Little change to 90L; flow of oil southwards towards Loop Current shuts off

By: Dr. Jeff Masters , 7:57 PM GMT on May 22, 2010

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An extratropical low pressure system a few hundred miles northeast of the Bahamas (90L), has changed little over the past day. (For those of you who were wondering, a discussion of what an "Invest" is can be found in the Tropical Cyclone FAQ). This low has the potential to develop into the season's first depression or subtropical storm, and could be a threat to the Southeast U.S. coast by Tuesday or Wednesday. The SHIPS model predicts that shear will be in the high 30 - 40 knot range through Tuesday, though. The high shear combined with the large amount of dry air to 90L's west seen on water vapor satellite loops will greatly hamper transition of this system to a subtropical storm. This system is expected to move slowly north and then northwestward towards the Southeast U.S. coast over the next three days, and could bring 20 - 30 mph winds and heavy rain to the coast of North Carolina by Tuesday night. Most of the models indicate that Wednesday will be when 90L gets closest to the coast, with a position just off the North or South Carolina coast. All of the major models currently indicate that 90L will not make landfall, but will move slowly northeastward out to sea late next week as a trough of low pressure moving across the Eastern U.S. picks up the storm. While the storm will initially form in a region of high wind shear and be entirely extratropical, it will move into a region of lower wind shear in a gap between the polar jet stream to the north and the subtropical jet stream to its south by Wednesday. At that time, the low will be positioned near the warm waters of the Gulf Stream, and will have the opportunity to develop a shallow warm core and transition to a subtropical storm. The counter-clockwise flow of air around this low will probably lead to offshore winds over the oil spill region Tuesday through Wednesday, keeping oil away from the coasts of Alabama and the Florida Panhandle, but pushing oil southwards towards the Loop Current. Wunderbloggers Weather456 and StormW have more detailed discussions of the potential development of 90L.


Figure 1. Visible satellite image of 90L this afternoon.

Heavy rainfall threat for Haiti diminishes
Moisture is expected to increase across most of the Caribbean next week, leading to seasonally heavy rains across much of the region. A concentrated tropical disturbance capable of bringing dangerous flooding rains to Haiti is no longer being indicated, but the normal heavy rains that we can expect this time of year will likely begin affecting the island over the next several weeks.

Flow of oil southward towards the Loop Current shuts off
Light southeast to east winds are expected to blow over the northern Gulf of Mexico today through Monday, resulting in potential oiling of Louisiana shorelines from the mouth of the Mississippi River westward 150 miles, according to the latest trajectory forecasts from NOAA. These winds shut off the flow of oil southwards towards the Loop Current, as seen in the latest SAR satellite imagery (Figure 2). However, winds will shift to offshore out of the north or northeast Tuesday and Wednesday, due to counter-clockwise flow of air around the approaching 90L storm. This wind direction change should give some relief to the hard-hit Louisiana coast. If 90L becomes strong and lingers off the Southeast U.S. coast for several days, a significant amount of oil could get pumped into the Loop Current late next week.


Figure 2. Synthetic Aperture Radar (SAR) image of the oil spill taken at 8:53am EDT May 22, 2010, by the Canadian Radarsat-1 satellite, operated by MDA GeospatialServices of Richmond, Canada. The plume of oil being drawn south towards the Loop Current has been cut off. Image credit: Center for Southeastern Tropical Advanced Remote Sensing, University of Miami Rosenstiel School of Marine and Atmospheric Science. SAR images have a resolution of 8 - 50 meters, and can be taken through clouds and precipitation.

Oil threat to the Keys uncertain
Satellite imagery from today's pass of NASA's Terra satellite and the European Envisat satellite were inconclusive as to the presence of oil in the Loop Current. It is likely that the oil has dispersed significantly over the 500-mile course it has taken from the site of the Deepwater Horizon blowout. I expect some oil is close to completing the full loop of the Loop Current and is now headed east towards the Keys, as depicted in the "Uncertainty" area in the latest NOAA 72-hour offshore trajectory forecast. If this estimate is correct, the Keys could see oil as early as Wednesday. However, this is not a sure thing. As I discussed in my post Wednesday, the Loop Current is very unstable right now, and is ready to cut off into a giant clockwise-rotating eddy, an event that occurs every 6 - 11 months. This event could occur today or tomorrow, in which case the ribbon of southwestward-moving oil would turn due west and then north, eventually winding up back near the site of the Deepwater Horizon blowout. Roffer's Ocean Fishing Forecast Service has a nice discussion on the possibility of the Loop Current cutting off into a Loop Current Eddy, and they note in today's discussion that there appears to be a developing eastward flow of water directly from the Yucatan Peninsula to the Florida Keys. Keep in mind, though, that during the first month that a Loop Current Eddy forms, it exchanges a considerable amount of water with the Loop Current. Even if a Loop Current Eddy forms today, I still expect we will see some oil make the turn eastward and flow past the Florida Keys by Wednesday. My guess is that the oil will be too thin and scattered to cause significant problems in the Keys, but there is great uncertainty on this.

