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 smarterthanyou:
Funny!

all the right wing
government hating
whackos
are now crying
like a bunch
of little pansies
for the
government
to do
something


Ok, forget my previous comment, you're just a troll...
Member Since: Posts: Comments:
Quoting smarterthanyou:
the problem is
no backup plan
was mandated

and that pre-dates
this administration

this is hardly
Obama's Katrina

it's just the latest
Bush/Cheney
tragic-comedy


Why do people continuously feel the need to play the blame game. "It's Obama's fault! It's Bush's fault!"
Progress can only be made when people stop blaming their least favorite government officials and actually become actively involved with this crisis. Why is there so much hate in the world?
Member Since: Posts: Comments:
Obama became president in 2009, not 2010, this is Obamas situation and he has failed to get there quick enough, like he cares lol. Heck, he rather go on vacation to Chicago then honor our troops who are fighting for their lives for us tomorrow.
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//I posted this last night

was just on BP.com clicked on response in pictures then command center at the bottom. Look at this clearly photoshopped pic of the "command center" Link

zoom in on the heads of the 2 guys in the back of the room, you can see the image on the large projection screen was manipulated.

I think it just a quick contrast/brightness adjust on the proj. screen but still, I don't trust these guys
Member Since: Posts: Comments:
Quoting smarterthanyou:
the problem is
no backup plan
was mandated

and that pre-dates
this administration

this is hardly
Obama's Katrina

it's just the latest
Bush/Cheney
tragic-comedy


You need to get over it... I am not blaming any one person. Both BP and the current administration have EPICALLY FAILED. It dosen't matter what you walk into, it's how you handle it once you are inside.
Member Since: Posts: Comments:
Quoting PanhandleChuck:


Wishful thinking Tampa... I think the govt. and BP are both in the Oh Sh*t mode and are grasping at straws.

And the govt has been "in charge of this disaster since the moment it occurred", BP is operating at the govt's direction...makes me feel better, how about you all?
Member Since: Posts: Comments:
3850. kingy
Quoting TampaSpin:
Live video link from the ROV

Can this get any uglier....YES IT CAN! Wait another 2 months and just 1 storm in the GOM!


it is an enviromental disaster that they will write books about in the future, and it is unfolding right before our eyes with the media mostly blind to what is coming.

The currents will be spreading this oil far and wide over coming months, many storms bringing oil to beaches and marshes, in the end few will escape it.

Not so long in the future people will start rethinking their views of eating anything caught in the gulf.

The loop currents combined with storm effects will be the perfect way to distribute this to all shores on most coastal counties. Sinking oil will systematically foul each ocean layer they penetrate.

It hasn't really hit home as a major disaster yet and won't until the first big slick comes in. That could be in a weeks time with the onshore winds. Then other slicks will wash ashore but in general the media will be behind the game so far as the significance of this.

I think their will be oil-impact forecasts accompanying hurricane warnings by the NHC by the time this geyser has finished spewing.
Member Since: Posts: Comments:
the problem is
no backup plan
was mandated

and that pre-dates
this administration

this is hardly
Obama's Katrina

it's just the latest
Bush/Cheney
tragic-comedy
Member Since: Posts: Comments:
TampaSpins Tropical Update
Member Since: September 2, 2007 Posts: 177 Comments: 20430
Chuck this thing could tank the US economy what recovery we have going and bring it to a halt and start things the other direction if it gets in the LOOP!

Quoting PanhandleChuck:


Wishful thinking Tampa... I think the govt. and BP are both in the Oh Sh*t mode and are grasping at straws.
Member Since: September 2, 2007 Posts: 177 Comments: 20430
Quoting TampaSpin:


Maybe our Government will start taking this serious and stop escorting BP! This has been taken to the next level now. This is the greatest Country in the world with the most creative minds. This is totally unexceptable to allow this to continue.


Wishful thinking Tampa... I think the govt. and BP are both in the Oh Sh*t mode and are grasping at straws.
Member Since: Posts: Comments:
Quoting Weather456:


Yea but we can't apply everything to the Atlantic. Each basin has a unique climatology. At 5N in the WPAC is the monsoon trough and at 5N in the Atlantic basin is the ITCZ. The former favors cyclogenesis while the latter does not.

