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

By: Dr. Jeff Masters , 2:54 PM GMT on May 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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If anyone would like to know what's my take on the area that should be moving into the Caribbean later this week please WUmail me.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting IKE:
Nice job by Dr. Masters on-air.

92 degrees outside right now at my location.


Dats a Hotsui afternoon Ike.


Yesterday was Like Aug here.

We hit 95F and 103f Heat Index around 4pm-5pm
Member Since: July 3, 2005 Posts: 427 Comments: 129352
Quoting IKE:
Nice job by Dr. Masters on-air.

92 degrees outside right now at my location.

92 degrees here in Minneapolis too... that ain't right!!
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481. IKE
18Z NAM @84 hours...

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Did you hear what the President of BP said today re: the oil spill going into the current?
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478. IKE
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Generation behind me has no chance from what I'm seeing, having debt, not making huge salaries to pay off debt, and make payments on a house, taxes, car, family.
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I hate to say it but by the looks of things I think we are looking at around 20 named storms this yr, something like that. Were gonna be busy guys(and ladies)!
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474. IKE
(CNN) -- BP will not be replaced by the federal government in the ongoing cleanup efforts of the Gulf oil spill, said Coast Guard Commandant Adm. Thad Allen, the Obama administration's point man for the spill.

"To push BP out of the way would raise the question: to replace them with what?" he said at the White House. BP is "exhausting every technical means possible" to deal with the spill, he said on Monday.
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473. IKE
Nice job by Dr. Masters on-air.

92 degrees outside right now at my location.
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T-minus 60 minutes and counting to Taco's first ever live tornado chase broadcast on 7674u.com...

...and still no word from him.
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471. Skyepony (Mod)
Giant Wave Impact

Big waves buffeted and caused a 174-ton cargo vessel to tilt and threaten to capsize off Bataan province before dawn Monday. The Philippine Coast Guard sent rescue teams to the MV Ivatan to aid its crew and to watch out for possible oil spills. Crew men of the ship decided to drop anchor because big waves were causing the ship to repeatedly hit the pier at Basco. At about 2:30 a.m. Monday, the waves were too much for the anchored ship, and it titled. Coast Guard commandant Admiral Wilfredo Tamayo ordered the ship’s captain to submit a marine protest, and ordered a Coast Guard team to conduct an aerial survey of the site of the incident.
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Jeff Masters excerpt from the Spuds McKenzie show on WWL.com Radio NOLA today.

Member Since: July 3, 2005 Posts: 427 Comments: 129352
Quoting CycloneOz:
The countdown clock for the live severe weather webcam broadcast on 7674u.com is now approaching 1:30:00 (90) minutes and counting...mark.

Uh Taco, we've got a launch scheduled here, and we thought that maybe...uh you could send us a signal to ground control personnel.


LOL!!!
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Quoting atmoaggie:
Take care, northshore friends.

Bye, all...gotta go.

L8R.

hope you make it through the weather ok today. have a good one
Member Since: September 10, 2008 Posts: 0 Comments: 1294
Seems dat Booming outside is getting closer Uptown as it develops.Right over da River.

Outflow boundary traversing the Lake too.



Member Since: July 3, 2005 Posts: 427 Comments: 129352
Seems to be more and more houses being built in the 200s thru 400s in Galveston county. Makes you wonder. Figure in taxes, and those damn MUD taxes they keep making up and homeowners insurance, huge HOAs...hey better them than me. When fantasy land runs out it should be a hard fall, because the more you have, the more you got to lose.
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Take care, northshore friends.

Bye, all...gotta go.

L8R.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting sarahjola:

and once again it goes right past mandeville. it is so funny that since i've lived here we have not had any strong storm come over us. all around us but my house stays dry.


I know how you feel! We've been quite dry for the last month or so. My friend up on Lee Road on the other hand is constantly drenched.
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Quoting atmoaggie:

We have been there more than once to catch the Boat Parade and the live brass/Jazz band on the upstairs deck afterwards. Been a solid couple of years, though.


I always liked Madisonville; reminded me of growing up (I had all kinds of relatives in little Missouri River towns)...
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Quoting sarahjola:

and once again it goes right past mandeville. it is so funny that since i've lived here we have not had any strong storm come over us. all around us but my house stays dry.

