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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Ok so Ive really got issues when it comes to understanding hurricanes on radar when it comes to rain. Having to mix in the spin with fwd motion really does me in.
I am in Eastern Puerto Rico (Humacao) and it has been pretty dry and windless for a while now. Safe to say the worst has passed or is everything south of St Croix going to make it's way in to PR?
Thanks!
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Quoting GetReal:



Azores high strengthening and nosing westward, north of Earl, preventing a more pronounced WNW to NW turn.... IMO


GR, that's lookin' like troubles, friend.
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1428. angiest
Quoting Tropicaddict:


Thank you...what is the liklihood that Earl misses it?


I wouldn't want to venture a guess. It is not *supposed* to miss it, but he, so far, is not showing any definitive sign that he is going to make it through.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting lickitysplit:
Just think. If Earl hits NYC is may just wash the scuzz off of Wall St.


How about... if Earl hits NYC as a Cat 2 or greater, it will;
1) Devastate one of the largest ports in the U.S.
2) Seriously wipe out one of the largest, busiest airports in the U.S.
3) Knock out the financial hub of the U.S. for banking and stock trading for the foreseeable future.
4) Knock out major rail transport terminals for the North-East
5) Flooding may ruin the aged electrical, steam and plumbing infrastructure under New York City.
6) Flood many historical buildings.
7) Probably knock out power for MONTHS to major portions of Long Island and Lower Manhattan.
8) The disorder and chaos of a New York without power, water or gas makes the aftermath of Katrina look tame by comparison.

A landfall around the coast of New York would affect an area MUCH bigger than just New York City. It will impact daily life for Millions of people who live a thousand miles from the storm. It's not a good scenario and one our country doesn't need right now.

9) Oh, yeah... and then there's the human aspect of the devastation as well.
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1426. HCW
Quoting Hurricanes101:


how did you get it to zoom out?


Go here and you can do what you want with the radar :)

Link
Member Since: August 10, 2002 Posts: 0 Comments: 1409
1425. snowboy
90 degrees and cooking here in Canada near Toronto. The famous trough nowhere in sight - we MAY see it late Thursday.

Interesting Forecaster Discussion for nearby Buffalo which speaks for itself:

Long term /Thursday through Sunday/...

At the start of the period strong ridging will still be in place
across the eastern third of the nation on Thursday. This is in part
due to Hurricane Earl...with the impacts of its outflow on the upper
troposphere helping to hold the ridge up and the approaching middle
latitude system at Bay for about a day longer than it would
otherwise. By Friday Earl will be gaining latitude and allow the
next Pacific system to spread east into the Great Lakes region. By
next weekend most model guidance allows a trough to dig into the
Great Lakes and northeast...although there are expected differences
with amplitude.


Looking at the details...on Thursday a weakening frontal boundary
will try to sag south towards the region...but will be held at Bay
and wash out owing to strong/persistent ridging over the northeast.
Model consensus among the past few runs of the GFS/ECMWF/gefs mean
give enough confidence to remove mention of precipitation for Thursday.
850mb temperatures up around +20c will bring one more very warm day. A
surface cold front is then forecast by GFS/European model (ecmwf) and most ensemble
members to sweep across the area late Thursday night or Friday. Will
continue with chance probability of precipitation for this period.
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The ridge moving westward is a good thing, it helps to open that slight weakness enough to help Earl turn NW

What we do not want is for the ridge to move NE
Member Since: March 10, 2010 Posts: 1 Comments: 7872
Quoting Tropicaddict:
Sorry if this has already been asked and answered...but, what exactly is keeping Earl out of the Gulf/Caribbean? Is it the trough that is SUPPOSED to pull it North?? If the trough doesn't, what will steer it?


Its not going in the Gulf. The trough will steer Earl, it just depends on how much and when.
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1422. angiest
Quoting GetReal:



Azores high strengthening and nosing westward, north of Earl, preventing a more pronounced WNW to NW turn.... IMO


The break looks like it is getting kinda small.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
wow it seems the NHC has dropped 97L by 72 hoursLink
Member Since: June 29, 2007 Posts: 0 Comments: 1136
1420. will40
ty Stef i may well need them i will send back if i dont use them tho :-)
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I am getting worried for Haiti. I know it is suppose to turn NW, but what a disaster for Haiti if it does not.
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Quoting angiest:


There is a break between the A/B high and the eastern US high that was left by Danielle. If he misses that break, well... steering looks more west.


