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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I am getting real nervous here in Nova Scotia..a cat 1/2 sounds bad, new models showing cat 4/5 off NY would mean likely cat 2/3 hit in NS...OMG

So much can happen, but as it stands now, it's nervewracking
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1230. angiest
In two different recent velocity scans the San Juan radar has reported 122kt winds.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting FloridaHeat:
what does it mean for the ridge to "nose" on top of earl


Just a figure of speech actually. It is used to describe the sharp end of a ridge of high pressure that sticks out as opposed to a ridge that has a more rounded structure like a ball, kind of like how the nose on your face sticks out in a profile view.
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1223. Patrap
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Quoting yonzabam:
Looks NW to me.


Earl moving NW

I agree looks more NW than West.
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Wow Earl is a MONSTER. Praying for all those it might eventually affect.
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Quoting yonzabam:
Looks NW to me.


Earl moving NW


Looks like a more western movement in the last frame or two.
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Quoting TampaSpin:
I sure Hope the city of NY is ready for such a possbile REAL THREAT NOW.......WOW!


You're right. An NY landfall certainly isn't out of the question.

If you are from NYC, I urge you to call friends and family who are not into meteorology and warn them of this very viable threat. Not many NYC residents have experienced a hurricane, and thus don't know how to prepare for it. If you do, I urge you to inform them.
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1218. Patrap
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1217. Thaale
Quoting NASA101:

That's not a 12Z EURO! That's a 00Z EURO - EURO models come out twice a day, hence 00Z and 12Z!

Just checked 12Z EURO has FIONA back in the GULF through Cuba - at 240 hrs it has FIONA shockingly at 932mb in central-northern GULF!!


That was yesterday's Euro. Today's is leaping back to the Atlantic.
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Thanks for the reply, Hurricane4life.....I live in Cape Breton, right beside the beach! I'm preparing for Earl, just incase! I was living in Halifax during Hurricane Juan, and it scared the living bejeesus out of me!
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Looks NW to me.


Earl moving NW
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AL, 06, 2010083018, , BEST, 0, 410N, 501W, 60, 973, TS
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1212. HadesGodWyvern (Mod)
939 hPa for Earl
Dvorak Intensity: 6.5
125 knots..

dang he has changed since I last looked.
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1209. NJ2S
Quoting GetReal:


right on target
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Quoting FloridaHeat:
what does it mean for the ridge to "nose" on top of earl


Not "nose on top" but "nose over"...if the ridge extends eastward and passes over the "top" of Earl, it will effectively close off the trof and he will not have the weakness to turn into, pulling him out, first NW, the N then NE...he will be "trapped" in a more westerly course
Member Since: August 2, 2006 Posts: 10 Comments: 9922
we now have a CAT 4

AL, 07, 2010083018, , BEST, 0, 190N, 642W, 115, 954
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1205. shawn26
Earl looks to be moving just South of West in the last few frames.
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Quoting CybrTeddy:
ECMWF now showing a Category 4/5 Hurricane heading towards New York (Earl)

Not wishcasting, just telling what it shows.


Just dropped my Daughter off for college in New Haven, Conn last weekend so I am watching this very closely even though I live in Florida........Will have to fly her out (back to Florida) if this model pans out.......LOL
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1203. angiest
Quoting yonzabam:


Earl was due east of PR earlier today and is now NE of it. That's a NW movement.


No, it has been a very consistent WNW motion at around 295 degrees.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
I sure Hope the city of NY is ready for such a possbile REAL THREAT NOW.......WOW!
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1201. NASA101
Quoting CoopNTexas:
12z EURO sends 97L/Fiona out to sea


That's not a 12Z EURO! That's a 00Z EURO - EURO models come out twice a day, hence 00Z and 12Z!

Just checked 12Z EURO has FIONA back in the GULF through Cuba - at 240 hrs it has FIONA shockingly at 932mb in central-northern GULF!!
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Quoting RitaEvac:


Follow StormW. His focus is on Earl right now, but 97L or Fiona he will talk about later

Again, Thanks. Have gone through enough storms (Betsy, Camille, Elena, Katrina, to name some of them) to know how life changing they can be. I worry, as does everyone else, maybe cos I am on my own and know how hard it can be.
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Quoting StormW:


I hear ya kman! I'm puttin that mojo on da ridge to keep it in place.

