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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720. IKE
Quoting severstorm:
Good Morning, StormW, Ike, 456 and all. looking like hot dry weather for w c fl rest of the week.


I had over an inch of rain yesterday afternoon. Gotta check my gauge for the exact total.
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Quoting severstorm:
Good Morning, StormW, Ike, 456 and all. looking like hot dry weather for w c fl rest of the week.
Quoting StormW:
Good morning 456! Good morning all!


morning
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Good Morning, StormW, Ike, 456 and all. looking like hot dry weather for w c fl rest of the week.
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717. IKE
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714. IKE
6Z GFS @ 168 hours...

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Quoting all4hurricanes:
How many models are calling for development in the Caribbean?


I have a model summary map to the bottom of my blog.
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How many models are calling for development in the Caribbean?
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I think we may see at most a TD, if anything before June 1. I'm still in the more conservative camp that says conditions haven't yet ripened sufficiently.

However, we shall see!

Have a great day, all. I'll look in later if time permits....
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Good Morning to all

Blog Update

40-50% chance of La Nina this summer/fall; two areas to watch next week

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We now have model support for a tropical cyclone to develop in a few days. Maybe the models are predicting an anti-cyclone to develop over the system? That would explain why the models have a system forming in the face of those strong May westerlies. I've been calling (just randomly guessing) for the first storm to form on May 23rd since February.. how amazing would it be if I got it dead on? lol.
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ATLANTIC OCEAN...
RADAR AND SATELLITE IMAGERY SHOWS SCATTERED MODERATE CONVECTION
REACHING THE CENTRAL BAHAMAS AND EXTENDING W TO BEYOND 80W AND
THE STRAITS OF FLORIDA. FURTHER E...A SURFACE TROUGH EXTENDS
FROM 26N70W TO HISPANIOLA NEAR 20N72W. SCATTERED SHOWERS ARE
WITHIN 60 NM OF THE TROUGH AXIS.

Hmmm.... the germ of a genesis? or just a patchy beginning to MJO upswing?
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Oh, wow.... looks like we may indeed get some rain from this .... thought the weekend forecasts wouldn't pan out.

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Quoting HadesGodWyvern:
IMD advisory releases are still about 5-6 hours behind.. I would hope they fix that some day. =/
Morning, HGW... why do u think that is? They should be able to look at everything in more or less real time... we can and we're not "government officials"....
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703. HadesGodWyvern (Mod)
IMD advisory releases are still about 5-6 hours behind.. I would hope they fix that some day. =/
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702. HadesGodWyvern (Mod)
India Meteorological Department
Tropical Cyclone Advisory NUMBER THIRTEEN
CYCLONIC STORM LAILA (BOB01-2010)
8:30 AM IST May 19 2010
====================================

Subject: Cyclonic Storm LAILA over southwest and adjoining westcentral Bay of Bengal:

Cyclone Warning (Orange message).

At 3:00 AM UTC, Cyclonic Storm Laila over southwest and adjoining west central Bay of Bengal moved northwestward during past 6 hours and lay centered over southwest and adjoining west central Bay of Bengal near 13.5N 82.0E or about 190 NM east northeast of Chennai, 320 kms south southeast of Machilipatnam, and 480 kms south southwest of Visakhapatnam.

3 minute sustained winds near the center is 45 knots with a central pressure of 990 hPa. The state of the sea is very high around the system's center.

Satellite imagery indicates banding pattern of the system. The dvorak intensity of the system is T3.0. Associated broken intense to very intense convection observed over the Bay of Bengal between 10.0N to 18.0N. The lowest cloud top temperature due to convection is around -90C in association with the system.

Vertical wind shear of horizontal wind over the region is 10-15 knots. The system lies to the south of tropospheric ridge, which roughly runs along 17.0N. The system is under the influence of anticyclonic circulation located to the northeast of the system's center. Shear tendency over the past 24 hours is negative to the north of the system center.

Considering all the above and numerical weather prediction model guidances, the system is likely to intensify further and move in a northwesterly direction and cross Andhra Pradesh coast between Nellore and Kakinada, close to Machilipatnam by the morning of May 20th.

