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 indianrivguy:
Good morning gang.. good afternoon Aussie!

Good Evening
Member Since: Posts: Comments:
1706. leo305
Quoting gulfcoastdweller:
wow TWC just rolled the words REPETE OF 2005? and now saying be prepared and talking about the EPac system, says the NHC says it could be named by 11 am


the CDO is spinning.. when you see that, it's not an invest..

2005 had 31 storms.. that is nuts, to say repete is just crazy..
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1703. scott39
Bastardi explains why this season will be so active very well. Basically this year the water is cooler in the N of the Atlantic and warmer in the S. This sets up for good upward motion. Also the Pacific is going to cool more and the Atlantic has to release heat which causes TCs. Same setup as 2005.
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Good morning indianrivguy
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GulfCoast, I hope your wrong but I think your right. And as for not being a long run to "your" casino, we just got back from the Isle yesterday after being there for a week. In the last month or so we have spent more time in MS than we have in AL.
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Good morning gang.. good afternoon Aussie!
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Quoting Jeff9641:
I think it is funny how so many on here critized me for saying 90e will move toward FL when it was obvious that this trough out west will shoot whatever 90 e is across the state. I went to school for this and have a lot of knowledge about potential weather patterns. Models are all in agreement that some sort of will move into Tampa then head up the SE US coast.



We can use any rain here in tampa ya want to send us.
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Quoting Jeff9641:
I think it is funny how so many on here critized me for saying 90e will move toward FL when it was obvious that this trough out west will shoot whatever 90 e is across the state. I went to school for this and have a lot of knowledge about potential weather patterns. Models are all in agreement that some sort of will move into Tampa then head up the SE US coast.

it's got to stay together as it crosses Guatemala, Belize and the Yucatan Peninsular.
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1695. IKE
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT SAT MAY 29 2010

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

LATEST MICROWAVE SATELLITE IMAGERY INDICATES THE LARGE LOW PRESSURE
AREA CENTERED ABOUT 200 MILES WEST-SOUTHWEST OF PUERTO DE SAN JOSE
GUATEMALA IS ORGANIZING INTO A TROPICAL DEPRESSION AS IT MOVES
EAST-NORTHEASTWARD AT ABOUT 5 MPH. THERE IS A HIGH CHANCE...NEAR
100 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE...AND
FORECAST ADVISORIES WILL LIKELY BE INITIATED LATER THIS MORNING.

HEAVY SQUALLS CONTINUE TO MOVE ONSHORE THE COASTAL AREAS OF EXTREME
SOUTHEASTERN MEXICO AND MUCH OF GUATEMALA...AND THE AREA OF HEAVY
RAINS EXTENDS AS FAR EAST AS EL SALVADOR. THESE RAINS ARE EXPECTED
TO CONTINUE FOR THE NEXT COUPLE OF DAYS CAUSING LIFE-THREATENING
FLASH FLOODS AND MUD SLIDES IN THESE AREAS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER STEWART/KIMBERLAIN
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1693. scott39
Quoting IKE:


As long as it's going to be over land...not sure it matters.
Thanks, The models at 2am see the same steering pattern N as you do. I just hope 90E doesnt become a potential threat for GOM SE US Coast.
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That would be my plan Aussie but we have to do a long mileage run Tuesday and it is her radiator that is leaking so I am going to change it with a new one. And this car has 375K miles so a little scared if I wash it then it might quit running.....LOL
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1691. IKE
Quoting scott39:
Does 90E have a better chance over land when it is only a Invest or TD at best, than a stonger storm?


As long as it's going to be over land...not sure it matters.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1690. scott39
Does 90E have a better chance over land when it is only a Invest or TD at best, than a stonger storm?
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1689. RTLSNK
Note to self: Season starts Tuesday, no more cartoons after Monday!
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1688. RTLSNK
Quoting SouthALWX:

He tried the first day. It didnt work. No one will pay him for longer than 24 hours. At this point, the only way to seal it is to send Chuck Norris down there. "Help us, Chuck Norris, you're our only hope!"


Sorry, crashed early last night and didn't see your request until this morning. :) I don't know if Chuck is going to be able to help us, depends on if his new uniform is waterproof!!!
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Quoting msgambler:
Weather wise great. We had a T-Storm come through Mobile yesterday and cool things down for this morning nicely. Bad thing is, have to work on wife car this morning. By the way, I don't like doing that in any kind of weather....lol

just wash it and you'll guarantee it will rain
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Scott, 40% chance of rain today so a dry set may be your best bet. These afternoon pounders have been building almost every day. Good Luck and Goos Morning.
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1684. IKE
Birmingham,AL. extended...

"CLOSED LOW WEAKENS BY TUESDAY AND OPENS AS UPPER LEVEL FLOW ACROSS
THE SOUTHEAST BECOMES MORE ZONAL. AIRMASS ACROSS THE AREA WILL
REMAIN UNSETTLED AND MOIST. NO REASON TO THINK AT LEAST SCT ACTIVITY
WILL NOT BE POSSIBLE EACH DAY. MODELS SHOW A TRANSITION TO TROUGHING
ACROSS THE EASTERN CONUS NEXT WEEKEND...WITH A SHORTWAVE ENHANCING
RAIN CHANCES BY THE END OF NEXT WEEK. THIS IS FOLLOWED BY A STRONG
FRONTAL PASSAGE...UNLIKELY FOR THE BEGINNING OF JUNE.
GIVEN THE
UNCERTAINTY IN THIS PATTERN CHANGE WILL MAINTAIN SCHC/CHC POPS FOR
NOW."


New Orleans extended....

"LONG TERM...
WEAK MID LEVEL RIDGING WILL OCCUR TUE INTO WED AS REMNANTS OF THE
TROF PUSH EWD...BUT STILL CAN`T RULE OUT SOME WIDELY SCT DIURNAL
PRECIP. CHANCES OF RAIN AGAIN INCREASE THURS/FRI AS THE NEXT TROF
APPROACHES FROM THE WEST - POSSIBLY ALLOWING A WEAK FRONTAL BOUNDARY
TO MOVE INTO PORTIONS OF THE CWA."
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1683. scott39
90E at least looks like a TD to me.IMO
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1682. scott39
Quoting msgambler:
Weather wise great. We had a T-Storm come through Mobile yesterday and cool things down for this morning nicely. Bad thing is, have to work on wife car this morning. By the way, I don't like doing that in any kind of weather....lol
Im in a outside wedding in NW Mobile county at 4:00pm today. I told them to have a backup plan, they said it will be alright! I got a feeling we better bring dry clothes fo the reception.LOL
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1681. IKE
90E getting closer to land....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
1680. IKE
Quoting scott39:
Ike , do you think it will be protected from wind shear in the GOM from anticyclone?


GFS shows high shear in the northern and central GOM lowering some in about 6 days.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Weather wise great. We had a T-Storm come through Mobile yesterday and cool things down for this morning nicely. Bad thing is, have to work on wife car this morning. By the way, I don't like doing that in any kind of weather....lol
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It' raining
It's pouring
The old man
Is snoring
He bumped his head
He went to bed
He can't get up in the morning

Good morning all.

It's really pouring here! It started at about 6:15 at my location, and has been coming down steadily ever since. I've heard both thunder and a frog! lol



Hmmm..... not quite sure WHERE all the water is coming from.... lol
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Quoting msgambler:
Good morning Ike good afternoon Aussie.

Good Evening. How is your part of this wonderful world we all live on.
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1676. scott39
Quoting IKE:


91L. Already had 90L east of the Carolinas.
Ike , do you think it will be protected from wind shear in the GOM from anticyclone?
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1675. IKE
Quoting AussieStorm:

even though 90L has been deactivated it goes to 91L?


Yup.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:


91L. Already had 90L east of the Carolinas.

even though 90L has been deactivated it goes to 91L?
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Good morning Ike good afternoon Aussie.
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1672. IKE
Quoting AussieStorm:

I guess if it becomes something in the GOM/W Carib it would be 90L?


91L. Already had 90L east of the Carolinas.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1671. IKE
Here's what I think will draw 90E(or what's left of it), north into the GOM....

From the Tallahassee,FL. extended discussion...

"LONG TERM...
MONDAY NIGHT THROUGH NEXT SATURDAY...A BROAD LONGWAVE TROUGH WILL
REMAIN IN PLACE ACROSS THE EASTERN CONUS. THE GFS SHOWS A COLD
FRONT PASSING THROUGH OUR CWA FRIDAY NIGHT/SATURDAY WITH A MUCH
DRIER AIRMASS FILTERING IN ON NORTHERLY WINDS.
OTHERWISE...FOR THE
UPCOMING WEEK WE WILL SEE A CONTINUATION OF UNSETTLED WEATHER WITH
DEEP SOUTHERLY FLOW...ABUNDANT MOISTURE AND SEVERAL UPPER LEVEL
IMPULSES FOR THE GENERATION OF DAILY SHOWERS/TSTMS. MIN TEMPS WILL
BE SLIGHTLY ABOVE NORMAL WHILE AFTERNOON TEMPS WILL BE NEAR
SEASONAL LEVELS EACH DAY. AFTERNOON TEMPS WILL EDGE UPWARDS A
DEGREE OR TWO EACH DAY."
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:



CMC 00Z at 96 hours...


I guess if it becomes something in the GOM/W Carib it would be 90L?
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1669. IKE
Quoting AussieStorm:

And i'm just showing what NOGAPS says.
Do any other models show anything?



CMC 00Z at 96 hours...

Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:


You may be right...we'll see.

I'm not saying you're wrong, just throwing the GFS out there.

And i'm just showing what NOGAPS says.
Do any other models show anything?
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1667. IKE
Quoting AussieStorm:





You may be right...we'll see.

I'm not saying you're wrong, just throwing the GFS out there.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:


6Z GFS @ 102 hours...




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1665. IKE
Quoting AussieStorm:
90E is going to go poof by Monday over the Yucatan Peninsular. Interaction with land will kill it.


6Z GFS @ 102 hours...

Member Since: June 9, 2005 Posts: 23 Comments: 37860
90E is going to go poof by Monday over the Yucatan Peninsular. Interaction with land will kill it.
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1663. shakaka
Quoting futuremet:
Hi JFV and SevereHurricane,

I have been doing great lately. However, I will not post on the blog as much as use to. I am still planning on creating some more YouTube educational videos.


Glad to hear it! I really enjoyed the ones I watched last year.
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1662. JLPR
I'm impressed with this one, there is actually something left after hitting water, in fact, I think of that of that happened once it did.
Not a good sign at what the Cape Verde season could be like.


I can't believe I'm going to bed now.
Nighty night, or good morning, you choose. XD
Member Since: Posts: Comments:


Here comes the wet

EMERGENCY services are bracing for cyclonic conditions as a large low pressure system off the coast threatens heavy rain and winds of up to 100km/h over the weekend.

Police and Bureau of Meteorology forecasters have issued warnings to people from the South Coast, through Sydney and as far north as the Hunter to expect torrential rain, gale force winds and big seas.

As well as warning motorists of added dangers on the road, police have issued specific warnings to rock anglers, bushwalkers and canyoners following a series of recent deaths and rescue operations.

SES volunteers have been put on stand-by, with the weather expected to worsen over the weekend and the most severe wind gusts expected tomorrow afternoon or evening.

Meteorologist Dmitriy Danchuk said even if Sydney avoided the worst of the weather, the city could still expect heavy rain.

``The most significant rain we are expecting is on Sunday and during the day the rain could become heavy,'' he said.

Meanwhile, the safety of the flood levees which protect more than 70,000 people across the state
has been called into question with figures showing up to 80 per cent may be inadequate. The structural integrity of the levees is being investigated by the SES and a water engineering specialist firm.

While councils are required to maintain the levees, the SES found they were more focused on drought and few even kept information about their levees. Of the 59 examined, the structural integrity of 80 per cent was ``either unknown, or considered likely to be inadequate''.

``We have been lobbying the State Government for some time but not getting anywhere,'' chairman of the Floodplain Management Authority Allan Ezzy said.

``There's over 600km of levees throughout the state. It's really quite a mess.''
Mr Ezzy said he also had concerns, based on flood information from the 1800s, about Sydney's northwest and the Nepean area in a major flood.

NSW SEVERE WEATHER WARNING

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GFS, NOGAPS, ECMWF and CMC show a tropical cyclone in the Arabian Sea

The phase diagram of the GFS model is particularly strong




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1659. xcool




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Quoting KoritheMan:


Some things more so than others, however.

well a surface low with organized convection, can help move an upp anticyclone, once it's mature. But yes, you are right we really can't be sure. The only things we are REALLY good at forecasting are tilted upper features, stacked is much harder .... (a left tilt with height on a low is MUCH easier to predict than a stacked low) but I digress, point is this: hard forecast.
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1657. xcool



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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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