Oil spill resources
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

I'll be back with a new post Monday morning.

Jeff Masters

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Quoting Levi32:
90L is struggling with the massive amount of dry air coming into its southwest quad. This is making it difficult for convection to take advantage of the lessened wind shear and form closer to the COC. The current low center is backing away SSW, but we've seen this twice before now. 90L is not about to just go away, not as long as there is an upper feature supporting it aloft.

90L is still baroclinically driven. A tropical system looking like this would be in pretty bad shape, but we've already gone through this twice and 90L has no problem forming new lows under the area of upper divergence and dumping the old dried-out ones into the low-level flow that leads to their death. We should see another new low try to form to the north of the current one sometime overnight tonight.
Correct. The NHC 8:05 Discussion said that a new low is developing under the strongest convection. I'm sure there will be many more low replacements to come.
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Atlantic Tropical Weather Discussion

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN MAY 23 2010

...SPECIAL FEATURES...

A BROAD DEEP LAYER TROUGH IS OVER THE WESTERN ATLANTIC. AN UPPER
LEVEL LOW IS EMBEDDED IN THIS TROUGH...NOTED ON WATER VAPOR
IMAGERY...AND SUPPORTS A 1007 MB SURFACE LOW CENTER NEAR 24N70W.
A SURFACE TROUGH CROSSES THE LOW CENTER ALONG 29N68W 24N70W
21N70W. MARINE OBSERVATIONS NEAR THE LOW CENTER INDICATE 8 FT TO
12 FT SEAS. GALE FORCE WINDS ARE DEVELOPING NORTHEAST OF THE LOW
CENTER FROM 25N TO 32N BETWEEN 65W AND 70W. THIS SYSTEM IS BEEN
FURTHER ENHANCED BY THE FORMATION OF A UPPER LEVEL LONGWAVE
SOUTHWEST OF THE SYSTEM. WHILE THE CURRENT LOW SHIFTS
SOUTHWARD...SATELLITE IMAGERY SUGGESTS THAT A SECOND LOW IS
DEVELOPING TO THE NORTH OF THE CURRENT LOW AND IT IS EXPECTED TO
BE ADDED TO THE SURFACE UNIFIED MAP BETWEEN 24/0000 UTC AND
24/0600. COMPUTER MODELS SUGGEST THE SECOND LOW WILL STRENGTHEN
AND MOVE NORTHWEST TO NEAR 30N71W OVER THE NEXT 24 HOURS. MOST
OF THE CONVECTION IS FOUND EAST OF THE SYSTEM FROM 19N TO 32N
BETWEEN 55W AND 71W. MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS
ARE NORTH EAST OF THE LEEWARD ISLANDS FROM 17N TO 24N BETWEEN
57W AND 62W.
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Looks like there will be some disappointing forecasters from 90L.....Things have not changed and its now very exposed center will probably go pooffff.....from all the dry air.



Member Since: September 2, 2007 Posts: 177 Comments: 20430
1748. beell
Quoting Levi32:
90L is struggling with the massive amount of dry air coming into its southwest quad.


And SE, NE, and NW quadrant!
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1747. MZV
This is quite reminiscent of prior year seasons... usually in May or June, there is a low close to South Carolina that storm watchers on here all gaggling about ... these tend to be near-misses and don't develop but give us a sense that the season is about to take off.
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1746. leo305
Quoting Patrap:


Oil response on Grand Isle angers residents, officials

They say the response has been too slow and their anger is now beginning to manifest itself in different ways.


the response is still slow as heck.. I mean honestly waiting an entire week to just try something is really slow.. why not just seal the dam thing already with there mud method, instread of waiting 7 days to do so.
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting stormwatcherCI:
Well, when I look at it that way it looks like the circulation is moving south and the convection is moving north or north east.

