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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And for those without enough to fret about,

the Arctic sea-ice extent has fallen below 2007's
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**REPOST**
TROPICAL STORM AGATHA
2 pm EDT Advisory Graphics Update
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2403. pottery
Quoting TexasGulf:
About that 'junk shot", I'm thinking that BP had sent rubber strips, golf balls and other relatively hard materials down the hole. Mud won't bond with the rubber and rubber pieces won't necessarily mesh together easily.

I'm wondering why BP didn't try something like shooting a ton of Peanut Shells down into the hole along with the mud. Peanut shells have ridges and cavities that will pack in the mud and stick. The shells also will have more friction vs. mud than rubber pieces would. They would pack in pretty tightly. Peanut shells don't biodegrade easily, even in the presence of oils.

Another material that could be sent down the well would be hemp. Hemp is very ropey, swells in water and hemp strands would have a tendency to tangle very easily, creating a thick, crude net which can help hold the mud in place.

I don't understand this thing about... well, we tried hard rubber and golf balls & it didn't work, so now we'll just watch the oil flow for a few more weeks.

Another thing to mix with the mud would be a gelatin. It dissolves in warm water easily, but sets up around 40 degF. Gelatin would bond with the mud particles. Thickening the mud, while still making it flowable, might just give it a chance to stay in place. Naturally, the blowout preventer does have a cavity space that can be packed. There's always room for jello.

I think that the "junk" included rope, shredded rubber, and 'balls' of different sizes.
Peanut shells, and some of your other ideas are good, but not under 2500 PSI of pressure.
I really do not understand the failure with the 'junk'. In theory, it should work. Why has it not? Maybe they cannot pump big enough peices through the pipe from the surface to get enough big 'junk' into the BOP/riser.
Cant figure it out...
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2401. Patrap
Quoting plywoodstatenative:
Pat, can you buzz John or ron and remind them to check their emails at portlight. I sent some information about a walk that I discovered here in South Florida to them.


You can wu mail me the info and I'll call them on the landline or cell as they are on Holiday weekend most likely.

As com & relief coordinator I can do that,..easily.
If the info needs to get out here or the PL blog.





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2400. Skyepony (Mod)
nrtiwlnvragn ~ I recently rain across a site that had a bunch of bizarre radar images from world wide(well maybe not..nevermind), some like that, some bizarre in their own way (should have bookmarked it for fun).. They all seemed fairly recent. Of course there was a conspiracy.. Noticed frame before last of the expanded northEPAC from a GOES had an odd black line draped across it..
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2399. scott39
Quoting xcool:
They got that all up in the GOM. How much does an anticyclone help a storm at the level of wind shear that is in the GOM?
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2398. Drakoen
Quoting plywoodstatenative:
Drak, your microwave imagery, where is that coming from mind you?


That's the NASA TRMM which can be found at the bottom of this page

Link
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Quoting xcool:

More models are keeping this system alive right?
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2396. Patrap
2km Storm Relative IR Imagery with BD Enhancement Curve

1715 UTC



2km Storm Relative IR Imagery with BD Enhancement Curve

The same infrared imagery shown in the earth relative framework is displayed in a storm relative framework, with a 2km resolution and enhanced with the "BD Curve" which is useful for directly inferring intensity via the Dvorak Enhanced IR (EIR) technique. Scaling is provided by two lightly hatched circles around the center. The two circles have radii of 1 and 2 degrees latitude, respectively.
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Pat, can you buzz John or ron and remind them to check their emails at portlight. I sent some information about a walk that I discovered here in South Florida to them.
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2394. leo305
SHIPS has it surviving..

mhm..

it has increased in speed for sure though
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Quoting nrtiwlnvragn:
The mexican radar that would show Agatha is not working, but did find this neat radar image.




Reminds of one of the Grateful Dead shows I saw ;)
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Drak, your microwave imagery, where is that coming from mind you?
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Quoting Skyepony:


Missed a day or 2 looking at it. Was such a slow mover at first but seemed to get on the train heading across Africa & started gaining convection again.. I think it's this one..



It will be very interesting to see what it does if anything when it emerges West Africa.
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One thing I regret is not being on this blog in 2005. I can only imagine what must have been going on here. It must have been insane right?
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2389. Drakoen
Quoting StSimonsIslandGAGuy:
I gotta get back to work, or I'd look for the station's local topography on Google Earth.


Yea I edited post 2374 with some station data you might wanna take a look at
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2387. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15672
wow, anyone see that La Nina forming of the coast of S. America. That's new. Also, 90+ degree water off the coast of southern Cuba ALREADY?! Jeezus, this could be a helluva year! All we need now is for things to calm down upstairs and we could start seeing TS's within the next week or two. Hell, if Agatha stays together and follows that southerly course predicted in the cone, it could emerge into the Caribbean in a relatively shear-free environment and assuming it isn't ripped apart by those mountains running down the spine of Central America, could easily reform. As I recall from the latest shear maps, the area around Placencia is relatively calm as far as shear goes - 10-15 MPH - no? Of course, if it winds up in the Bay of Campeche forget it but if it emerges around southern Belieze - well - Agatha gets a sex change I guess and becomes Alex, unless the names carry over. Anyone know anything about that?
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2385. Patrap


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Quoting Drakoen:
This microwave imagery from an hour an a half ago shows the system just off shore. May the station reporting the northerly winds is something locally influenced...




