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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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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1105. Patrap
EARL Floater - Rainbow Color Infrared Loop
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Quoting Chicklit:
Fiona The Undead...

"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."

Dr. Jeff Masters


Zombie-Cane! I like it!
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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
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Winds were 167mph at the 925mb level.

I fear tomorrows headlines if those work their way down to the surface.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
1101. marmark
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.
Don't take it personally...sometimes the blog just moves so fast that people miss it. Good job on raising that topic, though!
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1100. will40
Quoting PcolaDan:


Welcome. The buoys and east coast beach webcams should be interesting to watch. Gotta see if I still have my list of them.


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

Link
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1099. snotly
Annular I.M.H.O.
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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.


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.
Member Since: July 29, 2005 Posts: 21 Comments: 794
Large Eye can cause problems since it can pass 50 miles off shore and have eyewall on shore
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keeeyawwww
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Quoting marmark:
when is the next update from NHC? 11?

Yep...
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I would say fl 100% not going to get hit by earl,what the heck are some people thinking????
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1093. kokaken
Quoting Stormchaser2007:


I really hope they didnt.


Oh, but they did!! I came on here to kinda verify that!
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Quoting angiest:


People with portable TVs:

Make sure it has a digital tuner! If the one you have is a few years old and you haven't used it in awhile, there is a chance that it is analog and is liable not to work.


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.
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Quoting angiest:


See my post 1004.

I do seem to recall reading that transition to annular occurs during or shortly after an EWRC. It is almost like the entire core turns into a huge eyewall.


Yeah. An EWRC usually leaves the storm with a broader windfield and a larger eye, both of which are characteristics of annular hurricanes. The symmetrical core develops over time as the outer eyewall supersedes the inner core. Your idea of a "quasi annular" TC is very interesting.
Member Since: July 30, 2007 Posts: 76 Comments: 4063
1089. 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.
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1088. marmark
when is the next update from NHC? 11?
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1087. dmaddox
check out the last frame:

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wrbn on livestream.com. Broadcast Live Free

Everyone, The Barometer Bob show is on now. Find out the latest on Earl and friends. Just sign into the storm chat with your WU name. I am there now. StormW has called in tonight and is currently on the Phone with Bob, hear the great man's thoughts and prediction on Earl and Friends.
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1085. Max1023
When we get an annular hurricane we will know, it will look ridiculous. Also Considering the diameter of Earl's eye an EWRC will take awhile to complete, that outer wall seems to be at least 80 miles wide, it would need to shrink to 50 with the inner wall shrinking to 20 before we start to see the effects through the central pressure and on satellite.
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1084. angiest
Quoting iceman100:
CNN BREAKING NEWS

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

What?


Don't trust CNN. Those may be some flight level winds or maybe gusts, but if they were sustained we would probably be seeing pressures at or below 900mb.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting iceman100:
CNN BREAKING NEWS

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

What?


I really hope they didnt.
Member Since: June 9, 2007 Posts: 4 Comments: 15946
1082. Patrap
WOWZA..

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Quoting pottery:

Appreciate that..


Welcome. The buoys and east coast beach webcams should be interesting to watch. Gotta see if I still have my list of them.
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1080. angiest
Quoting ElConando:


It is getting some annular characteristics but it is not near becoming Annular imo.


That's my assessment as well.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting msmama51:


thank you for the answer. I am ignorant of stuff like that. Maybe they'll have a book somewhere that will tell me how and what I need to have to do it. Had more than enough of primitive living after Katrina. And Gustav was little better, just not nearly as long lasting. Camping is fun, but I like to do it voluntarily and very temporarily.
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
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CNN BREAKING NEWS

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

What?
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Due N

Member Since: June 9, 2007 Posts: 4 Comments: 15946
Quoting MiamiHurricanes09:
I think this is the first time since I've been on the blog that we may be dealing with a true annular hurricane. I usually don't call a hurricane annular but think about it, it never really did fluctuate in intensity when it underwent an EWRC. The eye is very symmetrical as well. I guess the only thing that is left to be seen is if it can maintain major hurricane status longer than what the NHC is forecasting after encounters the cooler waters and potentially higher shear.


