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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2057. JamesSA
Quoting Patrap:
Looks Like they cut one of the Top Kill fill Lines,maybe the choke inlet side

I see now that they are working at the top of the BOP. Interesting.
Member Since: August 17, 2009 Posts: 0 Comments: 579
2056. Patrap
Looks Like they cut one of the Top Kill fill Lines,maybe the choke inlet side
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2055. scott39
Quoting MiamiHurricanes09:
It can't do that because steering currents won't allow for that. And if it stays in the GOM it will be ripped apart by shear. I think that Agatha will just dissipate over the Yucatan and then energy from it will develop in the western Caribbean. Agatha could also go over Guatemala and Belize and then into the Caribbean, but it would have to hurry up in speed.
Ok, thanks
Member Since: June 13, 2009 Posts: 0 Comments: 6912
Yeah, do any of the models at all incorporate the topology of the land into their calculations for tropical weather/storms/etc? Or do they just assume it's "land" at sea level, that is, either just "land" or "anti-water" or a const value? I'm assuming it's just a const value with zero or near zero elevation for most of the models. If this is so, of course it would explain why these models think there's going to be redevelopment in the gulf considering the likely outcome that the storm will be torn to shreads by the mountains of Central America.
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2053. leo305
Quoting MiamiHurricanes09:
It can't do that because steering currents won't allow for that. And if it stays in the GOM it will be ripped apart by shear. I think that Agatha will just dissipate over the Yucatan and then energy from it will develop in the western Caribbean. Agatha could also go over Guatemala and Belize and then into the Caribbean, but it would have to hurry up in speed.


I think it is doing the latter

http://www.ssd.noaa.gov/goes/flt/t6/flash-rgb.html
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Quoting scott39:
If Agatha followed the far W Model, and stayed more in the BOC off the coast and then turned more to the NE at the tip of the Yucatan, would it still be ripped when it hit the GOM?
It can't do that because steering currents won't allow for that. And if it stays in the GOM it will be ripped apart by shear. I think that Agatha will just dissipate over the Yucatan and then energy from it will develop in the western Caribbean. Agatha could also go over Guatemala and Belize and then into the Caribbean, but it would have to hurry up in speed.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2051. will45
Quoting divdog:
Quoting MahFL:
Oh oh, looks like they are about to cut a pipe off the BOP in the Gulf !!!

Absolutely false. Please stick to the facts !!



well they fixin to cut something they have a saw down there



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2050. leo305
it will make landfall today.. its moving faster than suggested..

http://www.ssd.noaa.gov/goes/flt/t6/flash-rgb.html

if you look closely you can see the center embedded into the strongest area of convection, and its moving ENE/NE at atleast more than 8mph
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2049. Patrap
A ROV is getting in position to cut something with a Carbide,diamond blade.

BP
Live feeds from remotely operated vehicles (ROV)
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2048. JamesSA
Can any of you figure out what part it is that they are sawing on? Is that part of the BOP? Top area? Bottom area? I'm trying to figure out what the purpose of that little operation might be. Thanks.
Member Since: August 17, 2009 Posts: 0 Comments: 579
2047. scott39
Quoting MiamiHurricanes09:
Yeah, I base it on the models, but you know how off models can be some of the time.
If Agatha followed the far W Model, and stayed more in the BOC off the coast and then turned more to the NE at the tip of the Yucatan, would it still be ripped when it hit the GOM?
Member Since: June 13, 2009 Posts: 0 Comments: 6912
2046. divdog
Quoting MahFL:
Oh oh, looks like they are about to cut a pipe off the BOP in the Gulf !!!

Absolutely false. Please stick to the facts !!
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Quoting StormW:


Wow, look at the Atlantic tri-pole. That's pretty crazy.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting Orcasystems:


I figure with it being that close to the shore.. and the general direction its going... close enough :)
LOL.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Member Since: Posts: Comments:
Quoting reedzone:


He left lol
No he didn't he singed in, lol. (I think).
Member Since: September 2, 2009 Posts: 130 Comments: 21194
2040. Levi32
Quoting MiamiHurricanes09:
Good Morning!


Morning MH09 :)
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Quoting MiamiHurricanes09:
Good Morning!


He left lol
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Quoting MiamiHurricanes09:
Yeah, I base it on the models, but you know how off models can be most of the time.


I figure with it being that close to the shore.. and the general direction its going... close enough :)
Member Since: October 1, 2007 Posts: 81 Comments: 26512
Quoting Orcasystems:


Close enough to match the models

Yeah, I base it on the models, but you know how off models can be some of the time.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
MiamiHurricanes09 - 12z Agatha Forecast Cone.

*Keep in mind this is my forecast cone and it can be completely wrong.



Close enough to match the models

Member Since: October 1, 2007 Posts: 81 Comments: 26512
Quoting Levi32:
Good morning all.
Good Morning!
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Partial ASCAT pass from last night showing relatively strong winds on the western quadrant.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
2033. Levi32
Good morning all.
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Member Since: September 2, 2009 Posts: 130 Comments: 21194
2031. Motttt
they droped the saw
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2030. scott39
Sounds like Agathas forecast has her dying over land and some models are picking up her ghost to develope again?
Member Since: June 13, 2009 Posts: 0 Comments: 6912
MiamiHurricanes09 - 12z Agatha Forecast Cone.

