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: 257 - 207

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

90E looking good.



Possible slow eastward motion can be noted on satellite animation.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
255. IKE
GFS @ 12Z through 144 hours.
Member Since: Posts: Comments:
90E looks like it's moving east
Member Since: Posts: Comments:
Quoting Drakoen:
ASCAT:



The monsoon trough is still evident along with cyclonic turning SW of Jamaica. The 12z surface map is now reflecting this with a bubble-shaped area of sub-1010mb pressures in the area.

Member Since: Posts: Comments:
I believe the good doc stated that sheer might remain high thru the begining of TC season,due to the remaint effects of el nino,so the STJS staying put for another 2-3 weeks is a good bet,IMO....no TC's in the GOM stregthening until the end of june begining of july...
Member Since: Posts: Comments:
251. IKE
Quoting jackzig:


...and occasional gunfire.


And quite a few killed....

Jamaican police say 73 people have been killed since authorities launched an assault Sunday for an alleged drug lord wanted by the United States....Link
Member Since: Posts: Comments:
Quoting Jeff9641:


GFS has it's moisture streaming right across Florida and then develops a low off NE FL moving ENE.
No it isn't. Can you post the image?
Member Since: Posts: Comments:
Quoting hurricanelover236:
This season will be a record for inactivity. Its not going to be any more active than 2009 and thats a guarantee. All of you people are going to be very disapointed.


I give you 8/10 on the troll-o-meter
Member Since: Posts: Comments:
It looks like we have a surface low west of Jamaica, good catch Levi. Take a look:

Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Kingston, Jamaica

75 °F
Light Rain
Humidity: 89%
Dew Point: 72 °F
Wind: 5 mph from the SSW
Pressure: 29.83 in (Falling)
UV: 16 out of 16
Clouds: Few 500 ft


...and occasional gunfire.
Member Since: Posts: Comments:
Quoting Floodman:


This individual never provides reasoning; he is a troll...
Yeah your right just want to give him a chance to explain himself but i guess thats not going to work wow not even in hurricane season and we already have this unreal.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
ASCAT:

Member Since: Posts: Comments:
Quoting Jeff9641:


Have you seen some of the models. The steering patern that you are showing is today but that will change in time as the trough out west is showing
The only model taking a system to SFLA is the CMC.
Member Since: Posts: Comments:
the mo-jo's a risinnn'.........into the westcarib it goes.....
Member Since: Posts: Comments:
Quoting alexhurricane1991:
Explain your reasoning i have yet to see any from you.


This individual never provides reasoning; he is a troll...
Member Since: Posts: Comments:
Quoting hurricanelover236:
This season will be a record for inactivity. Its not going to be any more active than 2009 and thats a guarantee. All of you people are going to be very disapointed.
Explain your reasoning i have yet to see any from you.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
Quoting Hurricanes101:


I agree with that lol

I was trying to breakdown my 19 named storm prediction

I was like 2 in June, 4 in July, 6 in August, 5 in September; hmmmmm ok that is 17 so only 2 more, but wait October and November has to have more than 2 named storms lol

You would be surprised how quickly the numbers add up when you expect activity in all months


Remember that despite the "heart" of the season being August through mid-September, there are a large number of storms, historically spekling, in October and even November...if memory serves, though, there are very few instances where the Atlantic Basin has had nmore than 2 or so features simultaneously after September
Member Since: Posts: Comments:
*
Member Since: Posts: Comments:
This season will be a record for inactivity. Its not going to be any more active than 2009 and thats a guarantee. All of you people are going to be very disapointed.
Member Since: Posts: Comments:
Storms are really starting to pop in Florida.
Member Since: Posts: Comments:
Quoting Jeff9641:


I'm not saying that. The map that you posted would indicate that the extreme SE GULF could be a somewhat favorable enviroment albeit not ideal but could support a TS as models are starting to indicate. S FL might want to be on watch over the weekend to see if Alex maybe in the works.
Why south Florida? 1. Steering currents don't support for a system to impact south Florida. 2. The subtropical jetstream will tear anything apart the nears south Florida.
Member Since: Posts: Comments:
Quoting Jeff9641:


I'm not saying that. The map that you posted would indicate that the extreme SE GULF could be a somewhat favorable enviroment albeit not ideal but could support a TS as models are starting to indicate. S FL might want to be on watch over the weekend to see if Alex maybe in the works.


30-knot westerlies....even higher as you near Florida.

There is one model showing what you're saying, the CMC. One model, and its solution doesn't look likely based on the steering pattern. It could be right, but even it still has the subtropical jet screaming over south Florida with 60-knot wind shear at the time of 90E passing near.
Member Since: Posts: Comments:
Steering currents suggesting that 90E might get into the Caribbean.



Member Since: Posts: Comments:
Quoting Jeff9641:


Everyone is focusing on the Caribbean when it's 90E that will become the topic of conversation as there is a chance now for 90E to redevelope in the SE gulf and track toward S FL. There will be som shear but not as strong as it is now as the Sub tropical jet is forecast to shift north.
The shear should weaken considerably (according to some of the models) but you know how that goes. I believe the shear will be way down in a week, and there will be a named system in the Gulf or N.W.Caribbean by June 7. I also think the S.E. United States is in for some flooding issues from weak steering currents in that region.
Member Since: Posts: Comments:
Quoting Chucktown:


He is Mr. Gloom & Doom when it comes to severe weather and tropical development.


Yea that has become painfully obvious the last few days lol

*still waits for 90L to give me some rain*
Member Since: Posts: Comments:
Quoting Hurricanes101:


you are really pushing for a storm or its moisture to come to Florida aren't you?



He is Mr. Gloom & Doom when it comes to severe weather and tropical development.
Member Since: Posts: Comments:
Quoting Floodman:


Well, if we're going to have 23 or so named, it has to start early...time is a consideration, you know


I agree with that lol

I was trying to breakdown my 19 named storm prediction

I was like 2 in June, 4 in July, 6 in August, 5 in September; hmmmmm ok that is 17 so only 2 more, but wait October and November has to have more than 2 named storms lol

You would be surprised how quickly the numbers add up when you expect activity in all months
Member Since: Posts: Comments:
Quoting Floodman:


Well, if we're going to have 23 or so named, it has to start early...time is a consideration, you know
Thanks Floodman for understanding what I'm saying.
Member Since: Posts: Comments:
Quoting Jeff9641:


If 90E is in the SE Gulf then conditions will be somewhat favorable.


you are really pushing for a storm or its moisture to come to Florida aren't you?

Member Since: Posts: Comments:
Quoting Hurricanes101:


What he is saying is 2 named storms for June is a lot of activity even for an above-average season


Well, if we're going to have 23 or so named, it has to start early...time is a consideration, you know
Member Since: Posts: Comments:
Quoting beell:
Passed on to me from a WU Blogger who prefers her sense of humor to remain somewhat anonymous.



"I'd like to make the point that most of these ships are built so that front end doesn't fall off..."
"Well, wasn't this one built so that the front wouldn't fall off?"
"Obviously not, Ken...the front end fell off, 20,000 tons of oil spilled out and caught fire. I'd call that a dead give away..."

Dude, you're a riot!
Member Since: Posts: Comments:
This is a weather station located just east of the western tip of Jamaica. It's currently reporting a pressure of 29.79in Steady.

Member Since: Posts: Comments:
Quoting Jeff9641:


If 90E is in the SE Gulf then conditions will be somewhat favorable.


The presence of a tropical disturbance does not dictate the atmospheric conditions above it. You need a powerful hurricane to have a strong influence on the synoptic environment. A weak tropical disturbance like 90E would be likely to be in such a situation would not alter the course of the subtropical jetstream.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
I get what he is saying. I'm not going to say anything else because that would be considered changing my mind. LOL.


Lol. I'm talking about post 199, but nevermind.
Member Since: Posts: Comments:
Quoting Levi32:


So you changed your mind in 2 minutes... Ok lol.
LOL, I didn't mean to change my mind.
Member Since: Posts: Comments:
Quoting Hurricanes101:


What he is saying is 2 named storms for June is a lot of activity even for an above-average season
I get what he is saying. I'm not going to say anything else because that would be considered changing my mind. LOL.
Member Since: Posts: Comments:
Quoting Levi32:


So you changed your mind. Ok lol.
What? I didn't change it again. LOL, "I think we will get up to Bonnie before July 1st, not too much activity, imo." Final Answer. lol.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Lol, well considering that we are forecasted to have a "hyperactive" season you would think we will see a lot of activity. I think we will get a named storm in early June and another one in late June. I'm not crazy, well maybe a little bit, lol, jk.


What he is saying is 2 named storms for June is a lot of activity even for an above-average season
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Lol, well considering that we are forecasted to have a "hyperactive" season you would think we will see a lot of activity. I think we will get a named storm in early June and another one in late June. I'm not crazy, well maybe a little bit, lol, jk.


So you changed your mind in 2 minutes... Ok lol.
Member Since: Posts: Comments:
Quoting Levi32:




So which is it...lol.

And Bonnie by July 1st IS a lot of activity. The average date of the first named storm is July 10th.
Lol, well considering that we are forecasted to have a "hyperactive" season you would think we will see a lot of activity. I think we will get a named storm in early June and another one in late June. I'm not crazy, well maybe a little bit, lol, jk.
Member Since: Posts: Comments:

Viewing: 257 - 207

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

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.