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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Looks like we may see the true intensity on this pass.

Do they have any GRIP planes in there? I know there was one last time Earl rapidly intensified.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting CaneWarning:


They were just showing guys surfing in the dark in Jersey...

Chum in a few days.
Unfortunately, somebody's mamma and papa will be very upset. They do it every time there's big surf. Glad my son has more sense than that!
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1254. Patrap
Quoting kmanislander:


At least I didn't say 19 N 81 W !!


Or 30n 90w
Member Since: July 3, 2005 Posts: 420 Comments: 127543
1253. leo305
the fact the conditions aren't even that favorable for a strong CAT 4...

imagine if this was in the carribean.. with warmer waters.. completely moist environment.. and perfect upper level conditions.. if this thing could get near CAT 5 strength in this environement.... imagine the carribean?
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting bwat:
Ok, intensity forcast for 11pm? Im going with 140mph. Your thoughts?


I'm going with 150 mph and an update before 11pm.
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Quoting kmanislander:


Hi there LOL

Gaston may well be the first true test for the Caribbean this year. Zonal flow from E to W, negative NAO and the MJO always swinging back to the Atl basin. Factor in very high SST and off the charts TCHP and you have a recipe for real problems. If Gaston makes it to 70 W and 17N expect a CAT 5


Agree - could be really bad. (No wishcastin')
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1250. Greyelf
Quoting marmark:

Heh...sorry. I just thought it might be appropriate for this blog. :)
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Quoting aasmith26:


=Annular.

Isabel 2003.


Yes.

But annular is more of a description of a storm's inner core than outflow structure. Earl, while he isn't annular yet, is starting to take on that appearance with a very elevated eyewall and large eye.

Take Daniel 2006 which still had feeder bands at peak intensity.

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Quoting stormwatcherCI:
Bite your tongue.


At least I didn't say 19 N 81 W !!
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Quoting jasblt:
He's gonna hit 75 before he hits 30...just my opinion


Agree - Didn't think so after the Northern wobble - But seems to be back on track.
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the 120mi. bouy off florida is reading 15ft. at 16sec.
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Quoting bwat:
Ok, intensity forcast for 11pm? Im going with 140mph. Your thoughts?


Its up to 140mph on the FTP site already.

May be stronger.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting kmanislander:


Earl is not the strongest system we will see this year.


Sadly enough you are probably right...
Member Since: April 26, 2009 Posts: 3 Comments: 3667
the guy on the radio show (NOT STORMW, he is great!) but the radio host is bad with talking, he cannot come up with the words he wants to say, he is paying too much attention to the graphics. :-X
Member Since: June 30, 2006 Posts: 5 Comments: 229
1241. Patrap
The next indication to Look for if EARL continues to strengthen,,is radial symmetrical Spokes developing within the Eye itself.

A very rare occurrence we,may,..may see.
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting bwat:
Ok, intensity forcast for 11pm? Im going with 140mph. Your thoughts?


I am going with 150 (I think the northern eyewall has much stronger winds in it)
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1239. Max1023
Quoting MiamiHurricanes09:
Correct. Earl is not undergoing an EWRC.


According to a microwave image from this afternoon there was an outer eyewall forming, however the EWRC could have happened already or the intensification of the main wall could have destroyed the outer band, which can happen. However, in the south quadrant there is an outer wind maxima, however it is weak as of yet. I would estimate at least 6-12 hours before an EWRC can be fully underway.
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Earl's NHC Probabilities

Link

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1237. jasblt
He's gonna hit 75 before he hits 30...just my opinion
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Quoting Chicklit:
I have a very bad feeling about Gaston, sad to say.
Also think people may die with Earl if they don't stay out of the goshdarned water.
Happens every year with those crazies wanting to get into high surf.