It is getting some annular characteristics but it is not near becoming Annular imo.
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1075. leddyed
Quoting osuwxguynew:
Fun to watch animation showing the north movement and jog back to NW. Also shows the intense and complete eye ring of convection.

MIMIC TC GIF

That's some serious stair-stepping.
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1074. marktwx
Buoy to the East of Center reporting 31 ft. seas
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Today's SST map. Very warm where Earl's headed. Note the yellowish swath to the east of Bermuda; this indicates cold water upwelling due to Danielle. However, the swath disappears farther south; this is because A) the warm waters extend much deeper--by several hundred feet--in the lower third of the image, and B) there's been more time for the warm waters to head back to the top.

Eleswhere, opf oucrse, there's still a huge untouched buffet of near-record high SSTs extending down to 500 or 600 feet in the western Caribbean. Any system taking a seat at that particular table will be able to feast sumptuously. Ouch...

Click for larger image:
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Fiona The Undead...

"...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."
Dr. Jeff Masters
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1071. 2ifbyC
Quoting msmama51:


thank you for the answer... Maybe they'll have a book somewhere that will tell me how and what I need to have to do it.


You're more than welcomed!

I know you've heard it before, but in this case it's soooo true; Google is your friend. There are some fantastic sites out dere with the info you're seeking. Good luck!
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1070. 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
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1068. angiest
Earl has been very wobbly today. Don't be fooled by a few frames on a sat loop. Compare the first and last frame to get the short-term motion.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1067. Max1023
Who lit a fire under Earl!
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AL, 07, 2010090200, , BEST, 0, 271N, 734W, 120, 932, HU, 34, NEQ, 200, 180, 120, 180, 1008, 200, 20, 0, 0, L, 0, , 0, 0, EARL, D,
AL, 07, 2010090200, , BEST, 0, 271N, 734W, 120, 932, HU, 50, NEQ, 120, 120, 90, 100, 1008, 200, 20, 0, 0, L, 0, , 0, 0, EARL, D,
AL, 07, 2010090200, , BEST, 0, 271N, 734W, 120, 932, HU, 64, NEQ, 80, 80, 40, 60, 1008, 200, 20, 0, 0, L, 0, , 0, 0, EARL, D,


trying to make a run for cat 5
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1065. hydrus
Quoting Max1023:
http://www.wunderground.com/tropical/tracking/at201007_sat.html#a_topad

We got a convective burst wrapping around the eye with 2 meso-vortices in the eyewall. I think earl is now a sub-930mb cyclone.

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.
Thank you Max...Very interesting.
Member Since: September 27, 2007 Posts: 1 Comments: 21762
1064. Patrap
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Station 41047
NDBC
Location: 27.469N 71.491W
Conditions as of:
Wed, 01 Sep 2010 23:50:00 UTC
Winds: SE (140°) at 44.7 kt gusting to 54.4 kt
Significant Wave Height: 29.5 ft
Dominant Wave Period: 12 sec
Mean Wave Direction: SSE (160°)
Atmospheric Pressure: 29.54 in and steady
Air Temperature: 83.7 F
Dew Point: 77.9 F
Water Temperature: 84.0 F
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Quoting pottery:

Thanks, StormwatcherCI..
No problem. You can find all the buoys on the NHC/NWS site.
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1061. Max1023
http://www.wunderground.com/tropical/tracking/at201007_sat.html#a_topad

We got a convective burst wrapping around the eye with 2 meso-vortices in the eyewall. I think earl is now a sub-930mb cyclone.

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.
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1060. angiest
Quoting msmama51:


thank you for the answer. I am ignorant of stuff like that. Maybe they'll have a book somewhere that will tell me how and what I need to have to do it. Had more than enough of primitive living after Katrina. And Gustav was little better, just not nearly as long lasting. Camping is fun, but I like to do it voluntarily and very temporarily.


People with portable TVs:

Make sure it has a digital tuner! If the one you have is a few years old and you haven't used it in awhile, there is a chance that it is analog and is liable not to work.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1059. Patrap
00z Early Cycle NHC model tracks
Earl
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)





Dynamic Models (More sophisticated models)



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1057. pottery
Quoting PcolaDan:


You can find it somewhere in here. :)

National Data Buoy Center

Appreciate that..
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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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