Storm, could you elaborate a little...as usual, I am confused
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Quoting WatchingThisOne:


You seem to under the impression that The Weather Channel is a weather channel. It's a common error.


I agree - TWC has changed drastically - I can even watch US economic and political news! Its all we have in Belize along with the local Mets...hence the reason I am on this blog :)
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Quoting WatchingThisOne:


My understanding is that the box is not exactly a forecasting tool, but more of a rear view thing. Looking at major hurricanes landfalling in South Florida, you will find that 9 out of 10 of them had passed through the box(es) before landfall.

That does NOT mean that 9 out of 10 major hurricanes that pass through the box will landfall as majors on South Florida. If it did, there would be a whole lot more action in South Florida than there is in terms of boarding up and such.



I don't think FL is in play here but you may want to read back your statement. Doesn't sound logical :)
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For those of you in Nova Scotia, I personally believe it will be a similar storm to bill of last year and not juan of 2003. The strongest winds will remain on the north east side of the storm when it is in your region. So as long as the center of circulation remains to the east of you should fair out alright. However wind gusts of 100-120km will be felt in coastal communites, and waves will probably be 5m high or so.
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1195. angiest
Quoting PcolaDan:


I know, they show the "uncertainty" quite well. That's why they are so big. People were talking last night about how the NHC could be so far off. Well they weren't really. Earl has stayed in the cone, albeit on the left side, but the cone moves, as it should.
Hm can't quite convey what I'm trying to say.


Ike stayed within his cone too, but wound up hundreds of miles from where he was expected to go.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1194. Patrap
Visible rapid scan Loop,EARL
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From my local NWS (MHX)

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MON...THE LAST HALF OF THE WEEK WILL CONTINUE TO BE
DEPENDENT ON THE TRACK OF HURRICANE EARL. OFFICIAL NHC TRACK
CONTINUES TO SHOW EARL MAINTAINING MAJOR HURRICANE STATUS...BUT
REMAINING OFFSHORE OF CAPE HATTERAS THU INTO THU NIGHT. MODELS IN
PRETTY GOOD AGREEMENT OVERALL WITH TRACK OF EARL...THOUGH NAM
CONTINUES TO BE SLIGHTLY SLOWER. BEST CHANCE OF RAINFALL WILL BE
ALONG THE COASTAL AREAS...PRIMARILY THE OUTER BANKS. HURRICANE
EARL IS EXPECTED TO IMPACT COASTAL REGIONS THURSDAY AND THURSDAY
NIGHT WITH STRONGER WINDS...INCREASED RIP CURRENT RISK FOR ALL
BEACHES...INCREASED SURF...AND POTENTIAL FOR COASTAL FLOODING. AT
THIS TIME...THERE IS STILL MUCH UNCERTAINTY IN THE TRACK OF THE
SYSTEM. IT WILL CONTINUED TO BE MONITORED AS THE IMPACTS FROM THE
SYSTEM COULD VARY GREATLY DEPENDING UPON THE TRACK.

HURRICANE EARL SHOULD PULL OUT OF THE AREA FRIDAY MORNING WITH
WESTERLY FLOW DRYING THINGS OUT. A WEAK FRONT WILL DROP THROUGH
THE AREA SATURDAY MORNING BUT WITH LIMITED MOISTURE. HAVE KEPT
SLIGHT CHANCE WITH THE FRONT. HIGH PRESSURE WILL BUILD IN TO THE
NORTH OF THE AREA SUN-MON.
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1192. Engine2
Quoting kmanislander:


Not trapped but would delay the turn to the NW.
Earl will likely be too strong to be trapped now with a weakness off to the NE unless the ridge was build far East over him and push the weakness well off to the NE where it would be blocked off itself. There are no indications of any of that at this time.

There is also the trough that is forecasted to dig down from the NW and pick up Earl to the NE.
That is an event still to come.
OK I understand - thank you!
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DestinJeff, please post your graphics from Post 1070 again.

They did not make the blog. Something was corrupt.

