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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Quoting washingtonian115:
You didn't know we were playing hide-and-go-seek.Your it!


LOL i refreshed like 5 times, there was no updates, I thought maybe I lost internet connectivity. DOH!
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Quoting TerraNova:
This is the first time I've ever read this for a county in my state since I started tracking hurricanes in '05.

.SITUATION OVERVIEW...
IT IS VITAL THAT YOU DO NOT FOCUS ON THE EXACT FORECAST TRACK. TO
DO SO COULD RESULT IN BAD DECISIONS AND PLACE YOU OR THOSE YOU
ARE RESPONSIBLE FOR AT GREATER RISK. IT APPEARS INCREASINGLY
LIKELY THAT TROPICAL STORM FORCE WINDS WILL AFFECT THE COASTAL
AREAS OF DELAWARE AND NEW JERSEY
...ALONG WITH ROUGH SEAS AND HIGH
SURF.
Earl seems to want to get his name retired after several uses.Not so long Earl.
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THE CLOSEST PASSAGE THAT EARL MAKES WILL BE LATE FRIDAY MORNING
BEING A MERE 170 MILES OFF THE COAST OF DELAWARE AND SOUTHEASTERN
NEW JERSEY. WITH THE NHC`S PROJECTED TROPICAL STORM FORCE WIND RADII
IN THE NORTHWEST QUADRANT BEING ABOUT 180 MILES...WELL YOU CAN SEE
THE NEED FOR THE WATCH.

STILL EXPECTING THE MAJORITY OF THE HEAVY RAINFALL TO REMAIN WELL
OFFSHORE, EVEN WITH THE SLIGHTLY WESTWARD TRACK. THE QUESTION NOW
IS, DO THE MODELS TRY TO MOVE EARL CLOSER TO THE COAST, SAY ANOTHER
30 MILES? MODELS STILL SEEM CONSISTENT WITH EARL`S NORTHWESTWARD
TREK BEFORE HE SHARPLY MOVES TOWARDS NEW ENGLAND...AROUND THE 40/70
LINE FRIDAY EVENING.
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351. xcool
Gaston nott going out sea /
Member Since: September 26, 2009 Posts: 2 Comments: 15603
ok, thanks everyone...
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Quoting MiamiHurricanes09:
I consider the 18z GFS solution unrealistic beyond 192 hours, before that, I could certainly see Gaston getting into the Caribbean.


Nothing is reliable at this point MH...We need about four more sets of model runs before we get a real good idea of just the 100hr forecast. Much less 192.
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It's kinda interesting that there's a collective chill down the spine when anyone mentions Gaston.
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MOVING NORTH NOW
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I don't want to cherry pick a few frames, but it appears we may finally be getting the turn.
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344. VARob
Looks like Earl is that turn to the North.
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Quoting TexasHurricane:


What is OBX?


Outer Banks, NC
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Quoting TexasHurricane:


What is OBX?
The outer banks of North Carolina.
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Quoting StormJunkie:
Gaston could be trouble for someone between Brownsville and the OBX...

That cone will narrow some over the next week...lol


Lol, I think You nailed that one!! :)
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Quoting TexasHurricane:


What is OBX?


Outer Banks! ;)
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Quoting Barkeep1967:
For you that have been on here for a few years. Is it time to turn on the tunnels ?


Ahh, I think CB ran away with the keys to them...
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Quoting Barkeep1967:
Is it time to turn on the tunnels ?

Noooooooo..... don't tempt him.
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Quoting aasmith26:
is the blog silent?
You didn't know we were playing hide-and-go-seek.Your it!
Member Since: Posts: Comments:
This is the first time I've ever read this for a county in my state since I started tracking hurricanes in '05.

.SITUATION OVERVIEW...
IT IS VITAL THAT YOU DO NOT FOCUS ON THE EXACT FORECAST TRACK. TO
DO SO COULD RESULT IN BAD DECISIONS AND PLACE YOU OR THOSE YOU
ARE RESPONSIBLE FOR AT GREATER RISK. IT APPEARS INCREASINGLY
LIKELY THAT TROPICAL STORM FORCE WINDS WILL AFFECT THE COASTAL
AREAS OF DELAWARE AND NEW JERSEY
...ALONG WITH ROUGH SEAS AND HIGH
SURF.
Member Since: Posts: Comments:
335. xcool
gfs 384hrs shows Gaston hit fl soso far out .I'm not putting much faith
Member Since: September 26, 2009 Posts: 2 Comments: 15603
I consider the 18z GFS solution unrealistic beyond 192 hours, before that, I could certainly see Gaston getting into the Caribbean.
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Quoting StormJunkie:
Gaston could be trouble for someone between Brownsville and the OBX...

