90L heads for North Carolina, drenches Bermuda; oil spill changing little

By: Dr. Jeff Masters , 2:54 PM GMT en Mayo 24, 2010

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An extratropical low pressure system (90L) between the Bahamas and Bermuda is moving north-northwest towards North Carolina and is close to tropical storm strength. Last night's ASCAT pass saw a large area of 35 mph winds to the north and east of the center, and buoy 41048 to northeast of 90L's center was seeing sustained ENE winds of 36 mph, gusting to 43 mph this morning. Bermuda is seeing some heavy weather from this storm, with winds blowing at 35 mph on the west end of the island, and the Bermuda radar showing an area of moderate to heavy rain moving over the island. Seas are running 5 - 10 feet in the outer waters of Bermuda today, and are expected to increase to 10 - 14 feet tonight before diminishing on Tuesday.

Figure 1. Visible satellite image of 90L this morning.

Strong upper-levels winds out of the west are creating about 25 knots of wind shear over 90L, but the shear has been gradually decreasing over the past day. Visible satellite loops show that 90L does not have a well-defined surface circulation. The main thunderstorm activity is in a large curved band to the north and northeast of the center. This band is several hundred miles removed from the center, which is characteristic of subtropical storms. I expect that 90L will continue to grow more subtropical in nature today through Wednesday as the shear continues to fall. Sea surface temperatures are near 25°C today and will fall to 23 - 24°C on Tuesday. This is warm enough to support a subtropical storm, but probably not a tropical storm. On Wednesday, 90L will be nearing the warm waters of the Gulf Stream, and SSTs will warm again, to the 24 - 25°C range. This is still pretty cool for a tropical storm, and I expect 90L will never become fully tropical. To understand the difference between a tropical and subtropical storm and why we care, see my subtropical storm tutorial.

The SHIPS model predicts that shear will fall to the medium 10 - 20 knot range by Tuesday. A large amount of dry air to 90L's southwest associated with the upper-level trough of low pressure on top of the storm, as seen on water vapor satellite loops , will hamper transition of 90L to a subtropical or tropical storm. The system will move slowly towards the Southeast U.S. coast over the next two days, making its closest approach to the coast on Wednesday, when most of the models indicate the center will be 200 - 400 miles southeast of Cape Hatteras, North Carolina. All of the major models currently predict that 90L will not make landfall, but will move slowly eastward out to sea on Thursday, when a trough of low pressure moving across the Eastern U.S. picks up the storm. There presently isn't much to be concerned with about this storm, as it appears that it will remain offshore and will become, at worst, a 40 - 50 mph subtropical storm. The National Hurricane Center (NHC) is giving 90L a medium (30% chance) of developing into a depression or tropical/subtropical storm. Wunderbloggers Weather456 and StormW have more on 90L.

Western Caribbean disturbance
A small region of disturbed weather has developed in the Western Caribbean, off the east coast of Nicaragua. Moisture is expected to increase across in this area in the coming days, and by Saturday, the GFS and NOGAPS models predict that shear will drop low enough to permit the possible development of a strong tropical disturbance or tropical depression. This storm would then move northeastward over eastern Cuba early next week. The other models keep the shear high in the Caribbean all week, and do not show anything developing. Thus, the Western Caribbean bears watching later this week, but the conditions appear marginal for development.

Moderate risk of severe weather today in northern Plains
The Storm Prediction Center has placed western Nebraska and portions of South and North Dakota under their "Moderate" risk for severe weather today. They warn that "a couple of strong and possibly long-track tornadoes appear possible given the forecast scenario." Keep an eye on the activity today with our Severe Weather Page.

Major oil threat continues for the coast of Louisiana
Light winds are expected to prevail across the northern Gulf of Mexico all week, resulting in continued oiling threats to the Louisiana shoreline from the mouth of the Mississippi River westward 150 miles, according to the latest trajectory forecasts from NOAA. There is no longer a flow of oil moving southwards towards the Loop Current, and the oil that did move southwards last week was mostly entrained into a counter-clockwise rotating eddy attached to the northern boundary of the Loop Current. Synthetic Aperture Radar (SAR) imagery over the weekend showed that most of this oil has dispersed, and very little of this oil is now visible from space (Figure 2.) Imagery from NASA's MODIS instrument and from NOAA aircraft did not show any oil in the Loop Current headed towards the Florida Keys over the weekend, so that is good news. NOAA comments that there may be some "scattered tar balls" in the Loop Current headed towards the Florida Keys. I expect these scattered tar balls have completed the full loop of the Loop Current and are now headed east towards the Keys, and will pass the Dry Tortugas and Key West sometime Wednesday - Saturday. My guess is that the oil and its accompanying plume of toxic dispersants will be too thin and scattered to cause significant problems in the Keys.

