Earl a Category 4 storm again

By: Dr. Jeff Masters , 9:23 PM GMT on September 01, 2010

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Hurricane Earl has regained Category 4 strength this afternoon, and continues on a steady northwest path towards the North Carolina coast. Recent satellite imagery shows that Earl has become more symmetrical, with improved upper-level outflow and no signs of dry air wrapping into the core. The improved appearance is probably due to lower wind shear. Latest wind shear tendency imagery from the University of Wisconsin CIMSS group shows that shear on the southwest side of Earl has fallen by about 10 knots over the past 24 hours.


Figure 1. Afternoon satellite image of Earl.

Forecast for Earl
The latest set of model runs from 8am EDT (12Z) this morning shows little change to Earl's track. Thus, my write-up of the possible impacts to North Carolina, New England, and Canada in this morning's post remain unchanged. The latest SHIPS model forecast shows wind shear will remain moderate, about 15 knots, through Friday afternoon. This should allow Earl to maintain major hurricane status as it passes North Carolina early Friday morning. By Friday night, as Earl gets caught in the jet stream and accelerates to the northeast, wind shear will rise to 20 - 30 knots and ocean temperatures will plunge to 20°C, resulting in considerable weakening. Earl will still probably be a Category 1 or 2 hurricane early Saturday morning, when it will make its closest approach to New England. Earl is more likely to be a strong tropical storm or weak Category 1 hurricane early Saturday afternoon, when it is expected to make landfall in Nova Scotia, Canada.

Earl is a large hurricane, which gives it a higher potential for storm surge damage than a smaller hurricane with the same top winds. One measure of a storm's power, useful for gauging storm surge threat, is to measure the speed of the winds and multiply by the area over which those winds blow. This total is called the Integrated Kinetic Energy (IKE). Based on the storm's IKE, one can come up with a scale from 0 - 6 rating the storm's destructive power from its storm surge. A separate rating can be given to the destructive potential of the storm's winds. The IKE value of 112 Terrajoules for Earl, at 3:30pm EDT today, gives its storm surge a destructive power of 5.0 on a scale of 0 - 6. Earl's winds have a lower destructive power, 3.4 on a scale of 0 - 6. Let's hope the right front quadrant of Earl, where the main storm surge would occur, stays offshore! For comparison, the small Category 5 Hurricane Camille of 1969 had an IKE of 80 Terrajoules, and the very large Category 2 Hurricane Ike of 2008 had an IKE of 116 Terrajoules--similar to Category 3 Earl's.

Fiona
Tropical Storm Fiona is struggling due to high wind shear, courtesy of strong upper-level northerly winds from Hurricane Earl's outflow. The latest Hurricane Hunter center fix at 1:29pm EDT found Fiona had weakened some, with a central pressure of 999 mb. This is a rise of 1 mb from this morning. The wind shear analysis from the University of Wisconsin CIMSS group shows that shear has increased to a moderately high 15 - 20 knots this afternoon. Satellite loops show the classic signature of a tropical storm experiencing high wind shear--an exposed center of circulation, and all the heavy thunderstorms pushed to one side (the south side in this case). Martinique radar shows that the outer bands from Fiona are bringing heavy rain squalls to the same islands of the northern Lesser Antilles that were affected by Earl. Our wundermap for the northern Lesser Antilles shows no stations recorded winds over 20 mph this afternoon, though there was no reporting station on Barbuda, the island closest to Fiona.

Forecast for Fiona
Moderate wind shear and dry air should keep Fiona from attaining hurricane status over the next two days, as big brother Earl continues to bring high wind shear. The shear may be strong enough to destroy Fiona, as predicted by the NHC. However, by this weekend, Earl may pull far enough away for shear to drop and Fiona to survive. The 4 - 5 day track forecast is highly uncertain, as there is a large spread in the model solutions. It is possible Fiona may pose a threat to Bermuda on Saturday or Sunday, and the storm could wander for a week or more in the waters between Bermuda and the U.S. East Coast.


Figure 2. Afternoon satellite image of Fiona.

