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 IKE:
One thing about Earl...he has become a large system.



I was looking at that too Ike.....Pretty large impact wherever he ends up....Unfortunately, this may end up as beach erosion city for the Eastern Seabord with not a lot of sand protection left over for the next ones this season.....Enjoy the beaches now while you can.
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I think Earl could peak at 150 before a EWRC.

Category 5 isn't out of the question however, just they are pretty rare in the Atlantic. The last one was Hurricane Felix and the last one out in the Atlantic Ocean vs the Caribbean or the Gulf was Hurricane Isabel, 7 years ago.
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Anyone have a wide view of the water vapor loop? I want to see the CONUS and the Atlantic in one view. TIA.
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1578. will40
Quoting AtHomeInTX:


You are too kind. :) I hope it continues to work its magic for you. Earl is not playing. :(


ty again Stef :-). they just may be what i need
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I'm not sure if I can continue reading posts on this blog. Earl is definitely not moving to the west. Can you not read the satellite imagery? He's moving the WNW, and if you look at the overall system, I've seen more of a NW movement than before.

Let's not get overly hyped on this storm.
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1576. unf97
Quoting moonlightcowboy:



Hey, katadman. Seems you sort of answered your own question. That's how I see it, too.


Yes he did answer is own question LOL..
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Quoting CapeObserver:


If the temp change is forecast for this weekend, doesn't that mean the trough won't make it to the coast in time? Earl is supposed to up in that region, according to the models, by Thursday?


The cooldown happens behind the trough, but the southerly steering is in front of the trough. So if the cooldown is hitting Cleveland it means Earl is already being steered to the north.

BTW, I'm not saying E won't make US landfall at all...but if it happens it will be NC or north.
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Quoting ShenValleyFlyFish:


+1 one of the better today


Ditto...thanks!!
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1571. Relix
Whoops blog eating!
Member Since: August 3, 2006 Posts: 0 Comments: 2741
1569. 900MB
Quoting StormW:


I would guesstimate by looking at the tracking map, probably close to 25-30 mph forward motion.

The second question...I'll have to look at the model runs of the 500 mb setup forecast in the a.m....indications are he should still recurve.


Thanks, Storm!
Worst case we have a 115mph storm moving at 30mph hitting Long Island. Wow that is a really bad worst case!!!!
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1568. Relix
Yep, I officialy declare Earl


THE ROLLER COASTER CYCLONE!
Member Since: August 3, 2006 Posts: 0 Comments: 2741
Quoting Tazmanian:



C and B


Woah! Epic forecast there.
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Now that Earl is in the GHCC rapid-scan view we can get satellite images that update every 10 minutes or so. Here's the latest satellite image of Earl as of 19:32UTC/3:32pm EDT.

Wow is all I have to say.

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Quoting JLPR2:


A ts not a td


I know its my opinion as of now unless i see more organization and t'storms.. But its possible..
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1564. Relix
Yep, I officialy declare Earl


THE ROLLER COASTER CYCLONE!
Member Since: August 3, 2006 Posts: 0 Comments: 2741
Quoting snowboy:


The proof is in the pudding, good sir. We've been waiting some time for the promised trough, and its arrival keeps getting postponed..


Very true...I'm in Cleveland...and it's too hot for late August, that's for sure, and forecast to stay that way til Thursday afternoon...originally it was only suppose to be in the 90's til Wednesday.
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What do you all think the models will do at 5?
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1561. Relix
Yep, I officialy declare Earl


THE ROLLER COASTER CYCLONE!
Member Since: August 3, 2006 Posts: 0 Comments: 2741
Quoting will40:
ty Stef i may well need them i will send back if i dont use them tho :-)


You are too kind. :) I hope it continues to work its magic for you. Earl is not playing. :(
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Quoting Tazmanian:



it would go right too a TS


AL, 97, 2010083018, , BEST, 0, 142N, 477W, 35, 1007, LO


I know what it says.. But right now i dont see it happening at the moment.. it needs more storms near the center.. But hey it could happen.. lol
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Quoting katadman:
Storm W, Please tell me if I am understanding this correctly. According to the present NHC forecast, the initial turn to the NW is induced by the current weakness (which seems to have failed to have that effect) and then the trough later in the week is to pull Earl further north and eventually NE? If this first weakness doesn't pull him much, then even if the trough turns him later, he will already be far enough west to make an east coast landfall?



Hey, katadman. Seems you sort of answered your own question. That's how I see it, too.
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Quoting StormW:


Yeah...as I've said before..this is just the pre game show.


...um

Any Idea what the entertainment is going to be for the Halftime show?