Figure 2. Synthetic Aperture Radar (SAR) image of the oil spill taken at 11:41am EDT Saturday May 22, 2010, by the European Envisat-1 satellite. Only scattered patches of oil are evident in the counter-clockwise rotating eddy on the northern boundary of the Loop Current. A small amount of oil appears to be in the Loop Current, and is moving southward. Image credit: Center for Southeastern Tropical Advanced Remote Sensing, University of Miami Rosenstiel School of Marine and Atmospheric Science. SAR images have a resolution of 8 - 50 meters, and can be taken through clouds and precipitation.

Future threats to the Keys
Mostly offshore winds are expected this week over the northern Gulf of Mexico, thanks to the approach of the 90L storm along the Southeast U.S. coast. It is uncertain if these winds will be strong enough to push oil southward into the Loop Current, though at least one ocean trajectory model does show this occurring. As I discussed in my post Wednesday, the Loop Current is very unstable right now, and is ready to cut off into a giant clockwise-rotating eddy, an event that occurs every 6 - 11 months. At least one ocean model (the Global HYCOM model from the HYCOM consortium) is predicting that such an eddy will form this week. In the event a Loop Current Eddy does break off, it would create a rotating ring of water 250 miles in diameter to the south of the oil spill. Oil moving southwards would tend to enter the giant eddy and circulate around it, not threatening any land areas. Roffer's Ocean Fishing Forecast Service has a nice discussion on the possibility of the Loop Current cutting off into a Loop Current Eddy. Keep in mind, though, that during the first month that a Loop Current Eddy forms, it exchanges a considerable amount of water with the Loop Current. Thus we can expect that a portion of any oil moving southwards into a Loop Current Eddy will find its way into the Loop Current and move past the Florida Keys.

Oil spill resources
My post Wednesday with answers to some of the common questions I get about the 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 trajectory forecasts
Deepwater Horizon Unified Command web site
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Surface current forecasts from NOAA's HYCOM model
Synthetic Aperture Radar (SAR) imagery from the University of Miami

I'll be back with a new post Tuesday morning.

Jeff Masters

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Quoting RobertM320:

Maybe we do, but its time Louisiana starts adding 10 cents per gallon to every drop of crude thats produced. $4.20 per barrel. Then we will have the money to repair our own wetlands and coastline that the oil companies have destroyed the last 80 years.

An oil tax, for environmental clean-up is a good idea....
For every State in the Union that is NOT affected by the spill.
Member Since: Octubre 24, 2005 Posts: 0 Comments: 25408
Quoting TampaSpin:

If your gonna continue to blame President Bush. Here are the facts. BP gave Obama more money than in other Political figure.....so in return......some LAWS was passed over by Obama to allow this to Ocurr.....here is the facts as permitts was granted in 2009 by Obama's Adminstration and cut thru some Procedures to Protect this from happening! Make sure you tell the facts when you want to go POLITICAL on here. READ THIS ARTICLE.....it tells all from the LIBERAL NY TIMES also!

U.S. Said to Allow Drilling Without Needed Permits

Continuation of previous adminstrations policies.
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Quoting pottery:

This is really bad news.
Any idea how much rain has fallen?
Keep Safe!

Although I did check the weather at Canefield Airport, Roseau.
Precipitation yesterday 0"
Precipitation today 0"

What's up?
Member Since: Octubre 24, 2005 Posts: 0 Comments: 25408
Quoting winter123:

If you want 10 dollar per gallon gas prices then continue to take that viewpoint. Otherwise we need that 30% of our oil supply coming from the gulf.

Maybe we do, but its time Louisiana starts adding 10 cents per gallon to every drop of crude thats produced. $4.20 per barrel. Then we will have the money to repair our own wetlands and coastline that the oil companies have destroyed the last 80 years.
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174. xcool
May 2010
24th-27th. Heavy rains. Possible tropical weather system.
28th-31st. Clearing for holiday weekend.