THERE YOU ARE. Thought of you a bit ago when I looked at the radar.

Classic example of the seabreeze building storms a few miles inland and no rain (or minimal rain) at the coast.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting errantlythought:


Oh yeah, pain in the arse to get the mail sometimes. :) Mandeville office is literally 5 miles away. We have to use the covington office. :P

Now that sux. At the wrong time on the wrong day, that would be a whole wasted hour, round trip.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting atmoaggie:
Speaking of home:

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN ST. TAMMANY PARISH IN SOUTHEAST LOUISIANA...
THIS INCLUDES THE CITY OF COVINGTON...

* UNTIL 345 PM CDT

* AT 304 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
ABITA SPRINGS...OR NEAR COVINGTON...AND MOVING NORTHWEST AT 10 MPH.

and once again it goes right past mandeville. it is so funny that since i've lived here we have not had any strong storm come over us. all around us but my house stays dry.
Member Since: September 10, 2008 Posts: 0 Comments: 1294
Quoting Floodman:


Dat's de place!

I used to get over there quite a bit...

We have been there more than once to catch the Boat Parade and the live brass/Jazz band on the upstairs deck afterwards. Been a solid couple of years, though.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting atmoaggie:

Oh, by (or in) Covington country club estates.

I think that is just a mailing address thing. Covington's city limits end at the Bogue Falaya (which is why all of the car dealerships are fairly near you and I). I am between you and the city limits, near where US 190 crosses the Abita River.


Oh yeah, pain in the arse to get the mail sometimes. :) Mandeville office is literally 5 miles away. We have to use the covington office. :P
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Quoting atmoaggie:

Friend's Coastal Restaurant?


Dat's de place!

I used to get over there quite a bit...
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Quoting robert88:


90L will be going fishing. A trough should kick this thing out soon.


The trough your refering to wont dig deep enough southward to pick up 90L. Then once high pressure kicks in after the trough passes, watch what happens.
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Quoting errantlythought:


Technically. I'm just below the 12, near the hospital. You'd think it's mandeville, but Covington REALLY wanted Lakeview, so it's incorporated.

Oh, by (or in) Covington country club estates.

I think that is just a mailing address thing. Covington's city limits end at the Bogue Falaya (which is why all of the car dealerships are fairly near you and I). I am between you and the city limits, near where US 190 crosses the Abita River.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
90L making sme progress west by Nw,..and it has to, to get to them 23-25C SST's that may..may allow for a small window for it to build a lil column and become Alex,

..but the shear is keeping that in check still.

Member Since: July 3, 2005 Posts: 427 Comments: 129352
Quoting atmoaggie:

How hairy is it? I see a report at SPC already.

COVINGTON ST. TAMMANY LA 3048 9011 1 TREE DOWN ACROSS A ROAD.

(currently 16 feet underground in Slidell...even thunder, when happening, inaudible down here)


Few small downbursts, not the worst by any means i've seen here. I'd assume the tree that went down was weakened, because I have a half-dead tree, the last of three that survived Katrina and have been being knocked down by summer thunderstorms over the years. It swayed a tad, but didnt go down. Last one took out my bloody dish, too.

They cant be cut down, either.

Power went out for just a moment, enough to kick off my UPS, but the generator didnt even kick in before it was on again.
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Quoting atmoaggie:

Well, just to be perfectly clear, there are some houses here that are in the $500k to $2m range. But those aren't the basic 2000 sq feet, or a little less, regular household-sized homes...

Reasonable-sized house, reasonable cost (with special considerations for an exotic location...like the Quarter).
Yo caprende.
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Quoting Floodman:


He's on the channel there, on the Madisonville side of the bridge (the draw bridge, that is)...you know the houses up from the bar on that side (I can never remember what it's called)

Friend's Coastal Restaurant?
Member Since: August 16, 2007 Posts: 6 Comments: 12463
447. RMCF
Quoting gulfcoastdweller:


love John Goodman in Treme........btw, is anyone watching Treme on HBO?

Awesome show I was down there right after the storm fueling NOPD, Entergy then we set up the Fuel tanks in Jackson Square for I.C.E. But i am from Houston. That place went through something most of America cant even imagine.
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Quoting atmoaggie:

Could use it.