That cone will narrow some over the next week...lol


As long as it's not over Louisiana. Not that I'd wish it on anyone, but just don't want anymore here.
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Quoting StormJunkie:
Gaston could be trouble for someone between Brownsville and the OBX...

That cone will narrow some over the next week...lol


What is OBX?
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Quoting redUK:


It's been *almost* due north for the past hour:

http://wwwghcc.msfc.nasa.gov/GOES/goeseastconusir.html

put lat/lon on and animate...



Try again...turn off all the animation but the first and last image and you'll see a movement more like 310 or 315; NW
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For you that have been on here for a few years. Is it time to turn on the tunnels ?
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Just to clear this up:

Some people here (and elsewhere) have the stark misconception that you must add the forward speed to a hurricane in order to obtain its strongest winds (regardless of which ever quadrant that may be, which is dependent on the velocity, vertical state of the system, circulation,ambient conditions, etc.)
This is completely crooked logic, and is false.
When intensity is measured, especially so in actuality (directly within the circulation of a given system), that is true intensity. (It is being measured WITHIN the circulation! You can't obtain a more accurate reading.)
If a measurement is physically taken, such as with empirical data from a hurricane hunter, etc., Then the measurement itself is the final value, and the only exception is when HH's measure flight-level winds and use correspondence to estimate surface-level winds. However, those are accurate as well.

Now, part of this misconception can be applied to a reverse situation. On the opposite side of the strongest quadrant, it is true that you can DEDUCT the forward speed from the wind speed at the corresponding point opposite this side of system, to APPROXIMATE wind speed on this side of a system.

Think about it this way: If you're standing on the ground with an anemometer in your hand, in the path of a Category 3 Hurricane (Let's say Hurricane X w/ 115mph maximum sustained winds as measured by the Hurricane Hunters prior to landfall), and Hurricane X is traveling at 20mph and has traveled at this speed for at least the past day, you are NOT going to record maximum SUSTAINED winds of more than 115mph. The wind that the hurricane hunters measured (or estimated) will be the very wind that you will measure on the ground, there's no unique property that states "Well, this is moving 20mph, so the wind where I'm standing will be 20mph more than the wind that was measured by the hurricane hunters"

Those who believe this misconception are simply over-thinking a simple value. If I throw a baseball and the radar gun shows it was 80mph, does that mean because there was a 10mph wind at my back, it was actually 90mph? No. The radar gun gave me the actual speed of the pitch. There's no math needed, it was measured. However, it IS likely that if the wind halted, my next pitch would be LESS than 80mph, or I could DEDUCT the wind speed from the final pitch speed to obtain my true throwing speed. (It's a bit different with a baseball, though, because it has significant weight compared with parcels of air, etc, so you couldn't simply deduct 10mph to obtain 70mph, anyway.. You get the point, I hope.

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328. xcool
Weather Underground going offline
Member Since: September 26, 2009 Posts: 2 Comments: 15603
Quoting aasmith26:
is the blog silent?


If it becomes apparent that Earl will not make landfall, the blog will become more and more quiet.
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Gaston could be trouble for someone between Brownsville and the OBX...

That cone will narrow some over the next week...lol
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Hmmm now while everyone was ignoring what would become Gaston on sunday I was the one that pointed it out,and a few days later people started to catch on.Now the once ignored/neglected 98L could become a serious threat down the road.Pat on the back.
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Quoting JamesSA:

It sounds like there is a very dangerous culture problem at the lab where you work if people are compelled to only report the conclusions that the bosses want to hear for fear of losing their jobs. Business culture dysfunction of that type was a main contributing factor to the Deepwater Horizon disaster.

My experience has been that few things in science and in nature are so black or white. Most involve a blend of probabilities. Certainly the case with storm forecasts.

I sincerely hope your lab doesn't do work on anything that could impact life or property.

We dont tell them what they want to hear. We tell them what will happen to the best of our abilities. We do not say well sir there is a 50 50 chance it is going to rain today.
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Quoting CaribBoy:
Gaston, a caribbean cruiser


No its not!
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Quoting CaneWarning:


It must be a record!


Too bad it's not a platinum LOL

Member Since: December 6, 2001 Posts: 0 Comments: 22
Charley was expected to make landfall just North of Tampa.
But during the night it headed straight for Ft. Myers. On the morning of Friday the 13th, it was very apparent that Charly was headed straight for S.W. Florida.

It looked like Charley's eye would go right over Ft. Myers, but Charely made a last minute jog (to the north) and came in on North Captiva Island.

Charley made landfall in the middle of the afternoon, and anyone that was watching local T.V should have know Charley was headed for S.W. Florida.

But it was a suprise that it hit S.W. Florida, because all the local mets and TWC said it should make landfall North of Tampa. But S.W. Florida was in the cone and under a Hurricane warning.
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EARL looks awesome and highly organized
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Quoting TexasGulf:


My advice for people who are willing to take it is... watch the birds and do what they do.

