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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457. IKE
6-10 day temps...




6-10 day precip...

Member Since: Posts: Comments:
WOW - just had a rotational t-storm in frostburg, MD, elevation 2000 feet on top of a mountain. Quarter sized hail, lightning ~5 seconds, VIL of 62, and a top of 37k feet. Don't get too many like that around here.
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455. xcool
yeah.he go be missss
Member Since: September 26, 2009 Posts: 2 Comments: 15603
453. IKE
Quoting xcool:
Former Child Star Gary Coleman Dead at 42


Sorry to read that. I knew he was on life-support since yesterday.
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k drak i posted comment in your blog
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I am sorry but they did not find him yet and I am sorry for the caps
Member Since: June 13, 2009 Posts: 2 Comments: 9553
450. IKE
I think 90E is heading toward a TD...soon.

Everything in the western ATL...western Caribbean and east-PAC seems to be moving to the ENE. Almost a winter like pattern of movement. Just doesn't look conducive for the GOM for the next week.

Now watch something spin up in the GOM and prove me wrong.
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449. xcool
Former Child Star Gary Coleman Dead at 42
Member Since: September 26, 2009 Posts: 2 Comments: 15603
Quoting belizeit:
Link Latest ascat pass on 90E


Looks like a tropical depression is forming. The circulation has become much better defined
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447. xcool
lmao
Member Since: September 26, 2009 Posts: 2 Comments: 15603
Quoting Jeff9641:
I just checked the Euro and it does not show a tropical system moving over Florida BUT it does show the remnants of 90E moving over Florida ahead of the trough moving in from out west. If the Euro latches on to the CMC then we really need to be on alert.
why please explain if u do not mind
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I hope Stormtop has his NOAA cropduster ready for this season LOL
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Reserve all comments on my forecast in my blog please :)

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Link Latest ascat pass on 90E
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441. IKE
Quoting FIU2010:


it's out to lunch.


Well....it's got other models eating with it.
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Quoting FIU2010:


it's out to lunch.
I agree to some point i agree about it overblowing the intensity of 90E but i agree that we wont see anything in the atlantic in the short term.
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Great work Drak on that forecast
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Quoting Jeff9641:


Ecmwf model is the one i was referring to.
Nevermind, I found it. Dumb moment on my part.
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XtremeStormJunkies Update:

The full-scale portable power test of the live severe webcam is now at 4 hours with no interruption in any service.

All bluetooth devices, which are operating on their own, internal batteries are still functioning well.

The webcam system (computer, cell phone, and wireless 3G broadband card) are still fully operational and running off the "main batt."

You can see the progress of this full-scale portable power test by going to our media call-out URL of 7674u.com

I'm beginning to be impressed with the bluetooth devices!
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President live at this time from Grand Isle La.:

http://edition.cnn.com/video/flashLive/live.html?stream=stream1&hpt=T2
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432. IKE
Quoting stormhank:
Anyone buying into the noon CMC run concerning 90E?? Link


I don't believe it, for now.
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Anyone buying into the noon CMC run concerning 90E?? Link
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Quoting kimoskee:


Did you take a picture? You sure it's not DEA plane on standby to collect Dudus out of Jamaica?

Did they find Dudus?
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sorry no I did not take a pic and the plane took off going honduras way and I wad close up to the plane and there was no DEA just noaa any way we have a US coast gard ship in port
Member Since: June 13, 2009 Posts: 2 Comments: 9553
427. IKE
12Z ECMWF shows 90E turning into a significant system.

That's it....zip in the Atlantic through June 7th.
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That storm north of tampa is just to the east of me.
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Greetings.
Heavy, intermittent rain here today. Humidity 100% now.
May be a rainy weekend.

Just listened to the Swearing in, of the new Cabinet of Trinidad&Tobago.
Happy to report that the new Ministers individually swore on -
The Holy Bible, Christian.
The Gita, Hindu.
The Koran, Moslem.
according to their Faith.

The Cabinet includes people of African, Indian and European extraction. And a lot of them have some of all the above.

Here, every Creed and Race find an Equal place.
And Democracy is alive and well.

Makes a change...
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2010 Atlantic Hurricane Season Forecast
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422. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15603
421. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15603
Quoting Jeff9641:
I just checked the Euro and it does not show a tropical system moving over Florida BUT it does show the remnants of 90E moving over Florida ahead of the trough moving in from out west. If the Euro latches on to the CMC then we really need to be on alert.
The EURO 12z has yet to be released.
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A little rain in ft lauderdale isn't that a suprise
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Quoting spathy:
Alex I am so looking forward to our friend the rainy season.
Its such an interesting phenomenon to watch.
Its my fav. time of year here.
During rainy season my neck gets a crick from looking up so often.
LOL I love it too! So fun
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417. xcool
i'm back
Member Since: September 26, 2009 Posts: 2 Comments: 15603
DEA pilots on standby
http://abcnews.go.com/Blotter/us-set-grab-alleged-jamaican-drug-lord/story?id=10752025

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Quoting wunderkidcayman:
HEY GUYS I WAS JUST IN TOWN EARLER BY THE AIRPORT AND CAN SOMEONE PLEASE TELL ME WHAT IS THE P-3 HURRICANE HUNTER WAS DOING PARKED AT THE PARKING AREA RIGHT BY THE MET OFFICE


Did you take a picture? You sure it's not DEA plane on standby to collect Dudus out of Jamaica?
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Quoting Drakoen:


Here is a free site for upload storage and sharing if that is what you are asking :)

http://www.mediafire.com/
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There's a nice little storm north of Tampa.
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Quoting wunderkidcayman:
HEY GUYS I WAS JUST IN TOWN EARLER BY THE AIRPORT AND CAN SOMEONE PLEASE TELL ME WHAT IS THE P-3 HURRICANE HUNTER WAS DOING PARKED AT THE PARKING AREA RIGHT BY THE MET OFFICE
Caps lock on again?
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Quoting oceanblues32:
Does anyone think the low in the pacific could affect southeast florida when and at what intensity
I dont think so maybe left over moisture but nothing tropical
Member Since: April 8, 2010 Posts: 15 Comments: 2570
HEY GUYS I WAS JUST IN TOWN EARLER BY THE AIRPORT AND CAN SOMEONE PLEASE TELL ME WHAT IS THE P-3 HURRICANE HUNTER WAS DOING PARKED AT THE PARKING AREA RIGHT BY THE MET OFFICE
Member Since: June 13, 2009 Posts: 2 Comments: 9553
Does anyone think the low in the pacific could affect southeast florida when and at what intensity
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About JeffMasters

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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