Forecast and Intensity
=========================
9 HRS: 14.5N 81.0E - 60 knots (Severe Cyclonic Storm)
33 HRS: 16.5N 81.0E - 50 knots (Severe Cyclonic Storm)
57 HRS: 18.5N 83.5E - 40 knots (Cyclonic Storm)
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Quoting altesticstorm10:
Does the UKMET still exist or did it die for some reason? I haven't heard from it for a while. Either way it was out to lunch last year, westcasting Bill etc etc. If it doesn't develop anything it's certainly an outsider.


You can still find the UKMET here.
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Quoting altesticstorm10:

4 of our major models including the trusty ECMWF are predicting the Caribbean feature will develop, and 3 major models (including the ECMWF but excluding the NOGAPS) are predicting the western Atlantic feature will develop.

My gut feeling says we'll have one named storm before June, not both. I think the Caribbean one has the better chance since shear will likely plummet in the coming 5 days or so there (not in the Gulf, though).


Yet those same models are also forecasting the westerlies to be in place across that same exact region. Perhaps it's a feedback error?
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Does the UKMET still exist or did it die for some reason? I haven't heard from it for a while. Either way it was out to lunch last year, westcasting Bill etc etc. If it doesn't develop anything it's certainly an outsider.
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Quoting KoritheMan:
I'm more concerned about vertical shear right now than the possible Bahamas subtropical cyclone the models are developing. For one thing, that is so far out that at this point, it's merely an area of potential interest, but it is far from reality. First of all, I question whether or not vertical shear will be sufficient to allow anything to form, even something subtropical. Additionally, there appears to be a lack of significant baroclinic forcing in the area during that time, which would also lessen the probability of subtropical cyclogenesis in the area.

As far as shear goes, at the moment, the westerlies are well in control of the entire Atlantic hurricane breeding grounds, even in the Caribbean (the only exception to this is the extreme SW Caribbean just north of Panama).

In order for anything to develop, obviously, we need low vertical shear. This hasn't been the case for the last several days, and that doesn't look to be changing anytime soon, according to the models, as the longwave pattern still appears to favor troughing.

However, as a generally conservative forecaster, I'm always rather skeptical of the accuracy of long-term forecasts (I consider a forecast to be "long-range" when it goes beyond five days) of vertical shear, since that is one of the more difficult things to predict.

We shall see.

Regardless, even with the upward MJO on its way, at the moment, I think the prospects of us seeing a named storm before June 1 is slim at best.

4 of our major models including the trusty ECMWF are predicting the Caribbean feature will develop, and 3 major models (including the ECMWF but excluding the NOGAPS) are predicting the western Atlantic feature will develop.

My gut feeling says we'll have one named storm before June, not both. I think the Caribbean one has the better chance since shear will likely plummet in the coming 5 days or so there (not in the Gulf, though).
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Quoting xcool:



new new




ngp new


0Z NOGAPS shows high rainfall amounts in the NE caribbean, I'm impressed since this is a CONSERVATIVE model.
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I'm more concerned about vertical shear right now than the possible Bahamas subtropical cyclone the models are developing. For one thing, that is so far out that at this point, it's merely an area of potential interest, but it is far from reality. First of all, I question whether or not vertical shear will be sufficient to allow anything to form, even something subtropical. Additionally, there appears to be a lack of significant baroclinic forcing in the area during that time, which would also lessen the probability of subtropical cyclogenesis in the area.

As far as shear goes, at the moment, the westerlies are well in control of the entire Atlantic hurricane breeding grounds, even in the Caribbean (the only exception to this is the extreme SW Caribbean just north of Panama).

In order for anything to develop, obviously, we need low vertical shear. This hasn't been the case for the last several days, and that doesn't look to be changing anytime soon, according to the models, as the longwave pattern still appears to favor troughing.

However, as a generally conservative forecaster, I'm always rather skeptical of the accuracy of long-term forecasts (I consider a forecast to be "long-range" when it goes beyond five days) of vertical shear, since that is one of the more difficult things to predict.

We shall see.

