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 Ryuujin:
They're going by what the NHC is giving them, which is NNW. Which was correct (in a wobble) about 2 hours ago. Look at the link I posted up a bit and tell me if that's N or NNW. It's not. It's fairly clearly NW, and maybe a SHADE N of NW, by no means is it N.
Due north is 360
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were hrs ahead of the media, they're just talking about the NNW turn we knew about friggin hrs ago, it was temporary.
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2153. Ryuujin
Quoting rwdobson:
Gee, who should I believe, trained mets or a bunch of bloggers...The storm has turned north. It's on path to be to the east of its next forecast point.
Why don't you use your own mind and think for yourself and look at the Sat Data and the other links instead of towing the company line. It's people like you that stay because they don't think for themselves and then are the first to cry out for help.
Member Since: August 20, 2010 Posts: 0 Comments: 373
2152. Levi32
Quoting CloudGatherer:
I don't mean to be rude, Levi - you know vastly more about this than I do - but you've been harping on the dry air and its probable inhibiting effects for several days, and despite those predictions, Earl has rapidly restrengthened this evening. So if it didn't stop Earl then, why should it stop it now?


It won't be a Cat 5, it's got the dry air and wind shear now. Danielle strengthened despite the dry air but it still limited her. You can tell by looking at Earl's core. It's not perfect, and therefore not a candidate for a Cat 5 tonight, and probably not ever. I did say Earl peaked north of Puerto Rico and you could say he's peaking a 2nd time here at nearly the same intensity, but I don't think he'll really get stronger than this.

The dry air isn't going away and will induce weakening, just not as soon as I thought.
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2151. leddyed
Quoting FLdewey:
It's not THAT the wind bloweth... it's WHAT the wind bloweth.

Or maybe WHO the wind bloweth ...
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ROFL --- I'm just happy he's not hanging out on my beaches! : )
Quoting DestinJeff:
Jim's taking his goggles and gettin the fugg out.
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2149. xcool
btwntx08 no
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Quoting atmoaggie:
Ehh, according to some researchers, good ones at that, the Katrina was a cat 5 and, thus, caused more surge is a bit of a myth.

On a physics level, Katrina's size and windfield caused the surge at the coast, as a strong cat 3.

If Ike taught us anything, it should have been what a large system can do in surge, without having recently been much stronger. (Ike never eclipsed cat 3 in the Gulf)


Who are these good researchers?

You do realize that Cat 5's have lower barometric pressure and therefore can "lift" (re:suction effect) ocean water more easily that Cat 3's. So Katrina had already lifted more water than the typical Cat 3 max storm.
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2147. angiest
Ch 13 Houston reporter was on the GRIP mission.
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Quoting rareaire:
Why do the weather folks in North and south Carolina keep saying a north turn has begun when it clearly has not... Its still jogging NW.


I would trust the nhc..if they say it will turn north then i would put my trust in that..not what weatherman wannabees here say
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Quoting Stormchaser2007:
Gaston

"THE NEW OFFICIAL
FORECAST SHOWS A SLOWER MOTION OVER THE NEXT 36 HOURS...BUT IS
STILL ON THE SAME GENERAL TRACK AS THE PREVIOUS ADVISORY. BY DAYS
4 AND 5...THE RIDGE IS EXPECTED TO STRENGTHEN...AND THE CYCLONE
SHOULD BEGIN TO MOVE FASTER TO THE WEST."


Thank You
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Quoting leo305:


its not just you, the NNW movement was temporary, but the NHC decided to keep it on the advisory.. the eye is moving NW though in satellite


ridiculous they are being this conservative for a strong Cat 4 storm
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Quoting TexasGulf:


Tell them that the hurricane should pass to the East of Cape Cod, even if it might be near the coast.

Their high winds will start coming from the East, then the strongest winds from the North. They don't need to worry so much about windows & doors on the South and West sides of the house. Just secure the North and East... then evacuate if they are going to.

Tell them to look in their yard on the North & East sides. Anything that might blow, like trash cans, lawn furniture, empty flower pots, etc... needs to be moved into their garage.

