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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Quoting Levi32:




So which is it...lol.

And Bonnie by July 1st IS a lot of activity. The average date of the first named storm is July 10th.
Lol, well considering that we are forecasted to have a "hyperactive" season you would think we will see a lot of activity. I think we will get a named storm in early June and another one in late June. I'm not crazy, well maybe a little bit, lol, jk.
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Quoting Jeff9641:


Everyone is focusing on the Caribbean when it's 90E that will become the topic of conversation as there is a chance now for 90E to redevelope in the SE gulf and track toward S FL. There will be som shear but not as strong as it is now as the Sub tropical jet is forecast to shift north.


The subtropical jet is still racing right over Florida in 6 days. It's going to remain that way for quite a while. The upper ridge building into the western Caribbean won't be extending into the Gulf of Mexico.

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Kingston, Jamaica

75 °F
Light Rain
Humidity: 89%
Dew Point: 72 °F
Wind: 5 mph from the SSW
Pressure: 29.83 in (Falling)
UV: 16 out of 16
Clouds: Few 500 ft
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Quoting photomunkey:
Patrap,
The general population should be taught to salute our military, even enlisted men and women. Especially on Memorial Day weekend!

Isn't the rule "when in doubt as to whether someone outranks you, you should salute"? I see it as a matter of courtesy and recognition of someone's service to our country.

BTw-I also think that no school will ever permit this to be taught, outside of Annapolis perhaps. That's a shame.


Right On.....Many of the younger generations (particularly those who have never served the Country) have simply lost the meaning of the word "respect" over the past few decades, and, particularly respect for elders and those who have sacrificed for their own families and Country; just take a look around......The "Greatest Generation" was exactly that....God Bless All the Military in this County, past and present, and "salute" them every Day.
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We have been conducting a full-scale test of the live severe weather webcam system today.

This final test is critical, as all systems are now running on battery power only.

The main webcam, its computer and network connectivity are wired to the "main battery."

So far, the test has run uninterrupted for over 90 minutes...and we will continue to run the test until all batteries are out of power.

If you would like to pop in from time-to-time, you are welcome. Just use the media call-out URL of 7674u.com

Oz---
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Quoting MiamiHurricanes09:
Well we're watching an area of that might possibly have a surface low just west of Jamaica. This area should move NE right into the subtropical jet. The GFS is forecasting a system to develop within 72 hours in the Atlantic, it looks like it's being sucked up, so I doubt we'll see development. Subtropical development is possible though. And to answer your question even further, I don't think we will get much activity in June. When July comes around, I think, is when the season is really going to get going.


Quoting MiamiHurricanes09:
I think we will get up to Bonnie before July 1st, not too much activity, imo.


So which is it...lol.

And Bonnie by July 1st IS a lot of activity. The average date of the first named storm is July 10th.
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Good afternoon. It is a beautiful 95F degrees in the shade here in Arlington, TX, almost no wind at all, dew point near 65F, heat index about 98F, ahh the joys of late spring in N TX!!

90E is looking good and the Caribbean Sea is loaded with moisture.

Watching the BP mess is very upsetting,
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Quoting Levi32:


They already are going pretty good for May. I think we will see at least one named storm during the month of June. Whether that is at the beginning or the end of the month, I'm not sure yet. Conditions in the Caribbean will be conducive for the next couple weeks, so that area will have to be watched.
I think we will get up to Bonnie before July 1st, not too much activity, imo.
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Quoting FIU2010:
I want to apologies for being an ass with you as well, yesterday, Pat. :)


Like I said..it rolls off me back.


Forgetaboutit...
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Quoting FIU2010:
levi, how much longer before the tropics really get going? :(
Well we're watching an area of that might possibly have a surface low just west of Jamaica. This area should move NE right into the subtropical jet. The GFS is forecasting a system to develop within 72 hours in the Atlantic, it looks like it's being sucked up, so I doubt we'll see development. Subtropical development is possible though. And to answer your question even further, I don't think we will get much activity in June. When July comes around, I think, is when the season is really going to get going.
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Quoting oceanblues32:
Does anyone think the low in the pacific could reach south florida at at what intensity?
The Canadian GEM model has a tropical storm moving over South Florida in 6 days. That is a long way out but it is something to watch.
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Quoting StormW:
Good afternoon!