Tropical Storm Gaston forms
Tropical Storm Gaston developed enough heavy thunderstorms near its center this afternoon to get a name, and appears destined to become Hurricane Gaston by early next week. Water vapor satellite images show a large area of dry air to the north and west of Gaston, and this dry air will be the dominant inhibiting factor for development. The latest SHIPS model forecast predicts shear will remain moderate, 10 - 15 knots, for the next four days, and perhaps fall to the low range 4 - 5 days from now. Gaston is over warm 28°C waters, and should be able to steadily intensify into a hurricane by Saturday or Sunday, as predicted by the many of the intensity models. Gaston may threaten the northern Lesser Antilles Islands as early as Tuesday.

Next post
I'll have an update in the morning, and Dr. Rob Carver will have a late night update tonight.

Jeff Masters

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Quoting F4PHANTOM:
depends if the series of troughs develops as shown. it's just model guidance. remember gfs was re-curving earl and fiona and dropping fiona before the other models and some on this blog. location and timing are everything.


GFS has done pretty well so far.
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Quoting VAbeachhurricanes:


yeah they all do! but its already PORT of all of them...


I should never have shown you that PORT/STBD stuff :)
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From what XCOOL posting of models it looks like maybe the Gulf Cost is close for the season. It will have to be some good timing for something to get in the Gulf since we have had Cool Front after front steering the storms to the NE.
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2703. dmaddox
gonna be a longggg day tomorrow! goodnight everyone!
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2702. snowboy
Quoting Orcasystems:
The real question is... is it PORT or STBD of track... if its PORT... your hooped. I have
all of the previous Vortex plots.. and the last one is only a few hours old.





It was starboard after the jog north, but is now pulling to port and about to cross to the portside of track..
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2701. JLPR2
Quoting stormhank:
Does anyone feel Gaston could definately threaten florida or gulf coast??


Way far out to tell, ask again in 10 days. XD

Quoting traumaboyy:


What a STORM!!

Sure Do Hope He Turns quick or....WOW!!


Yeah, I got lots of relatives in NYC, got my fingers crossed.
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Quoting mkmand:

We'll see. The 30N, 75W intersection could be important. Because most of the models have it passing to the RIGHT of the "intersection"


yeah they all do! but its already PORT of all of them...
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Quoting stormhank:
Does anyone feel Gaston could definately threaten florida or gulf coast??


It's still way too early to tell.
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Quoting robj144:


Right, but he was saying that wind plays no role in the storm surge, so I pointed out it is used in SLOSH, so it must play a role. I know it also uses topology of the coast and direction of impact, but the wind was the key thing.


Never did I say wind played NO role. I just didn't know how significant a role. Here I was all this time, missing the obvious role of the wind. Better hit those books some more!
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Quoting stormhank:
Does anyone feel Gaston could definately threaten florida or gulf coast??



yes down the road
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2694. leo305
Quoting mkmand:

We'll see. The 30N, 75W intersection could be important. Because most of the models have it passing to the RIGHT of the "intersection"


still has a little bit to go before it reaches 75W, its almost half way through 74W..

still moving NW

If it passes 75W and continues the NW or NNW movement, chances of a hit are much higher.. been saying it all day.. and it looks likely.. since the center is already west of the model tracks.. and west of the model tracks = the U.S east coast..

Member Since: April 17, 2010 Posts: 0 Comments: 1753
2693. xcool
okay black out last for45min
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Quoting mkmand:
Which will Earl pass first?

30N or 75W?


It's going to be close. I'd like to see 30N, but it's going to be close, I think.
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2691. dmaddox
Quoting leo305:
the satellite is gone.. for a couple of hours..

check this link.. its GOES-15 .. it wont go out Link
Quoting mkmand:

We'll see. The 30N, 75W intersection could be important. Because most of the models have it passing to the RIGHT of the "intersection"
very true good point..
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About a 310-320 heading last 6 hrs.
Quoting thelmores:


REALLY?

What loop are you looking at?

Earl even in the latest frames available has a significant westward component..... and has made it all the way to 74W......

maybe you better look again! Link

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2688. mkmand
Quoting philliesrock:

75W.