Speaking of garages, the garage doors are one of the weakest points of a structure. They are only held by the light metal tracks on both sides of the doors, so can easily be blown inward. That is most often the cause of garages losing their roofs. If their garage doors are on the North or East sides of the house and they are parking the cars inside... then put some cardboard, old tires, carpet rolls or anything soft against the garage door (inside), then slowly back the car up to press that thing in place against the garage door. Set the emergency brake. That way, your car helps hold the garage door from bowing or blowing inward.

Tell them not to worry so much about any windows above man height. Boarding up windows mainly protects them from blowing debris. If the wind is strong enough to blow a LOT of debris into the 2nd floor windows, your roof will have problems anyway. Focus on the ground floor windows only. What you don't want is your neighbor's 5-gallon plastic bucket collection to wind up in your living room.

Also, tell them that if they intend to stay, identify the safest rooms in the house to be. Particularly, they want to be in a 1st floor room on the South or West side of the home with good walls and no windows (unless they are boarded).

If they are in a flood prone area, they just need to leave now.
Linkhttp://www.nae.usace.army.mil/projects/ma/hurricanemaps/wellfleet.pdf
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2142. ncstorm
Quoting rareaire:
Why do the weather folks in North and south Carolina keep saying a north turn has begun when it clearly has not... Its still jogging NW.


well speaking for me because the local media is telling people this..
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Has the pelican rescue team been placed on high alert in NC?
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2140. Ryuujin
Quoting ncstorm:


Wow..WECT TV6 in wilmington just said that it has begun its turn..so they are putting out misrepresentation on a cat 4 storm..
They're going by what the NHC is giving them, which is NNW. Which was correct (in a wobble) about 2 hours ago. Look at the link I posted up a bit and tell me if that's N or NNW. It's not. It's fairly clearly NW, and maybe a SHADE N of NW, by no means is it N.
Member Since: August 20, 2010 Posts: 0 Comments: 373
Gee, who should I believe, trained mets or a bunch of bloggers...The storm has turned north. It's on path to be to the east of its next forecast point.
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Well, two takeaways from the advisories:

1. Earl has probably peaked and will not make CAT 5 status.

2. Gaston forecasted to be at 16N and 54.5 W. Entry into the Caribbean on the cards and 65 W achievable South of 18N. The slow down in forward motion will allow the ridge to build back and force him West.

That's all for tonight. Back tomorrow.
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2137. angiest
Houston Ch 13 reporter spent the day on one of the flights Story is on now!
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2136. leo305
Quoting ncstorm:


Wow..WECT TV6 in wilmington just said that it has begun its turn..so they are putting out misrepresentation on a cat 4 storm..


look for yourself, and ask yourself if it is "TURNING"
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Quoting Hhunter:


MODEL CASTERS


oohhh noooooooo lol
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Atmo - great link, thanks for posting!

Good luck to everyone on the East Coast!
Quoting atmoaggie:


oops, link: http://ams.confex.com/ams/29Hurricanes/techprogram/paper_168955.htm

Aww, dang, modify, not quote.
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2133. Hhunter
Quoting rareaire:
Why do the weather folks in North and south Carolina keep saying a north turn has begun when it clearly has not... Its still jogging NW.


MODEL CASTERS
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2132. leo305
Quoting rareaire:
Why do the weather folks in North and south Carolina keep saying a north turn has begun when it clearly has not... Its still jogging NW.


because the advisory says NNW
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GASTON needs too be watch
Member Since: May 21, 2006 Posts: 5091 Comments: 114917
Latest F-18 satellite pass:

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2128. ncstorm
Quoting Ryuujin:
It hasn't.


Wow..WECT TV6 in wilmington just said that it has begun its turn..so they are putting out misrepresentation on a cat 4 storm..
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Thanks Miami - just saw your response. :)
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Quoting weatherdogg:
"I have friends in Wellfleet, Cape Cod, a mile from the ocean and a mile from the bay. They haven't worked out yet how to install their storm shutters. They are both in their 60s. What advice would you be giving them tomorrow morning, given there is just one road on the Cape to the mainland?"

Take a road trip - you don't want to be on the Cape, even in a Cat. 1.