5N is definitely too far south for development in the Atlantic. However, I wouldn't be so quick to dismiss something at 12N. We've seen development that far south plenty of times, maybe not this early in the season, but then again, this doesn't appear to be a typical season coming up...
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Evening all.
If you have Google Earth, you'll like this website, has plenty of weather add-on's.
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Quoting PanhandleChuck:


I agree TS.. When the leak was first announced that was the first thing I thought of. I don't think people are aware of what kind of devestation even a CAT 2 would bring to the shorelines and well up into all of the rivers and lakes if you are on the East side of the storm.


Maybe our Government will start taking this serious and stop escorting BP! This has been taken to the next level now. This is the greatest Country in the world with the most creative minds. This is totally unexceptable to allow this to continue.
Member Since: September 2, 2007 Posts: 177 Comments: 20430
Agatha may have just jumped ship??
Member Since: September 2, 2007 Posts: 177 Comments: 20430
and they have alot more ocean to form storms also 456
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Been very consistent



Looks like a LLC is developing off the Yucatan...GEESH.....SHEAR in the GOM is still very high tho.
Member Since: September 2, 2007 Posts: 177 Comments: 20430
Quoting TampaSpin:
Live video link from the ROV

Can this get any uglier....YES IT CAN! Wait another 2 months and just 1 storm in the GOM!


I agree TS.. When the leak was first announced that was the first thing I thought of. I don't think people are aware of what kind of devestation even a CAT 2 would bring to the shorelines and well up into all of the rivers and lakes if you are on the East side of the storm.
Member Since: Posts: Comments:
3838. cg2916
Quoting Weather456:
Shear is one factor. Remember for TC genesis we need a pre-existing disturbance, in this case, a tropical wave. The current tropical waves most northern extent are 12N, which is too far south to develop. The one that emerged off Africa has some northern extent to it and might be the one that kicks of the season in 7-10 days.


It may. We'll have to track that, mainly because there's nothing else to track. Ex-Agatha will be sheared, if it's not already gone, so we can't track that.
Member Since: Posts: Comments:
Live video link from the ROV

Can this get any uglier....YES IT CAN! Wait another 2 months and just 1 storm in the GOM!
Member Since: September 2, 2007 Posts: 177 Comments: 20430
Quoting aspectre:
3752 AussieStorm "you can call me 'Al'."

Great. Just what this blog needs, another one of them thar GlobalWarmers.

my name isn't really Al.
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Quoting stormhank:
U know the storms in west pacific have formed before though around 5 deg north..that basin always seems to have the right conditions since their season can last year round at times


Yea but we can't apply everything to the Atlantic. Each basin has a unique climatology. At 5N in the WPAC is the monsoon trough and at 5N in the Atlantic basin is the ITCZ. The former favors cyclogenesis while the latter does not.
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Quoting IKE:


I got lucky and you missed out.

Maybe today?


I hope not, kids want to swim today and grass is growing like wild fire.
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U know the storms in west pacific have formed before though around 5 deg north..that basin always seems to have the right conditions since their season can last year round at times
Member Since: Posts: Comments:
Shear is one factor. Remember for TC genesis we need a pre-existing disturbance, in this case, a tropical wave. The current tropical waves most northern extent are 12N, which is too far south to develop. The one that emerged off Africa has some northern extent to it and might be the one that kicks of the season in 7-10 days.
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3831. IKE
Quoting PanhandleChuck:


Hey Ike,

How's it go? A short distance to your SW, we only had thunder and a few drops of rain over here.


I got lucky and you missed out.

Maybe today?
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3830. cg2916
Quoting stormhank:
Im thinking along the lines of June 20th or later for the first storm,,due to all the shear in gulf n carribean


I have June 14th or so, because the shear has lifted into the Caribbean, and the shear should lift in the Gulf in June.
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3829. cg2916
Dang it, the blog is quieting down. IKE and 456 left.
Member Since: Posts: Comments:
Quoting IKE:
I had 1.10 inches of rain yesterday at my house, bringing my monthly total to 6.51.


Hey Ike,

How's it go? A short distance to your SW, we only had thunder and a few drops of rain over here.
Member Since: Posts: Comments:
Im thinking along the lines of June 20th or later for the first storm,,due to all the shear in gulf n carribean
Member Since: Posts: Comments:
3826. cg2916
Quoting aspectre:
3798 IKE "If you believe....
(1)The ECMWF...quiet in the Atlantic through June 9th.
(2)The GFS...quiet in the Atlantic through June 15th.
"

3)The INEPT...HurricaneSeason fires up between 11June and 14June...