This is suppose to happen with these sorts of systems, or so I've read to many times.
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1744. Patrap


Oil response on Grand Isle angers residents, officials

They say the response has been too slow and their anger is now beginning to manifest itself in different ways.
Member Since: July 3, 2005 Posts: 414 Comments: 125476
Quoting AussieStorm:

Have a look at this Loop then tell me what you see.
Well, when I look at it that way it looks like the circulation is moving south and the convection is moving north or north east.
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My Suburb in Sydney Australia Now
13.9°C / 57.0°F rising
Updated at 10:00 EST
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1741. Levi32
90L is struggling with the massive amount of dry air coming into its southwest quad. This is making it difficult for convection to take advantage of the lessened wind shear and form closer to the COC. The current low center is backing away SSW, but we've seen this twice before now. 90L is not about to just go away, not as long as there is an upper feature supporting it aloft.

90L is still baroclinically driven. A tropical system looking like this would be in pretty bad shape, but we've already gone through this twice and 90L has no problem forming new lows under the area of upper divergence and dumping the old dried-out ones into the low-level flow that leads to their death. We should see another new low try to form to the north of the current one sometime overnight tonight.
Member Since: November 24, 2005 Posts: 628 Comments: 26454
Quoting leo305:


the center is completely exposed .. and the shear is ripping the convection off the system
Looks more to me that the convection is being wrapped into the circulation.
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1739. pottery


Ignore the Intro. The Calypso is one of the Important Ones! Iconic.
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1738. KEEPEROFTHEGATE (Mod)
Quoting GeoffreyWPB:
Don't know why...
All the animals have to die...
Oily waters...
Keeps gushing all the time...


Member Since: July 15, 2006 Posts: 163 Comments: 52164
Quoting stormwatcherCI:




Looks pretty good in this.

Have a look at this Loop then tell me what you see.
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Quoting CybrTeddy:
Afternoon Pottery, KOTFG, Miami, Geoffrey and everyone else!

90L is actually doing better than I thought it would by now, I place odds of development at 35%.. up from yesterday. Again I ask, WUmail me if your at all interested in what I have to say about this system (I'll probably say that for the rest of the year) and also, come June 1st i'll be starting a daily Tropical Weather discussion blog.
Hello Teddy. I havn't been updating my blog lately but when the season starts I'll post much more often. I'm also interested in reading your blog.
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Quoting AussieStorm:
Looking at this Loop. One can see the COC/LLC clearing out to the south then the main body of convection clearing out to the north then dying off. A smaller firing of convection can be see almost due west of the COC/LLC.
In my honest opinion, 90L wont be around for much longer, but I maybe wrong.....I'm just sayin...


It seems to go in cycles as the intensity models have been showing the past few days. Tonight we shall see if convection can redevelop...
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1734. leo305
Quoting stormwatcherCI:




Looks pretty good in this.


the center is completely exposed .. and the shear is ripping the convection off the system
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Afternoon Pottery, KOTFG, Miami, Geoffrey and everyone else!

90L is actually doing better than I thought it would by now, I place odds of development at 35%.. up from yesterday. Again I ask, WUmail me if your at all interested in what I have to say about this system (I'll probably say that for the rest of the year) and also, come June 1st i'll be starting a daily Tropical Weather discussion blog.
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Looks pretty good in this.
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HORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
WILL BE WATCHING THE PROGRESSING OF AN AREA OF LOW PRES THAT IS
PRESENTLY DEVELOPING NE OF THE BAHAMAS THROUGH THE SHORT TERM.
MODELS CONTINUE TO LIFT THE VERTICALLY STACKED LOW PRES AREA
TOWARD THE AREA BUT KEEP THE LOW WELL OFFSHORE. MODELS COMING INTO
BETTER AGREEMENT WITH THE LOW STALLING ABOUT 250-300 MI SE OF CAPE
LOOKOUT TUE NIGHT AND WED. MAIN IMPACT FROM THIS SYSTEM WILL BE
ACROSS THE MARINE AREAS AS WELL AS BUILDING SURF AND INCREASING
THREAT OF RIP CURRENTS ALONG THE COAST. AT THIS TIME ANY THREAT OF
OCEAN OVERWASH LOOKS MINIMAL BUT WILL CONTINUE TO MONITOR THE
PROGRESS OF THE SYSTEM. THERE REMAINS SOME UNCERTAINTY REGARDING
THE AMOUNT OF MOISTURE THAT PUSHES ACROSS ERN NC AND WITH THE
MODELS TRENDING FARTHER OFFSHORE AND WE MAY NOT SEE AS MUCH RAIN
AS PREVIOUSLY THOUGHT. WILL KEEP CHANCE TO SLIGHT CHANCE POPS
THROUGH MOST OF THE PERIOD...HIGHEST NEAR THE COAST. BY SUN NIGHT
THE LOW PRES SYSTEM BEGINS TO DRIFT SEWD AS UPPER N/NWLY FLOW
INCREASES IN RESPONSE TO AN UPPER LOW RETROGRADING INTO THE
CANADIAN MARITIMES. TEMPS NEAR TO SLIGHTLY ABOVE NORMAL EXPECTE
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Quoting Patrap:
OIL,OIL,OIL....

