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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"Miss Piggy" headed back towards the eye of Earl. If it did continue to intensify, I wouldn't be surprised to see Earl peak at 135kt.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
Quoting MiamiHurricanes09:
LOL, where do you find that?


Its under the SHIPS text block



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1154. Patrap
Floater - Dvorak Infrared Loop
Member Since: July 3, 2005 Posts: 426 Comments: 128667
1153. hydrus
Quoting whipster:
Gaston gonna hit the Gulfzone?
Its 100,000 miles away. ask this weekend.:)
Member Since: September 27, 2007 Posts: 1 Comments: 21416
Hurricane Earl currently moving between NW and NNW.
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1151. angiest
Quoting TerraNova:
Expanding upon angiest's quasi annular idea, Earl's core resembles that of an annular hurricane but it still has feeder bands. However, notice dry air wrapping around the southeastern side right around the core without disrupting it.

Annular hurricanes are very compact storms that essentially crowd themselves inside their cores, shielding them from a lot of dry air and shear.


That was kinda my thought. Banding features are not as evident in the core, but they are on the periphery. Danielle was similar at one point, and hit 1 on the annular model or whatever that is.
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I think if the Big E makes it past 75 W. before hitting 30 N, then NC better really hunker down!! IMO
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000
ABNT20 KNHC 012347
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT WED SEP 1 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON HURRICANE
EARL...LOCATED ABOUT 565 MILES SOUTH-SOUTHEAST OF CAPE HATTERAS
NORTH CAROLINA. ADVISORIES ARE ALSO BEING ISSUED ON TROPICAL STORM
FIONA...LOCATED ABOUT 140 MILES NORTH OF ANGUILLA IN THE NORTHERN
LEEWARD ISLANDS...AND ON RECENTLY UPGRADED TROPICAL STORM
GASTON...LOCATED ABOUT 895 MILES WEST-SOUTHWEST OF THE CAPE VERDE
ISLANDS.

YET ANOTHER STRONG TROPICAL WAVE IS ABOUT TO MOVE OFF THE WEST COAST
OF AFRICA AND IS PRODUCING A BROAD AREA OF SHOWERS AND
THUNDERSTORMS OVER THE ADJACENT WATERS. SOME SLOW DEVELOPMENT OF
THIS SYSTEM IS POSSIBLE AS IT MOVES WESTWARD NEAR 10 MPH OVER THE
NEXT COUPLE OF DAYS. THERE IS A LOW CHANCE...10 PERCENT...OF THIS
SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.


ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

PUBLIC ADVISORIES ON TROPICAL STORM GASTON ARE ISSUED UNDER WMO
HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4.
FORECAST/ADVISORIES ON TROPICAL STORM GASTON ARE ISSUED UNDER WMO
HEADER WTNT24 KNHC AND UNDER AWIPS HEADER MIATCMAT4.

$$
FORECASTER BERG

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1148. will40
Quoting PcolaDan:


Good one thanks. Didn't have it.


u r welcome Dan
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Gaston gonna hit the Gulfzone?
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1146. bwat
Quoting david276:
Long term track still nnw looking at everything earl seems to be winning the race to the coast . As he has increased appearance and speed today. models tightening. in agreement, wonder if they will shift west by tomorrow morning anymore
I honestly don't think that they will. The only reason I say this is because of the more northern component Earl has taken. Im not saying they shouldnt be shifted west, but I think looking at model guidance, it will stay the same. Thats only my opinion, an an uneducated one at that.
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1145. Bonz
Quoting msmama51:


Found that out when TD5 was coming this way. Had not even thought of that. Boy, was I fooled!! Thought I was smart and had that covered. Now have to buy a new, improved (modern) one instead of a dinosaur.


Good luck with that. Most have their "built in" "rechargeable" batteries now, which SUCK as how can one charge a battery with no power?

They need to make them to take regular AAs or other normal batteries, not these "special" ones.
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1144. Patrap
When you see the Dvorak make a white Number 9.

Well..best not be around near landfall.

Member Since: July 3, 2005 Posts: 426 Comments: 128667
1143. leo305
lol...

even the gamign forums are talking about EARL..

btw.. 922?
Member Since: April 17, 2010 Posts: 0 Comments: 1753
1142. Max1023
Quoting MZT:
The models are aiming right for the bay of Fundy for final landfall. The cone-shape of that bay, would concentrate a storm surge.


Thankfully the landscape there can handle huge tides, a storm surge at any time other that high tide would have little effect in most places, at least compared to a place like NYC or NOLA. A 10 foot surge at low tide would be just another high tide there.
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1141. angiest
Quoting MiamiHurricanes09:
LOL, where do you find that?


That was run 2 hours ago?
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1140. KEEPEROFTHEGATE (Mod)
07L/MH/E/C4
MARK NEAR
27.30N/73.40W
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Expanding upon angiest's quasi annular idea, Earl's core resembles that of an annular hurricane but it still has feeder bands. However, notice dry air wrapping around the southeastern side right around the core without disrupting it.

Annular hurricanes are very compact storms that essentially crowd themselves inside their cores, shielding them from a lot of dry air and shear.
Member Since: July 30, 2007 Posts: 76 Comments: 4063
1138. hydrus
Quoting RecordSeason:
922mb surface pressure?!


Can anyone confirm that?
Last I saw was 927.5.
Member Since: September 27, 2007 Posts: 1 Comments: 21416
932 mb just reported on NHC website
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Well Gaston.... don't leave behind Hermine..
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Quoting Patrap:
PS: Earl is NOT annular, it has a full set of rainbands in all quadrants. Annular hurricanes are an eye + eyewall and almost nothing else.


