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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3778. aquak9
thank you walshy :)

figured it was something like that- kman's explanation prefaced it, all makes good sense
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3777. pottery
Quoting sailingallover:
Satellites don't think they just show..
There is no circulation, no COC,LCC nada..
Just an open wave...and with most of the convection heading north and getting sheared..

Agreed.
There are conflicting interpretations.........
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can we for get about the The John Hope rule are we be saying that with evere storm that comes a long too me its starting to get vary annyoing
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Quoting kmanislander:


93L is half way across the Caribbean and I don't think that vort will catch it. One scenario is that a new low spins up from that feature in the position where 93L is today in about 48 hours. We could see a new and entirely seperate threat develop from that very potent 850 mb feature.


Scottsvb was on here yesterday pointing out that is what's going to happen. He said Weds at the earliest for 93L and it would head into the Yucatan another feature was to develop behind and head NW, similar to what the CMC was showing yesterday. Seems reasonable looking at what's going on right now.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
3774. Drakoen
Quoting sailingallover:
Satellites don't think they just show..
There is no circulation, no COC,LCC nada..
Just an open wave...and with most of the convection heading north and getting sheared..


The descending pass comes out in the morning and has not loaded yet. Your image is showing the ascending pass.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
Time to get on with the day now. See you all later. Hopefully by then 93L will show signs of doing one thing or another.
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Quoting kmanislander:


One reason is that the winds tend to be very fast along the North coast of SA and this tends to undercut the formation of a West wind on the South side of a developing low. Ever been to Aruba ?. A calm day is 25 mph winds. I tried to play golf there once and the salt spray was so storng I had to clean my glasses every 10 minutes. Trees grow 6 feet tall and ten feet to the side. yesterday mornign winds were very light in the ABC islands but that is the exception rather than the rule.

These fast winds then tend to slow dramatically just off the coast of Nicaragua leading to big thunderstorm blow ups due to speed convergence.

Lastly, the Eastern Caribbean has less " sea room " than the Western Caribbean where the basin widens significantly with the area North of Panama. Thus, dry air entrainment from the SA continent can also play havoc with a weak system.

I am sure there are other elements I have not mentioned but put together they tend to discourage development there.


Usually just lurk and learn but just had to say thanks that was very clear, concise, and I think I understood it.
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Maybe the NHC can't access the Navy site either...lol. I think I see Alex starting to peek its head out from that diurnal mess!

Sailingallover you are in good company with KmanIslander; however, even though there is not yet a LLC it will take only a small nudge, possibly west, for that to happen.
Member Since: July 11, 2006 Posts: 14 Comments: 11390
Quoting Jeff9641:


THe coc has now formed and it seems to be pulling in all the moisture from the SE which tells me 93L is beginning to get more compact.

Show me on what you see a COC?
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3769. Drakoen
Quoting StormW:
Just got looking at some things (Drak, jump on board here if you wish)...I remember, I think it was last year, we had a system that didn't appear to be under any shear, but there was some at around 700MB if I remember...could be one thing here, as if you look at the vorticity map, doesn't appear to be too vertically stacked.

Water vapor imagery indicates some slight presence of dry air to the east of the "center"

WV LOOP


I see no evidence of mid level shear. Also the environment is very moist from 300mb to the surface based on the relative humidity out of San Juan, Puerto Rico.

Member Since: October 28, 2006 Posts: 57 Comments: 30615
3768. 7544
wow could this be right 2 states get hit at once lol

Link
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3767. pottery
Quoting kmanislander:


One reason is that the winds tend to be very fast along the North coast of SA and this tends to undercut the formation of a West wind on the South side of a developing low. Ever been to Aruba ?. A calm day is 25 mph winds. I tried to play golf there once and the salt spray was so storng I had to clean my glasses every 10 minutes. Trees grow 6 feet tall and ten feet to the side. yesterday mornign winds were very light in the ABC islands but that is the exception rather than the rule.

These fast winds then tend to slow dramatically just off the coast of Nicaragua leading to big thunderstorm blow ups due to speed convergence.