Thank you...what is the liklihood that Earl misses it?
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Quoting sarepa:
Did Earl just did a little jog to the west?

I believe its doing some wobbles right now.. To the west and a lil to the North.. The question is Does keep going more west past Puerto Rico.. Or does it start making that turn b/c its feeling that ridge to the north..
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do you think the track may shift more west at 5 pm
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1415. Relix
.1N
.4W

Heh, so much for the NW movement so far. 3 more hours of this and PR should get stronger winds.

So far here in Toa Baja getting gusty once more. Not many rains but definitely lots of breeze now. Preparing for the worst which should come soon!
Member Since: August 3, 2006 Posts: 0 Comments: 2741
1414. GetReal



Azores high strengthening and nosing westward, north of Earl, preventing a more pronounced WNW to NW turn.... IMO

Watch out those in the Se Bahamas....
Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting GetReal:


how did you get it to zoom out?
Member Since: March 10, 2010 Posts: 1 Comments: 7872
1412. angiest
Quoting Tropicaddict:
Sorry if this has already been asked and answered...but, what exactly is keeping Earl out of the Gulf/Caribbean? Is it the trough that is SUPPOSED to pull it North?? If the trough doesn't, what will steer it?


There is a break between the A/B high and the eastern US high that was left by Danielle. If he misses that break, well... steering looks more west.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
I dont think Beell is a "fellow"
Member Since: June 29, 2007 Posts: 0 Comments: 1136
Quoting GetReal:


west again after a north wobble............ omg
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1409. sarepa
Did Earl just did a little jog to the west?
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Closest approach to PR is coming up soon. I'm thinking 90-100 miles.
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Quoting myway:
Considering we may have a major hurricane impacting people. Can we at least stop the political stuff until there are no storms to watch. It never turns out well no matter what side you are on.


+1 one of the better today
Member Since: September 9, 2007 Posts: 36 Comments: 4687
1406. angiest
Over the last hour (using the 2position fix as a starting point) I see a ~306 degree motion. Earlier in the last hour it was ~316 degrees.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1404. RJT185
Quoting VAbeachhurricanes:


probable flash flooding occuring in central puerto rico, hope everyones hangin on tight


Jayuya is drowning pretty bad now, my grandma says a lot of the plaintain "trees" are going to be lost since the ground wont be able to support them as the winds blow around.
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Sorry if this has already been asked and answered...but, what exactly is keeping Earl out of the Gulf/Caribbean? Is it the trough that is SUPPOSED to pull it North?? If the trough doesn't, what will steer it?
Member Since: Posts: Comments:
1402. FLdewey
Quoting 1992Andrew:
Okay. No politics.

You can take light political jabs with a slight weather related tone, but much more than that and the natives turn on you. I should have warned you. ;-)
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1401. GetReal
Member Since: July 4, 2005 Posts: 204 Comments: 8898
Quoting FLPandhandleJG:


Hmm.. Time consuming.. How far west will Earl go.. Or will it get picked up by that trough..


is the brownish/organge color on that map the trough that will turn him
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Okay. No politics.
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1398. FLdewey
Quoting hydrus:
The wave off of Africa looks like a pouch.

Respect the pouch. RESPECT IT!
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1397. snowboy
From 3 pm NHC advisory:

HAZARDS AFFECTING LAND
----------------------
WIND...HURRICANE CONDITIONS WILL GRADUALLY SUBSIDE OVER THE
NORTHERN VIRGIN ISLANDS DURING THE NEXT FEW HOURS. TROPICAL STORM
CONDITIONS ARE EXPECTED TO SPREAD OVER PORTIONS OF PUERTO RICO THIS
AFTERNOON...WITH HURRICANE CONDITIONS POSSIBLE THIS EVENING AND
TONIGHT. STRONGER WINDS...ESPECIALLY IN GUSTS...ARE LIKELY OVER
ELEVATED TERRAIN IN PUERTO RICO.

