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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1556. leo305
Quoting cartking24:
What is so important about it not hitting 75w? I live in Va. Beach, we are at 76w. Even if it hits 75 it can still be driven ne well before obx.


if it hits and passes 75W, the chances of a landfall becoming high
Member Since: April 17, 2010 Posts: 0 Comments: 1753
1555. bwat
Quoting MZT:
These last few days have really been a match of the Titans. That was an impressive high over the Carolinas, getting into the 1025 MB range, not a cloud in sight and dead calm much of the time.
I can say your absolutly right on that! Today is was scary calm when we come across the albemarle sound bridge. You never see that water as slick as it was. Then we came back across around 4pm and it was still slick. Most time we get a little sea breeze around 3, but not today. Very tranquil
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Quoting wjdow:


there's time for people to get off the cape assuming some are already starting, except if it's anything like rita in houston/galveston, there won't be enough gasoline or open gas stations, so many cars may stall and clog the roads. hopefully, fuel trucks are on their way to the cape now and people will be encouraged and able to get gas before they get on the road.


It would be a good idea for the local emergency management to start evacs early. Tell all the tourists to go first. Labor Day weekend - you know folks won't WANT to leave a minute earlier than they have to. They've paid for their vacations and they will want to get every last minute of it. Then again, on a normal weekend it takes HOURS to get off the cape. Holiday Weekend, well the smart ones leave in the middle of the night!

I think the timing of Labor Day Weekend will make this more difficult.
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140 mph

AL, 07, 2010090200, , BEST, 0, 271N, 734W, 120, 932, HU, 64,
Member Since: June 9, 2007 Posts: 4 Comments: 15947
Quoting staffofthegods:


That and it is a massive storm. It would probably need a lower pressure than you might expect for Cat 5.


Earl's core is capable of supporting category 5 intensity but the odds of him getting there are very low because of a lack of energy in the upcoming environment. CAPE is low, LI is negligible, and warm waters don't extend very far down.
Member Since: July 30, 2007 Posts: 76 Comments: 4063
1551. Patrap
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1550. ussual
Quoting leddyed:

As someone who lives 60 miles from the coast in GA, I concur.


Heck I live 20 minutes from the SC coast and until I see the turn happen I won't believe I am out of the woods. Not running for the hills (yet) but not taking my eye off it till it turns.
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Quoting leo305:
its getting very close to 75W

Ominously close.....
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Quoting Stormchaser2007:
Perfect
Beautiful.This has got to be one of the best looking storms that I've seen in a while.
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No disrespect to Dr Jeff Masters, and the WU, if they banned OZ, did not know that, hmm? But, does anyone have the link to where we can find Oz's site/webcam?
He has a passion and is following it, whether it is crazy or not. He has given us all a lot to follow in previous storms, TIA
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Quoting cloudymix:

The way Earl is evolving, all sides may be very bad soon.

I don't understand a Dvorak number of 9. Is that anything like saying Earl could become a C6? A C5 means general widespread destruction; so a C6 can't mean anything different. What exactly does a 9 mean?


I mean you can roughly subtract the forward speed from the wind speed on the west side of a storm that is heading north.
Member Since: July 25, 2008 Posts: 0 Comments: 597
Quoting Patrap:
I see the motion..and its NW thru the Loop..they all wobble left and right along their paths.

3 Hours of motion is why the have 3 Hour Updates as well.


Good point!
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Quoting kmanislander:


I doubt that. The Caribbean is saving that honour for another system.


Gaston might be the one if it gets into W.Caribbean.
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Quoting Ameister12:
Earl is absolutely amazing, probably one of the most beautiful hurricanes I've seen.



Is the eye opening on the south side there?
Member Since: April 26, 2009 Posts: 3 Comments: 3667
What is so important about it not hitting 75w? I live in Va. Beach, we are at 76w. Even if it hits 75 it can still be driven ne well before obx.
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they had 47 ft seas earlier
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Quoting RitaEvac:
Miami09, Patrap, if your looking at this site, turn off all the frames except the first one and last one. Notice he's still moving NW on these 2 frames withing the past hr and half.

Link
Beginning to head towards the NW/NNW. Not a good sign if you live along the mid-Atlantic states.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
text shows six different planes in earl thurs. c130,p-3,gulfsteam,dc 8
global hawk,wl57. too bad they are not all flying tonight there is great science to be had.
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Quoting RecordSeason:
1077:

I just copied that image and zoomed in.

The flag says the pressure is 922mb...which is Andrew's landfall intensity.
Wrong. It is 932.
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1536. JLPR2
Quoting Ameister12:
Earl is absolutely amazing, probably one of the most beautiful hurricane I've seen.



Gilbert is still my favorite looking hurricane. XD
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Means that NNW was temporarily
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1533. xcool
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Quoting pilotguy1:


No facts in evidence.


True on both accounts !
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Quoting Manny:
I have a hard time believing that eye is open to the south as the last 2 Vortex messages have indicated.


