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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looken at the RAMSDIS I'd like to say this may be a 145-150 storm right now.
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2080. Asta
So only XTRP is different in the models and takes Earl into the GOM.. Why?
http://tropicalatlantic.com/plots/07-googlemaps.shtml
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Blowng harder end Gage gng from 30 durng lulls to 60 during squalls
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2% is pretty low I would put it around 10% IMO
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Quoting angiest:
All right, for others watching on radar, are all of the mesocyclones being picked up in the eyewall actually eyewall mesovorticies?


Yes ... part of Earl's continuing strengthening. PR is still to get an increasing wind field and Earl is not quite yet at his closest brush with the island.
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2076. shfr173
What effect if any will the low in GOM have on the future path of Earl?
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Quoting TexasHoosier:
Storm, what rank did you retire at in the Coast Guard? I am Army and not as familiar with the Coast Guard rank system (if they are different then the Navy).

Second, I have been busy at Lockheed today and would like to know if the High Pressure system that is/was centered over West Virginia the last two days has intensified and moved south, north, east, or just decided to stay put?

Can you help before dinner?


Coast Guard is the same ranking system as the Navy, there symbols are blue instead of black.
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I never understand this. NHC and other forecasters seem to blindly follow models. Earl is clearly moving W or possibly a slight north component. So to have a 6 hour point due NW is completely insane. But I see it very often.

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2073. TopWave
OBX needs to keep a close eye on this dangerous storm.
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Quoting StormW:
I have about 15 minutes before dinner.

Oooh - what's for supper?
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Quoting shadoclown45:
What are the chances that Ny city will see Earl as a landfalling hurricane?


Dr. Masters blog has it at 2%
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Quoting medicroc:
Earl looks as if he's about to greatly expand in size

Link
Agreed
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a couple good webcams from Puerto Rico

http://www.comoestaeso.com/forums/
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Storm, what rank did you retire at in the Coast Guard? I am Army and not as familiar with the Coast Guard rank system (if they are different then the Navy).

Second, I have been busy at Lockheed today and would like to know if the High Pressure system that is/was centered over West Virginia the last two days has intensified and moved south, north, east, or just decided to stay put?

Can you help before dinner?
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Earl looks as if he's about to greatly expand in size

Link
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2062. Or4590
Quoting MiamiHurricanes09:
I think it'll peak at 160mph before it undergoes an EWRC, should have another 24-36 hours before that happens.


Predicting an EWRC is just plain stupid...
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Quoting Barefootontherocks:
Hello bloggers,
Interaction between Fiona and Earl may be starting. Will they dance?

24 WVL animation shows her drawing closer to him. You can also see the large movements of atmosphere. Please click image for animated WVL through 2015 GMT today-RAMSDIS, flash


They're still over 1000 miles apart...need to close the gap a little before a real Fujiwhara can happen
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Quoting NOSinger:


Actually.....not true....they had Katrina making a right turn back into the panhandle of Florida...east of Panama City...


Correct, they did not start predicting a NOLA hit til late friday night before the storm.
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Quoting NOLA2005:


It's okay ;) You would've had to have been here...that changing track is permanently embedded in our brains!


So true. I remember distinctly the track moving further west with every update. It was like watching a train barreling towards a stalled car. Awful. I don't wish that on anyone.
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2057. will40
Quoting all4hurricanes:
Nobody can say that for sure though the prediction says winds will reach 150mph just 6mph more and you have a cat 5
Is it just me or did the track shift west?


just the lower part of it did
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Quoting portcharlotte:
You are nuts!...the storm is days away..wake up




It's Monday. It's nearly in line with it on Thursday. TS watches were released for Saint Martin 72 hours before Earl reached them.

So, it's not crazy. Didn't say it was going to happen, just 'not surprised' if it did.

Quoting all4hurricanes:
Nobody can say that for sure though the prediction says winds will reach 150mph just 6mph more and you have a cat 5
Is it just me or did the track shift west?


Didn't say it was for sure. Just a thought. Others think it will.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
2055. JLPR2
Total storms: 6
Hurricanes: 3
Major hurricanes (Cat. 3+): 2

Who thought we would reach this before September in early August? XD
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Doesn't take a genius to see a track to the west or wnw...the gap is almost gone and NW movement is not possible with this setup right now IMO
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IMO the day 4 and 5 points for Fiona are concerning for the SE US Coast. Definitely some uncertainty about whether the high builds back in and where.

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What are the chances that Ny city will see Earl as a landfalling hurricane?
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Quoting winter123:
I'm already looking over here, south of the CV islands.
I had been talking about this wave yesterday,but no one seemed to pay attention to it.I think this could go further south than Fiona or Earl.Gaston may very well be on his way.
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2048. hydrus
Quoting RecordSeason:
1995:

Almost guaranteed cat 5 by next DMAX, IMO.

The Tuesday 2am data point is like right in the first real "cat 5 sweet spot" and will be setting up a DMAX with the storm centered directly over a region that has a potential intensity rating of 150kts....so um...yeah...
Do you have a link to the "sweet spot"? I am just curious. I would like to see just how warm the temps are there.
Member Since: September 27, 2007 Posts: 1 Comments: 22728
Earl is like a nascar driver, he's making a leeffft tuuuuurrrn............. just kidding, wanted to make a joke.. have a wonderful day
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2045. marmark
My concern and can you imagine....Earl skirting all the way up the eastern seaboard? Everyone should be making preparations.
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2044. Asta
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Quoting StormW:
I have about 15 minutes before dinner.


thanks for the info! :P
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NEW BLOG
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2040. srada
Quoting marmark:
This is a good time to remind everyone that NHC average track forecast errors are 200 to 300 miles at days 4 and 5.


Exactly!! (SouthEastern NC)We will be 200 miles from the center of the storm per the advisory..and any deviation of 50 miles or more would probably put us in hurricane force winds..
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Quoting Relix:


There's no way I am feeling Tropical Storm winds here. Maybe a gust or so.


whenever the bands hit, they'll come
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****Unofficial**** Latest GRIP DC-8 dropsonde reported 941 mb in eye.
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This report from Aaron Soares
Neptune's Treasure, Anegada, BVI
re: Anegada logged at about 4:30pm.

"Our property: the dock is gone, Uncle Dean's dinghy & small boat are gone. The seas are breaking our sea wall and dumping on the restaurant roof. The felt paper on Dad's roof is gone and the seas are going to the back of the property next to the cottage. All other buildings there are OK.
The Hotel up the beach, 1/2 the dock is gone. Potter's roof is lifting/leaking and dock is almost gone. The ferry dock is under water. The cash & carry is under water as well and their rental cars are flooded inside. All of this is on the southern side of the island, so just imagine the northern side where the real [censored] is happening! :("
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The part in bold is new:

THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK
FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS
UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT PORTION OF THE U.S.
EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL.

They sound a little more certain that there will be some impacts.

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Quoting GeauxGirl:



Hmmm...I seem to remember it a little differently, but I could be mistaken.


Yeah, VERY differently...as in it was supposed to recurve into Florida's panhandle. I went to bed Friday night, thinking that and awoke the next day to a NOLA track.
Member Since: September 3, 2009 Posts: 0 Comments: 520
That cone keeps moving left...
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2032. Asta
re:1990. Barefootontherocks

LINK
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2031. primez
You know what's crazy? Alex still had a lower pressure than Earl has right now.
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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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