Subtropical Depression 17 forms; monsoon rains kill over 100 in Asia

By: Dr. Jeff Masters , 1:04 PM GMT on October 06, 2010

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Subtropical Depression Seventeen formed this morning, approximately 200 miles north of Puerto Rico. The storm is not a threat to bring high winds to any land areas, but will produce heavy rains over Puerto Rico, the Virgin Islands, the northern Lesser Antilles, and perhaps the eastern Dominican Republic. Radar estimated rainfall over Puerto Rico and the Virgin Islands (Figure 1) shows rainfall amounts in excess of eight inches have fallen near St. Thomas in the Virgin Islands, and the St. Thomas Airport officially measured 6.61" yesterday--its 5th wettest day in history. St. Thomas has picked up an additional 1.48" today as of 9am AST. Not surprisingly, Flash Flood Warnings are posted for the island. Weather radar out of Puerto Rico shows that a large area of heavy rain will continue to affect the Virgin Islands and eastern Puerto Rico this morning. Martinique radar shows somewhat less activity over the Lesser Antilles.

Satellite loops show STD 17 has a broad, somewhat ill-defined center of circulation, with the heaviest thunderstorms 50 or so miles from the center. This is characteristic of a subtropical storm, which is a hybrid between a tropical storm and an extratropical storm. An upper level low pressure system to the west of STD 17 has pumped cold, dry air aloft into STD 17, keeping it from being fully tropical. As the trough gradually weakens today and Thursday, STD 17 should become fully tropical and intensify into Tropical Storm Otto. Steering currents favor Otto being lifted northwards and then northeastwards out to sea by Friday.


Figure 1. Radar-estimated rainfall from Subtropical Depression Seventeen over Puerto Rico and the Virgin Islands shows that rains in excess of eight inches (white colors) have fallen near St. Thomas.

Elsewhere in the tropics
Most of the models indicate the possibility that a strong tropical disturbance or tropical depression forming in the Southern Caribbean, off the coast of Nicaragua, 5 - 7 days from now.

Monsoon flooding kills 83 in Indonesia, 28 in Vietnam
Heavy monsoon rains triggered flash flooding in a remote section of Indonesia this week that killed at least 83 people. Another 68 people are missing, and 3,000 homeless. In Vietnam, heavy rains of up to 51" (1300 mm) have fallen since Friday, resulting in river flooding that killed at least 28 people. Over 34,000 people are homeless from the floods, which hit five provinces from Nghe An to Thua Thien-Hue, a swath of territory starting some 300 km (180 miles) south of Hanoi and stretching south. Heavy monsoon rains also hit nearby Hainen Island in China, forcing the evacuation of 64,000 people.

Jeff Masters

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I sit in the camp that one or possibly two systems are possible in the western Caribbean. Maybe even one fairly strong but I think after all is said and done this season has not lived up to the dire warning that had been issued. Although hindsight is always 20/20, everything was there except upper atmospheric conditions which are certainty not getting better at this time in the season.
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Quoting gordydunnot:
I don't attach any conspiracy to any of the classifications but at least three of theses systems are highly questionable. IMO


Well part of it is definitely subjective. For example, here is one of the first advisories from Frances in 1998, written by former senior hurricane specialist Miles Lawrence:

WHAT WE HAVE HERE IS A VERY POORLY ORGANIZED LOW PRESSURE AREA IN
THE WESTERN GULF OF MEXICO. IF THE SYSTEM HAD NOT ALREADY BEEN
DESIGNATED AS A DEPRESSION...I WOULD NOT DO SO AT THIS TIME.
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I don't attach any conspiracy to any of the classifications but at least three of theses systems are highly questionable. IMO
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In other news, looking forward to the VERY brief taste of fall in SEFL tomorrow.

Thursday
Breezy
Hi 81 °F

Thursday Night
Breezy
Lo 69 °F
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Quoting katadman:



Notice all that activity south of Cuba? Sure is a lot of moisture and energy left down there still.


The SW Carib system should start taking shape if it is to be. There is a lot of air piling up down there atm. I agree, the area is rather interesting tonight.
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Quoting CycloneBoy:


And yours is the type of comment that everybody loves. A non-expert who questions professionals and then argues something without a shred of knowledge...good work.


+100
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Quoting sunlinepr:



Notice all that activity south of Cuba? Sure is a lot of moisture and energy left down there still.
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Nuff said on the naming controversy, there's no conspiracy, do some research.