June 2010
1st-3rd. Some rain.
4th-7th. Pleasant weather.
8th-11th. Scattered thunderstorms.
12th-15th. Fair and hot.
16th-19th. Hurricane could bring wind, rain.
20th-23rd. Pleasant, tranquil most everywhere.
24th-27th. Thunderstorms Gulf Coast north & east, then fair.
28th-30th. Scattered showers.

July 2010
1st-3rd. Fair, hot.
4th-7th. Big thunderstorms Tennessee, the Carolinas, northern portions Mississippi, Alabama, Georgia could dampen holiday activities.
8th-11th. Mostly fair, hot.
12th-15th. Rainy, windy, then fair.
16th-19th. Hot sultry.

Farmers alnamac
Member Since: Septiembre 26, 2009 Posts: 2 Comments: 15704

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Quoting java162:

we have had lots of heavy rain on the east coast of the island of dominica in the lesser antilities over the past 72 hours resulting in a landslides one of which has just buried 3 three people.

This is really bad news.
Any idea how much rain has fallen?
Keep Safe!
Member Since: Octubre 24, 2005 Posts: 0 Comments: 25408
Quoting Ossqss:
Brazil just got a big shaker 6.5

Not many folks very close.


which is a little concerning seeings how they just had a 6.1 in that general area.
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Quoting scottsvb:
CMC = Farmers alnamac

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169. xcool
Speaking of the midwest and the northern plains, the CFS is going to get killed on the May nowcast it had had out on the 10th with most of the nation below normal. Most of the nation east of a line from Duluth to El Paso is winding up above normal this month and its major cool pool it had from the start of the month over the mid Mississippi valley is being blown out of the water.

TPC is giving the area east of the Bahamas a 30% chance of development, whatever the heck that means. The "normal" chance at this time of the year is probably less than 5 %, so its an above normal chance against the averages, but below normal( according to them) against the absolutes. The cyclone phase diagram has it symmetric warm core already, but until the convection can pull in, I wont classify it. The idea remains the same from yesterday, a loop off the south atlantic coast, then northeast.

The system over central America will move slowly out into the Caribbean the next few days.

by joe
Member Since: Septiembre 26, 2009 Posts: 2 Comments: 15704
any of you think we'll get 20 named storms or more? Im goin with 16
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I was just looking at OIL SPILL live video and trying to figure out how much was coming out....my best guess if my calcualations are correct would be a barrel coming out every 10seconds. If that is the case, we would be looking at about 17,280 barrels every 24hours....that is far more than what BP is suggesting! JUST MY OPINON!

Here is the live feed....TampaSpins OIL SPILL VIDEO LIVE FEED
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Guys 90L still has to get near the Gulf Stream, it has till Thursday to make it's transition, no RIPing this off until it's done!
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Sorry Pat, didn't meant to sound that way. This disaster continues to increase as every hour goes by and it seems that we are in this horrible spot and are forced to have to rely on BP to solve & end this crisis. That is what really makes me sick! If we (US) are going to allow off-shore drilling than we MUST have contingincy plans in place for any/all types of accidents/disasters. Was this spill even an accident, or just some high exectutives that gave the word to go ahead without completing that 3rd/final test?
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Gotta go mow my grass and edge.....you all have a good afternoon....if i don't get it done....i won't be able to watch the RAYS kick the redsox booty tonite.......Have a good day....NO FIGHTING KIDS!
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Quoting Tropicsweatherpr:
It looks like the Caribbean will be the place to watch late this week.Here is the 12z CMC.

Almost the same as the GFS with the EPAC low crossing over
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CMC = Farmers alnamac
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It looks like the Caribbean will be the place to watch late this week.Here is the 12z CMC.

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Quoting JamesSA:
That's what I was seeing, it seems to have more pressure behind it. I agree, sickening!

Are there fish down there? Some of that 'debris' floating around has a motion like fish... but you can't see clearly what it is in the video.

I'm 90% sure that I saw a deep sea [oarfish,] night before last. It just floated by, between the camera and the broken riser, as if curious about the lights.
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SST's would support a alex,as the ULL's merge offshore sheer could drop to almost zero over the GS!!
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Quoting GetReal:
Is it time to pull out the proverbial R.I.P. marker for 90L???

Yes sir! I believe it might have been that same cannidate about 3 days ago......Never seen this ever truly coming together......but, it is the tropics and i still could be wrong.
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Brazil just got a big shaker 6.5

Not many folks very close.