It is hard to believe that it actually is, but they have an on-board radar.
Member Since: June 9, 2007 Posts: 4 Comments: 15947
1529. xcool
WHXX01 KWBC 020039
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0039 UTC THU SEP 2 2010

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE GASTON (AL092010) 20100902 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
100902 0000 100902 1200 100903 0000 100903 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 13.0N 37.1W 13.4N 38.5W 13.9N 39.7W 14.6N 41.3W
BAMD 13.0N 37.1W 13.3N 38.4W 13.8N 39.3W 14.4N 40.5W
BAMM 13.0N 37.1W 13.4N 38.4W 13.9N 39.3W 14.6N 40.6W
LBAR 13.0N 37.1W 13.5N 38.8W 14.3N 40.5W 15.2N 42.3W
SHIP 35KTS 42KTS 49KTS 56KTS
DSHP 35KTS 42KTS 49KTS 56KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
100904 0000 100905 0000 100906 0000 100907 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 15.4N 43.1W 17.2N 47.3W 18.6N 52.3W 19.6N 58.1W
BAMD 15.2N 42.2W 16.6N 46.8W 17.6N 52.5W 17.3N 59.2W
BAMM 15.5N 42.2W 17.3N 46.2W 18.6N 51.2W 18.6N 57.4W
LBAR 16.5N 44.1W 19.7N 48.0W 23.4N 51.6W 26.0N 53.5W
SHIP 63KTS 79KTS 86KTS 94KTS
DSHP 63KTS 79KTS 86KTS 94KTS

...INITIAL CONDITIONS...
LATCUR = 13.0N LONCUR = 37.1W DIRCUR = 280DEG SPDCUR = 11KT
LATM12 = 12.7N LONM12 = 35.0W DIRM12 = 277DEG SPDM12 = 13KT
LATM24 = 12.1N LONM24 = 32.1W
WNDCUR = 35KT RMAXWD = 45NM WNDM12 = 30KT
CENPRS = 1005MB OUTPRS = 1012MB OUTRAD = 200NM SDEPTH = S
RD34NE = 60NM RD34SE = 0NM RD34SW = 0NM RD34NW = 60NM
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Quoting kmanislander:


I doubt that. The Caribbean is saving that honour for another system.


My bad I meant so far lol I know the Caribbean is saving up for a 180 special.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting StormJunkie:
Hey Terra, good to see you...And nice post! I've posted that chart many a times.


Hey SJ, long time no see! I actually have that chart printed out and posted on the bulletin board behind me. Real useful!
Member Since: July 30, 2007 Posts: 76 Comments: 4063
1526. JLPR2
Quoting kmanislander:


I doubt that. The Caribbean is saving that honour for another system.


Once one gets there it could bomb down ridiculously fast with that ridiculous TCHP, it's all ridiculous! XD
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Earl is absolutely amazing, probably one of the most beautiful hurricanes I've seen.

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1523. Patrap
..ooofh

Dvorak
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Quoting Chicklit:
No worries.
Oz has a jet pack on his hurricane suit to allow him to fly over road blocks, I believe.


Yeah I can see him flying up by Cantore, snatching the goggles and continuing East..
Member Since: September 8, 2008 Posts: 1 Comments: 1085
1518. Patrap
I see the motion..and its NW thru the Loop..they all wobble left and right along their paths.

3 Hours of motion is why the have 3 Hour Updates as well.
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Quoting ElConando:


Despite that it is safe to say it will be the strongest storm this season come next advisory.


I doubt that. The Caribbean is saving that honour for another system.
Member Since: August 19, 2006 Posts: 0 Comments: 15948
Kudos to the bloggers posting the graphics! Really some impressive pics. (and a little scary)
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bouy 41047 reporting 30 foot seas
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1514. leo305
its getting very close to 75W
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting TOMSEFLA:
maybe earl be be east of the next forecast point.looking that way .{hope}


As Earl ramps up again, you'll see the stair stepping we did last time he was at this strength.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
1512. Manny
I have a hard time believing that eye is open to the south as the last 2 Vortex messages have indicated.
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1511. xcool


AL, 09, 2010090200, , BEST, 0, 130N, 371W, 35, 1005, TS

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Miami09, Patrap, if your looking at this site, turn off all the frames except the first one and last one. Notice he's still moving NW on these 2 frames withing the past hr and half.

Link
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I don't know if Earl is a Cat 5 or not....... but it Damed sure looks like it!!!!!

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Quoting kmanislander:
931 mbs

CAT 5 not likely with Earl. Too little time and too far down to go.


That and it is a massive storm. It would probably need a lower pressure than you might expect for Cat 5.
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1507. MZT
These last few days have really been a match of the Titans. That was an impressive high over the Carolinas, getting into the 1025 MB range, not a cloud in sight and dead calm much of the time.
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Quoting LongIslandXpress38:


The Perfect Storm!



LOL perfect!
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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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