INVESTIGATIVE AREA 90L/TROPICAL SYNOPSIS UPDATE ISSUED 12:40 P.M. MAY 28, 2010
Good Afternoon
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http://www.ireport.com/docs/DOC-450243?hpt=T2


Volcanic ash rains over Guatemala
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Quoting oceanblues32:
Does anyone think the low in the pacific could reach south florida at at what intensity?


The current steering flow does not support 90E moving towards Florida.
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Quoting FIU2010:
levi, how much longer before the tropics really get going? :(


They already are going pretty good for May. I think we will see at least one named storm during the month of June. Whether that is at the beginning or the end of the month, I'm not sure yet. Conditions in the Caribbean will be conducive for the next couple weeks, so that area will have to be watched.
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Does anyone think the low in the pacific could reach south florida at at what intensity?
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Patrap,
The general population should be taught to salute our military, even enlisted men and women. Especially on Memorial Day weekend!

Isn't the rule "when in doubt as to whether someone outranks you, you should salute"? I see it as a matter of courtesy and recognition of someone's service to our country.

BTw-I also think that no school will ever permit this to be taught, outside of Annapolis perhaps. That's a shame.
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Quoting MiamiHurricanes09:
Really? Surface Analysis (12z) not putting anything there. But I do have to say that there is good vorticity, in the lower levels, just west of Jamaica along with a decent amount of showers and thunderstorms.





Yeah you can see it spinning on satellite imagery. It's weak but I'm convinced it's a low. A surface station near the tip of Honduras/Nicaragua reported pretty low pressures last night relative to the surrounding stations, and the low was directly over the station at the time. The pressure this morning has now risen with westerly winds, indicating that the station is now on the south side of the monsoon trough, and the low has moved off to the northeast.
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12z Surface Analysis.
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Quoting Jeff9641:


Hey buddy, we have some storms bulding quick and some building near you.

I have been really busy today. I have been checkin the blog for storm updates THANKS. By the way have a great holiday weekend.
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Quoting Levi32:


No the GFS is correct this morning. The low is now finally there. It was the last 3 runs or so that kept putting it in that same exact spot, and that was incorrect. Now, however, the low is there.

Really? Surface Analysis (12z) not putting anything there. But I do have to say that there is good vorticity, in the lower levels, just west of Jamaica along with a decent amount of showers and thunderstorms.



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Lets hope this model is not correct.....OH NO!

TampaSpins blog update!

GFS MODEL SHOWS A STORM IN THE GOM FIRST WEEK IN JUNE
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Jamaica's having a rough day so far due to that low.

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Quoting MiamiHurricanes09:
12z GFS once again initialized incorrectly putting an area of low pressure (1009 MB) just to the west of Jamaica. At the moment the only thing in that area is the monsoonal trough which is causing the large amount of showers and thunderstorms along with a pretty strong upward motion MJO. Right now conditions are pretty much prime in the Caribbean for development.

12z GFS 0 hours:



No the GFS is correct this morning. The low is now finally there. It was the last 3 runs or so that kept putting it in that same exact spot, and that was incorrect. Now, however, the low is there.

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Quoting TampaSpin:



Look how current Shear has fallen compared to Climatology! NOT GOOD if this continues.
It will probably rebound quickly.
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Quoting gator23:


Right, but then you have guys like OZ who blame OBAMA for everything including an earthquake in Vanuatu. Short memories, that last eight years had 2 wars, Katrina, 2 economic collapses and terrorist attacks, and all of that wasnt Bush although some of it is directly his doing.