Ummmmmm......


Live video link from the ROV monitoring the damaged riser


Is the current feed still looking at the riser and is it obscured by oil or looking somewhere else? Patrap, did you see what happened?
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Quoting largeeyes:
Wondering when we'll see first effects of 90L here in NC. Tomorrow night?

Not at this rate, I doubt it...
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Quoting MrstormX:


Nice Rap!


No Oz...but I try :)
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1727. pottery
Quoting wadedanielsmith:
1713:

As all discovery channel nerds knew ahead of time, the dome had zero chance whatsoever of success at that depth when dealing with a blown well spewing methane and oil.

The dome became bouyant due to a combination of factors, as myself and countless others predicted, because methane hydrate crystals condensed inside the dome, blocking off it's funnel tube, and making it buoyant because methane hydrate is less dense than water (as is oil).

Because methane hydrate is not really "ice", but is a mineral formed from water and methane, it doesn't simply "melt" at those pressures even if you add heat or chemicals. It is a crystal structure, just like quartz or diamond, which forms under pressure. Then, once formed, it can stay that way even at surface pressures, at least temporarily.



The smaller "top hat" approach was a step in the WRONG direction, because it has all the same problems, and its "fixes" don't actually work, and because it is less massive than the "dome" it would buoy up anyway, though this effect would be offset some by the smaller volume.



This "junk shot" involving mud and debris is not going to work either, because the materials they have suggested is not heavy enough.

They need to use iron or lead shot of two sizes (the smaller size balls machined to fit in the empty space between ideal stackiing of the larger size,) and dump this down the pipe. Anything else will not be dense enough to work, and will just get pushed back out of the way.

Actually, I'd prefer molten lead or iron, but I have no idea how they'd get it down there...

How about one of the Super Fast-Setting Epoxy's, injected in 2 parts through a nozzle that blends them just before they enter the casing?
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1726. KEEPEROFTHEGATE (Mod)
Quoting GeoffreyWPB:
Don’t know why…
All the animals have to die…
Oily water…
Keeps gushing all the time…
because the innocent must suffer for the wicked
Member Since: July 15, 2006 Posts: 163 Comments: 52164
Wondering when we'll see first effects of 90L here in NC. Tomorrow night?
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Quoting GeoffreyWPB:
Don't know why...
All the animals have to die...
Oily waters...
Keeps gushing all the time...


Nice Rap!
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NHC taking a while on the 8:05 PM discussion, they usually have it out 30 minutes prior.
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Quoting wadedanielsmith:
1701:

I dont' know where the funds would come from, but instead of dredging, which doesn't help vs hurricanes anyway, why don't they buy like train loads of gravel and other aggragate and use that to make these levees? At least its denser and obviously heavier grain so it sticks vs hurricanes, and it still serves the purpose of blocking the oil...

Just seems to me if you are gonna do something, may as well do it right.


The wetlands need the tidal water that flushes in and out of them naturally. I think the idea behind sand levees is that they could be easily removed to restore the natural flow once the oil is gone.
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Don't know why...
All the animals have to die...
Oily waters...
Keeps gushing all the time...
Member Since: Posts: Comments:
1719. pottery
Quoting wadedanielsmith:
1711:

I understand that, but if they dredge it's just gonna make the intrusion of salt water that much worse in future years.

Unless someone plans on literally making a solid wall of levees around lousiana some time soon. Which has been proposed but never taken seriously.

It's kinda catch 22 right now, as I see it.


I got a better idea. I saw some (water)inflatable temporary levee/sandbagging products which were demonstrated on the weather channel a year ago or so. I guess these were maybe 4 ft in diameter or so. The deal is you fill them with water and they act as a storm barrier or flood barrier for a localized area.