Earlier today I put soup in the microwave and when I pulled it out it didnt look like that at all
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About that 'junk shot", I'm thinking that BP had sent rubber strips, golf balls and other relatively hard materials down the hole. Mud won't bond with the rubber and rubber pieces won't necessarily mesh together easily.

I'm wondering why BP didn't try something like shooting a ton of Peanut Shells down into the hole along with the mud. Peanut shells have ridges and cavities that will pack in the mud and stick. The shells also will have more friction vs. mud than rubber pieces would. They would pack in pretty tightly. Peanut shells don't biodegrade easily, even in the presence of oils.

Another material that could be sent down the well would be hemp. Hemp is very ropey, swells in water and hemp strands would have a tendency to tangle very easily, creating a thick, crude net which can help hold the mud in place.

I don't understand this thing about... well, we tried hard rubber and golf balls & it didn't work, so now we'll just watch the oil flow for a few more weeks.

Another thing to mix with the mud would be a gelatin. It dissolves in warm water easily, but sets up around 40 degF. Gelatin would bond with the mud particles. Thickening the mud, while still making it flowable, might just give it a chance to stay in place. Naturally, the blowout preventer does have a cavity space that can be packed. There's always room for jello.
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2382. Patrap
Large ULL over the Southeast CONUS,..with 2 STW in Place

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2380. Patrap
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my cone:
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2378. pottery
Quoting Patrap:
I hope we get to see "da Plume" when the ROV wack's off the Riser from the BOP.

Surgery at 5000 ft. down.

Who needs reality shows when we gotta Live 50's Horror Flick..

Oilzilla meets the Hypercane.


Coming JUNE 13th




I might see it from here!!
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2377. Skyepony (Mod)
Quoting Tropicsweatherpr:
Skypony,have the remains of Bandu turned into a wave as I see a big blob in eastcentralafrica or all of Bandu evaporated with the dry air of the dessert?


Missed a day or 2 looking at it. Was such a slow mover at first but seemed to get on the train heading across Africa & started gaining convection again.. I think it's this one..

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2376. KEEPEROFTHEGATE (Mod)
Quoting Patrap:


The Ol Orograhic Lifting is gonna squeeze her like a ripe Grapefruit . Slides are gonna be the dangers
yep 30 inches of rain runnin down a mountain is not meant to be pretty
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2375. scott39
How many hours will the steering currents be in place to keep Agatha going NE! Why is the wind shear so high in the GOM?
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2374. Drakoen
I just checked the actual station and it's only elevated 97ft

Also Wind switched from E to NE to N. That's what you would expect from a storm making landfall. Very odd...

Tapachula , Mexico
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2373. xcool
90e name storms what time???
Member Since: September 26, 2009 Posts: 2 Comments: 15672
2372. Patrap
I hope we get to see "da Plume" when the ROV wack's off the Riser from the BOP.

Surgery at 5000 ft. down.

Who needs reality shows when we gotta Live 50's Horror Flick..

Oilzilla meets the Hypercane.


Coming JUNE 13th



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Quoting Drakoen:


Very true
Could be.
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2370. Patrap
BP reminds me of Fredo.

..."Im smart,..I coulda been somebody"...
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2369. pottery
Quoting plywoodstatenative:


Like many times in life, its not the way you say it but the way it sounds. Pottery, I completely understand where you are coming from with the comments.

Whew! Thanks for that. It's why I love this Blog. Just when I begin to think I am the ONLY normal person left, another one shows up!
heheheheh
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Quoting AllStar17:
TROPICAL STORM AGATHA
2 pm EDT Advisory Graphics Update
That graphic is insane! Job well done.
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2367. Patrap
Quoting Skyepony:
Cloudsat of Agatha..looking at a slice of the storm from the side, starting from the left just offshore of El Salvador, running up through there, a corner of Gutemala, on nne through Belize & Mexico.

On the right side you can see where it's hit some mountains & raining like mad. May need some higher cloud tops (& there could be elsewhere) if it hopes to cross.


The Ol Orograhic Lifting is gonna squeeze her like a ripe Grapefruit . Slides are gonna be the dangers
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2366. kingy
BP may well have very good financial reasons to keep the topkill failure quiet for as long as they can.

The scale of the problem that BP is facing has very probably tripled in size. Instead of a 1-month leak they may well have at least a 3-month leak.

The clean up may be something hanging round their necks for 10 years and costing tens of billions.

As Pat might say "da stockmarket won't like dat"

betcha
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2365. Drakoen
Quoting StSimonsIslandGAGuy:
Wind direction could be affected by the mountains and valleys too.


Very true
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The mexican radar that would show Agatha is not working, but did find this neat radar image.


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2363. Kearn
TROPICAL STORM AGATHA? WTF?!?!

http://www.nhc.noaa.gov/graphics_ep1.shtml?5-daynl#contents
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Quoting Drakoen:
This microwave imagery from an hour an a half ago shows the system just off shore. May the station reporting the northerly winds is something locally influenced...


We are definietly close to landfall. NHC might be off on timing.
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TROPICAL STORM AGATHA
2 pm EDT Advisory Graphics Update
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Quoting Drakoen:
This microwave imagery from an hour an a half ago shows the system just off shore. May the station reporting the northerly winds is something locally influenced...



could always be bad data.
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2358. Skyepony (Mod)
Cloudsat of Agatha..looking at a slice of the storm from the side, starting from the left just offshore of El Salvador, running up through there, a corner of Gutemala, on nne through Belize & Mexico.

On the right side you can see where it's hit some mountains & raining like mad. May need some higher cloud tops (& there could be elsewhere) if it hopes to cross.
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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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