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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Quoting GBguy88:
Regardless of which model said what, I'd be getting ready if I lived in the Outer Banks, or anywhere along the mid-Atlantic coast for that matter. Even if the storm passes fairly well to the east, there is still the potential for some strong gusts and a measurable amount of water rise.




I think anyone living along the EC should be monitoring Earl. Even the NHC said and their latest discussion that Earl would pass 200-300 miles from NC. Then they turn around and say the models may be off by 200-300 miles.Lol, so this tells me NC may get more than just a brushing. Besides I'm not taking any chances of Earl making his guest appearance. When Earl First developed in to a TD, the NHC kept saying Earl would be turning out to sea before it got close to the U.S. Now how do you suppose Earl could be getting close to the U.S.? something tells me were going to be in for a treat.jmo
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00
ABNT20 KNHC 301755
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT MON AUG 30 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON HURRICANE
EARL...LOCATED ABOUT 65 MILES NORTHEAST OF ST. THOMAS...AND ON
HURRICANE DANIELLE...LOCATED ABOUT 420 MILES SOUTH-SOUTHEAST OF CAPE
RACE NEWFOUNDLAND.

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A LOW PRESSURE SYSTEM
LOCATED ABOUT 900 MILES EAST OF THE LESSER ANTILLES HAVE CHANGED
LITTLE IN ORGANIZATION DURING THE DAY. HOWEVER...AIRCRAFT DATA
FROM A RESEARCH MISSION BEING CONDUCTED BY THE NATIONAL CENTER FOR
ATMOSPHERIC RESEARCH...AS WELL AS SATELLITE DATA...SUGGEST THAT
THIS SYSTEM IS ALREADY PRODUCING TROPICAL STORM FORCE WINDS IN A
SMALL AREA NORTH OF THE CENTER. ONLY A SMALL INCREASE IN
ORGANIZATION OF THE SHOWER AND THUNDERSTORM ACTIVITY WOULD RESULT
IN THE FORMATION OF A TROPICAL STORM...AND ADVISORIES COULD BE
INITIATED LATER THIS AFTERNOON OR TONIGHT. THERE IS A HIGH
CHANCE...90 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES GENERALLY WESTWARD AT ABOUT 20
MPH.
Member Since: May 21, 2006 Posts: 5091 Comments: 114783
The BAM MODELS on INvest 97L have the deeper or stronger storm going South....That would not be good if 97L does become a Hurricane or a strong Storm.
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Earl is definitely moving west in the last few frames
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Quoting clwstmchasr:


In general, the models and the NHC did a pretty good job with Danielle. IMO, they have been way off with Earl.


I concur. Of course, Danielle was far enough out in the Atlantic, even with a near approach to Bermuda, that we didn't need to argue over differences between forecast and reality. However, Earl is impacting land which was absolutely not in the forecast a few days ago.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
973. unf97
I have noticed by radar that Earl is beginning to slow even more in forward speed. Hopefully, this may be an indication of the long awaited turn. I hope this is the case and Earl turns away from the rest of the islands within the next 24 hours.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
000
WTNT52 KNHC 301753
TCEAT2
HURRICANE EARL TROPICAL CYCLONE POSITION ESTIMATE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010
200 PM AST MON AUG 30 2010

AT 2 PM AST THE CENTER OF HURRICANE EARL WAS ESTIMATED FROM SAN
JUAN DOPPLER RADAR NEAR LATITUDE 19.0 NORTH...LONGITUDE 64.2 WEST
OR ABOUT 65 MILES...105 KM NORTHEAST OF ST. THOMAS AND 130 MILES...
210 KM EAST-NORTHEAST OF SAN JUAN PUERTO RICO.

$$
FORECASTER BROWN/BERG

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Storm,

I left you a message on your blog....
This was it....

I'm confused....I read your blog....but I'm still panicking....That stupid thing is most likely NOT going to come to South Florida, correct? >>very scared<< I went through Charlie in orlando and that was a little thing....I couldn't imagine this one....I hid in a closet with my son...the house was shaking....it was soooooooooo scary....


...sorry for buggin you, but I know that you know what you are talking about...lol... ;)
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Quoting BradentonBrew:
but not by the image you posted which is a complete misrepresentation.


Ahh my error, thank you. Looks like I had the Danielle track. Here's 4 days ago. I just find it hard to sing the praises of "It's following the NHC's track!"...when not only is it not following the track, it's not even in the cone.



Again, the NHC is always my first stop, but it's silly to say in one breath, "Fish/Bermuda because that is what the NHC shows", then 4 days later while it's hammering Puerto Rico, to say "it's following the NHC track when it isn't even in the cone, let alone track.


I am amazed how Earl is outside that cone.
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Quoting katadman:


Always appreciate your synopsis, Storm. Thanks once more.


Howdy, brother!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting 69Viking:


We're practically neighbors! Hopefully we can keep things out of the GOM this year but there's a long time to go with September and October ahead of us.


No kidding. September fostered Ivan, and October Opal. Both household names for anyone that's been here a little while.
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Quoting Floodman:


Yep...he'll have to slow down for one thing...can;t make that turn without slowing some first


And he is still heading WNW.

This is starting to sound like an exchange from the classic WWII movie, The Enemy Below, where the German sub captain keeps doggedly heading on a particular course.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting RitaEvac:
"no model support" lmao, hell the models said Earl was going to go east of Bermuda at first, that haven't got Earl right the whole damn time! 97L model support was to head NW into never never land as soon as it came off Africa. Go stare at your models.



Have to agree.