If all the birds in your area have gone, so should you be. If you walk outside and everything is quiet, squirrels are hiding and birds are gone, animals are nervous... then you are in a bad spot. Consider evacuating inland.

If, on the other hand, birds are flocking to your area or if they are staying put in the trees and ponds... then they probably sense that the storm won't be too bad in your area.

The birds were a great indicator before Hurricanes Rita and Ike.


I remember being Uptown in NOLA the first weekend that anyone was allowed back. There were no animals. No noise at all. It was very eerie.
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is the blog silent?
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Evening all. Wow, Earl was a Cat 2 when I left to teach my little ones, and now he's back to a 4. It does look like he's beginning to turn a little more north now?
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Quoting sammywammybamy:


Reports from private barometers helped establish that Andrew's central pressure, at landfall near Homestead, Florida, was 27.23 inches (922 hPa).[1] At the time, this was the third-lowest pressure on record for a landfalling hurricane in the United States (it is now fourth, after 2005's Hurricane Katrina).[20]

Andrew's peak winds in South Florida were not directly measured, primarily because of the destruction or failure of measuring instruments. The Coastal Marine Automated Network (C-MAN) station at Fowey Rocks, with platform elevation of 141 feet (43 m), in its last transmission at 4:30 a.m. EDT, August 24, recorded an 8-minute average wind of 142 miles per hour (229 km/h) with a peak gust of 169 miles per hour (272 km/h) shortly before the equipment was destroyed. It is probable that higher winds occurred at Fowey Rocks after the station was destroyed.[1]

Another important wind speed report came from the Kendall-Tamiami Executive Airport, located nine miles (14 km) west of the shoreline. While weather observations had been suspended at the station, the official weather observer there stayed on duty and continued to make wind speed readings. At 4:45 a.m. EDT, August 24, he noted that the wind speed indicator was "pegged" at a position a little beyond the instrument's highest value of 100 knots (190 km/h; 120 mph), at a point he estimated to be around 110 knots (200 km/h; 130 mph). The needle reportedly remained "fixed" at this location for 3–5 minutes before dropping to "0" when the anemometer failed. These observations were closely corroborated by two other observers. He also indicated that the weather conditions continued to worsen for an additional 30 minutes after the anemometer failed. It is probable that much stronger winds occurred at this location.[1]

The highest recorded surface gust, within Andrew's northern eyewall, occurred at the home of a resident about a mile from the shoreline in Perrine, Florida. During the peak of the storm, a gust of 212 miles per hour (341 km/h) was observed before both the home and anemometer were destroyed. Subsequent wind-tunnel testing at Clemson University of the same type of anemometer revealed a 16.5% error. The observed value was officially corrected to be 177 miles per hour (285 km/h).[1]

Data collected at the Turkey Point Nuclear Generating Station terminated at 5:05 EDT before winds reached maximum strength. The anemometer recorded sustained winds of 145 miles per hour (233 km/h) before it failed, and a barometric pressure of 922 mb was recorded. Gusts exceeding 175 mph (280 km/h) were also observed. The data from Turkey Point reflects shoreline measurements (not inland), as it is situated directly on the coastline.[21] A National Weather Service-Miami Radar image recorded on 24 August 1992 at 4:35 EDT [08:35 UTC] superimposed on a street map by the Hurricane Research Division of NOAA clearly indicates the most powerful winds within the northern eyewall (conditions greater than 48 dBZ) made landfall between SW 152 St. (Coral Reef Drive) and SW 184 St. (Eureka Drive) in the Perrine/Cutler Ridge area.[22] dBZ readings indicate Decibels of Z (radar echo intensity/reflectivity) and help map the relative strength of storm activity within a weather system. This extremely powerful band within the northern eyewall corresponds with the exact latitude range where the highest surface wind gusts of 177 mph (248.8 km/h) and lowest barometric pressure was recorded at a private home in Perrine and evaluated by Clemson University.[


Good info-but unless you wrote this article (which I saw on another website earlier this week) you you should give proper attribution.
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313. xcool


wow
Member Since: September 26, 2009 Posts: 2 Comments: 15603
I can't find the rapid scan lsu link..can someone please post it? tia
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Earl a "wet" hurricane. CV type.
Juan was a "dry" one, and tiny tiny tiny...
Earl is about 2x as big as Juan.
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Normally I bristle at the "don't get caught off-guard" mantra. However, this time we are talking about a populace who feel too secure in their environment...It cannot happen to them, to far north etc... That worries me. In summer who watches the weather north of the salt line?
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Quoting uptxcoast:
Remember those pictures that showed neighborhoods before the storm and the picture of one little house standing afterwords? A picture is worth a 1000 words...

And yet, I'll guarantee there's someone hunkering down and being defiant - "They can't make me leave." Insert Darwin effect again.
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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.