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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2557. cg2916
Quoting MiamiHurricanes09:
If that is true, Agatha I now in a new steering layer.


If THAT is true, then this thing has a chance of getting in the Caribbean.

IMPORTANT PART

A little while ago, that said Agatha was at 993 MB. About 5 minutes later, new advisory came out, and said it was at 1003 MB. The NHC and ADT don't usually agree.
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2556. Levi32
Quoting SouthALWX:

Not that I disagree or to be insulting but ...
is Joe Bastardi, by chance, your favorite forecaster ... lol some things you say seem to be exactly what Joe B said the day before, but rephrased .... maybe you just think alike ;)


I'm not ashamed to admit it....I am greatly influenced by Bastardi. He will always be my favorite Meteorologist, and that can sometimes be at the expense of my reputation around here, but that won't stop me. I've been saying all winter that this El Nino was reactionary, but JB's post yesterday did enlighten me a little more to the overall global pattern, and gave me a better understanding. I love his videos.
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2555. xcool
move to ne
Member Since: September 26, 2009 Posts: 2 Comments: 15684
2554. Drakoen
Getting into the Gulf of Honduras is a long shot. The 850mb ridge axis will set up off the southeastern United States and the flow is not conducive for things pushing into the Caribbean from the EPAC.



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2553. xcool
MiamiHurricanes09 100% free
Member Since: September 26, 2009 Posts: 2 Comments: 15684
On this side, Pat, that would be a major threat. Shows how little it takes to fire up a storm like Agatha so close to the coast
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Ashore, and by the looks of it in Mexico just to the West of the Guatemala border.

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Quoting gordydunnot:
I wonder if the US Government is ever going to let Jed Clampitt going fishing in the gulf again.


BWWWWHAHAHAHAHAHAHAHAHAHAHHAAAAA!!!!!!
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Levi, then if La Nina is just a passenger along for this crazy ride. What is driving the current pattern, and at the mention of 2005, are we looking at a copy of that setup?
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Quoting Levi32:


La Nina doesn't make it or break it....remember 2005 was neutral. It is the worldwide pattern and distribution of heat that is driving the up-tick in Atlantic activity that we are going to see this year, not La Nina. This ENSO phase has been reactionary to the global pattern, and this La Nina is a product of that pattern, not the driver of it.

Not that I disagree or to be insulting but ...
is Joe Bastardi, by chance, your favorite forecaster ... lol some things you say seem to be exactly what Joe B said the day before, but rephrased .... maybe you just think alike ;)
Member Since: August 27, 2008 Posts: 0 Comments: 1497
Quoting xcool:



wow look at storms..


xcool.
How much is the software to get those images.
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2546. Patrap
Rainbow 30 min earlier Ike

Member Since: July 3, 2005 Posts: 426 Comments: 129093
2545. IKE
Looks inland on the 2015 UTC visible...

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I wonder if the US Government is ever going to let Jed Clampitt going fishing in the gulf again.
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2542. xcool
pottery thanks
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Agatha could dump two feet of rain in those mountains. Swollen rivers and flash floods are a serious threat. I hope the Government there is on top of this with advisories and evacs. This is a country with 100 rivers
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2540. pottery
Great image, xcool.
Member Since: October 24, 2005 Posts: 0 Comments: 24653
2539. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 129093
2538. xcool



wow look at storms..


xcool.
Member Since: September 26, 2009 Posts: 2 Comments: 15684
2537. Skyepony (Mod)
Agatha got her 1st death yesterday. A 48-year-old woman drowned after after trying to cross an overflowing river in north-central Nicaragua. 150 were lost in Ida last fall from rain. They've evacuated only 2000 so far.
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2536. Levi32
Quoting plywoodstatenative:


If La Nina comes in early, are we looking at a rapid updwelling of storms?


La Nina doesn't make it or break it....remember 2005 was neutral. It is the worldwide pattern and distribution of heat that is driving the up-tick in Atlantic activity that we are going to see this year, not La Nina. This ENSO phase has been reactionary to the global pattern, and this La Nina is a product of that pattern, not the driver of it.
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2535. xcool
not go be fun for Central America
Member Since: September 26, 2009 Posts: 2 Comments: 15684
2534. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 175 Comments: 54858
2533. Patrap
THe ULL is a wet one..



447
WGUS54 KLIX 292021
FFWLIX
LAC051-075-292315-
/O.NEW.KLIX.FF.W.0007.100529T2021Z-100529T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
321 PM CDT SAT MAY 29 2010

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
CENTRAL JEFFERSON PARISH IN SOUTHEAST LOUISIANA...
THIS INCLUDES THE CITIES OF...TIMBERLANE...MARRERO...HARVEY...
EXTREME NORTHWESTERN PLAQUEMINES PARISH IN SOUTHEAST LOUISIANA...
THIS INCLUDES THE CITY OF BELLE CHASSE...

* UNTIL 615 PM CDT

* AT 317 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN POTENTIALLY PRODUCING FLASH FLOODING FROM A
THUNDERSTORM OVER THE WARNED AREA. RADAR INDICATES 2 TO 3 INCHES
OF RAIN HAS FALLEN IN THE LAST HOUR.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TERRYTOWN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE IN THE
WARNED AREA.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.



