Category 3 Hurricane Earl pounding northern Lesser Antilles and Puerto Rico

By: Dr. Jeff Masters , 2:40 PM GMT on August 30, 2010

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An intensifying Hurricane Earl is pounding Puerto Rico and northern Lesser Antilles Islands with heavy rain and high winds this morning. The eye of Earl passed just north of Anguilla at 9am EDT, and Juliana airport on neighboring St. Martin Island recorded sustained winds of 47 mph, gusting to 68 mph at 8am EDT before going silent. An Air Force Hurricane Hunter aircraft currently in Earl just found a central pressure of 960 mb at 9:42 am EDT. This is a significant drop of 25 mb in 25 hours. Top flight level winds at 10,000 feet seen by the Air Force aircraft were 128 mph. Using the usual rule of thumb that the surface winds are 90% of the 10,000 foot flight level winds gives one surface winds of 115 mph, which is right at the border of Cat 2/ Cat 3 strength. Top winds seen at the surface by the Air Force's SFMR instrument were lower, 104 mph. Recent satellite imagery shows that Earl is not perfectly symmetrical--there is still fewer heavy thunderstorms on the hurricane's north side, suggesting that upper-level northerly winds are bringing 5 - 10 knots of wind shear to the storm.


Figure 1. Radar image of Earl taken at 7am EDT 8/30/10 from the St. Maarten radar. Image credit: Meteorological Service of the Netherlands Antilles and Aruba.

Outlook for the Caribbean islands today
Latest radar animations out of Puerto Rico and St. Marten show that the eye of Earl is on track to pass just to the northeast of the islands of Anguilla, St. Maarten, and The Settlement in the British Virgin Islands today. The periphery of Earl's southern eyewall will probably bring Category 1 hurricane conditions to some of these islands today. NHC is giving its highest odds for hurricane-force winds to Saint Maarten--a 99% chance. These odds are 4% for St. Thomas in the Virgin Islands, and 2% for San Juan, Puerto Rico. The main threat to Puerto Rico will be heavy rains--up to eight inches in isolated areas. Earl's rains, in addition to causing flooding and dangerous landslides, will also help alleviate drought conditions that have affected many of the islands this year.

Intensity forecast for Earl
Wind shear as diagnosed by the latest SHIPS model forecast is nearly non-existent over Earl--just 3 knots--put is probably higher than that, based on the fact that the northern portion of Earl cloud pattern is ragged. Further evidence of this is the fact that Earl's eyewall had a gap in its west side, according to the latest report from the Hurricane Hunters. Ocean temperatures are a near-record 30°C, and very warm waters extend to great depth, resulting in a total ocean heat content highly favorable for rapid intensification. These nearly ideal conditions for intensification should bring Earl to Category 4 strength by Tuesday morning, and Category 5 is not out of the question. Earl should be able to maintain major hurricane status through Thursday, when it will make its closest approach to North Carolina. Sea surface temperatures are very warm, 29°C, along the U.S. East Coast, and wind shear is expected to remain low through Thursday. By Friday, when Earl will be making its closest approach to New England, wind shear will rise to a high 20 - 30 knots and ocean temperatures will plunge to 20°C, resulting in considerable weakening. Earl will still probably be a Category 2 hurricane on Friday, when it could potentially make landfall in Massachusetts or Nova Scotia, Canada.


Figure 2. Swath of surface winds from Earl predicted by the 2am EDT Monday August 30, 2010 run of NOAA's GFDL model. Hurricane force winds (yellow colors, 64 kt and above) are predicted to stay off the coast and tropical storm force winds (light green colors, 34 knots and above) are predicted to stay off the U.S. coast, but affect the coast of Canada. Image credit: Morris Bender, NOAA/GFDL.

Track forecast for Earl
Once Earl passes the Lesser Antilles, steering currents favor a northwesterly course towards North Carolina. History suggests that a storm in Earl's current location has a 25% chance of making landfall on the U.S. East Coast, and Earl's chances of making a U.S. landfall are probably close to that. None of the computer models show Earl hitting the U.S., but the storm will likely come uncomfortably close to North Carolina's Outer Banks and to Massachusetts. The latest set of model runs (2am EDT, or 6Z) project Earl will miss North Carolina by 200 - 300 miles on Thursday, and Massachusetts by a similar distance on Friday. Keep in mind that the average error in a 4 - 5 day NHC forecast is 200 - 300 miles, so the East Coast cannot breathe easily yet. The Outer Banks of North Carolina and Cape Cod, Massachusetts are both at the edge of the cone of uncertainty. NHC is giving Cape Hatteras a 9% chance of receiving hurricane force winds. These odds are 14% for Nantucket, 4% for Boston, and 2% for New York City. The main determinant of whether Earl hits the U.S. or not is a strong trough of low pressure predicted to move off the U.S. East Coast Friday. This trough, if it develops as predicted, should be strong enough to recurve Earl out to sea late in the week, with the storm just missing landfall in the U.S., but possibly making landfall in Nova Scotia, Canada.