2 wars- started by Islamic Extremists who brutally killed 3000 people in the World Trade Center attacks. Iraq was iffy. Katrina-How exactly does one justify blaming any sitting President for local and state government failures in leadership and planning? Feds do not intervene in a hurricane response because primary responsibility falls to local and state law enforcement and state leadership. That way the chain of command remains clear. LA's governor failed. Mayor Nagin failed. Katrina was first and foremost a communication failure at leadership levels. 2 economic collapses- Widely documented that deregulation directly causing this problem occurred mainly during the Clinton Administration, under the control of Barney Frank and Senator Dodd who pushed for subprime loans in economically-downtrodden areas. Great idea that, loaning money to people who can't afford it in the name of racial equality. Ex-pres Clinton, when interviewed in late-2008 or early 2009, stated that the returns were so high on these bundled mortgage assets, everyone went that way because returns were so low in the stock market. He still possesses a sharp analytical mind it seems. It was bound to cause problems eventually, as then-President Bush's TWO letters to Congress pointed out. What did you want the man to do? Walk around on Capitol Hill wearing a sign which read "Apocalypse Now: Fix Fannie Mae and Freddie Mac!". Senator Clinton even mentioned this problem in 2006, 2007, and 2008 after meeting with banking officials, and a search of Barney Frank quotes will quickly reveal how many times that man assured us that "nothing's wrong, Fannie and Freddie are sound". The "mark to market" rule was the killer though. Once one major brokerage house foundered, and no one would buy their mortgage assets, then EVERYONE had to mark down their mortgage assets to $0 on their spreadsheets, tipping the entire banking industry into turmoil as now all banks were nearly underfunded. The sale of these troubled assets under TARP, to the Feds, is actually a stroke of genius. Even though there will be some defaults within the blocks of mortgage assets, they will always have value, just now the entity holding the assets stands a chance of making a ton of money on them over time. The Feds could have solved the problem by revising the "mark to market" rule, but they refused to act because it was a political hot potato during an election year. Dems preferred to blame the current administration, a tactic they'd used since 2005 Congressional election. In a way, the financial collapse was a Congressional-political creation, and was mined by both parties for all it was worth. The Dems just had the better mining equipment this go-round, and had the support of the mainstream media who harbored a strong dislike of Pres. Bush.


Did Pres. Bush overspend? Yes. Did Congress overspend. Yes. And they're still doing even more overspending today even tho the nameplate on the door to the Oval Office has changed.

This is not a party problem, this is a corruption problem exacerbated by the lack of term limits on Congress.

With the exception of Iraq, none of the items mentioned can be blamed on Bush. Doing so is intellectual dishonesty, just as blaming BP's spill on Obama is equally dishonest.

Now can we cut through this political crap and get back to hurricanes, tropical depressions, named storms, who's-the-most-accurate-forecaster inanities, and following BP's efforts to stop this horrible oil spill?
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Look how current Shear has fallen compared to Climatology! NOT GOOD if this continues.
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12z GFS once again initialized incorrectly putting an area of low pressure (1009 MB) just to the west of Jamaica. At the moment the only thing in that area is the monsoonal trough which is causing the large amount of showers and thunderstorms along with a pretty strong upward motion MJO. Right now conditions are pretty much prime in the Caribbean for development.

12z GFS 0 hours:

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Quoting stormhank:
Anyone know when the shear over the gulf/ bahamas area is suppose to lessen? i saw where it suppose to stay high thru the next 3 days


Climatologically the gulf doesn't get shear down to consistently favorable levels for tropical development until July, but since it's an early-season breeding ground, shear does periodically lower to allow tropical development. The subtropical jet looks to be sitting over it for a while yet. The GFS is hinting at low shear in 15 days over the gulf, but this is long-range and unreliable. It will happen eventually.
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Love this blog
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Quoting gator23:


Interesting, you think that they have a chemical that turns oil clear. I agree, why dont they just drop a pipe down there to pick up the oil! Brilliant! Man it is so simple why didnt anyone come up with that? Question now is who do we call to tell them your great idea!?


They have already turned the oil clear.....University of South Florida has already found and confirmed what they have done with toxins....UNREAL
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Quoting Patrap:


WTF does that imply?

BP 's blowout happened in Federal,or International Waters Sport.

Thats the kind of self centered BS we cringe at on the wnderground.

From myself on up to Jeff Masters.

.."Calamity knows no Borders sport,only mens minds and maps do"...

You recieve 24 entry demerits for that one.

LOL


Good one Patrap. I don't want the oil to be a problem for anyone.
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Oh my goodness this blackberry ugh!!! Lol
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Anyone know when the shear over the gulf/ bahamas area is suppose to lessen? i saw where it suppose to stay high thru the next 3 days
Member Since: September 8, 2005 Posts: 0 Comments: 1384
Quoting MiamiHurricanes09:
Good Morning!


Morning MH09 :)
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Quoting Jeff9641:


Hey Pat sorry for being out of line yesterday as I was in a bad mood and certain people got under my skin.

Now thats what its all about. can man up great jeff9641
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Quoting FIU2010:
i feel all depressed when the tropics are dead, i cant stand it, :(
You wont be depressed for long.
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Quoting Levi32:
Good morning all.

Tropical Tidbit for Friday, May 28th
Good Morning!
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157. beell
Passed on to me from a WU Blogger who prefers her sense of humor to remain somewhat anonymous.

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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.