LAT...LON 2991 9013 2990 8999 2990 8998 2990 8993
2990 8992 2988 8991 2972 8991 2972 9012
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting Patrap:
Sometimes a weaker system can bump the Elevation and get shunted from angular mo,and not the steering layers..we may be seeing this here.

Interesting ,

With a Spock raised eybrow


And, one more thing. Orographic lift will produce copius amounts of rain from this as the system makes the traverse over high terrain. That could help keep the heat going in the convection and jump start it, so to speak, if it can get into the Gulf of Honduras without prolonged delay.
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Quoting Drakoen:


Yes but don't mistake that for it getting into the Western Caribbean at most it would be riding the eastern Yucatan Peninsula
Yeah, definetly.
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2529. Patrap
Agatha Floater - Dvorak Infrared Loop
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting Levi32:


There are no significant developments outside of Agatha on any of the models at the moment, but I believe the Caribbean will have to be watched for the next couple weeks as the upward motion pulse of the MJO lingers, especially if the monsoon trough remains farther north than normal.


If La Nina comes in early, are we looking at a rapid updwelling of storms?
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2527. Patrap
Sometimes a weaker system can bump the Elevation and get shunted from angular mo,and not the steering layers..we may be seeing this here.

Interesting ,

With a Spock raised eybrow
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting kmanislander:


After climbing 13000 plus feet there won't be much left to work with on the other side but it can happen if the mid to upper levels survive and start transitioning back towards the surface.
I can agree with that.
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2524. Drakoen
Quoting MiamiHurricanes09:
Exactly!


Yes but don't mistake that for it getting into the Western Caribbean at most it would be riding the eastern Yucatan Peninsula
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2523. Levi32
Quoting plywoodstatenative:
Levi, history has shown that when the Pacific season starts up with a tropical system. That we are not that far behind in our season. So the question becomes what are the models saying along that line.


There are no significant developments outside of Agatha on any of the models at the moment, but I believe the Caribbean will have to be watched for the next couple weeks as the upward motion pulse of the MJO lingers, especially if the monsoon trough remains farther north than normal.
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2522. KEEPEROFTHEGATE (Mod)
Quoting Patrap:


Oarfish,,seen da sucka too
are ya sure you didn't mean oilfish
Member Since: July 15, 2006 Posts: 175 Comments: 54858
Center Agatha must be now about 100 miles from the coast. and about 52kts winds.
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2520. Patrap
Quoting FIU2010:
but pat, th ull is moving west, and it now appears to be moving north of west.


Keep ya eye on the ULL ..and the Agatha Cirrus Outflow to the North..
Member Since: July 3, 2005 Posts: 426 Comments: 129093
from al.com:


"Recent stories in the Mobile Register revealed that oil and gas operations dump more than 1 billion pounds of mercury-contaminated drilling fluids into the Gulf each year. The drilling fluids cool and lubricate drill bits as crews bore new wells.

Studies by the U.S. Minerals Management Service, which regulates the nation's offshore oil fields, indicate that mercury levels in the sand around some Gulf rigs are three times higher than levels found at EPA Superfund sites that are closed to all fishing. Mercury levels in some creatures living around those rigs are at least 25 times higher than levels found elsewhere in the Gulf. "

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Quoting Drakoen:
Most of the models kept her off-shore for at least the next 24 hours. If she is making landfall now and has accelerated the better her chance of taking the eastern side of the guidance.
Exactly!
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Quoting MiamiHurricanes09:
If she goes over Guatemala and exits into the Caribbean after passing through Belieze, there's still a possibility. Do I think this will happen? No. I would give you a more in-depth explanation but it's hard to type on my phone.


After climbing 13000 plus feet there won't be much left to work with on the other side but it can happen if the mid to upper levels survive and start transitioning back towards the surface.
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2515. KEEPEROFTHEGATE (Mod)
Quoting FIU2010:
guys, will her accelerated spped increase chances of surviving?
fiu forecast calls for ne movement ok so been a little fast once on land it will begin to slowly pull n again and eventually nw then loop to the DDC point onshore south of the BOC
Member Since: July 15, 2006 Posts: 175 Comments: 54858
Storm, what models head what toward Florida?
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2512. Levi32
Quoting hydrus:
Storms can wobble quite a bit during the formation stage.


This is a little more than a typical wobble, which usually has more to do with the storm's direction than speed. I'm thinking it literally got pulled into the coast by frictional effects which helped it surrender to the weak steering flow.
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2511. hydrus
Quoting Levi32:


I'm doubting she has enough of an eastward component to her movement to take her into the western Caribbean. A track over the Yucatan seems more likely.
I believe you are right.
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Levi, history has shown that when the Pacific season starts up with a tropical system. That we are not that far behind in our season. So the question becomes what are the models saying along that line.
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Quoting kmanislander:


A cat 5 would have a hard time surviving those mountains let alone a weak TS. No chance IMO
If she goes over Guatemala and exits into the Caribbean after passing through Belieze, there's still a possibility. Do I think this will happen? No. I would give you a more in-depth explanation but it's hard to type on my phone.
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2507. Patrap
Quoting theman13:
I just watched a large strange looking fish swim straight into the oil plume on the live footage...


Oarfish,,seen da sucka too
Member Since: July 3, 2005 Posts: 426 Comments: 129093

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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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