*Keep in mind this is my forecast cone and it can be completely wrong.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
2028. Patrap
Oil spill video: Reporters give latest 'Top Kill' news











Oil spill video: Reporters give latest 'Top Kill' news
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2027. sotv
Quoting pottery:

They will have some showers, but also some great weather too.
Tell them to be sure to visit Charlotteville and BlueWaters Hotel in Speyside. The north tip of the island. Very nice scuba off Speyside. Manta Rays and stuff.


Can't get in touch with him, have visited the island before myself and had a lovely holiday, stayed on Turtle beach and was lucky enough to see a couple of leatherback turtles come up to the beach and lay there eggs one night in May very memorable, visited Speyside and Pigeon Point amongst other places myself and recommended them to my brother before he went.
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Be Back Soon...Going ot make a new Blog Entry...
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2025. Motttt
http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/homepage/STAGING/local_assets/b p_homepage/html/rov_stream.html
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2024. pottery
Quoting Motttt:
rov Link

Thanks guys, but I cannot open that link.
Will try to install some stuff...
Member Since: October 24, 2005 Posts: 0 Comments: 24785
Afternoon all, just incase anyone missed here's a repost of my morning update.

NOAA predicts stunning numbers, Tropical update 5/29/10

Sees we have Agatha, first storm of the EPAC season. The EPAC season should be quite different that last year, as El Nino came to play.. this year La Nina is. I'm predicting about 13-15 named storms this year from the EPAC. Last year had 20.
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Quoting Stormchaser2007:


Models are confused..But would can you expect for this time of the season?
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2021. pottery
Quoting sotv:


My brother flew out to Tobago from UK for two weeks holiday with his family on Thursday. Any chance of them being able to be doing a bit of sunbathing and sightseeing while there or is it going to be a complete washout? Rain forecast for next five days at least on BBC website.

They will have some showers, but also some great weather too.
Tell them to be sure to visit Charlotteville and BlueWaters Hotel in Speyside. The north tip of the island. Very nice scuba off Speyside. Manta Rays and stuff.
Member Since: October 24, 2005 Posts: 0 Comments: 24785
Agatha future track

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Quoting WinterAnalystwx13:


Ahh...What'd you use? Powerpoint?
Yep
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Quoting kmanislander:
Late yesterday afternoon there was a discussion here about what may happen IF what was then 90E developed and came ashore in Guatemala.

I made the point then that the terrain in that country, which reaches over 13,000 feet in places, including the Western side where the storm is headed, would decouple the system and prevent it from traversing into the Caribbean intact.

If anyone has watched what the mountains of Hispaniola has done to major hurricanes before you will easily picture what lies in store for this storm.

The mid to upper level circulation may make it into the extreme Western Caribbean and if conditions are right could work its way back down to the surface. If that happened it might regenerate into a cyclone but all of that is conjecture that is way off into the future for a slow mover like this.
Agreed.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting cyclonekid:
Haha. Thanks Cody. But don't thank me, thank AllStar17. He helped me make them :)


Ahh...What'd you use? Powerpoint?
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Back later
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2014. Motttt
rov Link
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2013. scott39
Quoting WinterAnalystwx13:


Umm...Uts not going to happen. It would die..
Ok, umm thanks it really helped!
Member Since: June 13, 2009 Posts: 0 Comments: 6912
2012. JamesSA
Quoting Motttt:
there going to do some cutting on the bop
Ahh! I see that now. An ROV with a circular saw on the BP site feed. That should be interesting! Link

CNN is showing 5 hour old recorded video of the plume instead.
Member Since: August 17, 2009 Posts: 0 Comments: 579
2011. sotv
Quoting pottery:
Heavy rain here this morning, and a friend in Tobago just called to say it has been Torrential there all night long.
May rainfall is setting records here ...


My brother flew out to Tobago from UK for two weeks holiday with his family on Thursday. Any chance of them being able to be doing a bit of sunbathing and sightseeing while there or is it going to be a complete washout? Rain forecast for next five days at least on BBC website.
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Quoting StormW:
I usually don't work on Saturday, but I'll do some analysis and have a synopsis, to include my thoughts on Agatha.


Good morning W. How is the cold pool in the equatorial Pacific doing? That full disk image that you post is nitid.
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Quoting MiamiHurricanes09:
What?!?!?!?!? That's what I've been saying for the past 20 minutes.


Just ignore him and move on.

Its not worth it...
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Quoting MiamiHurricanes09:
What?!?!?!?!? That's what I've been saying for the past 20 minutes.



Well I apologize.. I thought you said that if the storm becomes a hurricane.. it will move faster and create its own steering current.
Member Since: January 22, 2006 Posts: 0 Comments: 1723
2007. pottery
Quoting MahFL:
Oh oh, looks like they are about to cut a pipe off the BOP in the Gulf !!!

Where to go, to see that?
Not showing that on the CNN feed.
Member Since: October 24, 2005 Posts: 0 Comments: 24785

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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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