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

By: Dr. Jeff Masters , 2:54 PM GMT on May 24, 2010

Share this Blog
3
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 884 - 834

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25Blog Index

Quoting KEEPEROFTHEGATE:
gettin hot here big fish


Payback, the fans auto-reverse towards summer.
Member Since: Posts: Comments:
Quoting stormhank:
I assume u all read that link about the 28 named storms Do any of you feel thats possible?? Im personally goin with 16 8 4..any season that could top 2005 would be an namoly..and and just in fun could lead to the retirement of a couple of hurricane forecasters

Do you have the link? I just go on. TIA
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
LOL. Who old are you 42?


Somewhere between you and Pottery !
Member Since: Posts: Comments:
881. xcool
wow 95
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Im gonna name the storm I think will be the worst this year,,,,my pick is Igor...the name alone is intense lol
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Well you beat me there, I got interested in weather at age 6. That same year I asked for a radar for Christmas, I never got it, but I did get a small basketball hoop, lol.


Quoting nrtiwlnvragn:
To bad the UKMET went ECMWF and stopped sharing their model output. Since their recent upgrade to the model, errors in the tropics are almost comparable to the ECMWF now.

Rms vector wind error
Rms error of u-component
Rms error of v-component


Explains why PSU E WALL hasn't been updating some of their stuff over the past few days.
Member Since: Posts: Comments:
Quoting kmanislander:
I was thinking of joining in the discussion but the age thing kind of made me think twice LOL
LOL. Who old are you 42?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting pottery:

Well, that pic. is about 4 years old.
But thanks for the compliment LOL.
your 61 Pott? well, we will have to put ya on The Antiques Road Show along with the Floodmeister.......Just... kidding..really..
Member Since: September 27, 2007 Posts: 1 Comments: 22728
95 here today...plus humid. Not pleasant.
Member Since: Posts: Comments:
Quoting GeoffreyWPB:
pottery is young at heart. One of my favorite bloggers!
Me too.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
I was thinking of joining in the discussion but the age thing kind of made me think twice LOL
Member Since: Posts: Comments:
Quoting Orcasystems:


AOI

AOI

AOI

AOI

Humor in Comments
gettin hot here big fish
Member Since: Posts: Comments:
Quoting pottery:

I am 61. And I am impressed by the weather knowledge you young people have.
'Nuff Respect!!


Wow, your birthday cake must set off the smoke alarms :) J/K (sprinklers)

Member Since: Posts: Comments:
pottery is young at heart. One of my favorite bloggers!
Member Since: Posts: Comments:
hey pottery,,,do any fishing today??
Member Since: Posts: Comments:
41048
Member Since: Posts: Comments:
Quoting Funkadelic:


oh my! I honestly thought you were like 17-20 years old. Gotta giv ya credit kid, I'm 28 and am really impressed. Good luck this year btw, hope Miami has it easy. I'm in Boca and keeping my fingers crossed.
Thanks a lot. Not looking good for us in SFLA so far though.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
mail miami hurricane
Member Since: Posts: Comments:
To bad the UKMET went ECMWF and stopped sharing their model output. Since their recent upgrade to the model, errors in the tropics are almost comparable to the ECMWF now.

Rms vector wind error
Rms error of u-component
Rms error of v-component
Member Since: Posts: Comments:
Quoting extreme236:


That sounds reasonable. There definitely would need to be more consistency.
Yes. It does seem to be headed in that direction though.
Member Since: September 27, 2007 Posts: 1 Comments: 22728
864. xcool


Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting MrstormX:


Wow your 13! Surprised me... I guesstimated 17
"Guesstimated" LOL, thanks.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
So you're in my age group. I'm 13 and will be turning 14 later this year. BTW good job on the synopsis.


Wow your 13! Surprised me... I guesstimated 17
Member Since: Posts: Comments:
Quoting pottery:

Well, that pic. is about 4 years old.
But thanks for the compliment LOL.
Any time, lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting SevereHurricane:


I have been interested in wx since I was 3 when Georges hit my local.


8 for me, 1997 Danny caused major flooding on the east coast while i was on the beach vacationing. stayed inside and played minigolf in the house, i still remember it clearly.
Member Since: Posts: Comments:
I think Grothar is older than all of us. I think he was the Marconi operator on the Carpathia.
Member Since: Posts: Comments:
Quoting SevereHurricane:


Thanks 2007, it means a lot. I have been interested in wx since I was 3 when Georges hit my local.
Well you beat me there, I got interested in weather at age 6. That same year I asked for a radar for Christmas, I never got it, but I did get a small basketball hoop, lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting DEKRE:


This is a strong statement. Obviously, I don't know the geographic situation, but just as an example, within my city, temperature differences can be quite drastic, especially in winter when differences of 10 °C are not uncommon, the colder the bigger the difference. If we have -25 at the airport and a low ice-cover on the St. Lawrence river, -15 is normal close to the river.
In summer the gradient is in reverse.