(4) The CFS... quiet through June 5th.
Member Since: Posts: Comments:
3825. cg2916
Quoting kingy:
good morning all,

Agatha may be done but the oil spewage continues, seemingly faster than before. Perhaps the topkill did indeed flush the pipework sufficiently to allow increased spewage. Life is not without its irony, call it karma if you will. But BP is in a hell of a mess just as the gulf is being poisoned.

By the time this summer is done man will have wreeaked environmental chaos in the gulf. The food chain may well be showing signs of oil contamination for many a year to come. After just 1 month BP says it has spent half a billion dollars on the clean up, imagine what they will be forced to spend in the next decade. This will be the biggest financial hit that ANY company will have ever taken in corporate history by the time this is done.

The bad news is that we have perhaps another 60-90 days (maybe much more) of oil gushing at around a million gallons a day.

And then we got the storm systems ploughing through it all. What a legacy.


I know, we got a mess.
Member Since: Posts: Comments:
3798 IKE "If you believe....
(1)The ECMWF...quiet in the Atlantic through June 9th.
(2)The GFS...quiet in the Atlantic through June 15th.
"

(3)The INEPT...HurricaneSeason fires up between 11June and 14June...
Member Since: August 21, 2007 Posts: 0 Comments: 4860
3823. cg2916
It's too far south, though (look at the E end of the ITCZ).

Member Since: Posts: Comments:
3822. kingy
good morning all,

Agatha may be done but the oil spewage continues, seemingly faster than before. Perhaps the topkill did indeed flush the pipework sufficiently to allow increased spewage. Life is not without its irony, call it karma if you will. But BP is in a hell of a mess just as the gulf is being poisoned.

By the time this summer is done man will have wreeaked environmental chaos in the gulf. The food chain may well be showing signs of oil contamination for many a year to come. After just 1 month BP says it has spent half a billion dollars on the clean up, imagine what they will be forced to spend in the next decade. This will be the biggest financial hit that ANY company will have ever taken in corporate history by the time this is done.

The bad news is that we have perhaps another 60-90 days (maybe much more) of oil gushing at around a million gallons a day.

And then we got the storm systems ploughing through it all. What a legacy.
Member Since: Posts: Comments:
3821. cg2916


Nice wave rolling off of Africa. Doesn't have terribly strong convection, but it looks pretty strong.
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3820. cg2916
Quoting stormhank:
Yea those waves off africa look decent for so early,,,hence the forecast for active season


Yup. If the ITCZ would move north a little bit, we could have a fairly active June/July. IMO, of course.
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Yea those waves off africa look decent for so early,,,hence the forecast for active season
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3818. cg2916
Quoting IKE:


And quickly.

I know. Only got 2 advisories out of it after it made landfall (not counting 3a).
Member Since: Posts: Comments:
3817. cg2916
Good post, 456.

I never really expected Agatha to re-organize in the Atlantic. It would either hit the GOM, or the NW Caribbean, and then the GOM.

Even if it made it into the SW or Central W Caribbean, it would have much time before it would hit Cuba, and then the subtropical jet stream.
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3816. IKE
Quoting cg2916:


Morning, Ike. Doesn't quite look as good anymore, the mountains really killed it.


And quickly.
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3815. cg2916
Quoting Weather456:
Good Morning

Blog Update

Agatha floods Central America


Good morning 456!
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3814. cg2916
Quoting IKE:


Morning...



Morning, Ike. Doesn't quite look as good anymore, the mountains really killed it.
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Good Morning

Blog Update

Agatha floods Central America
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3812. IKE
Quoting msgambler:
Good morning Sir Ike


Morning...

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3811. cg2916
Hey, I just noticed! Dr. Masters was gone this whole time, and Agatha formed!

And so the curse continues...
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3810. cg2916
Good morning everyone!

Just got done editing the Wikipedia page on Agatha.
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Good morning Sir Ike
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Decent wave exiting africa at the moment. Showing some good 850mb vorticity and upper divergence, lower convergence isn't very high though. Shear is low and the wave is producing new cloudtops over water. One to watch over the next day to see if it can keep convection going over water.
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Any previous discussion and/or thoughts what the oil in the GOM will do to the SST?
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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.