Category 3 Hurricane Earl pounding northern Lesser Antilles and Puerto Rico
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
Reader Comments
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They show the TS, 50-kt, and 64-kt wind radii.
SNORT
The ECMWF showed Earl hitting NYC on the 12z run.
Will it happen? Probably not but it shows the many variables of the situation.
Be careful out there... been reading your posts.
thanks for providing them as you can.
what island are you on again? I forgot but I know it is one of the ones in the path here.
Different wind radii (all those numbers at the end) for each level, 34kt, 50kt and 64kt.
http://tropics.hamweather.com/maps/clir/atlantic/loop.html
If it did pan out for the NE, the good news is that the storm should be picking up speed by the time it got out there so it would be a relative short-lived wind event as opposed to a flooding event.......Of course the question is how strong the winds would be.
thanks... I wonder if NHC will every add 100 knt radius to their maps???
Again, if a poss Cat 3/4 is only 50-100 miles off our coast this friday,,,think hurricane force gust should be expected for Va Beach?
I'm running for the Catskills!!
'tis the season.
This would look odd in April.. but totally expected now...
http://www.stormcarib.com/reports/current/anguilla.shtml
- O-M-G!!!!!
* By "Steve Donahue"
* Date: Mon, 30 Aug 2010 14:31:49 -0400
2:15 PM – Monday
Back on line with gen power – battery pack & laptop both went down. So Earl was supposed to have gone by early morning and tht was it. Didn’t happen. Was a lot of wind during the night and especially this morning when my wind meter broke at 88 mph. with the wind from the west. Wind started to clock around to the SW and when it got south, it started REALLY blowing – I guess because of the SE quadrant. I recall what 88 mph was like and these winds had to be over 100 mph. They started about 11:30 or 12:00, and are just dying now – a little. I know they were stronger because up until then, we just lost branches – at noon, we started losing trees and electric lines. It’s been raining for a good 3 – 4 hours now, about 1.5 in. so far. The seas are unbelievable - the south shore will definitely get the worst of it. Starting to die a little, but the past 3 hours were the worst. Cheers, Steve
Steve Donahue
www.anguilla-weather.com/
Anguilla, AI2640, B.W.I.
US Phone – 410-505-8661
Anguilla Phone – 264-497-8177
TCPAT2
BULLETIN
HURRICANE EARL INTERMEDIATE ADVISORY NUMBER 21B
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010
300 PM AST MON AUG 30 2010
...EYE OF EARL PASSING JUST NORTH OF THE BRITISH VIRGIN ISLANDS...
probably for us on the coast, how far from the coast are you?
I'm worried. Apathy is one problem. Other concern: Closing down the City will cost biliions in lost revenues(just the interruption to Wall Street operations would cost billions if this thing hit on weekday)plus the evacuation of millions of people would create a logistical nightmare (the evacuation of Long Island's 3 million residents would be through the city), compounding problems, along with the speed that these systems usually move as they run up the coast. My concern is that government officials will wait too long in sounding the alarm. I mean what elected official would be so ready to commit political suicide if he called an evac and ....nothing happened?
Someone needs to cut the umbilical cord.
AL, 06, 2010083018, , BEST, 0, 410N, 501W, 60, 973, TS, 34, NEQ, 180, 240, 240, 210, 1009, 300, 60, 0, 0, L, 0, , 0, 0, DANIELLE, D,
AL, 06, 2010083018, , BEST, 0, 410N, 501W, 60, 973, TS, 50, NEQ, 90, 120, 90, 90, 1009, 300, 60, 0, 0, L, 0, , 0, 0, DANIELLE, D,
Cat 5 at 11 PM???
When will he have a better grasp on Earl??
The OBX seems like we will be fine but if not we may be caught off guard. What are your thoughts on the future path, seems it changes with each model run. When will the next model runs be??
This morning we were really in the cone, now not so much. Do you think we will remain just outside of the cone from this point on???
Its going nuts! May make that 5 ?
..then it fun in the dark
I thought that was Fiona?
I thought the 12z runs didn't come out for ecmwf till about 4????
probable flash flooding occuring in central puerto rico, hope everyones hangin on tight
If they do, they would probably call it 96-kt to coincide with the major hurricane threshold.
Respect WWB, always appreciate your posts, but I see it the other way around. A major category storm moving at a fast clip would be extremely devastating at landfall, imo - like a Cat 3 or 4 shot out of a cannon - a horrific wind event. The only advantage I could see would possibly be that a fast-moving storm would not have as much time to build an expanding windfield and subsequently push a larger volume of surge over a broader area. Nonetheless, surge at impact, in front/right of the eyewall, would also be devastating.
If Earl is gonna feel and move towards this Danielle weakness, I sure wish it'd get on with it! ;)
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