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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3207. Patrap
2km Storm Relative IR Imagery with BD Enhancement Curve

0115 UTC



2km Storm Relative IR Imagery with BD Enhancement Curve

The same infrared imagery shown in the earth relative framework is displayed in a storm relative framework, with a 2km resolution and enhanced with the "BD Curve" which is useful for directly inferring intensity via the Dvorak Enhanced IR (EIR) technique. Scaling is provided by two lightly hatched circles around the center. The two circles have radii of 1 and 2 degrees latitude, respectively.
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Quoting weather42009:


That is mind boggling and that chart is for the week ending Thursday. Most of the tropical storm rains are ongoing. What will this do to the ash?


Living near a volcanic island - Soufriere Hills in Montserrat, I personally know what heavy rains can do with ash. It creates a cement-like mixture that just creates a mess.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
3205. JLPR
Quoting MrstormX:


Yes! If we had 4-6 Gustav's, Ike's and Dennis's around then things wont be pretty


yep, in fact, scratch that, many cat 3s are bad xD
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3204. help4u
What do you all think the president will try next to stop the oil?
Member Since: September 18, 2006 Posts: 0 Comments: 1276
Tipping my glass..or mug..to Patrap and saying adieu!
Those were the days......
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Quoting JLPR:


But many cat 4s are bad too XD
Yes they are
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3200. Patrap
Oil-zilla...
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Quoting JLPR:


But many cat 4s are bad too XD


Yes! If we had 4-6 Gustav's, Ike's and Dennis's around then things wont be pretty
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I think the best satellite picture to find the COC of a system overnight is the Dvorak.

Member Since: September 2, 2009 Posts: 130 Comments: 21193
3197. leo305
Quoting MiamiHurricanes09:
Blog moving quickly.


that's good news for once =P
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Quoting Dakster:


70,000 BBL/Day I think it still too low...

Do the math. A 21" pipe with liquid leaving at 1 MPH (velocity) will flow 95,000 Gallons per hour or a little over 50,000 bbls/day... I don't think the oil is leaving at 1 Mph... At 2 mph it jumpes to 190,000 Bbls/Day...

Try again, BP...


I've done that kind of math. It does not lead to happy conclusions. 70,000 bbl/day is bad enough.
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3195. JamesSA
I' was watching BP's ROV feed. It looks like they are dismantling the top kill apparatus now.
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3194. Patrap
Quoting SiestaCpl:



Hmm Blue Oyster Cult used that line in their song Godzilla....


As I saw them in Houston in 79 opening for Judas Priest


Oil-Zilla...!!
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3193. help4u
All we our is dust in the wind,like a speck of sand in time.
Member Since: September 18, 2006 Posts: 0 Comments: 1276
Quoting PanhandleChuck:
Is there still any live webcams of the oil from the deepwater. I heard that BP cut it off


More censorship?! The control of the oil industry over the US is redonkulous!
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hehehehe PcolaDan! Well said!
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Blog moving quickly.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
3189. JLPR
Quoting MrstormX:
Any Cat 5s, technically I said no in Ossgss's contest... I suspect many cat 4s, but I am thinking no on 5s


But many cat 4s are bad too XD
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3188. Dakster
Quoting WatchingThisOne:


I'm not holding out any hope for the next two known approaches (cutting off the riser and trying to put a pipe above it, and then trying a second BOP).

Realistic estimates from independent experts put this thing at something like 70,000 bbl/day. If it takes them to the end of August to complete (they are estimating late July or early August but I think that estimate assumes calm seas and blue skies) that will put something like 6.3 million more barrels into the gulf. That is about 250 million gallons, around 25 Exxon Valdez's. That is what is yet to come, not what has already been dumped into the Gulf over the, what, 40 days of spewage so far.

I'm hoping that the other approaches will do something. Hoping very hard. Or this is going to get very very ugly.


70,000 BBL/Day I think it still too low...

Do the math. A 21" pipe with liquid leaving at 1 MPH (velocity) will flow 95,000 Gallons per hour or a little over 50,000 bbls/day... I don't think the oil is leaving at 1 Mph... At 2 mph it jumpes to 190,000 Bbls/Day...

Try again, BP...
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Quoting Patrap:
..History shows again and again
How nature points up the folly of men..




Hmm Blue Oyster Cult used that line in their song Godzilla....
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3186. Ossqss
Quoting USSINS:


CIMSS's new, experimental "IR/WV Difference" graphics.