We'll see. The 30N, 75W intersection could be important. Because most of the models have it passing to the RIGHT of the "intersection"
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2687. xcool
stormhank best things to do is closel monitered.
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Quoting Orcasystems:


Then... your hooped


i dont wanna be hooped though... :p fix it
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2685. leo305
Quoting dmaddox:
check this link.. its GOES-15 .. it wont go out Link


thank you
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Asked this earlier tonight, but it probably got missed.. how close does that midwest trough have to be to the coast before it starts to turn Earl North and Northeast?
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Quoting TexasHurricane:


oh, I didn't know you had a crystal ball....


LMFAO!!
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Quoting redUK:
Eye being sheared:




its a perfect circle...
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Quoting atmoaggie:
And Dr. M's take on surge from a small storm, Camille (not unlike Charley) and a large storm, Katrina.
http://www.wunderground.com/hurricane/surge_details.asp
(references Fitzpatrick, too)


"Katrina set in motion a volume of water about four times greater than Camille did." kinda lost track of what side of the discussion you were on (too many beers) but this seems to suggest that the duration of high wind and momentum of the water created by those winds is one of the prime factors in producing a large storm surge....right?
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Does anyone feel Gaston could definately threaten florida or gulf coast??
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2677. xcool
TexasHurricane lololol
Member Since: September 26, 2009 Posts: 2 Comments: 15626
2676. dmaddox
Quoting leo305:
the satellite is gone.. for a couple of hours..

check this link.. its GOES-15 .. it wont go out Link
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2675. xcool
superweatherman yea


F4PHANTOM you know better that 300hr out not
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Quoting F4PHANTOM:
not going to texas


oh, I didn't know you had a crystal ball....
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New run, shifted west because the steering shows me that Earl is still moving fast at 18 mph., nice ridge steering it NNW for a while with some NW wobbles. Trough should be enough to recurve it a tad, but not a sharp recurve.. This new run is very similar to the new GFS run, and Hurricane Bob in 1991. I am now predicting a possible direct hit on Cape Cod, MA. Glad Hurricane Watches have been posted there this evening. Hurricane Watches need to be extended south to Long Island, NY soon enough. Prepare for Earl NOW, don't wait till the last minute.

Photobucket
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Quoting xcool:


As always, remember 300hr out but every run will change between now and next time.



looks like we will have the H storm by then and the may be the I storm
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Quoting VAbeachhurricanes:


its looking PORT right now...


Then... your hooped
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Quoting superweatherman:
Is that Gaston?



Yes, were trying to forget that one now, lol.
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2669. leo305
the satellite is gone.. for a couple of hours..

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2668. JLPR2
Quoting xcool:


As always, remember 300hr out but every run will change between now and next time.


384hrs is even more interesting, three storms all in the CATL, would be interesting to see how those interact, if they ever form.
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Quoting Orcasystems:
The real question is... is it PORT or STBD of track... if its PORT... your hooped. I have
all of the previous Vortex plots.. and the last one is only a few hours old.





its looking PORT right now...
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Quoting xcool:


As always, remember 300hr out but every run will change between now and next time.
Is that Gaston?
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Quoting JLPR2:


It's more like night to me. XD
Hiya!


What a STORM!!

Sure Do Hope He Turns quick or....WOW!!
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Quoting mkmand:
Which will Earl pass first?

30N or 75W?

75W.
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Quoting mkmand:
Which will Earl pass first?

30N or 75W?


75W
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The real question is... is it PORT or STBD of track... if its PORT... your hooped. I have
all of the previous Vortex plots.. and the last one is only a few hours old.



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2659. dmaddox
Quoting mkmand:
Which will Earl pass first?

30N or 75W?
75 IMO..
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2658. redUK
Eye being sheared:


Member Since: August 18, 2008 Posts: 0 Comments: 53
Quoting SCwannabe:
This could be the "It could happen tomorrow" storm for NYC!!


Easy there 2012, Earl is going to be a whole lot of nothing for immediate NYC...
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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.