STORM SURGE...STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS 3 TO
5 FEET ABOVE GROUND LEVEL PRIMARILY NEAR THE COAST IN AREAS OF
ONSHORE WIND WITHIN THE HURRICANE WARNING AREA...AND 1 TO 3 FEET IN
THE TROPICAL STORM WARNING AREA. THE SURGE WILL BE ACCOMPANIED BY
LARGE AND DANGEROUS BATTERING WAVES.

RAINFALL...EARL IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS
OF 4 TO 8 INCHES OVER THE LEEWARD ISLANDS...THE VIRGIN ISLANDS AND
PUERTO RICO...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 12 INCHES...
ESPECIALLY OVER HIGHER ELEVATIONS. THESE RAINS COULD CAUSE
LIFE-THREATENING FLASH FLOODS AND MUDSLIDES.
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1396. angiest
Quoting CybrTeddy:
The 21B advisory did not have a Category 4 because the information on the upgrade to Category 4 status came out while they where writing it, at 5 pm it will have it.


That could warrant an Update message.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1395. trey33
Quoting CoopNTexas:
yes...future Fiona 12z euro...Georgia


Can someone pretty please post a pic for 12z euro Fiona - where is she on Monday / Labor Day?
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Where is Beell and Sully to give us some CONUS trough yack?


C'mon fellas! ;P
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1393. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #3
TROPICAL STORM NAMTHEUN (T1008)
3:00 AM JST August 31 2010
=============================

SUBJECT: Category One Typhoon In East China Sea

At 18:00 PM UTC, Tropical Storm Namtheun (994 hPa) located at 25.6N 121.3E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The cyclone is reported as moving southwest at 8 knots.

Dvorak Intensity: T2.5

Gale Force Winds
================
60 NM from the center

Forecast and Intensity
======================
24 HRS: 25.3N 120.7E - 40 knots (CAT 1/Tropical Storm)
48 HRS: 24.6N 120.7E - Tropical Depression
Member Since: Posts: Comments:
Quoting NEwxguy:
Hmmm,I'm suppose to fly out of Boston Friday at 6:30 p.m.that almost cinches he's coming my way.If I fly any where in the winter,we usually get a blizzard,thus I fly somewhere in the fall we get hurricane,who needs models.


All I have to do is go major grocery shopping and then I can guarantee that I have a target on my house. I lost approximately $300 in groceries when Charley hit.
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1391. hydrus
Quoting jason2010xxxx:
wow at 24 west
The wave off of Africa looks like a pouch.
Member Since: September 27, 2007 Posts: 1 Comments: 21744
Hey StormW,

What is the confidence factor compared to normal with Earl 72-96hrs out. From the sounds of it, it seems as though this is a low confidence forcast that NHC has put out?
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Hmm.. Time consuming.. How far west will Earl go.. Or will it get picked up by that trough..
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1353:

It's the NHC low-balling it again. They did the same thing with Alex.

Sometimes, they don't report any new strengthening in the "official" update until 3 to 6 hours after the data are first gathered...even though their own data that they have already published showed 125kts...which is ~144mph...

Maybe they discarded the data or couldn't verify it or something, but what about the consistent 115kts that several other data points had? Even 115kts = 132mph, which is still category 4...
Member Since: June 13, 2010 Posts: 0 Comments: 2336
EYE OF EARL PASSING JUST NORTH OF THE BRITISH VIRGIN ISLANDS...
3:00 PM AST Mon Aug 30
Location: 19.1°N 64.4°W
Max sustained: 125 mph
Moving: WNW at 15 mph
Min pressure: 955 mb
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1386. HCW
18Z Earl runs from the NHC with Wind intensity

Member Since: August 10, 2002 Posts: 0 Comments: 1409
1385. DVG
Storm....re the continental ridge. Was the center in N mexico and now moving ne and is S Texas? Second...is that good, bad, indifferent?
Member Since: August 29, 2007 Posts: 0 Comments: 264
there are several floating buoys in the path of earl. sould be interresting getting data
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1383. myway
Considering we may have a major hurricane impacting people. Can we at least stop the political stuff until there are no storms to watch. It never turns out well no matter what side you are on.
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The 21B advisory did not have a Category 4 because the information on the upgrade to Category 4 status came out while they where writing it, at 5 pm it will have it.
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.4N .8W...the overall movement over the last 4 hours is WNW or 292.5 degrees.
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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.