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 Floodman:


That's the rumor...

Surge models show that...I am on that side of the equation...not a MET but I do make a living from aftermath
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Quoting BLee2333:
First off, my thoughts and best wishes to everyone in the path of Earl!

Secondly, there were some posts of at least one model showing a potent cat4ish storm in the GOM on or about 8 Oct in yesterdays runs. Anyone remember which model that was so I can ccompare the current runs?


October 8? Wow... that's crazy far into the future...
Member Since: June 20, 2005 Posts: 22 Comments: 1054
Quoting clwstmchasr:


Oct 8? Too far out for me to worry about.


Probably meant Sept 8.
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Can anyone on here can give me information as to the current surface winds in P.R. ?
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Quoting StormW:
Just took a look at the last update on the GFS shear forecast...it could get very busy.


what does that mean.. I do not like it when statements are made without the meaning attached! ":o)

does "very busy" m ean more wind shear showing on the map or
is it less wind shear to help more storms.



This board is hard enough to follow with so many much out there to talk about and so many contradictions going on.

But Thank you Storm and others for your information...
we all appreciate your help here!

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Wouldn't the storm have to move north to make South Florida in play? So what is all this talk about missing the turn north?? Aside from needing a turn north it would have to move very far west to even graze south Florida.
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It's not looking good for 97L. It may become a depression today, but not sure if it will ever be named. It's getting too close to Earl and will probably be torn apart and what's left spit out towards Bermuda. RIP 97L. We will wait for other invests to possibly get excited about.
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St. Maarten Radar

http://www.weather.an/radar/ppisxm.html
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Quoting Codaflow:
Thanks folks, but the show all function isn't sticking. I'll send an e-mail to an admin.


Trust me, you're not missing much.
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Quoting Codaflow:
Thanks folks, but the show all function isn't sticking. I'll send an e-mail to an admin.


Try logging out and back in. I had the same problem....it seemed to have corrected itself over time after I changed the filter....seems to be related to the logout, etc.
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Recon is heading home... when is the next time it takes off??? are all they doing is refueling on land and then heading out again
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Quoting katrinakat5:
well brandi thats the exact same thing i was told when katrina was going into the panhandle of fla and then the computers made the 250 mile shift to the left and put new orleans in the bulls eye...dont believe me i have 25 years of forecasting these storms i know them pretty well..i will tell you this if earl does not make the nw turn by by 66west then all bets are off for sou fla...

____________________
Well if you have 25 yrs worth of hurricane experience, why would you of listened to the NHC to begin with?
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Quoting IamTheCanesSurfer:

Any official landfall ? Please provide link id so.
Does it really matter if a house landed on half of your house or all of it?
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Quoting weatherxtreme:

Please stop inducing panic here. There are lurkers here that may panic based on your comments.


Just put him on your iggy list. That's what a lot of others have done.
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First off, my thoughts and best wishes to everyone in the path of Earl!

Secondly, there were some posts of at least one model showing a potent cat4ish storm in the GOM on or about 8 Oct in yesterdays runs. Anyone remember which model that was so I can ccompare the current runs?
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Levi says Florida is not a threat at all and I trust what he says.
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Quoting Levi32:


If the current forecast track holds true then I don't think New Hampshire would see anything more than tropical storm force gusts, but again only a small deviation in track could change that a lot.


Thankyou I will check back tonight
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Quoting WatchingThisOne:


Yes re: timing ... and as he strengthens he will need a stronger tug. The tug is not forecast to be all that strong by tomorrow evening.

E-Wall 12Z GFS, CMC, Navy 36 hours out ... top row


I mentioned on the last blog, right before this one came up (unless the post got eaten) that, even if the NHC "ignores" the forecast track from the models, they still use those global models (GFS, Euro, NAM) to determine the steering. If those forecasts miss the steering, then the forecast can still be off, even if not using the forecast track those models generate.
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Storm,

hope you had a nice birthday! quick question for you. based on the forward speeds of both 97L and Earl, do you foresee deveopment of 97L into Fiona? If so, what strength do you forecast and where do you think it would make landfall?

thanks!
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eastern bahamas getting pounded 36 out on the gfs
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109 knt surface winds found... translates to 109 knt surface winds LOL
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Quoting Relix:
Holy hell!! It's 11 30 and the heavens have split intwo! Wow just wow. I did some storm hunting and had to come back. It's that bad


It is a darn shame that the networks and the "Weather Channel" or is it the (Whether or Not Channel) don't have live feeds from OR today. That they do not have these live feeds is some indication of the miss on the forecast track. Yesterday when they would have been making preps for that live feed they were convinced that no such events would be occurring in PR.
Member Since: June 26, 2008 Posts: 0 Comments: 383
Quoting errantlythought:


Sorry mate, but it's still considered a strike. A few of those islands were stuck in the eyewall for hours on end as well.

Don't downplay the fact that its eye didnt pass overtop of an island to say it's not a landfall.

