Loop Current Eddy cuts off; oil danger to Keys now greatly reduced

By: Dr. Jeff Masters , 2:24 PM GMT on May 28, 2010

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A major ocean current re-alignment is underway the Gulf of Mexico right now, and the new configuration that is developing greatly reduces the threat of oil entering the Loop Current and affecting the Florida Keys and U.S. East Coast. As I explain in my Loop Current Primer, the Loop Current is an ocean current that transports warm Caribbean water through the Yucatan Channel between Cuba and Mexico. The current flows northward into the Gulf of Mexico, then loops southeastward just south of the Florida Keys (where it is called the Florida Current), and past the western Bahamas. Here, the waters of the Loop Current flow northward along the U.S. coast and become the Gulf Stream. With current speeds of about 0.8 m/s, the Loop Current is one of the fastest currents in the Atlantic Ocean. Every 6 - 11 months, the top bulge of the Loop Current cuts off, forming a 250-mile diameter circular eddy in the middle of the Gulf of Mexico. This clockwise-spinning eddy is filled with warm water from the Loop Current, and is called a Loop Current Eddy. The main body of the Loop Current then takes a fairly direct eastward path from the Yucatan Channel to the Florida Keys.

Over the past two days, surface currents in the Gulf of Mexico have aligned to form a Loop Current Eddy, as seen in the analysis of surface currents done by the U.S. Navy (Figure 1, and see also a 30-day animation of the eddy forming.) It remains to be seen if the deep water currents have followed suit, and a stable Loop Current Eddy cannot exist until the deep water currents also cut off into a clockwise-rotating ring of water at depth. A NOAA Hurricane Hunter aircraft is out over the Gulf of Mexico today dropping expendable buoys and current probes to determine if a stable Loop Current Eddy has formed. Roffer's Ocean Fishing Forecast Service has a nice discussion on the Loop Current Eddy formation.


Figure 1. Comparison of surface currents in the Gulf of Mexico on May 19 (top) and May 27 (bottom) as simulated by the HYCOM model. On May 19, the Loop Current made a large northward loop into the Gulf, and was able to transport oil from the near the spill location southwards through the Keys. By May 27, this loop had cut off, and new oil moving southwards from the spill will now be trapped in the clockwise rotating Loop Current Eddy that is cut off from the Loop Current. Note on the west side of the Gulf of Mexico, off the coast of Texas, there is an old Loop Current Eddy that cut off from the Loop Current in July 2009. This eddy cut off in the same location as this week's eddy, and has drifted west-southwestward at 3 - 5 km per day over the past ten months. Image credit: U.S. Navy.

If the eddy does remain in place, it will greatly reduce the chances of oil making it to Cuba, the Florida Keys, and beyond. Any oil moving southwards from the spill location will now become entrained in the eddy, and will move in a 250 mile-wide clockwise circle in the east-central Gulf of Mexico. A small portion the oil will get shed away from the eddy's periphery and make it into the Loop Current and waters surrounding the eddy, but the concentrations of oil doing so will be small. Keep in mind, though, that during the first 1 - 2 months that a Loop Current Eddy forms, it is common for the eddy to exchange substantial amounts of water with the Loop Current, and in some cases get re-absorbed into the Loop Current. A 1-year animation of the Loop Current shows that the last Loop Current Eddy, which cut off in mid-July 2009, experienced a 2-week period in early August when it re-attached to the Loop Current. A significant portion of any oil entering the eddy during a period of re-attachment will be able to enter the Loop Current and flow past the Keys.

One bad result of the eddy breaking off is that now we have an extra source of heat energy for passing hurricanes during the upcoming hurricane season. Loop Current eddies have high-temperature water that extends to great depth, and hurricanes passing over such eddies often undergo rapid intensification. Hurricanes Katrina and Rita of 2005 both underwent rapid intensification as they passed over warm Loop Current eddies in 2005. The formation of a Loop Current Eddy during hurricane season means that a much greater portion of the Gulf of Mexico has deep, warm water capable of fueling rapid intensification of hurricanes.

Oil spill update
Light offshore northwesterly winds are expected to blow over the northern Gulf of Mexico today through Saturday, resulting decreased threats of oil to the Louisiana shore, according to the latest trajectory forecasts from NOAA. These offshore winds may be able to transport oil southwards into the Loop Current Eddy that just formed; a streamer of oil moving southeastward into the Loop Current Eddy is visible in yesterday's NASA MODIS imagery (Figure 2). Winds will shift to onshore out of the south on Saturday night, then shift to southwesterly by Tuesday. The long-range forecast from the GFS model indicates continued southwesterly winds all of next week. If this forecast verifies, we will see our greatest chances yet of significant amounts of oil reaching the beaches of Mississippi, Alabama, and the Florida Panhandle.


Figure 2. Visible satellite image of the Gulf of Mexico taken at 2:55pm EDT Thursday May 27, 2010, by the MODIS instrument on NASA's Aqua satellite. Thin streaks of oil can be seen moving southeast and then southwest around the eastern side of the new Loop Current Eddy. Image credit: NASA.

Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
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

Central American disturbance
The Atlantic is currently quiet, with none of our reliable global forecast models predicting tropical cyclone development over the next 6 days. There is an area of disturbed weather (90E) just off the Pacific coast of Mexico that will be a major concern for southern Mexico and much of Central America over the next 3 - 4 days. The disturbance will bring heavy rains to Central America during the weekend, potentially bringing serious flooding rains to portions of Mexico, Guatemala, El Salvador, Honduras, and Nicaragua. NHC is giving the disturbance a high (>60% chance) of the disturbance developing into a tropical depression by Sunday. Wunderbloggers Weather456 and StormW have more on the tropics.


Figure 3. Satellite image of the Central American disturbance 90E this morning.

Join the "Hurricane Haven" with Dr. Jeff Masters: a new Internet radio show
Beginning next week, I'll be experimenting with a live 1-hour Internet radio show called "Hurricane Haven." The show will be aired at 4pm EDT on Tuesdays, with the first show June 1. Listeners will be able to call in and ask questions. Some topics I'll cover on the first show:

1) What's going on in the tropics right now
2) Preview of the coming hurricane season
3) How a hurricane might affect the oil spill
4) How the oil spill might affect a hurricane
5) New advancements in hurricane science presented at this month's AMS Conference on Hurricanes and Tropical Meteorology
6) Haiti's vulnerability to a hurricane this season

I hope you can tune in to the broadcast, which will be at http://www.wunderground.com/wxradio/wubroadcast.h tml. If not, the show will be recorded and stored as a podcast.

I'll be back with at least one update over the coming 3-day Memorial Day weekend. Have a great holiday!

Jeff Masters

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3607. xcool
:0
Member Since: Posts: Comments:
3606. EricSFL
Quoting WxTracker15:
GEM continues to indicate the low re-developing next week and move into Florida by next Thursday/Friday...


Maybe shear will relax by mid-week and allow for regeneration.
Member Since: Posts: Comments:
as I say if Agatha was to be alive in the caribbean/atlantic it need to stay in the caribbean and do what I think it might do which is wobble around in the mountains and move into the W Caribbean cross ing Central Cuba and into bahamas and in that process redevelop into a TD or TS Alex.
Member Since: Posts: Comments:
Quoting FIU2010:
alex, he deserved it after hurting my feelings, my apologies, sir.
If someone hurts your feelings you dont have to lash back like you do sometimes either ignore him or just carry on your conversation with someone else alright.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
FIU or whatever alias you go by, that question has been answered several hundred times on this blog the last 2 weeks

maybe if you actually paid attention instead of insulting people in Spanish and sparking arguments you would know that
Member Since: March 10, 2010 Posts: 1 Comments: 7831
Quoting FIU2010:
likewise, you australian bumblebee.
Quoting alexhurricane1991:
Dude that was uncalled for im this close of putting you on ignore i want to like you but you are making it hard for me to.


a personal attack..... i wonder what the admins will think of that???
Member Since: Posts: Comments:
Quoting FIU2010:
wow, geeze, xcool, when did wind-shear becoem so high in the GOM? maybe this guys are right, aggy cannot survive throuh all of that, its impossible.
Im glad your seeing the same things we were seeing for some time now.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3597. xcool
EricSFL LMAO.SHE BE SMOKE TO EAST TO WEST LMAO
Member Since: Posts: Comments:
GEM continues to indicate the low re-developing next week and move into Florida by next Thursday/Friday...
Member Since: Posts: Comments:
Quoting FIU2010:
wow, geeze, xcool, when did wind-shear becoem so high in the GOM? maybe this guys are right, aggy cannot survive throuh all of that, its impossible.


wind shear has been high in the GOM for quite some time now
Member Since: March 10, 2010 Posts: 1 Comments: 7831
Quoting FIU2010:
likewise, you australian bumblebee.
Dude that was uncalled for im this close of putting you on ignore i want to like you but you are making it hard for me to.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3591. EricSFL
xcool, I think Agatha might be torn into shreds by those upper level winds.
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3589. xcool
anticyclone IN ATL TP
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3588. guygee
Quoting EricSFL:


It is not about speaking Spanish, it's about what is beeing said in Spanish.


OK, I admit I did not read all the way back.
My bad.

With that said, I bid you a chagrined goodnight.
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
1900hurricane, an explosion of banned trolls coming back.

And FIU2010, if you think Spanish is a beautiful language, then you shouldn't use it in such an ugly way.

A serious blog cleanup is in order.


Cripes, people are dying right now in flooding in Guatemala and this drama is going on. It's really disgusting.

Sigh... I was a prolific poster back in 2006 and 2007, but I rarely post in here anymore. Now I remember why...
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
1900hurricane, an explosion of banned trolls coming back.

And FIU2010, if you think Spanish is a beautiful language, then you shouldn't use it in such an ugly way.