Tell them that the hurricane should pass to the East of Cape Cod, even if it might be near the coast.

Their high winds will start coming from the East, then the strongest winds from the North. They don't need to worry so much about windows & doors on the South and West sides of the house. Just secure the North and East... then evacuate if they are going to.

Tell them to look in their yard on the North & East sides. Anything that might blow, like trash cans, lawn furniture, empty flower pots, etc... needs to be moved into their garage.

Speaking of garages, the garage doors are one of the weakest points of a structure. They are only held by the light metal tracks on both sides of the doors, so can easily be blown inward. That is most often the cause of garages losing their roofs. If their garage doors are on the North or East sides of the house and they are parking the cars inside... then put some cardboard, old tires, carpet rolls or anything soft against the garage door (inside), then slowly back the car up to press that thing in place against the garage door. Set the emergency brake. That way, your car helps hold the garage door from bowing or blowing inward.

Tell them not to worry so much about any windows above man height. Boarding up windows mainly protects them from blowing debris. If the wind is strong enough to blow a LOT of debris into the 2nd floor windows, your roof will have problems anyway. Focus on the ground floor windows only. What you don't want is your neighbor's 5-gallon plastic bucket collection to wind up in your living room.

Also, tell them that if they intend to stay, identify the safest rooms in the house to be. Particularly, they want to be in a 1st floor room on the South or West side of the home with good walls and no windows (unless they are boarded).

If they are in a flood prone area, they just need to leave now.
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Looking at the recent Sat loops, I think Earl is going to miss the OBX, but just barely. The western eyewall will probably come within 20 miles of at least one barrier island. Let's hope we don't get some last-minute wobble but that is less likely in the stronger steering environment E will be in by then.

Let's hope. If I were on one of those sand bars/islands, I'd have evacuated.
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Quoting TampaSpin:
For those wanting i have Oz on my Website when he is live......go to my blog and follow the link as i have a community chatroom and Instant messanger set up as well.
Has he already put on his kevlar suit? I really don't need to watch that again...lol
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Anybody know of any good (and live) North Carolina coastal radio stations with good information on Earl, and that stream on the web?
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Why do the weather folks in North and south Carolina keep saying a north turn has begun when it clearly has not... Its still jogging NW.
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Cantore is on Hatteras island.
Member Since: June 9, 2007 Posts: 4 Comments: 15872
2117. leo305
Quoting MrstormX:
Is it me or has Earl re-picked up a Northwest Jog.

Link


its not just you, the NNW movement was temporary, but the NHC decided to keep it on the advisory.. the eye is moving NW though in satellite
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Quoting DestinJeff:
Jim's on.

No goggles.


He sent them to me.
Member Since: August 27, 2006 Posts: 0 Comments: 249
Quoting MrstormX:
Is it me or has Earl re-picked up a Northwest Jog.

Link


I Don't like the look of that at all...wayyy to close to land.
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PHEW

ALTHOUGH THE MULTI-MODEL CONSENSUS FORECAST HAS NUDGED EASTWARD ABOUT 20 N MI ON THIS CYCLE.

PHEW
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Is it me or has Earl re-picked up a Northwest Jog.

Link
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11:00 PM EDT Wed Sep 1
Location: 27.8°N 73.8°W

Now 3.1 W of me. 840 km.....
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Quoting Neapolitan:
The Atlantic A.C.E. (Accumulated Cyclone Energy) for 2010 has reached 52.44. Couple of things notable about that:

1) This year's A.C.E. is more than 500% of what it was just a little over a week ago (it stood at 9.42 fewer than eleven days back);

2) This year's A.C.E. has already exceeded the totals for both that of 1997--the lightest year of the current "active" hurricane period--and last year, 2009.

3) This year's A.C.E. is already higher than the totals for that of 15 of the past 60 seasons;

All this, and we're only one day into September. So...any of you downcasters still want to call the season a bust? ;-)


Im gonna save this post.

Good job.
Member Since: June 9, 2007 Posts: 4 Comments: 15872
Quoting Ryuujin:
It hasn't.


It sure hasn't.
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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.