Loop Current Eddy cuts off; oil danger to Keys now greatly reduced

By: Dr. Jeff Masters , 2:24 PM GMT on May 28, 2010

Share this Blog
3
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 807 - 757

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80Blog Index

hey MiamiHurricanes09 please disregard the 18Z model runs
Member Since: Posts: Comments:
806. IKE
NOGAPS isn't that different then the CMC and GFS as far as track through 4 days wanting to bring it north some.
Member Since: Posts: Comments:
There are two chances-Slim & None
Member Since: Posts: Comments:
Quoting atmoaggie:

Yeah. Yaaaaawwn, stretch. Oops.
LOL. It's only 5:30 PM CDT (It's 6:30 for me).
Member Since: September 2, 2009 Posts: 130 Comments: 21032
kuppensup

even if it was none of the above, we could still have 22 named storms, no CAT 5s making landfall and no storm stronger than Wilma and it would still be one heck of a season

so even if none of those 3 happened, that has nothing to do with it being like last season
Member Since: Posts: Comments:
**tips hat**

Howdy, 456!
Member Since: Posts: Comments:
Quoting Weather456:
Good evening all
Good evening weather456!
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Quoting MiamiHurricanes09:
Keep in mind that the red/orange/yellow are the favorable conditions, the green/blue is the unfavorable conditions. Take a look at the lower left-hand side of the image.

Yeah. Yaaaaawwn, stretch. Oops.
Member Since: Posts: Comments:
Quoting Weather456:
Good evening all
Hey 456!
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting kuppenskup:


D-None of the above U guys are going to be very dissapointed this yr. This will be a seson very similar to last yr.


Tell the truth, you're a relative of he-who-shall-not-be-named, aren't you?
Member Since: Posts: Comments:
Quoting atmoaggie:
If anything at all is going to happen, it sure has some harsh shear to plow through to get to that band of notsomuch...and things don't appear to be all that dynamic...not much motion.

Keep in mind that the red/orange/yellow are the favorable conditions, the green/blue are the unfavorable conditions. Take a look at the lower left-hand side of the image.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Good evening all
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting CycloneOz:


I think it could jump the TD status and go straight to Alex!
You mean Agatha? lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
If anything at all is going to happen, it sure has some harsh shear to plow through to get to that band of notsomuch...and things don't appear to be all that dynamic...not much motion.

Misread, sorry. I mean it has been showing a harsh band of shear around our coasts that doesn't seem to want to move on. This is what getting up 5 hours earlier than one is used to does...

Member Since: Posts: Comments:
so is TD-1E going to move into the gulf or will the mtns beat it to a pulp?
Member Since: Posts: Comments:
Quoting cyclonekid:

I say either A or C...My percentages of possibility A >> 30% C >> 70% JMO.


D-None of the above U guys are going to be very dissapointed this yr. This will be a seson very similar to last yr.
Member Since: Posts: Comments:
Quoting IKE:
18Z NOGAPS is running...hmm...
Yup, If they are showing the same solution as the GFS and CMC, I'm convinced.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting MiamiHurricanes09:
Beginning to look like a TS on satellite.

*I expect TD 1-E in the next 3 hours.



I think it could jump the TD status and go straight to Alex!
Member Since: Posts: Comments:
Quoting wunderkidcayman:
hey well I am very sorry but I think that all of them will most likely happen


again I am not surprised lol, cant you just pick one?
Member Since: Posts: Comments:
Wow, pots and kettles flying around the blog...
Member Since: Posts: Comments:
Quoting help4u:
Bp is no longer in charge ,the president made that VERY CLEAR yesterday!!!!Anything being done now is with his approval only!!He said they have been in charge from day one.Nothing has been done without his approval!!!!Listen to his press conference.


I think you must have listened to a different press conf than I did.
Member Since: Posts: Comments:
784. IKE
18Z NOGAPS is running...hmm...
Member Since: Posts: Comments:
hey well I am very sorry but I think that all of them will most likely happen
Member Since: Posts: Comments:
Beginning to look like a TS on satellite.

*I expect TD 1-E in the next 3 hours.

Member Since: September 2, 2009 Posts: 130 Comments: 21032
Obama made it clear yesterday,he is in charge and nothing is done without his input.
Member Since: September 18, 2006 Posts: 0 Comments: 1256
Quoting msgambler:
OK Flood, I guess I will be the fall guy for the one who wants to ask but won't. What is the probability of the moisture rebuilding and hitting South Florida as a hurricane....LOL No need to answer. I know the answer already.


