close to a land mass? Would that prevent it?
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2576. Drakoen
Looks like wewe will be getting a Windsat pass tonight on the system
Member Since: October 28, 2006 Posts: 57 Comments: 29714
2575. ryang
Vorticity increasing

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http://www.ecmwf.int/products/forecasts/d/animate/catalog/products/forecasts/medium/deterministic/msl _uv850_z500!Wind%20850%20and%20mslp!144!North%20America!pop!od!oper!public_plots!2010062100!!!step/
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Quoting scott39:
Why did the intensity models drop after 108 hours? Is there some help in the GOM to knock 93L down some after developement?
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2571. Grothar
Quoting Acemmett90:

this storm may have a pin wheel eye if it ever gets up the hurricane status


I hope not, but it is a large system.
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2570. pottery
Quoting CosmicEvents:

It doesn't help them spin no matter how much you YELL at them.

Brilliant!
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This is going to be a painfully long season with all of this back and forth and misinformation
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Quoting Acemmett90:

people are jsut doing that cuz they want to stir up crap


Exactly
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2567. Patrap
www.hurricanecity.com/closeup 98L
Member Since: July 3, 2005 Posts: 415 Comments: 125628
Quoting tropicfreak:
GUYS WE ARE GOING THROUGH DMIN, DON'T WRITE THIS OFF JUST BECAUSE IT IS WEAKENING, WHAT ARE YOU THINKING, IT WILL HIT DMAX SOON. IT DOESN"T TAKE LESS THAN A DAY TO FORM BE PATIENT!!!!!!

It's not weakening, it remains structurally sound. It is even improving in organization.
Member Since: May 16, 2009 Posts: 1 Comments: 1231
Quoting tropicfreak:
GUYS WE ARE GOING THROUGH DMIN, DON'T WRITE THIS OFF JUST BECAUSE IT IS WEAKENING, WHAT ARE YOU THINKING, IT WILL HIT DMAX SOON. IT DOESN"T TAKE LESS THAN A DAY TO FORM BE PATIENT!!!!!!

It doesn't help them spin no matter how much you YELL at them.
Member Since: August 3, 2005 Posts: 10 Comments: 5459
KEEPEROFTHEGATE,does 93L getting close to TCFA status?
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Quoting bappit:


Yep, very disorganized, like you say Centex. I'm inclined to write this one off. No center, no nothing.


Agree.
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2559. scott39
Why did the intensity models drop after 108 hours? Is there some help in the GOM to knock 93L down some after developement?
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Quoting TampaSpin:


EXCELLENT.....there is hardly much at 850mb Vorticity....that is not an Excellent sign IMO!
We are speaking about structure. Anyways there is a weak broad area of low pressure at the surface, just take a look at the TWD.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
2555. JRRP
Quoting MiamiHurricanes09:
Amazing how accurate they are. Time for the shutters. Lol.

jejejeje
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GUYS WE ARE GOING THROUGH DMIN, DON'T WRITE THIS OFF JUST BECAUSE IT IS WEAKENING, WHAT ARE YOU THINKING, IT WILL HIT DMAX SOON. IT DOESN"T TAKE LESS THAN A DAY TO FORM BE PATIENT!!!!!!
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Quoting TampaSpin:


ONe can see on the Wind Barbs that a Surface Low is forming.....HERE WE GO!


It still seems to be an inverted trough. I see no significant west winds at the southern side.
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2552. fire635
Quoting Grothar:
From this image, it won't probably be long before it starts trying to wrap around that large circulation.



I agree... its definitely setting the stage.. soon (relatively speaking) it should start to wrap around and consolidate
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Quoting weatherwatcher12:

It is not disorganized. Well convection wise maybe, but structurally as Drak said it is excellent.


EXCELLENT.....there is hardly much at 850mb Vorticity....that is not an Excellent sign IMO!
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2549. Patrap
Floater - RGB Color Infrared Loop
Member Since: July 3, 2005 Posts: 415 Comments: 125628
Quoting Stormchaser2007:
Looks like 93L is going to consolodate tonight.

We still have people writing this off...so impatient. Tropical cyclone formation does not take 12 hours. Its a process.
Especially that this is just the genesis, 93L just begun, long ways to go.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
2547. fire635
Quoting Acemmett90:

wow d-min is brutalising 93L


I wouldnt say its being "brutalized" by any means
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2546. Grothar
From this image, it won't probably be long before it starts trying to wrap around that large circulation.

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Quoting bappit:


Yep, very disorganized, like you say Centex. I'm inclined to write this one off. No center, no nothing.


You forgot something


SARCASM: ON
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2544. pottery
Quoting kimoskee:
when did NHC upgrade to a 50% chance of becoming a cyclone?

What is the chance of it increasing further in the next 12 hrs?

1- at 8:00pm
2- dont know for sure, but.....
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Quoting bappit:


Yep, very disorganized, like you say Centex. I'm inclined to write this one off. No center, no nothing.

It is not disorganized. Well convection wise maybe, but structurally as Drak said it is excellent.
Member Since: May 16, 2009 Posts: 1 Comments: 1231


ONe can see on the Wind Barbs that a Surface Low is forming.....HERE WE GO!
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Looks like 93L is going to consolidate tonight.

We still have people writing this off...so impatient. Tropical cyclone formation does not take 12 hours. Its a process.
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2537. Patrap
Floater - Rainbow Color Infrared Loop
Member Since: July 3, 2005 Posts: 415 Comments: 125628
Quoting JRRP:

this is from the last season

Amazing how accurate they are. Time for the shutters. Lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting P451:
93L
9 Hour IR Loop
30 Minute Increments per frame
Ending 915PM ET



Great structure, but very weak circulation.
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2534. bappit
Quoting Patrap:
0045 UTC



2km Storm Relative IR Imagery with BD Enhancement Curve

The same infrared imagery shown in the earth relative framework is displayed in a storm relative framework, with a 2km resolution and enhanced with the "BD Curve" which is useful for directly inferring intensity via the Dvorak Enhanced IR (EIR) technique. Scaling is provided by two lightly hatched circles around the center. The two circles have radii of 1 and 2 degrees latitude, respectively.


Yep, very disorganized, like you say Centex. I'm inclined to write this one off. No center, no nothing.
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2533. JRRP
Quoting MiamiHurricanes09:
Want scary graphs?






this is from the last season

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when did NHC upgrade to a 50% chance of becoming a cyclone?

What is the chance of it increasing further in the next 12 hrs?
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Celia up to 100mph
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2528. hydrus
Quoting RecordSeason:
Is it just me, or is this thing BIGGER than Ike in radius?

It has a long way to go to develop and may shed some of the excess stuff far from the center, but still...

Massive wave...
92L was way larger when it was in the Central Atlantic.
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.