Regardless, even with the upward MJO on its way, at the moment, I think the prospects of us seeing a named storm before June 1 is slim at best.
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695. xcool



new new




ngp new
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Tazmanian:
THATS FOR HAIL


Impressive.
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THATS FOR HAIL
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TELL ME EVERE ONE WHEN WAS THE LAST TIME YOU SAW THIS


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691. xcool



cmc aND GFS NOW
Member Since: September 26, 2009 Posts: 2 Comments: 15684
690. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting Tazmanian:
I HAVE NOTED THAT THE GFS IS FORCASTING 2 TS AT 192HRS ON THE NEW 00ZS



If you mean blob storms and scrutinizing for any hint of a LLC then yes.
Member Since: January 14, 2007 Posts: 17 Comments: 4140
688. xcool
nv mind
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting KEEPEROFTHEGATE:
Magnitude 6.0
Date-Time Wednesday, May 19, 2010 at 04:15:42 UTC
Tuesday, May 18, 2010 at 11:15:42 PM at epicenter
Time of Earthquake in other Time Zones

Location 5.069S, 77.559W
Depth 125.6 km (78.0 miles)
Region NORTHERN PERU
Distances 125 km (80 miles) NNW of Moyobamba, Peru
130 km (80 miles) NNE of Chachapoyas, Peru
545 km (340 miles) S of QUITO, Ecuador
775 km (480 miles) N of LIMA, Peru

Location Uncertainty horizontal /- 6.7 km (4.2 miles); depth /- 9.2 km (5.7 miles)
Parameters NST=200, Nph=200, Dmin=595.1 km, Rmss=0.91 sec, Gp= 97,
M-type=teleseismic moment magnitude (Mw), Version=7
Source USGS NEIC (WDCS-D)


Event ID us2010wlaq



should be deep enough not cause a ton of damage - hi keeper


ni-night
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686. xcool
"0
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting RitaRefugee:
I gotta go to bed, folks. Gotta be at work at 7:30 and it's 11:15 here. Going agin the grain, but I hope we don't have a busy cane season. We were quiet here for almost 50 years, then had Rita, Gustav, and Ike...Oh, and Humberto...I'm not evacuating for anything less than a C5. Still paying off Gustav and Ike evac costs.


Funny how one storm can inspire so many WU names. Lol. I think we got a RITAEVAC somewhere in WU land. I live just across the border on the TX side of things. I dont wanna evac any more either. I and my vehicles are getting too old for this. :) We evaced for Gustav even though he missed us. The 10 day turn around for Ike was tough. Especially on the pocket book. I think we (me and my fam) have evaced 5 times been hit twice. Andrew, Lili, Rita, Gustav and Ike. We decided to stay home for Humberto seeing how we woke up to it! Lol. Evacing is a pain but I'll always probably do it. If for no other reason than I would just be in the way if I stay. Oh well i'm used to hitting the road. And my favorite evacs are the ones where we drive home the next day in perfectly sunny weather to find everything the same as we left it. :)
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I HAVE NOTED THAT THE GFS IS FORCASTING 2 TS AT 192HRS ON THE NEW 00ZS

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Member Since: July 15, 2006 Posts: 175 Comments: 54827
Magnitude 6.0
Date-Time Wednesday, May 19, 2010 at 04:15:42 UTC
Tuesday, May 18, 2010 at 11:15:42 PM at epicenter
Time of Earthquake in other Time Zones

Location 5.069°S, 77.559°W
Depth 125.6 km (78.0 miles)
Region NORTHERN PERU
Distances 125 km (80 miles) NNW of Moyobamba, Peru
130 km (80 miles) NNE of Chachapoyas, Peru
545 km (340 miles) S of QUITO, Ecuador
775 km (480 miles) N of LIMA, Peru

Location Uncertainty horizontal +/- 6.7 km (4.2 miles); depth +/- 9.2 km (5.7 miles)
Parameters NST=200, Nph=200, Dmin=595.1 km, Rmss=0.91 sec, Gp= 97°,
M-type=teleseismic moment magnitude (Mw), Version=7
Source USGS NEIC (WDCS-D)


Event ID us2010wlaq
Member Since: July 15, 2006 Posts: 175 Comments: 54827
Member Since: July 15, 2006 Posts: 175 Comments: 54827
Quoting BahaHurican:
Huh? How big are these tarballs anyway?