LOL...you're asking me? How many ways are there to say zero? That is as long as you're talking about 90E...I'm not downcasting here(despite the need for some of that to counteract the wishcasting I've seen all day). The moisture may make it but first the feature has to clear central America with some semblence of organization and even if it does that the steering is all wrong. Now wait 24 hours and that could change...

See why I like the tropics? Wait 20 minutes and the answers could all change...LOL
Member Since: Posts: Comments:
WEATHER ALERT!

In what has to be one of the most amazing coincidences I've experienced recently...

A very nice looking thunderstorm cell is building and moving into my city.

All hell may break loose, so you may want to go to 7674u.com and watch the weather here for awhile.
Member Since: Posts: Comments:
Quoting wunderkidcayman:
hey Hurricanes101 I pick A, B, and C


why am I not surprised

you cant pick all 3, question asks which is most likely to happen
Member Since: Posts: Comments:
hey Hurricanes101 I pick A, B, and C
Member Since: Posts: Comments:
Quoting Hurricanes101:
So far the voting is

Which is most likely to occur during the 2010 Hurricane Season?

A) Category 5 landfall in the United States - (3)
B) 2010 being more active than 2005 - (1)
C) A storm during the 2010 Season will become the most intense storm in Atlantic Basin History (881mb or lower) - (4)



A
Member Since: Posts: Comments:
Quoting wunderkidcayman:
IKE the 18Z runs are bull discard them wait for the 00Z runs
I wouldnt say there bull but i agree wait for the 0Z runs.
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Model runs need more consistency to allow for such a concern that this invest will survive the crossing of 13,000FT+ volcanoes to redevelop further east and impact the US.

Seems like a stretch to me...

Member Since: Posts: Comments:
So far the voting is

Which is most likely to occur during the 2010 Hurricane Season?

A) Category 5 landfall in the United States - (3)
B) 2010 being more active than 2005 - (1)
C) A storm during the 2010 Season will become the most intense storm in Atlantic Basin History (881mb or lower) - (4)
Member Since: Posts: Comments:
Ok. Get this. BP bused in hundreds of temp works for Obama's visit to make it appear as if they were doing clean up...

read about it
Member Since: Posts: Comments:
IKE the 18Z runs are bull discard them wait for the 00Z runs
Member Since: Posts: Comments:
Quoting IKE:


Beginning to buy into the CMC some.
Yeah im starting to bilieve it trackwise development im not sold on yet.
Member Since: April 8, 2010 Posts: 15 Comments: 2570
OK Flood, I guess I will be the fall guy for the one who wants to ask but won't. What is the probability of the moisture rebuilding and hitting South Florida as a hurricane....LOL No need to answer. I know the answer already.
Member Since: Posts: Comments:
Quoting IKE:


Beginning to buy into the CMC some.
Not me. I'm jump aboard if the NOGAPS or ECMWF start showing that solution.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
765. IKE
Oh no...at 138 hours...toward the spill?

Member Since: Posts: Comments:
Hey guys before you all go crazy over GFS and CMC if I was you I would wait for the 00Z runs and all of tomrrow run so we can get a better idea of what will happen but I have to say that you are to scrap the 18Z runs and beg for the 00Z runs
Member Since: Posts: Comments:
762. IKE
Quoting alexhurricane1991:
What do you think about this run?


Beginning to buy into the CMC some.
Member Since: Posts: Comments:
761. IKE
BP orchestrating relief workers for Obama's location...then when he left...they left, except for a dozen...per a Louisiana councilman.

Are you kidding me?
Member Since: Posts: Comments:
Quoting FIU2010:


chill, broder, lo que pasara, pues, pasara, de acuerdo?
I modified my post earlier.
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Anyway, here's a good overview loop of 90E.
Link
Member Since: Posts: Comments:
Quoting IKE:
120 hour GFS 18Z....

What do you think about this run?
Member Since: April 8, 2010 Posts: 15 Comments: 2570
Quoting atmoaggie:

I wonder how well a UPS can handle either generator or inverter...some of those can provide plenty of conditioned power to run most any home electronics.
(I know we have a room full of UPSs charged by generator at my office, but possibly involves equipment to condition the generator power? likely beyond what anyone one might try at home due to equipment cost)
A natural gas generator might be okay, dunno. One of my neighbors got a really good deal on one of those last year. Runs quiet, too.

Member Since: Posts: Comments:

Viewing: 807 - 757

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80Blog Index

Top of Page

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.