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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Member Since: Posts: Comments:
Quoting Levi32:


40% makes me laugh.....you really going with the IRI on this one?


the IRI had 35% and no I'm not going with them. You'll see why.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Yea, El Nino's been dead for a few days actually..

Posted May 12th..
El Nino event of 2009/10 ends
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Quoting Stormchaser2007:



Sure

Thanks! We are at about -0.2%u02DAC.
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NEXRAD Radar
Amarillo, Storm Relative Mean Radial Velocity 1.45 Degree Elevation Range 124 NMI

Member Since: July 3, 2005 Posts: 426 Comments: 128749
Kind of disappointed that IRI hasnt updated their ENSO forecast yet.
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Quoting Weather456:
There is a 40% of La Nina developing by end of August that's the theme of tomorrow's blog.


40% makes me laugh.....you really going with the IRI on this one?
Member Since: November 24, 2005 Posts: 635 Comments: 26661
Quoting Weather456:
Just for kicks....the CFS has a tropical cyclone impacting the NE Caribbean around the end of next month (27 June)...appears to develop in the western tropical atlantic

lol, it's just 984 hours away. Well, I think the only useful thing out of that model at that time period is the location of the Bermuda high.
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Quoting AstroHurricane001:
The storm that brought tornadoes to much of the US, including Texas, the Midwest and Southeast, is now moving out to sea over the Gulf Stream. This current will be a major factor for strengthening subtropical and tropical systems this year.


A system in the Gulf is developing an eye-like feature but is under high shear and is devoid of vorticity.


....which is exactly why that isn't an eye-like feature.
Member Since: November 24, 2005 Posts: 635 Comments: 26661
Quoting MiamiHurricanes09:
Pretty bad weather over Cuba, Yucatan, and many more places.

Just sprinkled a little rain here in Cayman, but no major rainfall the last 24 hours.
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There is a 40% of La Nina developing by end of August that's the theme of tomorrow's blog.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting MiamiHurricanes09:
Stormchaser can you post the Niño dailies, please?I go by dailies so for me we are already below 0.0˚C.



Sure

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Quoting Levi32:


My numbers are 18-10-6. My Atlantic hurricane outlook for this year can be found on my blog.
My numbers are 18, 10, 6. lol. You can find all the numbers on ossgss's blog.
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NEXRAD Radar
Amarillo, Vertically Integrated Liquid Range 124 NMI


Member Since: July 3, 2005 Posts: 426 Comments: 128749
Just for kicks....the CFS has a tropical cyclone impacting the NE Caribbean around the end of next month (27 June)...appears to develop in the western tropical atlantic

Member Since: July 24, 2005 Posts: 407 Comments: 19076
The storm that brought tornadoes to much of the US, including Texas, the Midwest and Southeast, is now moving out to sea over the Gulf Stream. This current will be a major factor for strengthening subtropical and tropical systems this year.


A system in the Gulf is developing an eye-like feature but is under high shear and is devoid of vorticity.
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Stormchaser can you post the Niño dailies, please?
Quoting xcool:
El Nino 100
% over
I go by dailies so for me we are already below 0.0˚C.
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Quoting stormhank:
Levi what numbers are you going with for this season??...Im goin with 16 8 4


My numbers are 18-10-6. My Atlantic hurricane outlook for this year can be found on my blog.
Member Since: November 24, 2005 Posts: 635 Comments: 26661
U got mail Levi
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Member Since: July 3, 2005 Posts: 426 Comments: 128749
Quoting Levi32:


Also, both of the last two vigorous tropical waves occurred during a downward burst of the MJO in our basin, which is impressive.
Indeed it is, I'm sure there will be a wave like Fred (2009) in this upcoming upward MJO.
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247. xcool
El Nino 100
% over
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Quoting Acemmett90:


Fan-freaken-tastic
won't be long now soon we will be issuing TCFA for atlantic basin
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18Z GFS ensemble - 1 week

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Levi what numbers are you going with for this season??...Im goin with 16 8 4
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Quoting Levi32:


The northerly position of the ITCZ similar to 2005 and the active wave train are more signs that an active season is on the way. We saw nothing like this last year. The early ITCZ and tropical waves were pathetic to say the least. The deep tropics getting active early is a bad sign.


Also, both of the last two vigorous tropical waves occurred during a downward burst of the MJO in our basin, which is impressive.
Member Since: November 24, 2005 Posts: 635 Comments: 26661
El Nino is over so SW Carib GOM open for business again :( Hurricane season almost here :((
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Quoting stormhank:
Levi...an active ITCZ for may isnt it? just wandering is that a harbinger of things to come??


The northerly position of the ITCZ similar to 2005 and the active wave train are more signs that an active season is on the way. We saw nothing like this last year. The early ITCZ and tropical waves were pathetic to say the least. The deep tropics getting active early is a bad sign.
Member Since: November 24, 2005 Posts: 635 Comments: 26661
Quoting Weather456:
NOGAPS agressive on 18Z

Pretty much all models are being pretty aggressive. I just hope Haiti doesn't get any of it.
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NEXRAD Radar
Amarillo, Storm Relative Mean Radial Velocity 0.50 Degree Elevation Range 124 NMI

Member Since: July 3, 2005 Posts: 426 Comments: 128749
Sweet T-storm in Texas Panhandle...
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Its going to get pretty moist in the Caribbean.