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Post 117 - Pat, how can we believe any research that BP does? When the Cousteau team was blocked from documenting the GOM disaster was when I lost all confidence/faith/respect for this giant corporation. The only thing they care about is the bottom line "profit".
I'll bet they don't even have a base line to start their research from.
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I could and pray Im wrong but i honestly dont see 28 named storms,,,,If that link i posted comes to pass we are in for alot of troubles this year
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Quoting Drakoen:

Scroll down to Geophysical Retrievals

Thanks, that lead me to the paper it referenced:

Wind Vector Retrievals under Rain with Passive Satellite Microwave Radiometers

I haven't throughly read the paper, but it appears they use a statistical algorithm to "correct" Windsat measurements. Now need to investigate if manati.orbit.nesdis.noaa.gov is using their method. First thought is I don't think so.

Edit: I see you also posted this paper while I was scimming through it, thanks.
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long time lurker, first post

Great job in advance to all of the knowledgeable posters as we enter this busy season. Hopefully the less knowledgeable will sit back quietly and learn rather than add confusion.

I also hope that the obvious jealousy displayed last year towards featured bloggers will not be repeated this year. Unfortunately it's already beginning and it's downright sad. Seriously, grow up.
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Is it time to pull out the proverbial R.I.P. marker for 90L???
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Quoting stillwaiting:
the GS,TS how's the heat up in tpa??? its been like a oven down here in srq the last 4 or 5 days..

Dude it has been horrible hear.....hot and humid
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144. DVG
Quoting Jedkins01:
I hate when people talk about nations as a whole being wicked, evil, disgusting, etc.

There are people like that in every country, but to blame an entire nation of people for what some do, is arrogant, stupid, and ignorant.

Sorry but no matter how intelligent you think you may be, the world is too big to grasp for your finite mind. The whole nation of Jamaica cannot be blamed for a group of people that live there, just as no other nation should.

You should be ashamed of yourselves.

History disagrees with you.
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the GS,TS how's the heat up in tpa??? its been like a oven down here in srq the last 4 or 5 days..
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The Gulf south of Texas should be warming up nicely all week. Forecast for the Houston area is for clear to partly-cloudy skies, high of 90F, lows of 70F from Monday-Friday with a 20% chance of rain Friday.

Gulf waters are already anamolously warm, but not enough to really support a tropical storm yet. After this week, SST's should be borderline for supporting a tropical storm.

Agreed, it will be a significant year. The thing that will make it worse will be when a warm water eddy splits off from the loop current in June or July. That pool of warm water will be fuel for rapid intensity change for any system heading toward La or Tx late this summer.
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Quoting stillwaiting:
My current thinking is that 90L will be absorbed into a new AOI forming off VA/NC...91L?????......a warm core low may then form in 24-48hrs,IMO

Please explain how that will happen in those cold waters? I just don't see a Warm Core happening in any way! JMO
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Nrtiwlnvragn, here's another link

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heres a site posted earlier this morning forecasts for this season I hope this doesnt come to pass......Link
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My current thinking is that 90L will be absorbed into a new AOI forming off NC...91L?????......a warm core low may then form in 24-48hrs,IMO
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136. BDAwx

90L yesterday

90L today
Looks much more organised in this perspective.
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Magnitude 6.5 - ACRE, BRAZIL
2010 May 24 16:18:29 UTC
DetailsMapsScientific & TechnicalEarthquake Details
Magnitude 6.5
Date-Time Monday, May 24, 2010 at 16:18:29 UTC
Monday, May 24, 2010 at 11:18:29 AM at epicenter

Location 8.072°S, 71.569°W
Depth 580.5 km (360.7 miles)
Distances 127 km (79 miles) ESE (111°) from Cruzeiro do Sul, Brazil
328 km (204 miles) E (84°) from Pucallpa, Peru
464 km (288 miles) WNW (297°) from Rio Branco, Brazil
749 km (465 miles) NE (54°) from LIMA, Peru

Location Uncertainty horizontal +/- 5.4 km (3.4 miles); depth +/- 6.7 km (4.2 miles)
Parameters NST=326, Nph=326, Dmin=722.3 km, Rmss=0.87 sec, Gp= 29°,
M-type=teleseismic moment magnitude (Mw), Version=7
Source U.S. Geological Survey, National Earthquake Information Center:
World Data Center for Seismology, Denver

Event ID us2010wrbc
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134. IKE
Convection has waned on 90L...

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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.

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