Any official landfall ? Please provide link id so.
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I am concerned about the heading of 285 nothing else. When that heading number begins to increase then the anxiety level of the East Coast should decrease. The longer it stays the same or doesn't move much then it would be time to VERY concerned. I believe that is why the cone keeps getting further west. Just pray for that 285 to go up soon. 285 is just north of due west at 270 degrees.
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Quoting WatchingThisOne:


and as he strengthens he will need a stronger tug.


Actually it's the opposite. A stronger hurricane is pulled northward more easily.
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Quoting RecordSeason:
148:

Several reasons remain for the storm to basicly continue its 3 to 1 ratio movement...indefinitely...



http://www.ssd.noaa.gov/goes/east/carb/flash-rgb.html

click wind over lays and tell me where you see anything that would push the storm north? The only winds you see moving in that direction are part of the storms own anti-cyclone...


http://www.ssd.noaa.gov/goes/east/gmex/flash-rgb.html

Of interest here is the pressure isobars showing us the ridging in the gulf and into the bahamas and cuba.

The hurricane is not going to just cut through perpendicular a 1016 to 1024mb ridge. When it hits that, it will get pushed even harder west than it has already been moving. It's already got that much westerly momentum, and then when it starts to contact this ridge, it's going to be like a sling-shot pushing it even further west. At this point, a northerly turn would typically require a front or an actual opposing low pressure system in direct contact with Earl, which there certainly isn't one anywhere in sight.

Right now it's sort of in a boundary between two ridges, but I think it's already passed the weakest part of the boundary, else it should have turned north by now.


Thats kinda what i was seeing also though im no pro or even a met and no super computers
or planes "buttt" i still think it missed the boat sort of speak (imo)
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What people need to understand is... those 118kt winds from the HH, are flight level winds, not surface! After all, need to understand more, just look at the temperature taken at the time of the obs, 46.8 F... which means they are in flight (since it NEVER gets that cold on the surface in the Leewards, VI, or PR)
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Quoting TreasureCoastFl:


Earl is not a threat to any part of Florida.. people are wishcasting. IMO


I realize this, I was just showing how absurd some of the forecasts are, I dont remember the last time I saw people argue about where the landfall would be over such a large area like that
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Quoting Levi32:


Yes. In general, Earl really has been following the projected path up until this point fairly closely. It's after Puerto Rico that the path could start diverging from the forecast, and we'll have to watch it more closely then. Certainly any northward wobbles are good news for everyone concerned :)


The only two times he has been to port of track (say it that way instead of south) has been when its close to an island.
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Gotta run now, later all.
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Quoting OBXNCWEATHER:
Hi there. Question.

As it stands right now, 1) do you think that watches or warnings will be posted for the Outer Banks and extreme eastern NC, and 2) if so, when would the first watches be issued?


Hurricane Watch - A weather watch issued for coastal areas when there is a threat of hurricane conditions within 24 to 36 hours

Hurricane Warning - A weather warning issued for coastal areas when there is a threat of hurricane force winds within 24 hours or less
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Quoting shawn26:
Levi, do you think there is any chance at all that Earl could possibly hit Florida?


No.
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Quoting bassis:
Levi or Storm
Living in Dover, Nh as I do and the track of 100 miles off the coast holds true, what kind of winds can we expect. this past Feb we got slammed with 90 mile winds from Nor'easter and lost power for 3 whole days (got damn cold) Are we looking at that kind of WIND GUSTS

Not looking for definite, just guestiments


If the current forecast track holds true then I don't think New Hampshire would see anything more than tropical storm force gusts, but again only a small deviation in track could change that a lot.
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Quoting Codaflow:
Is there any way of turning off the auto-hide on some of the selected bloggers here? I'd like to see the entire discussion, the good and the bad. Thanks!


Top of the comments entry .... set your filter to show all.
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290. dader
Quoting katrinakat5:
latrendsetter i been saying this all morning...gee why wont you people LISTEN


No you arent getting it- everyone has HEARD you, but noone is LISTENING to you. Reason is you are guessing-using no data/history, etc. Enough already
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289. HCW
12Z 97L runs from the NHC

Member Since: August 10, 2002 Posts: 0 Comments: 1409
Quoting katrinakat5:
scroll up brandi you will find it i posted it at least 10 times..


I live in Charleston... I'm not running around waving my arms in circles telling folks to prepare or flee. Anyone who lives in a coastal area should be aware of what is going on in the tropics. If they don't make the choice to prepare, that is the choice they made. You can't change that. Calm down, relax, breathe. Do not be the harbinger of destruction.
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Quoting tornadodude:
So according to some, Earl could make landfall anywhere from Florida to NS??

sheesh


Earl is not a threat to any part of Florida.. people are wishcasting. IMO
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284. bwi
Looks like lowest pressure this pass at
15:28:00Z 18.817N 63.750W
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Outer bands starting to hit puerto rico
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Quoting Bordonaro:

Flight level winds, not surface.


Thought so, translates to roughly 120 on the surface.
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281. HCW
12Z Earl runs from the NHC

Member Since: August 10, 2002 Posts: 0 Comments: 1409

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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.