Hurricane Warning

CARIBBEAN SEA
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 PM EDT WED OCT 06 2010

OFFSHORE WATERS FORECAST FOR THE TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W...THE SW N ATLANTIC S OF 31N W OF 65W
INCLUDING BAHAMAS...AND THE CARIBBEAN SEA.

SEAS GIVEN AS SIGNIFICANT WAVE HEIGHT...WHICH IS THE AVERAGE
HEIGHT OF THE HIGHEST 1/3 OF THE WAVES. INDIVIDUAL WAVES MAY BE
MORE THAN TWICE THE SIGNIFICANT WAVE HEIGHT.

AMZ080-070930-
SW N ATLANTIC S OF 31N W OF 65W INCLUDING BAHAMAS
1130 PM EDT WED OCT 06 2010

...HURRICANE WARNING FROM 22N TO 28N E OF 70W...

.TONIGHT AND THU...TROPICAL STORM FORCE WINDS WITHIN 90 NM N
SEMICIRCLE 80 NM SW AND 90 NM SE QUADRANTS OF CENTER OF TROPICAL
STORM. HIGHEST WINDS 60 KT GUSTS 75 KT. SEAS 12 FT OR GREATER
WITHIN 180 NM NE QUADRANT...30 NM SE QUADRANT...90 NM SW
QUADRANT...AND 90 NM SW QUADRANT WITH HIGHEST SEAS 17 FT.
ELSEWHERE WITHIN 270 NM N AND 150 NM S SEMICIRCLES WINDS 20 TO
33 KT. SEAS 9 TO 12 FT N SEMICIRCLE AND 7 TO 9 FT S SEMICIRCLE.
W OF FRONT N TO NE WINDS 20 TO 25 KT. SEAS 8 TO 12 FT NE OF
BAHAMAS AND 7 TO 9 FT SW OF BAHAMAS. SCATTERED TO NUMEROUS
SHOWERS NEAR TROPICAL STORM.
.THU NIGHT...TROPICAL STORM FORCE WINDS WITHIN 100 NM NE...120
NM SE...100 NM SW...AND 90 NM NW QUADRANTS. HIGHEST WINDS 65 KT
GUST 80 KT. SEAS 12 FT OR GREATER WITHIN AREA OF TROPICAL STORM
FORCE WINDS WITH HIGHEST SEAS 18 FT. ELSEWHERE WITHIN 300 NM N
AND 210 NM S SEMICIRCLES WINDS 20 TO 33 KT. SEAS 9 TO 12 FT N
SEMICIRCLE AND 7 TO 9 FT S SEMICIRCLE. ELSEWHERE E OF 70W WINDS
15 TO 20 KT. SEAS 5 TO 8 FT. ELSEWHERE W OF 70W N TO NE WINDS 15
TO 20 KT. SEAS 8 TO 11 FT IN NE SWELL E OF BAHAMAS AND 4 TO 7 FT
W OF BAHAMAS. SCATTERED TO NUMEROUS SHOWERS AND TSTMS NEAR
TROPICAL STORM.
.FRI...OVER FORECAST WATERS TROPICAL STORM FORCE WINDS WITHIN
110 NM SW AND 85 NM NW QUADRANTS. HIGHEST WINDS 65 KT GUST 80
KT. SEAS 12 FT OR GREATER WITHIN AREA OF TROPICAL STORM FORCE
WINDS WITH HIGHEST SEAS 15 FT. ELSEWHERE WITHIN 270 NM W
SEMICIRCLE WINDS 20 TO 33 KT. SEAS 8 TO 12 FT. ELSEWHERE E OF
70W WINDS 15 TO 20 KT. SEAS 5 TO 8 FT. ELSEWHERE W OF 70W N TO
NE WINDS 15 TO 20 KT. SEAS 7 TO 10 FT IN NE SWELL E OF BAHAMAS
AND 4 TO 6 FT W OF BAHAMAS. SCATTERED TO NUMEROUS SHOWERS NEAR
TROPICAL STORM.
.FRI NIGHT...E OF 70W N OF 25N N TO NE WINDS 15 TO 20 KT. SEAS 8
TO 10 FT IN MIXED SWELL. S OF 23N E OF 68W SW TO W WINDS 10 TO
15 KT. SEAS 5 TO 7 FT. ELSEWHERE S OF 25N E OF 70W N TO NE WINDS
10 TO 15 KT. SEAS 7 TO 9 FT. W OF 70W NE TO E WINDS 10 TO 15 KT.
SEAS 5 TO 8 FT NE OF BAHAMAS...3 TO 5 FT SE OF BAHAMAS.
.SAT...W OF 70W N TO NE WINDS 10 KT. SEAS 4 TO 7 FT IN N SWELL E
OF BAHAMAS AND 2 TO 4 FT W OF BAHAMAS. E OF 70W NW TO N WINDS 10
TO 15 KT EXCEPT W TO NW WINDS S OF 22N. SEAS 5 TO 8 FT IN N
SWELL.
.SUN AND MON...NE TO E WINDS 10 TO 15 KT. SEAS 3 TO 6 FT E OF
BAHAMAS AND 2 TO 4 FT W OF BAHAMAS.

