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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Wow look at this
Link
major flooding in St Martin
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Quoting FunkStorm:


Theres nothing on Radar for NC.


Carolina is a state in puerto rico
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My
*list*
is now up to 118

...life is good.
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478. wjdow
Quoting FloridaHeat:


? i just got on for the first time today what are you talking about


Sorry FH, misunderstood your post, my bad.
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477. Prgal
Quoting FunkStorm:


Theres nothing on Radar for NC.


Carolina, PR
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to eliminate Florida from potential trouble is not prudent. Like storm says pay attention. Earl has done little they expected him to do.
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Question: As a resident of S. Florida and Hurricane Wilma recipient, the experts in describing developing tropical systems often refer to the development of "Heavy Thunderstorm" around the eye wall. Yet, having actually been in Wilma, Jeanne, Irene and skirted by Francis, I haven't ever seen or heard thunder or lightning. Is the reference to heavy "thunderstorms" inaccurate?

Thanks in advance for an expert reply
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Vortex message suggests that Earl is nearing Category 4 status.
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Quoting wjdow:


signed on today? says july 21. poof.


? i just got on for the first time today what are you talking about
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471. wjdow
Quoting Floodman:


He didn't say he joined today; he said he sifgned on...

Easy, folks!


sorry. my bad.
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slamming NS
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Quoting FunkStorm:




Put a wig on and a skirt, StormW will notice you.


Please just POOF that person and quit quoting them.
Member Since: September 22, 2005 Posts: 18 Comments: 2343
Quoting MahFL:
Dare I say "pinhole" eye ?


Nowhere close. It is still something like 10-12nm wide.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting wjdow:


signed on today? says july 21. poof.


I think he may have meant it was his first time on *today*? not *ever*..
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Quoting Relix:
Its moving back west in the radar image. Heh.
wnw not west
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Link

Ocean cam may be interesting this weekend
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Florida is not a realistic possibility so don't worry; Fiona may be a different scenario but Earl is targeting carolina to newfoundland barring a 1% outlier that has no chance of happening. If it might, you will have time to prepare as PR did, cause it would be slow moving. Bigger thing is to lookout to make sure Earl doesn't turn quickly so the weakness stays in place for fiona to follow if she doesn't just catch up and get sheared to death.
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TampaTom - thank you for your response earlier.
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Quoting rarepearldesign:


During high tide it would be very dangerous. I've seen the tides personally many times, even done rafting in them out Shubenacadie. Even lost my car keys to rapidly rising coastal waters. I would wander a guess that a Cat 2 surge at high tide would be something I wouldn't want to witness close by live.
Didn't say it would be safe to see. One thought I had when I was there was that if the H2o ever made it on land there was nowhere to run. Why I'm happiest close to mountains.
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Quoting wjdow:


signed on today? says july 21. poof.


He didn't say he joined today; he said he sifgned on...

Easy, folks!
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CI# /Pressure/ Vmax
5.3 / 965.7mb/ 97.2kt


Final T# Adj T# Raw T#
5.3 6.5 6.5
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
459. Prgal
Checking in before I lose power here in Carolina. There is light rain right now but there are occasional strong wind gusts and thunderstorms. We are up for a ride!
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Quoting FloridaHeat:


i just signed on today and this is the first thing i see and it has me very concerned i have not seen anyone else on the news even mention florida as a possibility

Put him/her on your ignore list. They are inciting panic. Just keep a watchful eye, like always.
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Quoting Flyairbird:
I remember when I Lived in S Florida that someone was in their hammock in the Bahamas, and when the eyewall crossed they got blown out of their hammock right into a brick wall...LOL I couldn't ordinarily laugh at that but people do dumb things.

hehe - I remember the dude that was kite surfing and actually hit a wall in south fl a few years back :) i think there is a youtube video of it...
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Storm,

good afternoon. If I can get your expert insight analysis on 97L please. Three quick questions. 1) Will it develop at all, 2) how strong do you think it will get and 3) florida in the picture?

thanks
Member Since: July 12, 2010 Posts: 0 Comments: 1133
Quoting FloridaHeat:


i just signed on today and this is the first thing i see and it has me very concerned i have not seen anyone else on the news even mention florida as a possibility
dont be concerned .. you just got unlucky enuf to read that post first. Try follwing storm or levi and your blood pressure reading will stay normalized.
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Quoting StormW:


link


thank you storm. i was stressing for her. i wanted to answer her with a guess from looking at loops, but i didn't think a guess from lil ol me was appropriate.
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Tampa Tom, the European Operational Model was showing 97L becoming large and powerful hurricane Fiona moving into the GOM near Sept 6-8. However, that was yesterday and today it has changed its thinking to agree with the other models which all say 97L will get too close to Earl and destroyed by Earl's outflow. If anything is left, it will go out to sea or possibly effect Bermuda.
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449. Relix
Its moving back west in the radar image. Heh.
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people....Earl is heading generally wnw...but probably closer to wwnw. a coupla frames show a nw movement, but remember, the eyewall is shaping up to be quite round now. you can see a definite trend that is SET. remember, the fact this is approaching cat 4 status...soon to be cat 5....dictates that we consider future paths with that in mind. the stronger it becomes...the harder it will be to turn....meaning in short...the US is about to get hammered...!!!!!
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12Z GFS Earl track shifts westward again. This time it strafes the entire Eastern Seaboard in a scenario entirely too close for comfort.