Really want to see those barometric maps. That's where we can see what is going to play out with Earl.

Thanx!
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1190. divdog
Quoting FloridaHeat:


the scary thing is i am starting to think you may be right but then again if i read something enough times maybe im just starting to believe it
dude we warned you about him hours ago.. if you do not want to listen i guess that is your choice. dont add to the drama.
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1189. angiest
Quoting GeoffreyWPB:


Do people even read the NHC Discussions anymore?

EARL IS EXPECTED TO TURN TOWARD
THE NORTHWEST WITHIN THE NEXT DAY OR SO AS IT MOVES AROUND THE
WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF
DAYS.


From discussion 1. Sounds like what you posted, except this was a few days ago:


THE DEPRESSION IS MOVING TOWARD THE WEST OR 275 DEGREES AT 15 KNOTS
TO THE SOUTH OF A SUBTROPICAL RIDGE. THIS GENERAL MOTION IS
EXPECTED TO CONTINUE DURING THE NEXT 2 TO 3 DAYS. THEREAFTER...THE
CYCLONE MOST LIKELY WILL DECREASE IN FORWARD SPEED AS IT REACHES A
WEAKNESS IN THE SUBTROPICAL RIDGE LEFT BY DANIELLE. BY THEN...THE
CYCLONE SHOULD BEGIN TO TURN TOWARD THE WEST-NORTHWEST. THE
OFFICIAL FORECAST IS BASICALLY IN THE MIDDLE OF THE TIGHTLY
CLUSTERED GUIDANCE ENVELOPE. MOST OF THE NUMERICAL GUIDANCE SHOWS A
PERSISTENT TROUGH OVER THE WESTERN ATLANTIC. IF THIS PATTERN
MATERIALIZES...IT WOULD STEER THE CYCLONE TOWARD THE NORTHWEST AWAY
FROM THE LESSER ANTILLES.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
1188. trey33
Definitely breezy today in downtown Tampa, which is a nice change from the stagnant steamy heat of the last month.
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Quoting CybrTeddy:
ECMWF now showing a Category 4/5 Hurricane heading towards New York (Earl)

Not wishcasting, just telling what it shows.




i new it would come some day
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Quoting TampaTom:


You do realize how that cone is derived, correct?

http://hurrnet.com/tutorial/forecasts/track/cone.html


I know, they show the "uncertainty" quite well. That's why they are so big. People were talking last night about how the NHC could be so far off. Well they weren't really. Earl has stayed in the cone, albeit on the left side, but the cone moves, as it should.
Hm can't quite convey what I'm trying to say.
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1185. HadesGodWyvern (Mod)
1148. Capeskies 6:33 PM GMT on August 30, 2010
I just hope that they all don't hit the same place.


Lionrock is suppose to make landfall over southern China

Kompasu is suppose to make landfall over southern Japan islands, skirt eastern China, and make landfall over Korea

Namtheun is suppose to make landfall over Taiwan
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Quoting Engine2:
Is the thinking if the ridge nosed over top of him that he would be trapped on a westerly course?


Not trapped but would delay the turn to the NW.
Earl will likely be too strong to be trapped now with a weakness off to the NE unless the ridge was build far East over him and push the weakness well off to the NE where it would be blocked off itself. There are no indications of any of that at this time.

There is also the trough that is forecasted to dig down from the NW and pick up Earl to the NE.
That is an event still to come.
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Quoting FLdewey:

Do you need a lesson on the ignore feature?

Just ignore the troll, otherwise you're just facilitating the disruption.


Snakes and mice come to mind...
Member Since: August 2, 2006 Posts: 10 Comments: 9922
Hey Senior Chief and Hey Flood,

Just watching as this all unfolds. It will be intersting to see where Earl ends up and how things pan out after 9/7 as Storm mentioned about the African storm train taking off.

Semper Paratus,

Dave
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Quoting yonzabam:


Earl was due east of PR earlier today and is now NE of it. That's a NW movement.


wnw actually...And pretty much in line with guidance for now. Granted, he is remaining on the southern edge of guidance. He's done that for quite a while now...But again, he is still staying within guidance and the cone.
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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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