$$
FORECASTER AL





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Quoting KerryInNOLA:
This is the type of comment that big govermental agencies love. The loyal "citizen" who completely trusts the bureaucracy and who is willing to pay his last hard earned dollar for plenty of nothing.


And yours is the type of comment that everybody loves. A non-expert who questions professionals and then argues something without a shred of knowledge...good work.
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Kerry - I agree with your thought in principle, but Sherwood is right on this one.

They're calling it as they see it.

11pm discussion, for example, perfect, imo.
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Bigger picture:

Eastern US WV

N Atl WV

Along with others.

Signs of it in there to me but not likely.
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Yep.

No support except what I see on sat. :)
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844. beell
That's some serious grain to go against!
:)

Atl WV Loop
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Otto is going tropical.

Going against the grain, I would not rule out the possibility of the two H's bridging.
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Time and time again I see ego-centric people on this blog assuming that the NHC has its ego as the main priority; or paranoid conspiracy theorists, assuming the NHC has shady ulterior motives for classifying storms...

It's just PROJECTION! These comments are nothing more than a glimpse into the commenters' own inner workings.

The NHC has formulas for classifying storms. They follow them. They're not concerned about fighting to be right, they're not plotting against anyone, their jobs are not in jeopardy so their numbers do not need padding.

It's pointless to argue with people who make these comments about the NHC, because nothing you say will make a bit of difference to them. Their world is a very different place from ours. Just minus and move on. It's all you can really do.
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Quoting TropicalAnalystwx13:


Dude, you realize that Winds of over 60 mph WERE recored in Otto, right?

And that they've been naming non-tropical systems for a LONG time?
I believe that for most of the historical record we didn't asign a name to sub-tropical systems. Many ships were lost in gales at sea.
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SubtropicalStormOtto's heading had turned northeastward to (5.4degrees north of) NorthNorthEast
from its previous heading of (9.2degrees west of) NorthWest
StS.Otto's average speed moving between its last 2 reported positions decreased to ~3.7mph(~5.9km/h)
from its previous moving speed of 4mph(~6.4km/h)
Invest 97L -- 6hours between consecutive center positions
5Oct 06amGMT - - 18.6n65.0w - - 25knots - - 1006mb -- NHC-ATCF *18.5n65.0w
5Oct 12pmGMT - - 19.5n65.3w - - 30knots - - 1006mb -- NHC-ATCF *19.0n65.3w
5Oct 06pmGMT - - 20.6n65.7w - - 30knots - - 1004mb -- NHC-ATCF
6Oct 12amGMT - - 21.4n66.2w - - 30knots - - 1002mb -- NHC-ATCF *21.5n66.1w
6Oct 06amGMT - - 21.9n66.7w - - 30knots - - 1001mb -- NHC-ATCF
StD.17 -- 3hours between consecutive center positions
6Oct 12pmGMT - - 22.2n67.0w - - 35mph - - - 1001mb -- NHC.Adv.#1
6Oct 03pmGMT - - 23.0n68.0w - - 35mph - - - 1001mb -- #2
StS.Otto -- 6hours between consecutive center positions
6Oct 09pmGMT - - 23.2n68.3w - - 60mph - - - - 990mb -- #3
7Oct 03amGMT - - 23.5n68.2w - - 65mph - - - - 990mb -- #4
* Before NHC reevaluated&altered the ATCF numbers.
25knots=~28.8mph=46.3km/h __ 30knots=~34.5mph=~55.6km/h
35mph=~56.3km/h __ 60mph=~96.6km/h __ 65mph=~104.6km/h

Copy&paste 18.6n65.0w, 19.5n65.3w, 20.6n65.7w, 21.4n66.2w, 21.9n66.7w-22.2n67.0w, 22.2n67.0w-23.0n68.0w, 23.0n68.0w-23.2n68.3w, 23.2n68.3w-23.5n68.2w, bym, tbi into the GreatCircleMapper for a look at the last 21^hours.