I hope it is good, we do have some good DJ's and entertaining people here on WU
Member Since: July 12, 2007 Posts: 0 Comments: 6065
Earl has been going West for the past 2 hours now! http://www.ssd.noaa.gov/goes/flt/t2/flash-vis.html

It seems that the expert forcasters are "hanging on" to those models until the very last minute. Every new run, the paths are looking more and more crunched up together as they stay conveniently off shore and not even making landfall. No outlier here. Is this to avoid\minimize mass panic? I feel there is something wrong here, in general. Something has to, and will give. If and where this hits, it will be very, very bad.

Anyone else feel the same way? I welcome your opinions (based on fact of course)
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Quoting naitsabes:

This has to be a CMC doomcast. Cat 5 just west of manhattan. Only CMC.

Seriously though, one wobble west (not to mention Earl has been trending west it's entire lifetime) would mean New England landfall. Probably as a major.
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Periods of 5 or 6 years between Category 5s isn't that uncommon.

In fact, it's about regular.

Always seems to be 4-6 years on, 4-6 years off.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
I know many disagree with Katrinakat5 but I think she could be right.Right here in South Florida we are keeping a close eye on it.
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1548. IKE
One thing about Earl...he has become a large system.

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1547. snowboy
Quoting rwdobson:


Ok, high temps in Cleveland are forecast to go from the 90s down to the 60s and 70s this weekend. And you're saying the trough is not that strong?


The proof is in the pudding, good sir. We've been waiting some time for the promised trough, and its arrival keeps getting postponed..
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1546. GetReal
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Quoting Flyairbird:
That does sound like something out of a movie doesn't it?


But not entirely inaccurate...as far as the financial district goes, all of those activities have a business continuity plan; they're required to by law. The stock market will continue...the ports all have recovery plans in place and the rail centers are the same. The airports will be effected but only by the passage of the storm; with the exception of loss of power the physical plant of the airports will be relatively unharmed. The city would be damaged and everyone will second guess why the power infrastructure wasn't upgraded years ago, but as far as the business aspect is concerned it will continue with hardly a hiccup...the loss of life, on the other hand, would be pretty astonishing
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Quoting HadesGodWyvern:


really?

It has been that long since Felix..


Indeed -

Strongest in 2009 - Bill - 135mph - Cat 4
Strongest in 2008 - Ike - 145mph - Cat 4
Strongest in 2007 - Dean - 175mph - Cat 5
(Felix - also 175 mph, but maxed out at 929 mb, where Dean hit 905 mb)
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1541. HarryMc
Quoting iammothernature:


I say B and D


A and A,B,C,and/or D :)
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Quoting SavannahStorm:
It's apt that Earl has a male name...

Missing his turn, getting lost, and not even asking for directions...
Hello my name is Earl....and I carry a nice swirl. lol
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Quoting iammothernature:


I say B and D


A and B+D.
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Quoting iammothernature:
POLL:

What intensity will Earl reach at its peak?

A. High Cat 4
B. Low Cat 5 (160-165 mph winds)
C. Mid Cat 5 (170-175 mph winds)

Where will Earl hit?

A. North Carolina
B. New York
C. Any other area of New England
D. Canada
E. Nothing



C and B
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Quoting IpswichWeatherCenter:


It says it will become a Tropical Storm if it were to form - on that.


Yea it does.. But how many times u've seen NHC to go right in tropical status with a storm.. Besides it needs more T'storms near the center.. Right now its looking weak.. at the moment..

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1536. GBguy88
Quoting SavannahStorm:
It's apt that Earl has a male name...

Missing his turn, getting lost, and not even asking for directions...


*Snicker*
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Quoting iammothernature:
POLL:

What intensity will Earl reach at its peak?

A. High Cat 4
B. Low Cat 5 (160-165 mph winds)
C. Mid Cat 5 (170-175 mph winds)

Where will Earl hit?

A. North Carolina
B. New York
C. Any other area of New England
D. Canada
E. Nothing


I say B and D
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1534. KEEPEROFTHEGATE (Mod)
07L/MH/E/C4
MARK
19.26N/64.48W
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1533. markot
looks like we could have watches warnings for se bahamas,.... eastern dom. republic....
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If the dark area thins out, or does not continue going down to us, then Earl will get closer to the US. If not it will stay to the east of us. We need to watch it & by late tmrw, we will know what is happening.
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Storm W, Please tell me if I am understanding this correctly. According to the present NHC forecast, the initial turn to the NW is induced by the current weakness (which seems to have failed to have that effect) and then the trough later in the week is to pull Earl further north and eventually NE? If this first weakness doesn't pull him much, then even if the trough turns him later, he will already be far enough west to make an east coast landfall?
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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.