Earl significantly weakening

By: Dr. Jeff Masters , 9:54 PM GMT on September 02, 2010

Hurricane Earl has significantly weakened today. The Hurricane Hunters found a central pressure of 948 mb at 4:06pm EDT, a large 20 mb rise from the 928 mb pressure of the 5am EDT advisory this morning. The aircraft found flight level winds at 10,000 feet of 124 mph, which translates to surface winds at the boundary between Category 2 and Category 3 strength, 112 mph. However, the SFMR instrument on the aircraft saw top surface winds of just 98 mph. Satellite imagery shows that Earl is no longer as impressive--the eye is less distinct, and the hurricane has a lopsided appearance. Dry air and wind shear of 15 - 20 knots have chewed away at Earl's southwest side.

Earl has made its turn to the north, and is headed for a close brush with North Carolina's Outer Banks. Rain bands from the hurricane have reached the coast, as seen on long-range Cape Hatteras radar.


Figure 1. Afternoon satellite image of Earl.

Forecast for Earl
If you're wondering about your chances for receiving hurricane force or tropical storm force winds from Earl, I highly recommend the NHC wind probability product. The highest odds of hurricane force winds for any location on the U.S. coast are for Nantucket--25%. Yarmouth, Nova Scotia has the highest odds for Canada, 15%, and Cape Hatteras has the highest odds for North Carolina, 19%. The latest set of model runs from 8am EDT (12Z) this morning show little change to Earl's track, and the latest SHIPS model forecast also shows no surprises. Wind shear will remain moderately high, 15 - 20 knots, through Friday morning. This should allow Earl to maintain Category 2 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 hurricane early Saturday morning, when it will make its closest approach to New England. Earl is more likely to be a strong tropical storm early Saturday afternoon, when it is expected to make landfall in Nova Scotia or New Brunswick, Canada. The expected impacts on the coast should somewhat less than what I outlined in this morning's blog post, because of Earl's recent weakening.


Figure 2. Wind field analysis of Hurricane Earl from 3:30pm EDT Thursday, September 2, 2010. Note the asymmetry in Earl's wind field, caused by the storm's forward motion of 18 mph to the north at the time. The highest contour has top winds of 80 kt (92 mph) surrounding the "+" on the NNE side of Earl--the strong right front quadrant of the storm. However, winds in the left front quadrant (on the west side) were just 75 knots (87 mph.) The asymmetry is not nearly as great as what was observed at 9:30am this morning. Image credit: NOAA/AOML/Hurricane Research Division.

Fiona
There is little change in the forecast for Tropical Storm Fiona, which is struggling due to high wind shear, courtesy of strong upper-level northerly winds from Hurricane Earl's outflow. 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). Wind shear from Earl and dry air should keep Fiona from attaining hurricane status, and the shear may be strong enough to destroy Fiona.

Gaston dies
Tropical Depression Gaston lost its battle with dry air. Satellite imagery shows that Gaston no longer has a surface circulation, and NHC has declared the system dead. The latest SHIPS model forecast predicts shear will remain low to moderate, 5 - 15 knots, for the next five days, so it is possible Gaston could regenerate.


Figure 3. Afternoon satellite image of Gaston (left) and the latest tropical wave to move off of Africa (right).

New tropical wave
A large and well-organized tropical wave moved off the coast of Africa last night, and this wave has the potential to follow the pattern set by Danielle, Earl, Fiona, and Gaston. Several models do develop this system into a tropical depression early next week, and NHC is giving the wave a 10% chance of developing by Saturday afternoon. Wind shear is currently too high, 30 - 40 knots, for the wave to develop. However, once the wave reaches a point a few hundred miles southwest of the Cape Verdes Islands two days from now, wind shear will drop and development will be more likely.

There is also a tropical wave over Central Africa which will emerge from the coast in 4 - 5 days. Some of the models are predicting development of this wave, 7 or so days from now.

Links to follow today
Cape Hatteras weather
Cape Hatteras radar

Next post
I'll have an update in the morning, and Dr. Rob Carver will have a late-night update.