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Levi...an active ITCZ for may isnt it? just wandering is that a harbinger of things to come??
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A Windsat pass barely caught the wave axis 3 hours ago:

Member Since: November 24, 2005 Posts: 635 Comments: 26661



WTIO21 PGTW 182230
SUBJ/TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 10.5N 55.7E TO 14.4N 51.4E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT
IMAGERY AT 182200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 10.8N 55.1E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 08
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.0N
55.5E, IS NOW LOCATED NEAR 10.8N 55.1E, APPROXIMATELY 110 NM
SOUTHEAST OF SOCOTRA ISLAND. ANIMATED INFRARED SATELLITE IMAGERY
DEPICTS A DEVELOPING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP
CONVECTIVE BANDING OVER THE SOUTHERN SEMI-CIRCLE. AN 181721Z
METOP-A IMAGE ALSO INDICATES A STRENGTHENING, WELL-DEFINED LLCC
WITH CONVECTIVE BANDING WRAPPING FROM THE SOUTHWEST INTO THE
NORTHWEST QUADRANT. THE 181721Z ASCAT AMBIGUITY ANALYSIS SHOWED
A SMALL, TIGHT LLCC WITH 20-25 KNOT WINDS NEAR THE CENTER AND 30-35
KNOT WINDS DISPLACED ALONG THE SOUTHWESTERN PERIPHERY OF THE LLCC.
UPPER-LEVEL ANALYSIS INDICATES A MORE FAVORABLE ENVIRONMENT WITH WEAK
VERTICAL WIND SHEAR AND DIFFLUENT FLOW OVER THE LLCC. THE SYSTEM
IS EXPECTED TO CONTINUE DEVELOPING, AIDED BY THE ENHANCED
SOUTHWESTERLY SURFACE FLOW AND IMPROVED NORTHEASTERLY FLOW OVER
YEMEN. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1001 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED
BY 192230Z.//
NNNN

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NOGAPS agressive on 18Z

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting CycloneOz:
tornadodude reports tornado on the ground.

I'll bet he does with that presentation...good call to be there...
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Quoting Stormchaser2007:


Not really 'intense'.


Well it is showing 30- 35 knot winds (35-40 MPH), that's a TS, that's not "intense" but pretty impressive from my stand point.
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tornadodude reports tornado on the ground.
Member Since: August 26, 2006 Posts: 10 Comments: 3753
Another tropical wave in the Central Atlantic is showing its teeth, and rather sharp ones for May. A tropical wave along 41W south of 10N has widespread moderate-strong convection along its axis, though mostly associated with the ITCZ, which is still expected at this time of year. Some low-mid level turning is evident on satellite imagery near 5.5N, 41W. This is confirmed by CIMSS 850mb vorticity analysis, which shows a vort max near that location. There is a weak reflection of vorticity at 700mb, but values are lacking there. Due to its position being so far south, development is not expected, and this is also normal for this time of year. It is, however, interesting to see such vigorous waves coming across with such frequency in May.



CIMSS 850mb vorticity (left) and 700mb vorticity (right):

   
Member Since: November 24, 2005 Posts: 635 Comments: 26661
Quoting stormhank:
If the system in sw carribena forms would it head NE and then out to sea?? What about the possible system near bahamas later?
If the system in the SW Caribbean develops models suggest (well at least the GFS does) that it will move N/NNE/NE towards Hispañola. The one near the Bahamas should obviously originate east of the Bahamas and then move N/NE out to sea.
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Patrick! Welcome back! You had me worried! By the way, is that a small bottle of Dawn tucked away in the eye of your iron man primary portrait?
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Thats most Likely a spinner on the ground with that severe right movement and Strong TVS Ping.


Member Since: July 3, 2005 Posts: 426 Comments: 128749
Quoting MiamiHurricanes09:
Yup, they're forecasting a pretty intense system in the SW Caribbean.


Not really 'intense'.


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Wasnt tornadodude and Oz's group in Dumas today?



Tornado Warning

Statement as of 6:30 PM CDT on May 18, 2010

... A Tornado Warning remains in effect until 715 PM CDT for northern
Moore and southeastern Sherman counties...

At 628 PM CDT... National Weather Service Doppler radar and storm
spotters were tracking a tornado. This tornado was located in
Dumas... moving east at 20 mph.

* Locations impacted include...
Dumas...
Sunray...

Precautionary/preparedness actions...

Heavy rainfall may obscure this tornado. Take cover now. If you wait
to see or hear it coming... it may be too late to get to a safe place.


Lat... Lon 3620 10163 3573 10163 3580 10210 3594 10211
time... Mot... loc 2330z 269deg 18kt 3585 10195
Member Since: July 3, 2005 Posts: 426 Comments: 128749
If the system in sw carribena forms would it head NE and then out to sea?? What about the possible system near bahamas later?
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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.