They were just showing guys surfing in the dark in Jersey...
Member Since: April 26, 2009 Posts: 3 Comments: 3667
OK - Soooo it wasn't a wobble...next three frames - Clearly back to just west of NW
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Miss Piggy creeping close to the eye from due south, encountering 120kt flight-level winds. Also, CIMSS is climbing on board the strengthening bandwagon - it has switched off both flags, and shows raw and adjusted T# of 6.3 on its most recent run. It has something of a lag - but if those numbers climb near 7, we'll see an upgrade from the NHC.
Member Since: August 18, 2009 Posts: 0 Comments: 460
1232. MZT
Look at that long tail... he just won't leave the Virgin Islands alone, will he? ;-)
Member Since: September 24, 2005 Posts: 0 Comments: 793
1231. leo305
Quoting Stormchaser2007:
WOW



that boy is a monsterrrr Ma ma ma Monster!! That boy is a monnsstterrrrr

Member Since: April 17, 2010 Posts: 0 Comments: 1753
Gaston is quite south. If it enters the caribbean (and doesn't get north of the islands), I doubt it will pose a threat to South Florida.
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Quoting kmanislander:


Hi there LOL

Gaston may well be the first true test for the Caribbean this year. Zonal flow from E to W, negative NAO and the MJO always swinging back to the Atl basin. Factor in very high SST and off the charts TCHP and you have a recipe for real problems. If Gaston makes it to 70 W and 17N expect a CAT 5
Bite your tongue.
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They haven't reached the circulation but are approaching it. Pressure down to 941.9mb and flight level winds up to 115kt. Again, I repeat, they are not at the center yet.

011100 2708N 07335W 7457 02076 9419 +207 +174 264109 115 082 006 03
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Quoting CaneWarning:


Agreed. As scary as Earl is right now, I expect we'll be just as terrified if not moreso in about a week. Call me Mr. Sunshine.


Earl is not the strongest system we will see this year.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Pressure dropped 6 mbs from the previous reading

011100 2708N 07335W 7457 02076 9419 +207 +174 264109 115 082 006 03
Member Since: June 9, 2007 Posts: 4 Comments: 15776
If Earls eye is 30 to 35 miles and hurricane winds extend 90 miles from the center it only has to get 100 miles from the cost to produce hurricsne force winds.So it better start that turn soon.
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1224. bwat
Ok, intensity forcast for 11pm? Im going with 140mph. Your thoughts?
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I have a very bad feeling about Gaston, sad to say.
Also think people may die with Earl if they don't stay out of the goshdarned water.
Happens every year with those crazies wanting to get into high surf.
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Colorized sat24 picture for West African Coast:

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Quoting LongIslandXpress38:


Earl is turing west towards Charlestown!


Um, no.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
1219. Patrap
Quoting TerraNova:

We have a winner! LOL, best post of the night Pat!



Sgt J.D. Peppa from Live and Let die.
La. State Troopa.

LOL
Member Since: July 3, 2005 Posts: 420 Comments: 127543
He is beautiful.
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Anyone ever notice the difference in the eye when they reach cat5. It usually doesn't last long, but it a perfect circle for a while.
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1213. Max1023
I'm still waiting for a solid ring of that last gray color on the right. Anything that gets that strong would be a synoptic level hurricane with record low central pressure.
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WV reveals no EWRC

Justa intense system.
Member Since: June 9, 2007 Posts: 4 Comments: 15776
Quoting SykKid:
earl starting EWRC now thank goodness


I doubt that. Too soon after the last cycle.
Member Since: August 19, 2006 Posts: 0 Comments: 15725
Complete Model update with all new tracks.



AOI

AOI

AOI

AOI

AOI

AOI


TS BUSTED FORECAST ALIBI
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Quoting CaneWarning:


Where are you seeing that? I see no evidence looking at it.
Correct. Earl is not undergoing an EWRC.
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Been a couple of seasons since we seen something like Earl.
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=Annular.

Isabel 2003.
Member Since: June 30, 2006 Posts: 5 Comments: 229

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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.