Jeff Masters

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The NHC has Earl recurving NE by the next forecast point, it will be interesting to see if it verifies.. If not, this would be bad news from Long Island, to Cape Cod, MA. The actual trough remains in the midwest, what's pulling Earl NNE is the high to the east. Earl is just going around the high, no trough pull yet.
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Quoting CaneWarning:


He's my favorite met by far.
....theirs a new met on channel 8 who's dam good imo,best in our area,younger fella
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1173. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15707
1171. EricSFL
GFS wasn't so wrong after all having shown Fiona (a few days ago) as a weaker system very close to Earl riding along with it.
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somebody help me! (sob)
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1168. xcool


alexhurricane1991 yeah from dead
Member Since: September 26, 2009 Posts: 2 Comments: 15707
1167. tkeith
Cosmic

There was a period when there were comments on Docs blog before people could make their own blogs. It was end of 04 or beginning 05.

I grew up in the 70's...my memory was stunted a bit :)
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Brian Osbourn is sitting his Van with live feed at a Gas Station. The awning at the gas station is rocking.
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Well...

Not only does dry air weaken a hurricane, as I was saying earlier today...it makes the actual winds at the surface a lot lower than they would otherwise be since the boundary layer is stable.

Not much to talk about in the OBX. Eastern Canada could be a little windy tomorrow though...

Good night all!
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Quoting DestinJeff:




Doc should have that graph as the site background.
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Tuning into Oz right now and if that gas station awning flies he is gonna flip out!!!
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Well Earl does seem to be rolling back to less than 360N heading..356 perhaps..if he had a heavy duty eyewall the OBX stragglers would be doing some rethinking, but given the wind speed they will just get roughed up if he holds that vector. But I think he's just teasing us....
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Brian Norcross is the best thing that happened for TWC.

I know it's late and I might be seeing things but it looks like Earl is trying to steal some moisture from the gulf.

Does anyone have a map for the current gulf stream currents and Earl's position in relation to it?
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Quoting SunnyDaysFla:
NHC 132 Blog 4

Which ones did you folks beat them on?
We got 2 points on a controversial safety call on Karen.
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Latest GOES imagery suggests this slight northern wobble/job has ceased. System should resume the NNE 15 degree motion momentarily...probably in the next couple base reflectivity frames. As w/ all large storms, these subtle deviations are common.
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Quoting xcool:
Gfs brings gaston back to life i see.
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HurricaneEarl's heading had turned northward to 5.1degrees north of NorthNorthEast
from it's previous heading of 4.9degrees north of NorthEast
H.Earl's average speed moving between its last 2 reported positions was~19.3mph(~31.1km/h)

02Sep . 03amGMT - - 27.8n73.8w - - 140mph - - 932mb - - NHC.Adv.#31
02Sep . 06amGMT - - 28.6n74.4w - - 140mph - - 932mb - - #31A
02Sep . 09amGMT - - 29.3n74.7w - - 145mph - - 928mb - - #32
02Sep . 12pmGMT - - 30.1n74.8w - - 145mph - - 932mb - - #32A
02Sep . 03pmGMT - - 30.9n74.8w - - 140mph - - 932mb - - #33
02Sep . 06pmGMT - - 31.7n75.2w - - 125mph - - 943mb - - #33A
02Sep . 09pmGMT - - 32.5n75.2w - - 115mph - - 947mb - - #34
03Sep . 12amGMT - - 33.0n74.7w - - 110mph - - 948mb - - #34A
03Sep . 03amGMT - - 33.8n74.4w - - 105mph - - 951mb - - #35

Copy&paste 27.8n73.8w, 28.6n74.4w, 29.3n74.7w, 30.1n74.8w, 30.9n74.8w-31.7n75.2w, 31.7n75.2w-32.5n75.2w, 32.5n75.2w-33.0n74.7w, 33.0n74.7w-33.8n74.4w, bwi, 33.8n74.4w-41.46n71.2w into the GreatCircleMapper for a look at the last 12hours.

Using straightline projection upon the speed&heading averaged
over the 3hours spanning the last two reported positions:
~28hours from now to SakonnetHarbor,RhodeIsland
east across the bay from Newport
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1155. xcool
DestinJeff .about to found outt soon
Member Since: September 26, 2009 Posts: 2 Comments: 15707
1154. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15707
Quoting PSLFLCaneVet:
He was the 1st one with his hand up to volunteer to go into the danger zones, back when it was kind of a crap shoot as to whether you were coming back from assignment. No one talks about how well the Weather Channel did "Local on the 8's. It was their hurricane forecasting and coverage that put them on the map. Always used to like watching John Hope, he was well-versed.