Lastly, the Eastern Caribbean has less " sea room " than the Western Caribbean where the basin widens significantly with the area North of Panama. Thus, dry air entrainment from the SA continent can also play havoc with a weak system.

I am sure there are other elements I have not mentioned but put together they tend to discourage development there.

Begins to make more sense. Thanks.
Never been to Aruba. But have seen those "DiviDivi" trees growing as though they have been sculpted by the wind.
Survival through aeronautical design!
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3766. Walshy
Quoting aquak9:
could someone give me a brief synopsis of the John Hope Rule?


The John Hope rule. If it hasn't developed by the time it gets in the eastern Caribbean, it won't until it reaches the western Caribbean.
Member Since: May 17, 2009 Posts: 2 Comments: 904
Satellites don't think they just show..
There is no circulation, no COC,LCC nada..
Just an open wave...and with most of the convection heading north and getting sheared..
Member Since: Posts: Comments:
Quoting RecordSeason:
Actually looks pretty impressive here.

Combination visible/ir



on 93L?
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Quoting DestinJeff:


you might be looking at the 00Z .. the 6Z takes it further west and not anywhere near as strong
Link


Thanks, I guess I was looking at an old run. I get most of my models from hamweather.com
Member Since: April 26, 2009 Posts: 3 Comments: 3667
3760. aquak9
sainthurrifan...whoa, blast from the past. :)
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Quoting Chicklit:

Good morning, is anyone else getting a server error when trying to access 93L on the Navy site?
Yes.
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Quoting stormpetrol:
take a good look at 93L on the visible sat loop, I think it actually looks more organized than some are giving it credit for, it actually has more of a spin with it this morning and seems to be in the process of establishing a well defined LLC, just my opinion of course.

Not really...still an open wave...I can't find any surface circulation yet.
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3754. IKE
Quoting SAINTHURRIFAN:
kaman thanks for the reply. im beginning to thank storm w and ike have me on block dont want to reply lol.


See post 3720. I was going to mention what the CMC shear run showed, but it looked like a bad run...or maybe it's just the CMC.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting SAINTHURRIFAN:
kaman thanks for the reply. im beginning to thank storm w and ike have me on block dont want to reply lol.


I doubt it. The blog is moving quite fast; not easy to field all the questions
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3751. aquak9
could someone give me a brief synopsis of the John Hope Rule?
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Quoting pottery:

Thanks. Clearly put.
I am still trying to understand WHY this is so.
There has to be a physical reason for it's behaviour, given the way it looked and was forecasted to behave.
50% is touch-and-go I know. But the mechanics is intriguing me!


One reason is that the winds tend to be very fast along the North coast of SA and this tends to undercut the formation of a West wind on the South side of a developing low. Ever been to Aruba ?. A calm day is 25 mph winds. I tried to play golf there once and the salt spray was so storng I had to clean my glasses every 10 minutes. Trees grow 6 feet tall and ten feet to the side. yesterday mornign winds were very light in the ABC islands but that is the exception rather than the rule.

These fast winds then tend to slow dramatically just off the coast of Nicaragua leading to big thunderstorm blow ups due to speed convergence.

Lastly, the Eastern Caribbean has less " sea room " than the Western Caribbean where the basin widens significantly with the area North of Panama. Thus, dry air entrainment from the SA continent can also play havoc with a weak system.

I am sure there are other elements I have not mentioned but put together they tend to discourage development there.
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Quoting IKE:


Mine works...Link

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kaman thanks for the reply. im beginning to thank storm w and ike have me on block dont want to reply lol.
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3743. IKE
Quoting Chicklit:

Good morning, is anyone else getting a server error when trying to access 93L on the Navy site?


Mine works...Link

EDIT...oops...you're correct. I get the same.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting DaytonaBeachWatcher:


Yeah, I know I know, me either. But we both know that what we want and what we are gonna get usually dont jive.