These would be much faster and less damaging than dredging. Basicly just put them in the water and fill them with water, and stack them two or 3 high till you have a barrier that is above water and would keep out the oil....Works like sandbagging, but without the sand or backbreaking work. Just set up the tube and pump it full of water...you could make a pyramidal wall of them, like 3 wide at the base, then 2 then 1 on top, etc.


OK. BUT...filled with water, they would be the same weight as water, and float away. Fill them with some heavy fluid, like oilwell mud (which is basically Barytes), and then you could sell this mud back to BP!
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Looking at this Loop. One can see the COC/LLC clearing out to the south then the main body of convection clearing out to the north then dying off. A smaller firing of convection can be see almost due west of the COC/LLC.
In my honest opinion, 90L wont be around for much longer, but I maybe wrong.....I'm just sayin...
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I don't think I have seen this notice posted here... so:

May 21, 2010: Systems maintenance will be performed on the GOES East and GOES West satellite antenna coaxial cables Monday May 24, 2010. Please expect outages of these data streams that day.

http://wwwghcc.msfc.nasa.gov/GOES/goeseasthurr.html
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BY THE END OF THE NEW WORK WEEK MODELS CONTINUE TO SUGGEST THE
POTENTIAL FOR A SIGNIFICANT HEAVY RAINFALL EVENT AS BROAD AREA OF
LOW PRES FORMS ACROSS THE SW CARIBBEAN. BULK OF THE MOISTURE LOOKS
TO AFFECT THE DOMINICAN REPUBLIC BUT CAN`T RULED OUT SOME MCS
ACTIVITY AFFECTING PARTS OF THE ISLAND. A SFC TROUGH WILL DEVELOP
LATER IN THE WEEK MOST LIKELY INDUCED BY THE LARGE UPPER TROF FCST
TO EVOLVE ACROSS THE ATLC. GIVEN THE AMPLITUDE OF THE UPPER TROF
AND EXTREMELY HIGH PWAT VALUES FCST THIS SITUATION WILL NEED TO BE
MONITORED VERY CLOSELY ESPECIALLY GIVEN THE CONSISTENCY OF THE
MODELS WITH THIS POTENTIAL EVENT.
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Quoting Patrap:
OIL,OIL,OIL....

Ummmmmm......


Live video link from the ROV monitoring the damaged riser


What happened to the dome that they lowered and were supposed to put over one of the leaks? Is it still sitting on the bottom, doing nothing??????
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1711. Patrap
A sand barrier is not a levee...speed is of the essence..to keep the Oil out the marsh.



Just seems to me if you are gonna do something, may as well do it right.


BP made the Hole in Hell's sewer,,not the Fisheries of the Marsh.

I'll pass yer quote on to BP my next E-mail out

Member Since: July 3, 2005 Posts: 414 Comments: 125476
later all
Member Since: July 24, 2005 Posts: 407 Comments: 19076
1708. pottery
Quoting Patrap:


Plaquemines officials consider paying for own oil containment effort

Posted on May 22, 2010 at 5:47 PM

Updated today at 11:49 AM

Oil is pushing into more and more stretches of coastal marsh in Plaquemines Parish, with stalks of cane now appearing to wilt from an onslaught of oil.

A Comedy of Errors.
Except, it just isnt funny at all at all.
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Quoting HaboobsRsweet:

that is what I have been saying for a week. yes they did well picking up on a feature but had no handle on that feature. They have jumped all over the place. That happens in transition season. they will get better in a few weeks.


and yet the models have been successful thus far.
Member Since: July 24, 2005 Posts: 407 Comments: 19076










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1704. IKE
Quoting KEEPEROFTHEGATE:
rufus your a dufus


LOL.
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18Z NOGAPS looks aggressive!
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Quoting leo305:
so the models are completely off..


that is what I have been saying for a week. yes they did well picking up on a feature but had no handle on that feature. They have jumped all over the place. That happens in transition season. they will get better in a few weeks.
Member Since: May 20, 2009 Posts: 0 Comments: 1640
1701. Patrap


Plaquemines officials consider paying for own oil containment effort

Posted on May 22, 2010 at 5:47 PM

Updated today at 11:49 AM

Oil is pushing into more and more stretches of coastal marsh in Plaquemines Parish, with stalks of cane now appearing to wilt from an onslaught of oil.
Member Since: July 3, 2005 Posts: 414 Comments: 125476

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.