Regardless of Earl's exact track, the U.S. East Coast can expect a long period of high waves beginning on Thursday. Significant beach erosion and dangerous rip current will be the rule, due to waves that will reach 10 - 15 feet in offshore waters (Figure 3.)


Figure 3. Wave forecast for 8am Friday, September 3, 2010, as produced by the 8pm EDT August 29 run of NOAA's Wavewatch III model. The model is predicting waves of 4 - 5 meters (13 - 16 feet) in the offshore waters from North Carolina to New Jersey.

Hurricane History for the northern Lesser Antilles
The last Cape Verdes-type hurricane to affect the Barbuda and the surrounding northern Lesser Antilles Islands was Hurricane Debby of 2000, which passed over the islands on August 28 as a Category 1 hurricane. Damage was less than $1 million, and no fatalities were reported. The last hurricane of any kind to pass through the northern Lesser Antilles Islands was Category 4 Hurricane Omar, on October 16, 2008. Omar took an unusual track, moving towards the northeast, and the storm's eyewall missed all of the islands. Omar did $80 million in damage to the Caribbean, mainly on the islands of Antigua, Barbuda, Dominica, the SSS Islands (Saba, St. Eustatius, and St. Maarten), and the U.S. Virgin Islands. No direct deaths were attributed to Omar, and the name Omar was not retired from the 6-year rotating list of hurricane names.

Links to track Earl
Wundermap of the northern Lesser Antilles Islands
Long range radar out of San Juan, Puerto Rico
Visible rapid scan satellite loop

97L
The tropical wave (Invest 97L) now 1000 miles east of the Lesser Antilles Islands has a well-defined surface circulation and enough heavy thunderstorms to be classified as a tropical depression, if it can maintain that state for another six or so hours. Satellite loops show the surface circulation clearly, but also that heavy thunderstorm activity has been slow to build. The storm is experiencing low wind shear of less than 5 knots, and is over warm 29°C waters. The main impediment to development continues to be dry air associated with the Saharan Air Layer (SAL) surrounding the storm. The latest SHIPS model forecast calls for shear to stay in the low range, 5 - 10 knots, through Tuesday, and this should allow 97L to organize into a tropical depression today or Tuesday. NHC is giving 97L a 90% chance of developing into a tropical depression by Wednesday.

97L is moving quickly to the west, at about 20 mph. This means it is catching up to Earl, which has slowed down to 14 mph. By Tuesday night, Earl is expected to be a large and powerful major hurricane with a well-developed upper-level outflow channel heading clockwise out from Earl's center at high altitudes. These strong upper-level winds will bring high levels of wind shear, 20 - 30 knots, to 97L, and probably arrest the storm's development. The most likely scenario depicted in the computer models is for 97L to be drawn into the low pressure wake of Earl and pass to the northeast of the Lesser Antilles. Earl would then eventually destroy 97L through high wind shear, and by robbing the storm of its moisture. An alternative scenario is that 97L will stay far enough away from Earl that it will be able to pass through the northern Lesser Antilles islands as a tropical storm on Wednesday and Thursday, then bend northwestwards to potentially threaten the Bahamas and U.S. East Coast. There is a very high degree of uncertainty on what may happen to 97L. History suggests that a storm in 97L's current location has a 25% chance of making landfall on the U.S. East Coast.


Figure 4. Morning satellite image of 97L.

Danielle
Hurricane Danielle is on its way to oblivion over the cold North Atlantic waters, and is only of concern to shipping interests.

Elsewhere in the Tropics
Over in the Western Pacific, tropical cyclone activity is ramping up, with two named storms expected to affect land this week. As is typical in a La Niña year, these storms have developed close to mainland Asia, and don't have a lot of time over water to intensify into strong typhoons. The storm of most concern is Typhoon Kompasu, which is expected to hit Okinawa today and recurve northward into Korea on Thursday. It now appears the Kompasu will not have major impacts on China's largest city, Shanghai. In the South China Sea, the fearsome sounding Tropical Storm Lionrock is forecast to hit the Chinese coast near Hong Kong on Tuesday, but is not predicted to develop into a typhoon.