http://raleighwx.easternuswx.com/models/gfs/12zgfs500mbHGHTPMSLtropicalGFSLoop.html
Member Since: September 22, 2005 Posts: 18 Comments: 2343
Quoting VAbeachhurricanes:
12z gfs is running

http://raleighwx.easternuswx.com/models/gfs/12zgfs500mbHGHTPMSLtropicalGFSLoop.html


Oh man, it just gets worse and worse for us in Eastern VA...
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12Z GFS coming in, looks a tiny little bit closer run to the east coast than earlier but very similar.
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444. wjdow
Quoting FloridaHeat:


i just signed on today and this is the first thing i see and it has me very concerned i have not seen anyone else on the news even mention florida as a possibility


sorry
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Quoting FloridaHeat:


i just signed on today and this is the first thing i see and it has me very concerned i have not seen anyone else on the news even mention florida as a possibility



dont listen to him he has been trolling all morning... it is getting rather annoying but just move on
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442. MahFL
Dare I say "pinhole" eye ?
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Quoting katrinakat5:
yes same to you storm w POOF


Man, you need to stop. Honestly....
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Quoting katroy:
I'm looking for a site where I can get the size of various wind fields for a tropical storm/hurricane. I know the NHC puts this in their Public Advisories (example below), but for hurricane-strength winds, they don't break it out by Category (i.e., Cat 1, Cat 2, Cat 3).

Example:
HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 185
MILES...295 KM.

This example is from the latest Advisory for Hurricane Earl (a Cat 3), so I'd like to know the size of the wind fields that are Cat 1, vs Cat 2, vs Cat 3.

Hope this makes sense. Thanks!


It's tough to say there are 'standard' distances from the COC for wind fields. Hurricane Charley had a very small wind field, but Hurricane Ike was huge...

Each storm is an individual.

If you start to research some storms, look for a stat called the RMW = Radius of Maximum Winds. That will show you how large the max wind field for the storm was, which has a major impact on surge flooding.
Member Since: June 20, 2005 Posts: 22 Comments: 1054
438. Vero1
Quoting divdog:
wave model shows 8-10 footers reaching the coast from central to the northern coast of florida as earl passes by.


Current:
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MELBOURNE FL
444 AM EDT MON AUG 30 2010


...WIND AND SEA IMPACT...
EAST TO NORTHEAST WINDS 15 TO 20 KNOTS WILL CONTINUE OVER THE
ATLANTIC COASTAL WATERS OFFSHORE. THE COMBINATION OF WIND WAVES
AND SWELL WILL PRODUCE TOTAL SEA HEIGHTS AROUND 7 FT OFFSHORE AND
5 TO 6 FEET NEAR THE COAST.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.
MARINE CONDITIONS ACROSS THE ATLANTIC WATERS OF EAST CENTRAL
FLORIDA WILL REMAIN HAZARDOUS WELL INTO THIS WEEK AS LONG PERIOD
SWELLS FROM MULTIPLE TROPICAL CYCLONES AFFECT THE AREA.

THE LONG PERIOD SWELL WILL MAKE FOR DANGEROUS CONDITIONS ON THE
COASTAL WATERS...BEACHES AND INLETS. A MODERATE TO HIGH THREAT FOR
RIP CURRENTS WILL LIKELY EXIST EACH DAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED OFFSHORE FOR A GOOD PORTION OF THIS
WEEK...AND NEAR SHORE FOR SEAS LATER IN THE PERIOD.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.

$$

SEDLOCK
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Just remember that you have to look for consistency on movement. Intense hurricanes love to wobble especially as they strengthen so keep in mind that you want to look for trends over several hours.
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07L/MH/E/C3 has 25 percent chance or greater to become a cat 5 storm the first of the 2010 season in atlantic
Member Since: July 15, 2006 Posts: 178 Comments: 55984
Quoting amd:
latest recon fixes suggests that Earl is finally beginning a true WNW motion (with an increase in speed)

1st fix: 18.5167 N 63.0000W 11:56:00Z
2nd fix: 18.6000 N 63.3333W 13:42:10Z
3rd fix: 18.8167 N 63.7333W 15:27:50Z

Also, pressures are falling quickly now with pressures of 964 mb, 960 mb, and 957 mb (with winds above 20 knots, so pressures could be 955 or 956 mb) respectively for each of the latest three vortex messages.




The track is pretty consistent over time
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Quoting angiest:


I wasn't here in '05, but I am pretty sure I remember stormtop had Gustav hitting NOLA directly as a cat 5. He seems to have to basic modes of operation. Storms swinging in the direction of LA (which Earl hitting South Florida would do), or just heading out to sea.


Yes all his forcast are generally to hit New Orleans... and he got one out of many correct ....all the others were wrong.

and even a broken clock is right two times every 24 hours.
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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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