Put that back in your pocket. We don't need to put up the panels to the NOA specifications just yet south of Tampa! I hope!

Although, I am ready and will leave the clear GE XL-10 ones up all season once they are reinstalled :)

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Quoting Weather456:
In one week, the total rainfall from 90E was about 80 855 tons of water. Most of it fell in the Pacific Ocean. How did I arrive at this figure.

Well the surface precip rate over the past week was about 0.00027 kg per second, and since there are 604 800 seconds in a week, that is about 163 kilograms of precip in one week. But that is just the amount for one square meter. The area affected by 90E is 450 000 m^2 for a total of 73 350 000 kilograms of precip.



That is mind boggling and that chart is for the week ending Thursday. Most of the tropical storm rains are ongoing. What will this do to the ash?
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Quoting SiestaCpl:
Good note all...stay safe...where ever you are...


b flat (sorry couldn't myself) :)
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3182. Patrap
..History shows again and again
How nature points up the folly of men..

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Good nite all...stay safe...where ever you are...
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Quoting Levi32:
Northern Hemisphere tropical cyclone activity is still running below-normal for May. As of May 24th, the average ACE by this time of year is 32. We're still stuck at 9, and Agatha will not add much to that. The slower the rest of the hemisphere starts, the better for the Atlantic.

Ryan Maue has some interesting thoughts on the recent NHC predictions for the Atlantic hurricane season.

"14 hurricanes ? 23 storms ? really?

Historically, the North Atlantic hurricane activity is usually characterized as a feast or a famine, thus making definitions of what is normal difficult. In "active" periods (1995-present), a "normal" season sees a tremendous amount of hurricane activity compared to the inactive period of ~1970-1994. In the above figure, the light blue line indicates the linear trend of NATL ACE from 1950-2009 -- a 60-year period of decent records -- and the line is flat. No trend since 1950. When seasonal forecasting outfits like Gray & Klotzbach at CSU and Tropical Storms Risk, etc. debut their upcoming seasonal forecast, they represent an entire season's worth of activity in an integrated sense either by predicting counts/frequency or ACE. However, there is no reason to assume that the entire period between June - November will experience the same favorable/unfavorable atmosphere/ocean conditions with respect to tropical cyclone formation. Indeed, the North Atlantic tends to spurt activity. For instance, one storm after another may form from African Easterly Waves and trek across the Main Development Region consecutively during the peak of the season.

The SH season was normal for 2009-2010. During the last 30-years, looking at the SH prior to the North Atlantic hurricane season is an excellent predictor of future activity (Maue 2010, Trop Conference). Indeed, one can expect at least normal activity this upcoming year, but likely not the extreme or hyperactive season at the HIGH END of forecasts expected by Gray, Accuweather, and others. One must keep a global context in mind when it comes to hurricane activity. Does it make any sense to consider El Nino as a major driver or inhibitor of North Atlantic activity but completely ignore what is going on in the other basins like the Western and Eastern Pacific? One must have a global perspective..."


One thing is that although easily-accessible data on southern hemisphere TC activity is limited, what data I have found doesn't seem to agree with his claim that the preceding southern hemisphere season is an excellent predictor of the north Atlantic season.

Looking at the southern hemisphere TC counts versus the North Atlantic, it doesn't seem to be the strongest correlation in the world.





Also, his talk about "global perspective" is very sensible, but he himself does not have a good "global perspective" if he still thinks the ENSO is the driver behind everything. I do wish he'd go into more detail in these posts, as I would like to hear more of where he's coming from.


High activity in the Southern Hemisphere usually means low activity in the Atlantic, but 2004-2005 was an average year in the SHEM...and look at what we ended up with in the North Atlantic. 2005-2006 was not that much different yes in the North Atlantic it was very much different. So average activity in the SHEM could mean anything, and since this season the SHEM activity was likely artificially high due to the pooling of warm water and the ENSO Modoki warm pool in the South Pacific, this is yet another indication of a hyperactive season for 2010.
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Hurricane Strength, Agatha remnants making landfall near Washington D.C.! 994mb

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3178. help4u
Great service tonight everyone !!
Member Since: September 18, 2006 Posts: 0 Comments: 1276
Judging from satellite imagery I think the current COC of TD Agatha is located at: 14.9˚N 91.6˚W.

Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting AstroHurricane001:


Probably not an earthquake. The frogs are migrating during mating season and the large number could be the result of heavy winter rains.


HMMMM who knows ;)

Traffic police spent nearly two hours trying to clear the frogs from the highway.

Experts were at a loss to explain the bizarre phenomenon.
---------------------
Thessaloniki. Turkey is in panic because of the invasion of frogs along a motorway with Greece, because it fears a strong earthquake, Greek online edition Zougla reports. The Turkish newspapers comment that the millions of frogs, which stopped the traffic along the Egnatia Motorway in Northern Greece, are a herald of a strong earthquake in Turkey and Greece.
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that's cool 456. i love how many things are just simple math problems. sorry it's the accounting in me!
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Any Cat 5s, technically I said no in Ossgss's contest... I suspect many cat 4s, but I am thinking no on 5s
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3171. Makoto1
Thanks everyone, that'll be a huge help.
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Quoting FIU2010:


hey, do you think will see any cat 5's this year?
Yes at least 1 possibly 2 cat 5s but not making landfall anywhere just my opinion as there very well be a cat 5 affecting someone.
Member Since: April 8, 2010 Posts: 15 Comments: 2572
3169. Levi32
Quoting Weather456:
In one week, the total rainfall from 90E was about 80 855 tons of water. Most of it fell in the Pacific Ocean. How did I arrive at this figure.

Well the surface precip rate over the past week was about 0.00027 kg per second, and since there are 604 800 seconds in a week, that is about 163 kilograms of precip in one week. But that is just the amount for one square meter. The area affected by 90E is 450 000 m^2 for a total of 73 350 000 kilograms of precip.



Impressive.
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The Hopi elders (and other American Indian traditionalists) meeting in the 1940's said that oceans would turn black before the modern world turns it's back on the stupid...maybe now they will? Those warnings were pasted down for generations before they voiced them in the public back in the 40's.
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3167. Levi32
Quoting Makoto1:


Thanks, I'll be sure to note that. I'm glad I have a place to go with questions like this.

So I take it that if we're trying to figure out the direction the mid-level remnants of a system, take Agatha just as an example, will go, I look a little higher up than what a typical 1000 mb surface low would usually be?


Yes. Because of the high mountains of Guatemala, Agatha's circulation will only remain intact above about 700mb. Thus, the 400mb-850mb layer is likely the best one to be looking at.
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Quoting FIU2010:


hey, do you think will see any cat 5's this year?
I think we can see up to 3 CAT 5's this year.
Member Since: September 2, 2009 Posts: 130 Comments: 21193
This graph converts feet above sea level to millibars. Use it in determining what steering layer relates to the pressure reading of a tropical cyclone.
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Quoting AstroHurricane001:


Get ready for the jellyfish...

They're waiting till mid-August for "relief wells"?! What if those wells get blown over, or worse, get struck by lightning and explode in a hurricane? Or the storm surge brings the spill as well as the new wells onto land?


I'm not holding out much hope for the next two known approaches (cutting off the riser and trying to put a pipe above it, and then trying a second BOP).

Realistic estimates from independent experts put this thing at something like 70,000 bbl/day. If it takes them to the end of August to complete (they are estimating late July or early August but I think that estimate assumes calm seas and blue skies) that will put something like 6.3 million more barrels into the gulf. That is about 250 million gallons, around 25 Exxon Valdez's. That is what is yet to come, not what has already been dumped into the Gulf over the, what, 40 days of spewage so far.

I'm hoping that the other approaches will do something. Hoping very hard. Or this is going to get very very ugly.
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3162. EricSFL
I would honestly rather have a strong tropical storm or hurrricane in South Florida out of Agatha than for it to sit around over those poor countries.
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3161. Dakster
Quoting Patrap:


Right after the 2nd Angel Poured its vile onto the GOM..

Oh wait,,that was BP


Sad... but true...
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3160. Patrap
Revelation :16

3The second angel poured out his bowl on the sea, and it turned into blood like that of a dead man, and every living thing in the sea died.
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3158. Patrap
Quoting Dakster:


Aren't Frogs the eleventh plague?


Right after the 2nd Angel Poured its vile onto the GOM..

Oh wait,,that was BP
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Quoting MiamiHurricanes09:
Interesting, anxious to see what plays out.


Aye, same here... we will have to see!
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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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