Definitely not annular..that word is always tossed around when a Major develops..its a rare Atlantic event also


Best post I've seen since I came on..
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1134. angiest
Quoting dmaddox:
check out the last frame:



Purples wrapping around?
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1133. marmark
Quoting Max1023:


Winds at 925mb are usually 130% of surface winds, TC winds are a LOT stronger about 1000 feet up. Once those winds hit 200mph we will have a 5 on our hands. The way earl looks now though something tells me that this would be a 160mph Cat 5 if all we had was Dvorak Estimates. Thankfully Earl is not that strong yet.
Well, I think he is plenty strong as he is and people have much to fear. IMHO
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Quoting Stormchaser2007:
This kills the annular debate...


## ANNULAR HURRICANE INDEX (AHI) AL072010 EARL 09/02/10 00 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=6 NFAIL=1 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
## ANNULAR INDEX RAN NORMALLY

LOL, where do you find that?
Member Since: September 2, 2009 Posts: 130 Comments: 21194
00z LGEM took Gaston to Category 4

Here's the 00z SHIPS:

V (KT) NO LAND 35 38 42 46 49 56 63 72 79 84 86 92 94
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1130. Greyelf
Quoting LADobeLady:


This blog moves fast during peak times, try doing a little research on your own and you'll probably get the answers quicker. Google is your friend.

Yeah, yeah. I did that when I didn't get an answer. I still didn't find out all I wanted to know, but it don't matter.
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Quoting Stormchaser2007:


I really hope they didnt.
Their they go trying to hype something....
Member Since: August 14, 2010 Posts: 10 Comments: 17091
Quoting will40:


heres one i have on the Island i am on Dan it is a pier cam

Link


Good one thanks. Didn't have it.
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1127. hydrus
Quoting Stormchaser2007:
Winds were 167mph at the 925mb level.

I fear tomorrows headlines if those work their way down to the surface.
925 flight level? Whoever is flying that low in Earl is a brave soul.
Member Since: September 27, 2007 Posts: 1 Comments: 21416
145mph at the surface.
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Earl is absolutely beautiful. I would love to have a large photo of him.
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1124. marmark
Quoting stillwaiting:
I would say fl 100% not going to get hit by earl,what the heck are some people thinking????
Maybe they are nervous since they have been hit so many times and it is so close. Looking at the maps, a scared person might think it would suddenly hook to the left! LOL
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1123. Max1023
Quoting Stormchaser2007:
Winds were 167mph at the 925mb level.

I fear tomorrows headlines if those work their way down to the surface.


Winds at 925mb are usually 130% of surface winds, TC winds are a LOT stronger about 1000 feet up. Once those winds hit 200mph we will have a 5 on our hands. The way earl looks now though something tells me that this would be a 160mph Cat 5 if all we had was Dvorak Estimates. Thankfully Earl is not that strong yet.
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Quoting dmaddox:
check out the last frame:

He jog to the west and the center is unreal!!!!!!!!
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1119. MZT
The models are aiming right for the bay of Fundy for final landfall. The cone-shape of that bay, would concentrate a storm surge.
Member Since: September 24, 2005 Posts: 0 Comments: 793
I had a bit of a "fright" today, walking out to my car by the house, I heard the sound of an engine in my backyard, sounding like a vehicle was coming up my drive from below. I stopped and listened and realized that the low sound was the roar of the surf on the North Shore, which is over a mile away on the other side of a 70 ft. ridge. ...Surfs up in the Turks and Caicos!
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Quoting stormwatcherCI:
I tried a converter with a car battery after Ivan to run a fan and as soon as I would start to doze off the doggone thing would shut off with a squeal.
Got a generator now and I think I would sell one of my grandchildren quicker than I would sell that. LOL


LMAO! It's very tempting sometimes when the little buggers are trying you patience.
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1116. Patrap
Quoting Stormchaser2007:
This kills the annular debate...


## ANNULAR HURRICANE INDEX (AHI) AL072010 EARL 09/02/10 00 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=6 NFAIL=1 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
## ANNULAR INDEX RAN NORMALLY



U betcha
Member Since: July 3, 2005 Posts: 426 Comments: 128667
Looks like a wobble west to me. Not good. That trough better not be late.
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1114. pottery
Quoting Greyelf:
Funny.. I asked a question about qualifications of an annular hurricane not even an hour ago (see post 754), yet I only managed one response (thanks Atmo). I guess I'm just chopped liver since now "annular" has been discussed in a good number of posts just in the last couple of pages. Funny how some get blown off, yet others merit response.

Happens to everyone.
Timing is everything LOL..
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1113. luigi18
Hebert Box dont lie!!!!!!
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This kills the annular debate...


## ANNULAR HURRICANE INDEX (AHI) AL072010 EARL 09/02/10 00 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=6 NFAIL=1 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
## ANNULAR INDEX RAN NORMALLY

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Expecting an intermediate advisory to be issued for rapidly deepening Earl...
Member Since: August 27, 2008 Posts: 0 Comments: 11
1110. amd
Quoting iceman100:
CNN BREAKING NEWS

They just said Earl's winds were 177 mph!!

What?


those were the highest winds recorded above the surface in a dropsonde (at 905 mb, or a couple of thousand feet above the ground). Those winds are NOT at the surface.
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lamad
Member Since: July 10, 2005 Posts: 3 Comments: 1279
1108. dmaddox
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Here's another good one:

BULLETIN
TROPICAL STORM GASTON ADVISORY NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092010
500 PM AST WED SEP 01 2010
...THE SEVENTH NAMED STORM OF THE SEASON FORMS...THE FOURTH TROPICAL STORM IN THE LAST ELEVEN DAYS...

Zing!
-- as Atmo would say....
Charlie Brown would say, Good Grief!

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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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