And, the CONUS trough that will eventually move Earl northwards is being shown on the HPC 48 sfc map indeed more amplified, but severely tilted swest to neast. I'm thinking that Earl, on its present speed and motion, will not be far enough north to feel the northern most part of the exiting trough. That would mean a shift in the eventual track more westwards and increasing the potential for seaboard impact. And, I think once Earl gets a path to any weakness, his fwd speed is gonna look like he's been shot out of sling shot.

width=width=

It's always better to err on the side of caution, and the Bahamas and the east coast should stay acutely aware of further developments. Earl's a bad boy, landfall would be horrific.

I'm hoping not - hoping that my novice observations are exactly wrong.
Member Since: July 9, 2006 Posts: 184 Comments: 29596
Quoting StormW:


Thanks Flood!


You're welcome!
Member Since: August 2, 2006 Posts: 10 Comments: 9922
962. xcool
look to me Earl moved at 17mph
Member Since: September 26, 2009 Posts: 2 Comments: 15626
Quoting angiest:


That's what the forecast has been. Thus far, it hasn't panned out.


Yep...he'll have to slow down for one thing...can;t make that turn without slowing some first
Member Since: August 2, 2006 Posts: 10 Comments: 9922
The latest San Juan radar almost looks like he wobble a little South of West?
Member Since: January 19, 2007 Posts: 0 Comments: 82
958. unf97
Quoting CaicosRetiredSailor:
FROM:
http://www.stormcarib.com/reports/current/stmartin.shtml

Earl still battering St. Maarten
It' been going on for hours now. I took a little video from inside my house. the wind was too strong to open the door.

http://barcann.livejournal.com/190757.html


I hope you stay safe down there. I just watched the video and it seems that you are getting battered there by Earl pretty good. I pray for the best for you and all in the warning areas in the islands!
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting GBguy88:


Whenever I start to get bored of the rain we've been having, I ask myself, "Remember what it's like to be in the grip of a severe drought?" And then the rain seems rather pleasant :)


+1 TD5, TD5 Pt. 2, and this low have brought heavy rains to some areas, but not near enough for me. Plus, I like cloud cover with 85-95 degrees way more than blazing sun with 95 to 105 degrees.

Is Patrap on vacation?
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My estimated motion over the last 2-2.5 hours is about 295 degrees.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting StormW:
HURRICANE EARL / 97L SYNOPSIS AUG. 30, 2010 ISSUED 1:30 P.M.
Thanks Storm! I went and looked at the upper pattern after you mentioned it yesterday..and the possibilities
are scary, to say the least...Could have some rapidly developing large storms if all plays out just right, Correct?
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Looking at the discussion from 96 hours ago Earl was expected to be at 20.0N 58.5W, he's a few hundred miles West of there.

Link
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951. JRRP
me voy para la uni
es mi primer dia en la clase de Climatologia II
cuidense mi gente alla en Puerto Rico
regreso en la noche
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Quoting Floodman:
Those of you who are downing the models, what do you propose we use instead? If you understand the basic weaknesses of the models, then you don't fall into the trap; if you "worship" the models then you don't understand how this works and you're no better than stotrmtop...regardless, does it really matter?
Excellent post. Great post. Terrific post.....:)
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wobble, wobble, wobble...

I'm getting prepared to duck
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Quoting Floodman:


No need to panic...go to storm's blog, here and have a look at the latest...
That photo of Afrrica Storm has on his blog, makes it looks like the storms are doing the Western congo across Africa
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Quoting DaytonaBeachWatcher:
I think the ECMWF has been the best so far this year.
Noticed tha ecmwf is no on board with other models concerning 97
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Quoting StormW:
HURRICANE EARL / 97L SYNOPSIS AUG. 30, 2010 ISSUED 1:30 P.M.


Always appreciate your synopsis, Storm. Thanks once more.
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Quoting StormW:
HURRICANE EARL / 97L SYNOPSIS AUG. 30, 2010 ISSUED 1:30 P.M.


Your the man Storm. What is your gut feeling tellin ya? My vacation house on Ocracoke Island gonna be ok? Thinking about heading down to trim up trees and pick up yard stuff? what would you do?
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Quoting CaicosRetiredSailor:
FROM:
http://www.stormcarib.com/reports/current/stmartin.shtml

Earl still battering St. Maarten
It' been going on for hours now. I took a little video from inside my house. the wind was too strong to open the door.

http://barcann.livejournal.com/190757.html

Thanks for posting. looks intense
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Quoting amd:
latest Earl center location: 18.9667N 64.0333W
previous Earl center location: 18.8167N 63.7333W

That's a 0.15N 0.30W movement in one hour and 30 minutes time, or a movement of 22 miles. This is an exact WNW movement of 15 mph.

No slowdown, no speedup is occurring. Earl is following the NHC track just about exactly.
That's because they get to change the model track at every update.
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Quoting clwstmchasr:


Looks like Earl should shoot right through that weakness.


That's what the forecast has been. Thus far, it hasn't panned out.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
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Those of you who are downing the models, what do you propose we use instead? If you understand the basic weaknesses of the models, then you don't fall into the trap; if you "worship" the models then you don't understand how this works and you're no better than stotrmtop...regardless, does it really matter?
Member Since: August 2, 2006 Posts: 10 Comments: 9922
"hell the models said Earl was going to go east of Bermuda at first, that haven't got Earl right the whole damn time!"

go to the tropical page and look at the model verification graphic. the models have not been that far off, and neither has NHC. as of 8/25 the models were NOT predicting earl to go east of bermuda. and while earl is definitely south of the NHC cone, it's only out by like 50 miles.
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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.