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 AstroHurricane001:


2010 is going to be a hyperactive season on a hyperactive Internet and a hyperactive weather community. I wouldn't be surprised to see a blog over 7,500+ comments.
I agree going to be a hectic year on the blogs i guess i picked a good year to start posting.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
This past hour (8:00 PM EDT - 9:00 PM EDT) we averaged about 2 posts per minute. If this trend was continuous for 24 hours we would have 2880 in just 1 day.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Might be time to head to the Greek Islands....

except for the earthquakes there...

and tsunami's...
Member Since: Posts: Comments:
3054. EricSFL
Hey KEEPER can you please post the link to the Plymouth satellite loop of Agatha. Thanks
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3053. Patrap
Member Since: July 3, 2005 Posts: 426 Comments: 128875
Quoting Weather456:
There are 5 people dead already in Guatemala due to floods from Agatha.


I am not sure of the warning system in the area but, I am sure these people were preparing for tomorrows storm.
Member Since: Posts: Comments:
Quoting CaicosRetiredSailor:
I believe the last Jeff Masters blog which had over 3,000 comments was Sept 1, 2009, and this one will probably surpass the 3,500+ comments which were on Sept 1st blog.


2010 is going to be a hyperactive season on a hyperactive Internet and a hyperactive weather community. I wouldn't be surprised to see a blog over 7,500+ comments.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
3050. Patrap
Quoting gordydunnot:
I here there kind of upset with the west Pat.


Wait till they ask where there GOM went and whose got all their gold.

Im gonna Point at BP.

U betcha
Member Since: July 3, 2005 Posts: 426 Comments: 128875
Quoting KEEPEROFTHEGATE:
how about 10000
I think we will see 10000 this year.
Quoting FIU2010:
that was a good special, phil covered it all
I agree. Very well done by Phil.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
By the way i am from south louisiana at the la/tx border
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Quoting MiamiHurricanes09:
Very rare and very nice image we've got here:



Like I said, the Caribbean outflow is through the Central Atlantic toward Newfoundland and Labrador.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Um...errr...they never left..the Mayan population is well over 1 million in the region of the volcano and TS....

But I love the sentiment there Patrap!
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3045. cg2916
Quoting KEEPEROFTHEGATE:
how about 10000


Depends on when the next post is. About an hour ago, there were 4 posts per minute!
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MiamiHurricanes09 - 00z Forecast Cone -

***Notice: This is my forecast cone and could be completely wrong even though it is based on the latest model runs.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
I here there kind of upset with the west Pat.
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Quoting Patrap:


Wait till the Mayans return.
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Tornado signature just North of Dauphin Island, AL
Member Since: February 27, 2010 Posts: 0 Comments: 1125
Wait a minute Keeper every man has to know his limitations.
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3038. Patrap
Quoting Weather456:
I saw some pictures of the ash from Pacaya and it was very thick and dark. Much darker than the ash from our volcano and the one in Iceland. There are reports that Agatha's rains mixed with the ash to clog drains in the city. I could imagine a substance with the consistency of mixing cement. Rather an unfortunate chain of natural disasters.


Wait till the Mayans return.
Member Since: July 3, 2005 Posts: 426 Comments: 128875
I am getting tired of hearing that all of these methods of shutting the oil off in the gulf of mexico is because of the depth of the well. if nothing had been tested at that depth then why are they allowed to drill that deep
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Quoting gordydunnot:
5000 post per blog should be a piece of cake this season. Do I get a 6000 going going gone to the highest bidder.
I say if theres a cat 5 out there easily 7000 posts maybe more if its threatining the US
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3035. KEEPEROFTHEGATE (Mod)
how about 10000
Member Since: July 15, 2006 Posts: 174 Comments: 54639
Quoting wunderkidcayman:
yeah weather456 thanks for the link but that is only GFS what about the outers and is ther not a model that finds the the averages of all the models put it together


It's three models - the GFS, CMC and NAVY NOGAPS. The TVCN is an average of all models but it is only available for invests and storms. The trick is to look for the model in the steering charts that has the best handle on the system and then use that model and compare it to the rest. Here you have to use both the current steering and the forecasted steering.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
6500!
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5000 post per blog should be a piece of cake this season. Do I get a 6000 going going gone to the highest bidder.
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hey CyclonicVoyage the next fewe model runs the tracks will move more and more east well that is what I think and if you look at the older run between last night and now and you will see that the models have shifted eastward from the other runs some goes from west to north and others from north to north-northeast, northeast and East-northeast
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Quoting CyclonicVoyage:


There are a lot of continuous tracks which means development would not be necessary, only re-strengthening.
My bad. Re-strengthening is what I meant.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Deep layer ridge pushes itself into the Caribbean as far west as 85W. Because the LLC will become disrupted over terrain we can ignore the shallow layer flow (but it basically shows the same thing) and concentrate on the deep layer flow.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting MiamiHurricanes09:
I agree with the HWRF. I just don't think we'll see development in the GOM due to the obvious subtropical jet-stream.
Quoting MiamiHurricanes09:
I agree with the HWRF. I just don't think we'll see development in the GOM due to the obvious subtropical jet-stream.


There are a lot of continuous tracks which means development would not be necessary, only re-strengthening.
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Quoting alexhurricane1991:
I agree nothing tropical happening in the gulf the only area right now thats primed for development is the caribbean.
Exactly.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
I agree with the HWRF. I just don't think we'll see development in the GOM due to the obvious subtropical jet-stream.
I agree nothing tropical happening in the gulf the only area right now thats primed for development is the caribbean.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
Quoting CyclonicVoyage:
A lot of the models showing a successful pass to the ATL. OHHH that TCVN would be messy, eeek.

I also like the TVCN.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
According to an article 12 are already dead in Guatemala.

Heavy rains brought by tropical storm Agatha kill 12 in Guatemala
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Good evening everyone!
Member Since: April 8, 2010 Posts: 15 Comments: 2572
Quoting wunderkidcayman:
yeah weather456 thanks for the link but that is only GFS what about the outers and is ther not a model that finds the the averages of all the models put it together



The TCVN in my link below is the average of all the models. Grey Boxed track heading up to the big bend of FL.
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Note to Hollywood, cut the crap and come out with the real Godzilla with the same special affects as in the video. Thats what made it a cult and beyond a true classic. IMO P.S. Please find some Japanese
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Quoting CyclonicVoyage:
A lot of the models showing a successful pass to the ATL. OHHH that TCVN would be messy, eeek.

I agree with the HWRF. I just don't think we'll see development in the GOM due to the obvious subtropical jet-stream.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
yeah weather456 thanks for the link but that is only GFS what about the outers and is ther not a model that finds the the averages of all the models put it together
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Quoting AstroHurricane001:


Why does the GFS show moderate nocturnal rain covering most of the US Southeast, Northeast, and Mideast, nightly from May 30 to June 5?
No idea.

Member Since: September 2, 2009 Posts: 130 Comments: 21194
A lot of the models showing a successful pass to the ATL. OHHH that TCVN would be messy, eeek.

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Quoting MiamiHurricanes09:
GFS 18z showing a piece of energy from Agatha emerging over by the extreme northwestern Caribbean, this area of convection later affects south Florida.

GFS 18z 48 Hours


Here at 102 hours there is a 1010 MB low over south Florida.

GFS 18z 102 Hours





Why does the GFS show moderate nocturnal rain covering most of the US Southeast, Northeast, and Mideast (total 29 states), nightly from May 30 to June 5?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Quoting JLPR:




That's terrible :(
Indeed.

Current number of fatalities:


Costa Rica 0
El Salvador 1
Guatemala 4
Mexico 0
Nicaragua 1
_________________
Total 6
Member Since: September 2, 2009 Posts: 130 Comments: 21194
3013. JamesSA
What is the shear like in the Gulf of Honduras?
Member Since: Posts: Comments:
I saw some pictures of the ash from Pacaya and it was very thick and dark. Much darker than the ash from our volcano and the one in Iceland. There are reports that Agatha's rains mixed with the ash to clog drains in the city. I could imagine a substance with the consistency of mixing cement. Rather an unfortunate chain of natural disasters.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
3011. JLPR
Quoting Weather456:
There is also a state of calamity in the country.


Quoting Weather456:
There are 5 people dead already in Guatemala due to floods from Agatha.


That's terrible :(
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Quoting Weather456:
There are 5 people dead already in Guatemala due to floods from Agatha.
Scratch that off, it's 6.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
There is also a state of calamity in the country.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:


You can use the steering maps at PSU. Other proxies for steering include 1000-500 mb average winds, water vapor imagery and climatology.
Thanks!
Member Since: September 2, 2009 Posts: 130 Comments: 21194
There are 5 people dead already in Guatemala due to floods from Agatha.
Member Since: July 24, 2005 Posts: 407 Comments: 19076

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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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