All we can do is prepare for the worst and hope for the best this year. The only thing is, how do you prepare for the possibility of millions of gallons of oil being washed ashore and inland? I think Pat is right when he talks about Oilzilla.
Member Since: May 13, 2008 Posts: 0 Comments: 1414
3741. Walshy
Quoting stormpetrol:
take a good look at 93L on the visible sat loop, I think it actually looks more organized than some are giving it credit for, it actually has more of a spin with it this morning and seems to be in the process of establishing a well defined LLC, just my opinion of course.



I guess if it relocated further north then it will get that spin it needed...
Member Since: May 17, 2009 Posts: 2 Comments: 904
Quoting Drakoen:
I see the GFDL, HWRF, CMC, UKMET, and ECMWF all develop 93L to some extent.


I don't like the latest model run of GFDL. It would go right over the oil.
Member Since: April 26, 2009 Posts: 3 Comments: 3667

Good morning, is anyone else getting a server error when trying to access 93L on the Navy site?
Member Since: July 11, 2006 Posts: 14 Comments: 11390
Quoting Drakoen:
I see the GFDL, HWRF, CMC, UKMET, and ECMWF all develop 93L to some extent.


Basically, 93L has great model support for the long range. We'll most likely see something. This is in the Central Caribbean, storms never develop there.. only in the Eastern or the Western.. remember the John Hope rule. Its likely that 93L might have genesis by Friday or Thursday night imo. People need to be patient with this system.
Member Since: July 8, 2005 Posts: 259 Comments: 24484
3736. Dakster
Quoting DestinJeff:
Some twice-barreled CMC love for the northern Gulf coast:

Click to enlarge


I see the CMC is living up to its namesake of Constantly Making Cyclones...
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3734. Drakoen
I see the GFDL, HWRF, CMC, UKMET, and ECMWF all develop 93L to some extent.
Member Since: October 28, 2006 Posts: 57 Comments: 30615
Quoting PanhandleChuck:


I'd rather not have one at all, Besides the SST's in the GOM are already smokin


Yeah, I know I know, me either. But we both know that what we want and what we are gonna get usually dont jive.
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3732. pottery
Quoting kmanislander:


Hi there,

Sorry I didn't reply but the internet on the computer I was on went out so I am on a different one now that is hard wired. Sometimes the wrieless coverage in the house goes bonkers.

I saw the explanation from Storm and mine is less technical. In simple terms, I think the problems plaguing 93L have more to do with climatology than anything else. It is in an area , and has been for the last 24 hours, that just does not allow TDs to develop save in the most exceptional circumstances.

The behaviour of 93L is therefore in keeping with what one would expect to see, not the other way around.


Thanks. Clearly put.
I am still trying to understand WHY this is so.
There has to be a physical reason for it's behaviour, given the way it looked and was forecasted to behave.
50% is touch-and-go I know. But the mechanics is intriguing me!
Member Since: Posts: Comments:
Quoting DaytonaBeachWatcher:
Ike,

In my opinion there is just about no way the gulf coast is gonna slide by without a hurricane this year. And having said that it might be better to get it overwith early when sst's arent as high as they will be later on in the summer.... just sayin!


I'd rather not have one at all, Besides the SST's in the GOM are already smokin
Member Since: May 13, 2008 Posts: 0 Comments: 1414
take a good look at 93L on the visible sat loop, I think it actually looks more organized than some are giving it credit for, it actually has more of a spin with it this morning and seems to be in the process of establishing a well defined LLC, just my opinion of course.
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Quoting SAINTHURRIFAN:
if i can get someone to awnser lol seems my post are not visible? if the conditions are going to be so favorable in the gulf why do al the models other than the crazy cmc, maintain a weak or weakenig system in the gulf? also i asked this once before with the favorable conditions we have now and nothing imenent to develop is there something else going on we are missing ike you mentioned this yesterday. also ike you have been spot on so far this year with your observations and you like me do not claim to be a pro lol


1. Models are notoriously unreliable with a weak system before it is classified as a TD. The models are probably all wrong about what will ultimately happen.

2. As to why 93L is the way it is, see my post 3718.

Hope this helps.
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Ike,

In my opinion there is just about no way the gulf coast is gonna slide by without a hurricane this year. And having said that it might be better to get it overwith early when sst's arent as high as they will be later on in the summer.... just sayin!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.