A serious blog cleanup is in order.


Cripes, people are dying right now in flooding in Guatemala and this drama is going on. It's really disgusting.

Amen to that brother.
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
1900hurricane, an explosion of banned trolls coming back.

And FIU2010, if you think Spanish is a beautiful language, then you shouldn't use it in such an ugly way.

A serious blog cleanup is in order.


Cripes, people are dying right now in flooding in Guatemala and this drama is going on. It's really disgusting.
I agree wholeheartedly this is getting ridicolous!
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3582. xcool



WT[[[[[ WT[[[[ THAT KIND CRAZYYYY
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Whats going on!? Why everyone fighting :((
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
1900hurricane, an explosion of banned trolls coming back.

And FIU2010, if you think Spanish is a beautiful language, then you shouldn't use it in such an ugly way.

A serious blog cleanup is in order.


Cripes, people are dying right now in flooding in Guatemala and this drama is going on. It's really disgusting.


agreed 100%

really everyone should ignore him, ignore his questions, ignore his insults

and get back to the more important things
Member Since: March 10, 2010 Posts: 1 Comments: 7831
3578. xcool
Member Since: Posts: Comments:
Quoting KoritheMan:


Not everyone goes to church, because not everyone is a Christian. You're getting rusty, Janiel.

He can comment to me all he like, I have him on ignore.
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South NSW hit by wild storm

DESTRUCTIVE winds are lashing southern NSW, causing damage to dozens of homes as a series of storms bringing flooding rains and huge seas approach the coast.

The town of Narooma was hit early this morning by a low pressure system and winds up to 135km/hr, the State Emergency Service (SES) said.

About 50 homes were damaged as windows broke, roofs were torn off and trees fell.

The state SES crews have so far attended to about 110 calls for help in the area.

The Bureau of Meteorology (BoM) has issued a severe weather warning for the south coast, the southern tablelands and the Illawarra region.

A series of offshore low pressure systems is due to cross the south coast today before moving north towards Batemans Bay, the bureau said.

It predicts gales exceeding 125km/hr and torrential rainfall, likely to cause flash flooding.
People are being warned to stay indoors and keep off beaches, and away from creeks, storm drains and causeways.

Sydney will avoid the brunt of the storms.

But, the SES yesterday warned Sydneysiders to stay indoors away from windows and to keep clear of power lines.

Extra SES volunteers are standing by to cope with increased call-outs.

Surf Life Saving Australia wants people to stay out of waterways and the surf, and waterfront residents should check their homes for erosion.

The severe conditions, whipped by an intense low, are similar to the storm that forced the Pasha Bulker container ship ashore in Newcastle in 2007.In the southern half of NSW, winds should exceed 90km/h today with at least 150mm of rain to be dumped on parts of the area.

Bureau of Meteorology spokesman Barry Hanstrum said: "Very strong to gale-force winds are expected along the southern coast, which will also result in very dangerous sea conditions and coastal erosion in vulnerable areas."

An SES spokesman said the service would closely watch Bulli, in Wollongong, where about 400 people from 130 homes were evacuated on Wednesday as a dam at an old mine threatened to flood homes.
Member Since: Posts: Comments:
Quoting KoritheMan:


Not everyone goes to church, because not everyone is a Christian. You're getting rusty, Janiel.


LOL!
Member Since: Posts: Comments:
Quoting btwntx08:

it is already

i've been told 3 times its been downgraded, does that mean its a 3 time downer?
Member Since: Posts: Comments:
Quoting FIU2010:
speak for yourself, aussie. it's sunday morning over there, dont you have to go to church or something, mate? anyways, EXt,w elcome back, sir.


Not everyone goes to church, because not everyone is a Christian. You're getting rusty, Janiel.
Member Since: Posts: Comments:
Quoting 1900hurricane:
Woah, what's going on in here tonight???


We both missed it.
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Quoting FIU2010:
I shall, XCool. is the ECW out yet?
Nope not yet
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3566. xcool
FIU2010 NOT YET
Member Since: Posts: Comments:
Woah, what's going on in here tonight???
Member Since: Posts: Comments:
Quoting xcool:
FIU2010 BE NICE .THANKS.

He doesn't know how to be nice, I wonder how many of his handle I have on ignore???
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
If google translate is accurate, some pretty bad things are being said. I'm not a fan of people trying to sneak bad stuff in through another language.

That is bad, They know not everyone, only a few can speak spanish. so they risk saying some pretty bad things and hope to get away with it.
Member Since: Posts: Comments:
3559. EricSFL
Quoting StSimonsIslandGAGuy:
If google translate is accurate, some pretty bad things are being said. I'm not a fan of people trying to sneak bad stuff in through another language.


Exactly.
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3558. xcool
FIU2010 BE NICE .THANKS.
Member Since: Posts: Comments:
Quoting AussieStorm:

i would downgrade it to a TD
It has been downgraded already.
Member Since: April 8, 2010 Posts: 15 Comments: 2572

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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.