The GFS model is predicting formation of a tropical depression off the coast of Africa about seven days from now.

Jeff Masters

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.4N .8W...the overall movement over the last 4 hours is WNW or 292.5 degrees.
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1380. Patrap
18z Early Cycle NHC model tracks
Earl
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)


Dynamic Models (More sophisticated models)






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I'm in Columbus, OH now, Ill let you when the infamous trough system comes through... It 94 here nothing in sight all of the way back to the Dakotas.
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1378. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #31
TROPICAL STORM LIONROCK (T1006)
3:00 AM JST August 31 2010
================================

SUBJECT: Category One Typhoon In South China Sea

At 18:00 PM UTC, Tropical Storm Lionrock (990 hPa) located at 20.8N 117.0E has 10 minute sustained winds of 45 knots with gusts of 65 knots. The cyclone is reported as almost stationary

Dvorak Intensity: T3.5

Gale Force Winds
================
90 NM from the center

Forecast and Intensity
========================
24 HRS: 21.2N 118.8E - 50 knots (CAT 2/Severe Tropical Storm)
48 HRS: 22.3N 119.0E - 50 knots (CAT 2/Severe Tropical Storm)
72 HRS: 23.4N 119.0E - 45 knots (CAT 1/Tropical Storm)
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Quoting angiest:
I see a lot of mentions or Earl being a cat 4 now, but the 21b advisory still says 125mph.


Recon and the ftp site information say its a Cat 4.

AL, 07, 2010083018, , BEST, 0, 190N, 642W, 115, 954, HU, 34, NEQ, 175, 160, 120, 160, 1010, 250, 20, 0, 0, L, 0, , 0, 0, EARL, D,
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Quoting moonlightcowboy:



Respect WWB, always appreciate your posts, but I see it the other way around. A major category storm moving at a fast clip would be extremely devastating at landfall, imo - a horrific wind event. The only advantage I could see would possibly be that a fast-moving storm would not have as much time to build an expanding windfield and subsequently push a larger volume of surge over a broader area. Nonetheless, surge at impact, in front/right of the eyewall, would also be devastating.

If Earl is gonna feel and move towards this Danielle weakness, I sure wish it'd get on with it! ;)


Respect you too Bro and perhaps I misspoke...I meant short lived in terms of "duration" but yup; you bring in a fast moving cane and add the windspeed to the forward speed and you create quite a problem with wind and surge issue (particularly along the NE coastal areas)....Can't wait for the turn...... :)
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1374. will40
1367. 1992Andrew 3:08 PM EDT on August 30, 2010

politics room is two doors down on the left
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1373. 7544
mother nature is in play forget the old runs we can see new ones soon evey hour he goes west put so fla in play
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1372. NEwxguy
Hmmm,I'm suppose to fly out of Boston Friday at 6:30 p.m.that almost cinches he's coming my way.If I fly any where in the winter,we usually get a blizzard,thus I fly somewhere in the fall we get hurricane,who needs models.
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1371. JLPR2
Quoting tatoprweather:
Radio stations reporting that a lot of areas have lost power in east Puerto Rico.


Still got power here, phew! XD
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Quoting obxnagshead:
Storm or anyone with knowledge...
When will he have a better grasp on Earl??
The OBX seems like we will be fine but if not we may be caught off guard. What are your thoughts on the future path, seems it changes with each model run. When will the next model runs be??
This morning we were really in the cone, now not so much. Do you think we will remain just outside of the cone from this point on???



I hope Johns sandwich shop makes it! can't live w/o the Rockfish Baskets.
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Earl



Not Good!
Member Since: August 15, 2008 Posts: 0 Comments: 2133
1366. will40
Quoting will40:


you are still on the western edge of the cone. we should know more by wednesday. you are def in a spot to keep both eyes on Earl


another note dont watch the center line of the cone look at the whole cone
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@medicroc, I know right?

That was the question with Katrina in N.O. So many hurricanes had threatened N.O. but always missed. In hind sight it was, duh, evac! But before it hit, who wanted to do something unprecedented and try and evac the whole city before a Hurricane might hit? Which, by the way, the Corp said several years earlier it could not be done without an airlift, which I guess happened anyway.
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Member Since: August 15, 2008 Posts: 0 Comments: 2133
Quoting ConchHondros:


So its going to JFV's house?
Wonder, if I put in an express order, whether I could get a fish print shower curtain in time to save the day for VA and NC?
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For those interested, this is the trough that we are watching for:

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1361. hydrus
Quoting CybrTeddy:
Wasn't expecting Earl to hit Category 4 before 11 pm tonight.
I got one right Ted. I said cat-4 by this morning. If it reaches cat-5 by 11 am tomorrow I will get two..yay
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AL, 97, 2010083018, , BEST, 0, 142N, 477W, 35, 1007, LO
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1357. luigi18
Quoting CaicosRetiredSailor:
FROM:

http://www.stormcarib.com/reports/current/anguilla.shtml



- O-M-G!!!!!