^ The 2 northernmost line-segments individually span 6hours between dots.
The following line-segment spans 3hours between dots.
The southernmost line-segment spans 6hours between dots.
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AP photo of the storms that rolled through Phoenix:
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837. JLPR2
Quoting TropicalAnalystwx13:


Dude, you realize that Winds of over 60 mph WERE recored in Otto, right?

And that they've been naming non-tropical systems for a LONG time?


I didn't even bother answering him. -.-
Member Since: September 4, 2007 Posts: 7 Comments: 8493
Quoting TropicalAnalystwx13:
Anyone have proof that a Subtropical hurricane is not possible?


By definition, a hurricane is a completely tropical system. That is, to be classified as a hurricane, a storm must be a tropical cyclone with winds above 74 mph. Any cyclone displaying subtropical characteristics with winds above at or above 34 knots is a subtropical storm, even if those winds are, say, 100 knots.

IOW: if Otto's winds reach 65 knots or higher, and if he is completely tropical, he'll be Hurricane Otto. If either condition is unmet, he'll stay a subtropical storm regardless of wind speed or pressure.

Here

Member Since: November 8, 2009 Posts: 4 Comments: 13455
Quoting KerryInNOLA:
I see the NHC is at it again. Naming non tropical systems to inflate the numbers. This comes on top of their having already jumped the gun on Nicolle and possibly Bonnie and Gaston. An investigation into their motives is in order.


Dude, you realize that Winds of over 60 mph WERE recored in Otto, right?

And that they've been naming non-tropical systems for a LONG time?
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834. JLPR2
Now this blob is plain interesting and it has some, 500mb, 700mb and 850mb vorticity.



Seems official that Otto lost its band of convection. :P
Member Since: September 4, 2007 Posts: 7 Comments: 8493
832. JLPR2



Little weak spin there too.
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Anyone have proof that a Subtropical hurricane is not possible?
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827. Relix
Well nothing interesting for now in the Atlantic. Guess PR is safe for this season quite probably, and with Otto delivering a lacking show here I'll be off for a while.
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hey guys take a look at 42057

Link

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...OTTO STRENGTHENS A LITTLE...

SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.5N 68.2W
ABOUT 230 MI...370 KM NE OF GRAND TURK ISLAND
ABOUT 640 MI...1035 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/HR
PRESENT MOVEMENT...N OR 360 DEGREES AT 3 MPH...6 KM/HR
MINIMUM CENTRAL PRESSURE...990 MB...29.23 INCHES

000
WTNT42 KNHC 070235
TCDAT2
SUBTROPICAL STORM OTTO DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL172010
1100 PM AST WED OCT 06 2010

AFTER THE LAST ADVISORY WAS ISSUED...THE HURRICANE HUNTER AIRCRAFT
MADE ONE MORE PASS THROUGH THE CENTER OF OTTO AND MEASURED A PEAK
1500-FT FLIGHT-LEVEL WIND OF 68 KT IN THE SOUTHEASTERN QUADRANT...
CORRESPONDING TO ABOUT 54 KT AT THE SURFACE. AN SFMR WIND OF 55 KT
WAS ALSO REPORTED EARLIER IN THE MISSION...AND THAT WILL BE THE
INITIAL INTENSITY IN THIS ADVISORY. WATER VAPOR AND INFRARED
IMAGERY SHOW THAT THE SURFACE AND UPPER-LEVEL LOW ARE ALMOST
COLLOCATED...BUT RECENT AMSU DATA INDICATE THAT THE WARM CORE IN
THE MID-LEVELS OF THE CIRCULATION IS STRENGTHENING. ALTHOUGH OTTO
STILL LOOKS LIKE A CLASSIC SUBTROPICAL CYCLONE IN SATELLITE
IMAGERY...IT APPEARS TO BE SLOWLY GAINING TROPICAL CHARACTERISTICS.