You a Covingtonian, too?


Technically. I'm just below the 12, near the hospital. You'd think it's mandeville, but Covington REALLY wanted Lakeview, so it's incorporated.
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Quoting errantlythought:


Damn thing's been sitting on my house for half an hour. Yay, rain!

How hairy is it? I see a report at SPC already.

COVINGTON ST. TAMMANY LA 3048 9011 1 TREE DOWN ACROSS A ROAD.

(currently 16 feet underground in Slidell...even thunder, when happening, inaudible down here)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting Jeff9641:



I agree buddy and they also mention the threat of severe thunderstorms due to the cold air aloft. The NAM has been consistant for days now showing this disturbance dropping down from the Carolina's and spawning a new low very near the east coast of FL. The NWS in Melbourne has done good as well but still a little conservative.



Yeah I noticed there is almost no mention of the strong thunderstorm threat either, in fact, the wording has been scattered showers and a thunderstorm or 2, with no mention of them being strong. Just ridiculous! Which by the way there are storm at severe levels around now as a speak. There is a strong storm near me with a whole lot of thunder coming out of it right now as well...

The NWS mentioned the threat of strong storms, possibly hail and gusty winds with them this week. But the local guys have no mention of it, plus they are showing only 20% chances which is just ridiculous.


The funny thing is, it seems like the reason for this is that they appear to be following exactly along with the GFS. Not a smart choice, because not only following exactly what one model shows almost always leads to a poor forecast, but following the GFS is definitely not a good idea.

For some reason there has been love for the GFS. Like its their beloved model or something lol.

The funniest part is, the GFS isn't very accurate or reliable, the NAM usually does a lot better, despite the GFS always being the model you hear about.
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Quoting atmoaggie:

That's the rumor...maybe a "hideout" ?


He's on the channel there, on the Madisonville side of the bridge (the draw bridge, that is)...you know the houses up from the bar on that side (I can never remember what it's called)
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..I see swirls within swirls..

90L Floater - RGB Color Infrared Loop

Member Since: July 3, 2005 Posts: 427 Comments: 129352
441. Skyepony (Mod)
90L looks really beautiful right now on RGB loop. Not like the usual hurricane way but you can clearly see smaller vorticity rotating around each other like simplified, weak, easy to see tornadoes in an eyewall or a storm that produces a ring of weak tornadoes that dance around each other.
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The countdown clock for the live severe weather webcam broadcast on 7674u.com is now approaching 1:30:00 (90) minutes and counting...mark.

Uh Taco, we've got a launch scheduled here, and we thought that maybe...uh you could send us a signal to ground control personnel.
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Quoting errantlythought:


Damn thing's been sitting on my house for half an hour. Yay, rain!

Could use it.

You a Covingtonian, too?
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting atmoaggie:

Conifer Mueniere just doesn't quite get the juices flowing, no...


Come on, man, who don't like a little pine cone ettuffe
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Quoting hydrus:
Good post. And when talking about the recession, they say that areas in the N.E were not even effected by it. Like you said, a $500,000 house in Florida would cost $150,000 in Tennessee.

Well, just to be perfectly clear, there are some houses here that are in the $500k to $2m range. But those aren't the basic 2000 sq feet, or a little less, regular household-sized homes...

Reasonable-sized house, reasonable cost (with special considerations for an exotic location...like the Quarter).
Member Since: August 16, 2007 Posts: 6 Comments: 12463
436. bwi
Good afternoon. We flew over the part of 90L yesterday on our way back from Bonaire to NYC. I hadn't been watching the blog all week while on vacation, so didn't even know about a disturbance. But you could easily see major white caps on the seas, even from 35k+ feet up. I was wondering what was going on down there.
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Uh...Earth to Taco!

It would be nice if you contacted your ground support.

Out---
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Quoting atmoaggie:
Speaking of home:

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTHWESTERN ST. TAMMANY PARISH IN SOUTHEAST LOUISIANA...
THIS INCLUDES THE CITY OF COVINGTON...

* UNTIL 345 PM CDT

* AT 304 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR
ABITA SPRINGS...OR NEAR COVINGTON...AND MOVING NORTHWEST AT 10 MPH.


Damn thing's been sitting on my house for half an hour. Yay, rain!
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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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