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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ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT FRI MAY 28 2010

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

1. ALTHOUGH SATELLITE IMAGES SHOW THAT THE SHOWER ACTIVITY ASSOCIATED
WITH THE BROAD AREA OF LOW PRESSURE CENTERED A LITTLE MORE THAN A
HUNDRED MILES SOUTH OF THE GULF OF TEHUANTEPEC REMAINS ORGANIZED...
THERE ARE NO EVIDENCES OF A WELL DEFINED CENTER AT THIS TIME.
ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR ADDITIONAL
DEVELOPMENT... AND A TROPICAL DEPRESSION COULD FORM AT ANY TIME
LATER TONIGHT OR SATURDAY AS IT DRIFTS NORTHEASTWARD. THERE IS A
HIGH CHANCE...70 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS. HEAVY SQUALLS ARE ALREADY
APPROACHING THE COAST OF EASTERN MEXICO AND GUATEMALA AND THE AREA
OF HEAVY RAINS EXTENDS AS FAR EAST AS EL SALVADOR. THESE RAINS ARE
LIKELY TO CONTINUE AND COULD CAUSE LIFE-THREATENING FLASH FLOODS
AND MUD SLIDES IN THESE AREAS OVER THE NEXT COUPLE OF DAYS.

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

$$
FORECASTER AVILA/CANGIALOSI
NNNN

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting 305st0rm:
Anyone have the link to TampaSpin's page?? Thank You in Advance.
Link
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Quoting Patrap:
Multiplatform Satellite Surface Wind Analysis


Thats all He said to put. Thanks


Does the "green" area have to completely surround the system prior to it being classified as a closed surface circulation?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Great job Jr. Hey may have trouble keeping his job now....Have a good night and a good holiday weekend
Member Since: February 27, 2010 Posts: 0 Comments: 1125
Multiplatform Satellite Surface Wind Analysis


Thats all He said to put. Thanks
Member Since: July 3, 2005 Posts: 420 Comments: 127521
Quoting Patrap:


2245

That's a nice picture
Member Since: August 26, 2009 Posts: 0 Comments: 411
Anyone have the link to TampaSpin's page?? Thank You in Advance.
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2km Storm Relative IR Imagery with BD Enhancement Curve
Member Since: July 3, 2005 Posts: 420 Comments: 127521
23:15 UTC - 7:15 PM EDT

Member Since: September 2, 2009 Posts: 130 Comments: 21091


2245
Member Since: July 3, 2005 Posts: 420 Comments: 127521
Well, remember that the CMC was referred to as "Create More Cyclones". At least that's what I remember it being referred to last year or whenever before the triple storms in 24 hours. Especially Claudette, that really made me think it was a Mesoscale Convective System rather than a tropical storm. For example, there was one in Southern Illinois last year? that had even briefly had a hurricane like eye to it, which did produce 100 mph winds and damage to Carbondale, Illinois.
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Quoting SevereHurricane:


Way to stick your neck out there.


CFS models still uncertain at this point. Remember what happened to ENSO in 1998; in 2004?
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Ahhh ok. We may just have to give you his job. Depending on how good you do here we'll just have to put him to pasture.
Member Since: February 27, 2010 Posts: 0 Comments: 1125
90e models
Member Since: July 3, 2005 Posts: 420 Comments: 127521
Quoting MiamiHurricanes09:
So you are going against every single model, and saying that we are going to have a El NiƱo. I don't think so.


No, I only indicated that there was a chance for a weak El Nino to resurface around late fall. Earlier some models were predicting a possible neutral-to-weak-El Nino stage by winter 2010.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Quoting msgambler:
Welcome back Pat. Sent you mail and I suppose it was your wife said you were sleeping. HOW DARE YOU.....LOL


Im Jr.He is still sleeping.
Im doing the update for him.
Member Since: July 3, 2005 Posts: 420 Comments: 127521
Flash Flood Watch extended

Trough across Jamaica and the western Caribbean

JamaicaObserver.com

Friday, May 28, 2010






THE Meteorological Service of Jamaica has extended the Flash Flood Watch for low-lying and flood-prone areas of all parishes until 5:00 pm tomorrow.

The watch means that flash flooding is possible and residents are advised to take precautionary measures, keep informed by listening to further releases from the Meteorological Service and be ready for quick action if flooding is observed or if a Warning is issued.

A trough across Jamaica and the western Caribbean continues to influence weather conditions across the island. Satellite imagery indicates cloudy conditions across most parishes with showers and isolated thunderstorm through last night into this morning with strongest activity affecting sections of north-western and southern parishes.

The trough is expected to remain across the central Caribbean, including Jamaica until Sunday, producing periods of heavy showers and thunderstorms at times. There is, therefore, the potential for flash flooding.

Fishers and other marine interests are advised to exercise caution, as gusty winds and rough seas are likely in the vicinity of showers and thunderstorms.

The Meteorological Service will provide further updates.
Member Since: Posts: Comments:
Quoting Bordonaro:

Let us all wait and see what is left of 90E after its trip across Central America. Odds are there will not be much left of 90E.

IF conditions allow, it is possible 90E may become some type of tropical system in the Caribbean Sea.


Another possibility is for 90E to cross into Campeche, then east over the Yucatan, effectively bypassing the mountains. Guatamala's terrain destroyed Felix in 2007, plus currently there's a volcano erupting there! The interaction of tropical depression Mitch with a volcanic slope in 1998 was disasterous.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Member Since: July 3, 2005 Posts: 420 Comments: 127521
Welcome back Pat. Sent you mail and I suppose it was your wife said you were sleeping. HOW DARE YOU.....LOL
Member Since: February 27, 2010 Posts: 0 Comments: 1125
The consensus of the 12Z global models imply the left-overs of 90E would be pulled into the GOM. Only the CMC projecting it to develop into something significant.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting FIU2010:


dude, your beyond oblivious, i would even bet my life on that NOT coming about, WAKE UP, ACERE.


No-Im not saying there will be an El Nino but Im just saying it's not going to be as active as what everyone is saying.
Member Since: August 26, 2009 Posts: 0 Comments: 411
Quoting Weather456:
I have a question, well perhaps just a clarification. I know the government funds the NWS and its agencies but which section does this come under in the government budget? For example, funds for roads and highways would go under infrastructure, no?


NOAA
Member Since: July 3, 2005 Posts: 420 Comments: 127521
Quoting bayeloi:


Thanks Ms! I've lurked for forever...I know how crazy it is!


That's the way I usually go, mostly lurk because it's sometimes too insane for me, lol.

Looks like we're getting our TD forming as we go here.
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Quoting AstroHurricane001:


The storm would have to survive many factors to make what the CMC predicts; that's probably our worst-case scenario. If the storm moves as quickly as that, it may survive the shear as well as the land impacts. As it would have about 60 hours to tap into the Gulf Stream under rapid (baroclinic) strengthening depicted by the CMC, it could strengthen enough to make an extratropical transition as it crosses into high shear and colder water. Barry survived as an extratropical storm and depression in 2007, and became large enough to dump thunderstorms in S. Ontario. It actually traversed land instead of warm water, but tapped into some of the Gulf Stream. The crossing of Florida depicted by CMC reminds me of Fay, and this scenario is possible if it survives shear and its eastern side taps into the Gulf Stream! However I don't see the CMC scenario happening and a TS like Barry is much more likely.


Let's see what remains of 90E after taking the "Central America Mountain Tour (crossing)".
'
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Quoting Weather456:
I saw the CMC run bringing an intense cyclone into Florida...I would like to believe the model but it has the cyclone under shear...its not being reasonable.
ghosts
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting Hurricanes101:


GFS and NOGAPS appears to bring a system into Florida as well now, not as instense as the CMC though


CMC is not great for intensity, but it had the best forecast track performance of all the major models in 2009.
Member Since: Posts: Comments:
Quoting xcool:



new




That's not good. If the storm emerges in the SW Caribbean, or even anywhere south of northern Belize, the storm could track toward Haiti and we know that the TCHP in the central Caribbean is very very high. Worse, if two lows emerge closely, we could have a Fujiwhara: southern system hits Cuba and the GOM, northern system hits Jamaica and Haiti.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
Quoting Hurricanes101:
NHC still projects that 90E has a broad center, as of the 805pm TWD, so I am not sure we will see a TD tonight

but that could be changing
They have yet to release the outlook.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting bayeloi:


Thanks Ms! I've lurked for forever...I know how crazy it is!


Welcome to WU!
Member Since: Posts: Comments:
SE El Salvador picked up 5 inches in the last 24 hrs

Member Since: July 24, 2005 Posts: 407 Comments: 19076
NHC still projects that 90E has a broad center, as of the 805pm TWD, so I am not sure we will see a TD tonight

but that could be changing
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Quoting msgambler:
Welcome to the blog. Check your sanity at the door cause this place is nuts....LOL. Have a good time.


Thanks Ms! I've lurked for forever...I know how crazy it is!
Member Since: Posts: Comments:
Quoting bayeloi:
I've never posted before.....but I thought I would share this tidbit.

Link

Welcome to the blog!!
Member Since: April 8, 2010 Posts: 15 Comments: 2572
Quoting Bordonaro:

The SST off of LI are in the 55-56F range. The warmest Gulf Stream waters off of C FL up to the Outer Banks region off of NC are only between 72-78F. It is NOT possible for any type of TC to survive those cold waters.

IF 90E survives its trip over Guatemala it will barely be an area of Low pressure. The mountains of that region range between 8-11,000 ft. That is enough to rip apart a mature hurricane, no less an area of Low pressure.

It is possible that we might have a TD in the Caribbean IF 90E can regroup. I would not count on anything at this point :o)!


The storm would have to survive many factors to make what the CMC predicts; that's probably our worst-case scenario. If the storm moves as quickly as that, it may survive the shear as well as the land impacts. As it would have about 60 hours to tap into the Gulf Stream under rapid (baroclinic) strengthening depicted by the CMC, it could strengthen enough to make an extratropical transition as it crosses into high shear and colder water. Barry survived as an extratropical storm and depression in 2007, and became large enough to dump thunderstorms in S. Ontario. It actually traversed land instead of warm water, but tapped into some of the Gulf Stream. The crossing of Florida depicted by CMC reminds me of Fay, and this scenario is possible if it survives shear and its eastern side taps into the Gulf Stream! However I don't see the CMC scenario happening and a TS like Barry is much more likely.
Member Since: August 30, 2008 Posts: 8 Comments: 2835
I have a question, well perhaps just a clarification. I know the government funds the NWS and its agencies but which section does this come under in the government budget? For example, funds for roads and highways would go under infrastructure, no?
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting xcool:
Bordonaro .hey .yeah..

It is possible that a portion of the Low center of circulation may survive the Guatemala crossing. Just need to see how much of it remains. That is a fairly mountainous area.
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Quoting bayeloi:
I've never posted before.....but I thought I would share this tidbit.

Link

Welcome to the blog. Check your sanity at the door cause this place is nuts....LOL. Have a good time.
Member Since: February 27, 2010 Posts: 0 Comments: 1125
18z
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Fay did make it into the Gulf

What is that all about? Who bet their life that Fay would not make it into the Gulf?
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Quoting FIU2010:


not you, miami, lol
That's what I thought, lol.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting SevereHurricane:


Just like you bet your life about Fay getting in the gulf.
ROFLMAO!!!!!!!!!
Member Since: September 2, 2009 Posts: 130 Comments: 21091
extra cool
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Quoting FIU2010:


dude, your beyond oblivious, i would even bet my life on that NOT coming about, WAKE UP, ACERE.
Did you quote the wrong person?
Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting FIU2010:


dude, your beyond oblivious, i would even bet my life on that NOT coming about, WAKE UP, ACERE.


Just like you bet your life about Fay not getting in the gulf.
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I have learned that if you want to laugh, just watch the CMC. If you want what's right, use other things. Tropical Storm out of this? Probably. Much more than that? I doubt it.
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I've never posted before.....but I thought I would share this tidbit.

Link

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Quoting AstroHurricane001:


No, it wasn't. There's a chance for the season to be mostly neutral, but also a chance for it to temporarily be above the +0.5C range late in the season. However the season could have Nino 3.4 indications anywhere from a weak El Nino to a strong La Nina (say +1.1C to -2.3C).


Way to stick your neck out there.
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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.