3 to 8 inches in diameter.

"Fear broadened across Florida on Tuesday as black tar balls and oily residue were reported in several areas in the Keys.

At the same time, scientists confirmed tendrils of the Deepwater Horizon oil spill were caught in the gulf loop current and would reach Florida's Keys as early as this weekend.

The discoveries deepened confusion over a situation that is stoking debate among researchers, politicians and environmentalists. While volunteers are organizing efforts to begin cleanup of a huge oil spill, experts are cautioning against panic.

Several marine experts were wary of linking the spill with tar balls in the Keys.

"I would be very surprised if this was oil from the spill," said Mitch Roffer, president of Roffer's Ocean Fishing Forecasting Service in West Melbourne, which tracks the spill several times a day.

He said if the tar balls are related to the Deepwater Horizon blowout, it would mean the surface oil traveled hundreds of miles south undetected by scientists, satellites and computer models.

Tar balls have been a nuisance on Florida shores forever, said Ted Van Vleet, University of South Florida chemical oceanography professor.

Tar balls can form from larger oil spills. Wind and waves mix a slick, breaking it into smaller patches. The chemical composition changes, but the ball retains some toxic properties, he said.

Tar balls also can form from oil seeping naturally from seabeds. They can be moved around the gulf by tides and currents."
...........
"The tar balls at Fort Zachary Taylor State Park, found by rangers Sunday and reported Monday, are about 3 to 8 inches in diameter. More reports came in at Big Pine Key, Loggerhead Key and Smathers Beach on Tuesday morning."

http://www.tampabay.com/news/environment/water/tar-balls-found-along-key-west-shores/1095742

Notable, is the very first word of the article...
Member Since: August 16, 2007 Posts: 6 Comments: 12463
679. HadesGodWyvern (Mod)
The IMD should have the system at T3.5 or 4.0 in the next advisory.
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678. xcool


new GFS .
Member Since: September 26, 2009 Posts: 2 Comments: 15684
677. HadesGodWyvern (Mod)


2010MAY19 040000 T4.0 976.0 hpa/ +0.0 / 65.0 knots
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Depending on currents, one can see tar balls on the beaches throughout the Bahamas, though walnut size seems pretty darned big to me. Untended beaches that face shipping routes are more likely to retain evidence.
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Quoting southfla:
atmoaggie -- it isn't that tar balls are washing up in the Keys -- it is the distribution of the tar balls all washing up from the Dry Tortugas to the middle keys in the same 24 hour period. That is a pretty wide stretch of coastline to suddenly have tar balls appear. I've never seen tar balls on Florida beaches bigger than a walnut -- so I am somewhat suspicious, but willing to wait on the testing.
Huh? How big are these tarballs anyway?
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Quoting RitaRefugee:
xxxxx@gmail.com

I'd pull that down...people build robots to search google for the "@"...boom, you are overwhelmed with junk.

(and to whomever has the email addy of xxxxx@gmail.com...that sux, but is your problem)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting RitaRefugee:
Atmoaggie....I'll send you a righteous jambalaya recipe...easy, cheap, and good. Send me your email...LOL

lol.
I don't really get the boxed dinners. I have a PaPa Sonnier from Opelousas. Opelousas being the official exception to the rule that yankees grow up north of I-10.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
mrj@gmail.com
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Atmoaggie....I'll send you a righteous jambalaya recipe...easy, cheap, and good. Send me your email...LOL
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Quoting southfla:
atmoaggie -- it isn't that tar balls are washing up in the Keys -- it is the distribution of the tar balls all washing up from the Dry Tortugas to the middle keys in the same 24 hour period. That is a pretty wide stretch of coastline to suddenly have tar balls appear. I've never seen tar balls on Florida beaches bigger than a walnut -- so I am somewhat suspicious, but willing to wait on the testing.

I didn't know they were that widespread. Did a natural seep belch a bunch out? We have no way of knowing.
For a dean of a college of marine sciences to say things like "it is exceedingly unlikely that", is pretty strong to me, but he could be wrong...
Member Since: August 16, 2007 Posts: 6 Comments: 12463

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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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