Just curious. Where is the sensor located? I.E. near a roadway/driveway or AC unit? I have one in my garage door area and it always registers about 10 degrees hotter during the day due to the concrete driveway and AC unit about 30 feet away. I know, Yep, I have been to lazy to move it :)
Member Since: Posts: Comments:
855. xcool
you 61 .i'm 28
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting winter123:
Named or not, I hope someone can post a loop of the life cycle of 90L. Most interesting invest of the year so far.
:)


Yup... #1 of ummmm 1
Member Since: Posts: Comments:
Quoting stormhank:
Great to have all that weather knowledge at that age...avila and stewart best watch out at NHC lol
LOL
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Stormchaser2007:


LOL

Heck that would be "not so bad" for most 30 year olds. Keep sticking to this stuff. One day you could be doing it for a profession. It looks like you have a real interest in it and it probably helps that you pretty darn good at it. Theres nothing more important in life than working at a job you love.

You and Miami seem to really have learned a LOT.


Thanks 2007, it means a lot. I have been interested in wx since I was 3 when Georges hit my local.
Member Since: Posts: Comments:
Anyways now that I have given up on 90L and so have most other people lets start looking ahead to the Caribbean. Im looking at the 12z GEM Model at +108 hours, which is when the low first moves over open waters. According to the model we are talking about a 1008mb surface low under 90% humidity. At +120 the low drops to 1006mb, but the rainfall is very high we are talking 60mm per 12 hours, with locally heavier rates. At +144 hours we will have a 1002mb closed low in between Jamaica and Cuba. This is something to watch!

+108


+144
Member Since: Posts: Comments:
Quoting Stormchaser2007:


LOL

Heck that would be "not so bad" for most 30 year olds. Keep sticking to this stuff. One day you could be doing it for a profession. It looks like you have a real interest in it and it probably helps that you pretty darn good at it. Theres nothing more important in life than working at a job you love.

You and Miami seem to really have learned a LOT.
Thanks.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting HaboobsRsweet:
Gezz you all are young haha. Shouldnt you be in bed j/k haha. I am 29. I am still young but gezz you are half my age.
LOL! I go to sleep late. During the season in the active parts expect me to be up all night (During Summer obviously, lol)
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Great to have all that weather knowledge at that age...avila and stewart best watch out at NHC lol
Member Since: Posts: Comments:
Named or not, I hope someone can post a loop of the life cycle of 90L. Most interesting invest of the year so far.
:)
Member Since: Posts: Comments:
Quoting SevereHurricane:


Thanks dude. Not so bad for a 15 year old, ehh?


LOL

Heck that would be "not so bad" for most 30 year olds. Keep sticking to this stuff. One day you could be doing it for a profession. It looks like you have a real interest in it and it probably helps that you pretty darn good at it. There's nothing more important in life than working at a job you love.

You and Miami seem to really have learned a LOT.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
You're 61!?!?! You look in your early 50s in your avatar seriously.

Well, that pic. is about 4 years old.
But thanks for the compliment LOL.
Member Since: October 24, 2005 Posts: 0 Comments: 24929
Link

enjoy your current gas prices
Member Since: Posts: Comments:
Gezz you all are young haha. Shouldnt you be in bed j/k haha. I am 29. I am still young but gezz you are half my age.
Member Since: Posts: Comments:
Its hard to predict how the bermuda high will set up....someone told me during la Nina years storms tend to track further west and south...I assume its the conditions that are present during the time a storm forms that states the movement it will take
Member Since: Posts: Comments:
Quoting pottery:

I am 61. And I am impressed by the weather knowledge you young people have.
'Nuff Respect!!
You're 61!?!?! You look in your early 50s in your avatar seriously.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting GeoffreyWPB:


Buy homeowners and flood insurance...cheaper in the long run.

have it and had it for katrina. thats how i got the house i have now. always solid advice though. thanks!:)
Member Since: Posts: Comments:
Quoting SevereHurricane:


Yeah, well I have been around the block on this blog. I have been around since 2007 and I watched drak and levi grow up and I intend to follow their footsteps.
Good for you, keep up the great work. Well I've been lurking since hurricane Felix in 2008.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
So you're in my age group. I'm 13 and will be turning 14 later this yeat.

I am 61. And I am impressed by the weather knowledge you young people have.
'Nuff Respect!!
Member Since: October 24, 2005 Posts: 0 Comments: 24929
Quoting MiamiHurricanes09:
So you're in my age group. I'm 13 and will be turning 14 later this yeat.


Yeah, well I have been around the block on this blog. I have been around since 2007 and I watched drak and levi grow up and I intend to follow their footsteps.
Member Since: Posts: Comments:
Quoting hydrus:
I believe that will take place in the next five to ten years.jmo. It has been a while since you have posted.


That sounds reasonable. There definitely would need to be more consistency.
Member Since: Posts: Comments:
new blowup near what looks like a mid level circulation center to me. (71W 31N)
Member Since: Posts: Comments:

Viewing: 884 - 834

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25Blog Index

Top of Page

About

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

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron