Clouds, unstable Loop Current making oil spill prediction difficult

By: Dr. Jeff Masters , 8:48 PM GMT on May 18, 2010

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It's cloudy over the Gulf of Mexico today, so it is difficult to tell how far into the Loop Current the Deepwater Horizon oil has penetrated using visible satellite imagery. Satellite imagery yesterday from NASA's MODIS instrument confirmed that a tongue of oil moved southeast from the Deepwater Horizon oil spill and entered the Gulf of Mexico's Loop Current. However, Synthetic Aperture Radar imagery from the European Envisat satellite posted at ROFFS Ocean Forecasting Service shows that while some of the tongue of oil that entered the Loop Current appears to be circulating southwards towards the Florida Keys, perhaps 80% of the oil in this tongue is caught in a counter-clockwise circulating eddy along the north side of the Loop Current. This oil may eventually circulate around and enter the Loop Current, but not for at least three days.


Figure 1. Oil spill forecast for this Thursday night as simulated by the 6pm EDT Monday May 17 runs of the Navy Gulf of Mexico HYCOM nowcast/forecast system and the Global HYCOM + NCODA Analysis from the HYCOM Consortium. See the University of South Florida Ocean Circulation Group website for more information. There are considerable differences between the two models, due in part to the fact that they have much different depictions of the sea surface temperatures (SSTs) and ocean currents at the beginning of their runs. The warm Loop Current is visible as the red colors of the SST field that form a heart-shaped area in the Gulf.

How long will it be until oil reaches the Keys?
Once oil gets into the Loop Current, the 1 - 2 mph speed of the current should allow the oil to travel the 500 miles to the Florida Keys in 5 - 10 days. Portions of the Loop Current flow at speed up to 4 mph, so the fastest transport could be 4 - 5 days.

How much oil has made it into the Loop Current?
According to the latest trajectory forecasts from NOAA, the tongue of oil flowing southwards has, at most, "light" concentrations. The oil will grow more dilute as it travels the 500 miles to the Florida Keys, and most of the oil appears to be caught in a smaller counter-clockwise rotating eddy on the north side of the Loop Current. My present expectation is that the oil entering the Loop Current this week will cause only minor problems in the Keys next week. However, there is a lot of uncertainty regarding how much oil will get to the Keys, and we cannot rule out the possibility of an ecological disaster in the fragile Keys ecosystem.

How is the Loop Current changing?
The Loop Current has been highly chaotic and unstable over the past week, making it difficult to predict how the ocean currents near the spill will behave. According to ROFFS Ocean Fishing Service, which has done a tremendous job tracking the spill, the Loop Current surged 7 - 10 miles northward Sunday and Monday. The Loop Current has gotten more contorted since Friday, and may be ready to cut off into a clockwise-rotating Loop Current Eddy. This process occurs every 6 - 11 months, with the clockwise-rotating ring of water slowly drifting west-southwest towards Texas. The last eddy broke off ten months ago, so the Loop Current is due to shed another eddy in the next few months. The latest 1-month forecast from the U.S. Navy does not predict an eddy forming, but these forecasts are not very reliable. If a Loop Current Eddy does break off, oil getting entrained into it might orbit the center of the Gulf of Mexico for many months inside the eddy. However, this eddy will probably reattach and detach from the main Loop Current flow for at least a month following when it breaks off, so oil will continue to flow through the Keys during this initial month.

When will the flow of oil into the Loop Current shut off?
Winds over the oil spill location are expected to be light and onshore at 5 - 10 knots through Saturday. This means that the chaotic contortions of the Loop Current will primarily control how much oil gets into it, making it difficult to predict when the flow will shut off. The long range (and thus unreliable) forecast for next week from the GFS model calls for a continuation of light winds over the eastern Gulf of Mexico. Thus, the flow of oil into the Loop Current could occur intermittently for several weeks.

Who besides the Keys are at risk next week from the Loop Current oil?
As I discussed in an earlier post, the coast of Southwest Florida from Tampa Bay to the Everglades is a "Forbidden Zone" for surface-based transport of ocean water to the coast, and is probably not at risk from this week's Loop Current oil. The northwest coast of Cuba east of Havana and the coast of Southeast Florida from the Keys to West Palm Beach are at the most risk. The western shores of the western-most Bahama Islands and the U.S. coast north of West Palm Beach northwards to Cape Hatteras are at slight risk. It would likely take ocean eddies 2 - 9 weeks to transport the oil to these locations, and the oil would probably be so dilute that ecosystem damage would probably be minor, at most. At this point, I see no reason for cancellation of vacation plans to any of the beach areas that may potentially be affected by the oil.

What is happening to the plumes of oil at depth?
Two research missions over the past week have detected substantial plumes of oil at depth, moving to the southwest. The deepest of the these plumes, near the site of the blowout at 5,000 feet depth, is in a region of slow ocean currents and has not moved much. At depths closer to the surface, the currents get stronger, and oil within a few hundred feet of the surface--if there is any--could potentially have been dragged into the Loop Current. At this point, we don't have a very good picture of how much oil is at depth and where it might be headed.

Oil spill resources
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
HYCOM ocean current forecasts from LSU

The tropics
For those of you interested in a detailed look at the early season tropical weather outlook, consult the excellent wunderblogs of StormW and Weather456, who are now featured bloggers for the coming hurricane season. We have some models predicting a possible subtropical storm off the U.S. East coast next week, but this does not appear to be a significant concern for land areas at this time. More concerning is the possibility that an area of disturbed weather will develop across the Western Caribbean late next week. While wind shear will likely keep anything in the Western Caribbean from developing, several models are predicting that this disturbance may bring major flooding rains to earthquake-ravaged Haiti late next week.

I'll be back with a new post Wednesday afternoon.

Jeff Masters

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1070. IKE
HPC 3-7 days
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1069. hydrus
FloodMan. The WU mail I posted is there. I posted it yesterday.
Member Since: September 27, 2007 Posts: 1 Comments: 20974
1068. pottery
1061. You are being completely pointless.
So long..........
Member Since: October 24, 2005 Posts: 0 Comments: 24236
Quoting Weather456:
I'm beginning to think we may have 90L and 91L.



.. wishcaster!! Kidding of course! :-)

Afternoon everyone.
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1066. Patrap
Oilmageddon GOM ..coming to a BEach near you.

Lets Hope not.


SSTs are juicy mid eddy,..lotsa MJO mojo to swing in.

Strap yerselves in real tight boyz,..boogity,boogity,"Let's go Storm-chasing Boyz 2010.


Member Since: July 3, 2005 Posts: 423 Comments: 127807
1065. xcool
may 23 or 21 .i'm call it. storm
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A tropical depression would be bad for Haiti, those things can deliver alot of rain.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Either way, there is a moderate chance of Alex forming this weekend into next week.
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Quoting Patrap:


A/c on BP on CNN..


A/c will rip um a new un..hes a coastie from way back..




hi pat,

are you going to post a question? i can't think of a better person.
Member Since: Posts: Comments:
well i knew the insults would come. and to pdan im going to one up you, i will be man enough to not insult you.Im sure you are much more educated than I. And yes i do have many admin aides and secretaries who take my dictation.You are right english was not my specialty.Although, when i got a second degree in industrial management english was not one of the most important subjects.Although i will take your advice and see tutoring on my sentence structure .Have a blessed day.
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1059. Levi32
Wow, the low actually strengthens again off of Florida at 240 hours.

Member Since: November 24, 2005 Posts: 635 Comments: 26594
1058. pottery
Quoting Weather456:
I'm beginning to think we may have 90L and 91L.

On the 21 st??
LOL
Member Since: October 24, 2005 Posts: 0 Comments: 24236
Thanks Weather456 and Levi, I admire your analysis'. This is gonna be an interesting weekend for sure! I'm closely watching the potential subtropical system more then the Carribean because I live on the NE/Central coastline of Florida. Although I agree that the Carribean potential system has more of a advantage.
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Quoting Levi32:


It appears that way, although the Caribbean low has the look of a tropical depression to me on the model. It is not a very tight circulation and the Euro doesn't seem to want to strengthen it much as it drifts NE towards Haiti.


Very true
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1055. Levi32
Quoting Hurricanes101:


So really the ECMWF has both Alex and Bonnie forming?


It appears that way, although the Caribbean low has the look of a tropical depression to me on the model. It is not a very tight circulation and the Euro doesn't seem to want to strengthen it much as it drifts NE towards Haiti.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
1054. xcool
look Subtropical to my eye
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Quoting Hurricanes101:


So really the ECMWF has both Alex and Bonnie forming?


Basically yea.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Member Since: Posts: Comments:
I'm beginning to think we may have 90L and 91L.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Weather456:
The ECMWF isnt playing with the hybrid low....its aggressive

Reedzone to answer your question....its subtropical/tropical...because its cut off from any cold air supply by the high over the NE.



So really the ECMWF has both Alex and Bonnie forming?
Member Since: March 10, 2010 Posts: 1 Comments: 7519
1035. Hey Flood! It's good to be back! I hope you are fully recovered now!

1037. I guess that is what the met in Tampa was talking about. It sounds like this year has the potential to be very dangerous.
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Quoting Patrap:


A/c on BP on CNN..


A/c will rip um a new un..hes a coastie from way back..




he's gonna nail him and i'm glad anderson is the first interview them.
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1046. Levi32
Quoting reedzone:
So Levi, does the EURO show completely Subtropical or hybrid? Sorry I can't realy tell by the picture.


Looks subtropical to me. You can see the surface low stacked neatly right below the upper low, which implies barotropic (convective) processes are at work, utilizing the cold pocket aloft. This would be a classic subtropical low, but unlikely to go completely warm-core as SSTs are running around 24C north of the Bahamas, although they do approach 26C in the Gulf Stream.



Member Since: November 24, 2005 Posts: 635 Comments: 26594
Quoting Hurricanes101:


Is that where your dart landed? lol


I'm 30 minutes south of there...
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1044. Patrap
NASA's Aqua Satellite Sees Sunglint off of Gulf Oil Slick

At 3 p.m. EDT on May 18, NASA's Aqua satellite swept over the Gulf of Mexico oil spill from its vantage point in space and the Moderate Resolution Imaging Spectroradiometer instrument captured sunglints in a visible image of the spill. The visible image showed three bright areas of sunglint within the area of the gray-beige colored spill. Sunglint is a mirror-like reflection of the sun off the water's surface. In calm waters, the rounded image of the sun would be seen in a satellite image. However, the waves in the Gulf blurred the reflection and created an appearance of three bright areas in a line on the ocean's surface. According to the May 18 National Oceanic and Atmospheric Administration (NOAA) web update of the Deepwater Horizon incident, "satellite imagery on May 17 indicated that the main bulk of the oil is dozens of miles away from the Loop Current, but that a tendril of light oil has been transported down close to the Loop Current." The May 18 NOAA update also noted that "NOAA extended the boundaries of the closed fishing area in the Gulf into the northern portion of the loop current as a precautionary measure to ensure seafood from the Gulf will remain safe for consumers. The closed area is now slightly less than 19 percent of the Gulf of Mexico federal waters." Image credit: NASA Goddard / MODIS Rapid Response Team Text credit: Rob Gutro / NASA's Goddard Space Flight Center
Member Since: July 3, 2005 Posts: 423 Comments: 127807
The ECMWF isnt playing with the hybrid low....its aggressive

Reedzone to answer your question....its subtropical/tropical...because its cut off from any cold air supply by the high over the NE.

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Yes, indeed Taco is from right around there in LA (that's Lower Alabama as we sometimes like to refer to the Gulf Coast. :)

oh, you mean The Republic of West Florida.. that's what it was called before is was STOLEN by the dang Americans....

doggon thieves gave it to the Territory of Orleans.. :)
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Quoting SAINTHURRIFAN:


Fairly obvious you did not type your own resume to get your job. Did someone do your Masters thesis also, and does your job know?
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Quoting Jeff9641:


It starting next week my friend. The Euro takes this Hybrid system to the NE coast of Florida as a pretty strong system. This could very well be a 60 mph Sub Tropical storm coming ashore near ST. Augustine, FL.


Is that where your dart landed? lol
Member Since: March 10, 2010 Posts: 1 Comments: 7519
1039. hydrus
Quoting SAINTHURRIFAN:
well this dum old conservative does know how to spell science lol. I guess i learned that from having a dumb old mba in business.And also have a dumb old job as executive vice president of ship building for NGSS.Thats the 2nd dumb old largest military contrator in the world.And with pride we build ships for our brave men and women who put thier lives on the line for this country so you can sit on the couch and insult all your fellow dumb conservative americans.GOd Bless.
It sounds like you take a lot of your fellow Americans views quite personally. In times like these maybe you should concern yourself more with the security of your shipyards, rather worry about the views or opinions of others. Remember, ALL walks of life native to this country have made huge sacrifices for the United States, even when they didnt agree with the governmental or political climate at that time.jmo
Member Since: September 27, 2007 Posts: 1 Comments: 20974
Summary of 12Z Models....

Which one will be 90L?

Member Since: July 24, 2005 Posts: 407 Comments: 19076
So Levi, does the EURO show completely Subtropical or hybrid? Sorry I can't realy tell by the picture.
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Hey, CaneWarning, been awhile!
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1034. Levi32
Still barely there sitting off Georgia on Day 9:



Member Since: November 24, 2005 Posts: 635 Comments: 26594
thanks reed you seem to be a fine young man remember all things are possible in christ. and to storm w, levi, weather 456 you gentlemen do a fine job.And storm we are christening the 3rd ship in the coastguards deepwater project, obamas wife will be here for the occasion. you should see one of these ships they are magnificent.They really show he quality of work hardworking american men and women can still accomplish iam very proud of them.And ike hope your health is better and you are having a better time of it GOD Bless BILLY.
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1032. Levi32
Oh the suspense! The Euro DOES hold on to its blocking pattern and retrogrades the trough-split back to the Carolina coast, though weakening as it does so.



Member Since: November 24, 2005 Posts: 635 Comments: 26594
Well said, kanc2001!
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1030. xcool
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Wow, I haven't been here in a while. It looks like the tropics will be interesting this year. A local met said he won't be shocked to see the season start early this year. He said he hasn't seen water temps like this in years.
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Quoting Levi32:
12z ECMWF 144 hours:

Really winds up the Bahamas low and brings it farther north than before, up west of Bermuda by this time. The Caribbean low shows up as a broad entity after 120 hours.

That's pretty scary.
Member Since: September 2, 2009 Posts: 130 Comments: 21115
Quoting CycloneOz:


My goodness, Chaser! I am so thankful you are on our team! The work you do is so incredible!

I hope tornadodude looks at his copy as soon as possible.


I'll put out another one in a little bit.
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1025. Patrap
Quoting WaterWitch11:
just thought i'd let you guys know that anderson cooper is suppose to interview some exec from bp tonight. there is a blog going wanting questions that you would ask this guy.

is t-dude ready for today?


A/c on BP on CNN..


A/c will rip um a new un..hes a coastie from way back..


Member Since: July 3, 2005 Posts: 423 Comments: 127807
1022. xcool
development down in the SW Caribbean


comeing soon...i guesss
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1021. Levi32
Quoting Weather456:


Not can, it does.

The monsoon trough by far accounts for the majority of typhoons and cyclones in the Indian and Pacific both north and south.

Other accounts, but smaller are fronts, ulls, and interactions with surface troughs.

The current cyclone in the Bay of Bengal formed out of the monsoon trough.

Monsoon troughs is a TC breeding ground and help played the role in the genesis of Mitch, Wilma, Lenny and Ida.

Currently, the monsoon trough is a factor in the SW Caribbean disturbance.

The monsoon trough is often confuse with the ITCZ by the TPC. They are two different creatures.


I do wish they would make the distinction.
Member Since: November 24, 2005 Posts: 635 Comments: 26594
Quoting StormChaser81:


OZ, check your yahoo email.


My goodness, Chaser! I am so thankful you are on our team! The work you do is so incredible!

I hope tornadodude looks at his copy as soon as possible.
Member Since: August 26, 2006 Posts: 10 Comments: 3622

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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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