* By "Steve Donahue"
* Date: Mon, 30 Aug 2010 14:31:49 -0400

2:15 PM – Monday

Back on line with gen power – battery pack & laptop both went down. So Earl was supposed to have gone by early morning and tht was it. Didn’t happen. Was a lot of wind during the night and especially this morning when my wind meter broke at 88 mph. with the wind from the west. Wind started to clock around to the SW and when it got south, it started REALLY blowing – I guess because of the SE quadrant. I recall what 88 mph was like and these winds had to be over 100 mph. They started about 11:30 or 12:00, and are just dying now – a little. I know they were stronger because up until then, we just lost branches – at noon, we started losing trees and electric lines. It’s been raining for a good 3 – 4 hours now, about 1.5 in. so far. The seas are unbelievable - the south shore will definitely get the worst of it. Starting to die a little, but the past 3 hours were the worst. Cheers, Steve

Steve Donahue

www.anguilla-weather.com/

Anguilla, AI2640, B.W.I.

US Phone – 410-505-8661

Anguilla Phone – 264-497-8177

Good Info take care buddy
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Quoting VAbeachhurricanes:
.4W and .1N ouch

I guess that will quite the northerly turncasters for a while. If anyone is possibly in the path of this storm you should monitor and get prepared. I have been prepared since the start of hurricane season it does not pay to procrastinate.
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1355. will40
Quoting obxnagshead:
Storm or anyone with knowledge...
When will he have a better grasp on Earl??
The OBX seems like we will be fine but if not we may be caught off guard. What are your thoughts on the future path, seems it changes with each model run. When will the next model runs be??
This morning we were really in the cone, now not so much. Do you think we will remain just outside of the cone from this point on???


you are still on the western edge of the cone. we should know more by wednesday. you are def in a spot to keep both eyes on Earl
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1354. Titoxd
From 21B:

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

THE GOVERNMENT OF ANTIGUA AND BARBUDA HAS REPLACED THE HURRICANE
WARNING WITH A TROPICAL STORM WARNING FOR ANGUILLA.
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1353. angiest
I see a lot of mentions or Earl being a cat 4 now, but the 21b advisory still says 125mph.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1352. HCW
Earl is now located right in the middle of Heberts box meaning only 8.82% of Canes in the box ever reach the GOM
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No renumber.
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1349. 7544
the trun is happening now and it west for earl
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yes...future Fiona 12z euro...Georgia
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1346. HadesGodWyvern (Mod)
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Quoting weathermanwannabe:


If it did pan out for the NE, the good news is that the storm should be picking up speed by the time it got out there so it would be a relative short-lived wind event as opposed to a flooding event.......Of course the question is how strong the winds would be.



Respect WWB, always appreciate your posts, but I see it the other way around. A major category storm moving at a fast clip would be extremely devastating at landfall, imo - like a Cat 3 or 4 shot out of a cannon - a horrific wind event. The only advantage I could see would possibly be that a fast-moving storm would not have as much time to build an expanding windfield and subsequently push a larger volume of surge over a broader area. Nonetheless, surge at impact, in front/right of the eyewall, would also be devastating.

If Earl is gonna feel and move towards this Danielle weakness, I sure wish it'd get on with it! ;)
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when is the next center fix per recon?
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1343. Titoxd
Quoting Thundercloud01221991:


thanks... I wonder if NHC will every add 100 knt radius to their maps???


If they do, they would probably call it 96-kt to coincide with the major hurricane threshold.
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1341. 7544
wow
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probable flash flooding occuring in central puerto rico, hope everyones hangin on tight
Member Since: September 6, 2007 Posts: 0 Comments: 6145
This is going to be a real nail biter over the next few days........BBL.
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Quoting CoopNTexas:
192 hrs...sorry about earlier posts...it was 0z

12z



I thought the 12z runs didn't come out for ecmwf till about 4????
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1334. Titoxd
Quoting CoopNTexas:
High res EURO says: Georgia landfall on 12z


I thought that was Fiona?
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Quoting FLdewey:

It's all fun and games until someone loses an eye.


..then it fun in the dark
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Quoting Thundercloud01221991:


Cat 5 at 11 PM???

Its going nuts! May make that 5 ?
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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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