I totally agree....it's sad how far they have fallen from their peak.
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Quoting Jeff9641:


How are you friend.
Good but right now i actually want gaston to strengthen tonight so he can go a little northward and miss the caribbean but its looking like thats not going to happen.
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Quoting whitewabit:
Blogs started in April 2005 ...
That's when the archives start, but there was some sort of blogging/commentary before that. I thought you were here, but I definitely don't remember if you first showed up in 04 or 05. I am sure that if it was before 04, I wouldn't know. Because though this site was here in some form, it wasn't until midway through the active 04 season that I found it.
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Quoting PrivateIdaho:


Dewey is great!...(but don't call him dude!!!)


Or Buddy!
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i believe houston will have a good yr too my other fave
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1147. tkeith
Quoting DestinJeff:


Trough will do its real work once Earl is north of obx.

clearly.
good...we are not all DOOM.
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1146. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15707
Quoting alexhurricane1991:
Unfortunately if the conditions are right you could be right.


How are you friend.
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Quoting david276:
In defense of Cantores Idiocy . Think of the adrenaline rush he must feel every time he does that. I know he ups it. But no one else really witnesses what he gets to unless you own a home or whatnot and stay through the storm. Everything in your mind and body are telling you to run and hide and he stands out there and stays in it until its just not safe most people would be like "screw this" if you were not getting paid . Or had some sort of psychopathic love of such things.
He was the 1st one with his hand up to volunteer to go into the danger zones, back when it was kind of a crap shoot as to whether you were coming back from assignment. No one talks about how well the Weather Channel did "Local on the 8's. It was their hurricane forecasting and coverage that put them on the map. Always used to like watching John Hope, he was well-versed.
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1142. Ryuujin
Man that trof better hurry up, cause he continues this little Northward trek, Cat 2/Cat 1 or not, he's going to give a rude awakening to a lot of New Englanders.
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Quoting PrivateIdaho:


Dewey is great!...(but don't call him dude!!!)


Or Buddy!
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Quoting Jeff9641:


Gaston will be the biggest beast in years if he takes that path.
Unfortunately if the conditions are right you could be right.
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Quoting JLPR2:
I dont expect Gaston to officially revive till it gets to or nears 50w.



It needs it's energy. XD


Agreed.
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Quoting btwntx08:
ummm he won a playoff game last yr hes over it its our time jeff :)


We'll see what happens buddy.
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Quoting tkeith:
Dewey tried to fill in for ya, but like me he's a "second stringer"...


Dewey is great!...(but don't call him dude!!!)
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Quoting JLPR2:
I dont expect Gaston to officially revive till it gets to or nears 50w.



It needs it's energy. XD


Gaston will be the biggest beast in years if he takes that path.
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Quoting JLPR2:
I dont expect Gaston to officially revive till it gets to or nears 50w.



It needs it's energy. XD
Wow! and look at all that energy for him. yikes!
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ummm he won a playoff game last yr hes over it its our time jeff :)
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Quoting Ryuujin:
Is it me or is Earl heading pretty much due N with a little NW wobble thrown in there for a FU measure to all of us.


Nope not your imagination..well maybe not NW but back a bit west of North..with his new 50 eye width Earl doesn't need much to put his slower but large eyewall on to the OBX..more than the wobble so far..but not much more...
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1130. JLPR2
I dont expect Gaston to officially revive till it gets to or nears 50w.



It needs it's energy. XD
Member Since: September 4, 2007 Posts: 7 Comments: 8963
Come on GFS. What do you have for me know.
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1128. tkeith
Quoting Ryuujin:
Is it me or is Earl heading pretty much due N with a little NW wobble thrown in there for a FU measure to all of us.
DestinJeff what's the latest on the approaching trough?
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Shoooooot, Earl's still coming mighty close! Man! Maybe a bit weaker and all that, but "whew" - talk about dodging a bullet. That's just too close for comfort!

...and somebody needs to get busy derailing that danged wavetrain! Ugh!
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Quoting geauxtigersaints:


Didn't you hear? He retired again.
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Quoting stillwaiting:
...,yea dennis philips,he's pretty darn good,penn state grad,he's visited docs blog before,smart met.......interesting suspenders!!!!


He's my favorite met by far.
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Dr. Masters (r) co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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