VERTICAL SHEAR IS EXPECTED TO BE LIGHT FOR THE NEXT 48 HOURS OR
SO...AND THE CYCLONE HAS AN OPPORTUNITY TO STRENGTHEN DURING THAT
PERIOD. THE STATISTICAL INTENSITY GUIDANCE SHOWS THE MOST
STRENGTHENING AND BRINGS OTTO TO AN 80-KT HURRICANE...BUT THESE
MODELS PROBABLY DO NOT HANDLE TRANSITIONING SUBTROPICAL CYCLONES AS
WELL AS PURE TROPICAL CYCLONES. THE OFFICIAL FORECAST LEANS CLOSER
TO THE DYNAMICAL HURRICANE AND GLOBAL MODELS AND SHOWS OTTO
REACHING 65 KT FROM 24 TO 48 HOURS BEFORE THE SHEAR INCREASES.
GRADUAL WEAKENING IS EXPECTED THEREAFTER WITH OTTO BECOMING AN
EXTRATROPICAL CYCLONE BY 96 HOURS...IF NOT SOONER.

THE INITIAL MOTION IS 360/3. THE TRACK GUIDANCE REMAINS IN
GENERALLY GOOD AGREEMENT...AND LITTLE CHANGE WAS REQUIRED TO THE
PREVIOUS FORECAST TRACK. OTTO SHOULD MOVE LITTLE FOR THE NEXT 12
HOURS OR SO BEFORE ACCELERATING NORTHEASTWARD BETWEEN A MID-LEVEL
HIGH OVER THE CENTRAL ATLANTIC AND A MID/UPPER-LEVEL TROUGH OVER
THE WESTERN ATLANTIC.

FORECAST POSITIONS AND MAX WINDS

INITIAL 07/0300Z 23.5N 68.2W 55 KT
12HR VT 07/1200Z 23.9N 68.1W 60 KT
24HR VT 08/0000Z 24.7N 66.9W 65 KT
36HR VT 08/1200Z 26.0N 64.8W 65 KT
48HR VT 09/0000Z 27.8N 61.6W 65 KT
72HR VT 10/0000Z 32.0N 52.0W 60 KT
96HR VT 11/0000Z 37.0N 38.5W 45 KT...POST-TROP/EXTRATROP
120HR VT 12/0000Z 42.0N 27.0W 40 KT...POST-TROP/EXTRATROP

$$
FORECASTER BERG
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Well, since there is No Imminent Threat to anyone.
(except from Orca, of course)
I will go to bed.
Keep safe all.......
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Quoting Orcasystems:


I think I might have to make a humorous version.

Oh!
I thought that was it....

LOL
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Quoting pottery:

Thanks.
But I am ahead of you. I already filled it out and have it here waiting....
heheheh


I think I might have to make a humorous version.
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Quoting Neapolitan:
For those using the incorrect developmental designators, here's a snippet from the official NOAA/ATCF list:

TS - tropical storm
TY - typhoon
ST - super typhoon
TC - tropical cyclone
HU - hurricane
SD - subtropical depression
SS - subtropical storm
EX - extratropical systems
PT - post tropical
IN - inland
DS - dissipating
LO - low
WV - tropical wave
ET - extrapolated
XX - unknown


best be careful with (XX - unknown), might get
community standardized like 50% of the comments.
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If Otto was a big hurricane effecting land, I would have coined it, "Otto, OhmyGodOh!" Pretty slick, huh?? I haven't had such a score since, "Katrina and the waves!"
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Quoting Orcasystems:


You might as well bookmark this now

POTTERY'S BUSTED FORECAST ALIBI

Thanks.
But I am ahead of you. I already filled it out and have it here waiting....
heheheh
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818. beell
Quoting WeatherMum:
and yet it still is warm enough to swim and play in......ahhhhh it was a lovely afternoon !


Extreme (-ly nice) weather!
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Quoting pottery:

LOL.
Nop...
and in any case, it is now Petit Careme (small dry season), so it's going to be Bright and Cheerfull for 2 weeks.
(this is written in chalk....)


You might as well bookmark this now

POTTERY'S BUSTED FORECAST ALIBI
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Quoting beell:
Very good conditions for radiational cooling in the GOM.

Dry air- Even when skies are clear, water vapor in the air will absorb and emit longwave radiation. Humid air can act like cloud cover when it comes to longwave energy trying to escape. It is ideal to have low dewpoints throughout the atmosphere...

Link
and yet it still is warm enough to swim and play in......ahhhhh it was a lovely afternoon !
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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.