NHC increases hurricane forecast lead times

By: Dr. Jeff Masters , 7:27 PM GMT on January 05, 2010

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The National Hurricane Center (NHC) announced today that beginning with the 2010 hurricane season, their hurricane and tropical storm watches and warnings for the U.S. coast will be extended in time by an additional 12 hours. Warnings will now be issued 36 hours in advance instead of 24 hours, and watches will be issued 48 hours in advance, instead of 36 hours. The increase in lead time for watches and warnings has been made possible by the tremendous improvement in hurricane track forecasts, which have improved by over 50% in the past twenty years (Figure 1). "With increases in population and infrastructure along vulnerable U.S. coastlines, emergency managers need more lead time in order to make life-saving decisions regarding evacuations", said Bill Read, director of NOAA's National Hurricane Center, in today's press release.


Figure 1. Average track errors for NHC Atlantic tropical storm and hurricane forecasts issued between 1990 - 2008. Track errors have improved by over 50% in the past 20 years. Image credit: National Hurricane Center.

Commentary
NHC has been debating for a number of years how best to "invest" the gains accrued from the steady improvement in hurricane track forecasts. One obvious savings from these better hurricane forecasts has come from the reduced evacuation costs. When a hurricane warning is issued 24 hours before the expected arrival of hurricane-force winds at the coast, it costs approximately $1 million to evacuate each mile of U.S. coast warned (Aberson et al., 2006). This number will be higher for more densely populated areas of the coast, such as Miami, and may be a factor of six lower for the North Carolina coast (Whitehead, 2003). According to a 2007 presentation at the 61st Interdepartmental Hurricane Conference, the length of coast warned decreased significantly in the past decade. During the decade of the 1990s, the average length of a hurricane warning was 455 miles, but that fell to just 335 miles between 2000 - 2006. Thus, an average of 120 fewer miles of coast were warned, at an average savings of $120 million per hurricane warning issuance. During this period, 17 storms requiring 25 hurricane warnings occurred. If the costs of coastal evacuations are indeed $1 million per mile, the improved hurricane forecasts between 2000 - 2006 resulted in savings of $3 billion compared to what the forecasts of the 1990s would have cost.

However, the new increased lead times for hurricane watches and warnings will lead to an increase in the length of coast warned, due to the higher uncertainties in hurricane tracks at longer forecast lead times. Between 2004 - 2008, approximately 25% of the coast that was placed under a hurricane warning actually received hurricane force winds; this percentage was 20% for areas placed under a hurricane watch. These percentages will decline with the new increased watch and warning lead times, costing money in unnecessary evacuations, and leading to increased complacency in the warned population due to too much "crying wolf".

Balanced against these increased costs is the potential disastrous loss of life should a hurricane hit an unprepared, heavily populated shoreline. With the U.S. population continuing to increase rapidly in coastal regions, the time needed to evacuate vulnerable populated regions is increasing. For example, evacuation times for the major urban areas of Texas are 28 - 34 hours for a major hurricane. Though the costs of overwarning the coast is significant, the savings in both human lives and dollars from increased warning times should outweigh these costs. In the 2002 book, Hurricane: Coping With Disaster, Dr. Hugh Willoughby, former director of the Hurricane Research Division of NOAA's Atlantic Oceanographic and Marine Laboratory, analyzed hurricane death statistics. In 1950, about 70 U.S. residents died per year in hurricanes. In the 50 years since, the coastal population expanded by a factor of 3.2, so if we were managing the hurricane problem the way we did in 1950, we would be losing about 220 people a year. The long-term average is still about twenty per year, not including the deaths due to the levee failures during Katrina. That means we're preventing about 200 deaths per year compared with 1950. How much are these saved lives worth? A life, is, of course, priceless, but in the cold world of economics, the value of life-saving scientific research and government regulations is estimated using statistics of what people are willing to pay to avoid certain risks, and what extra money employers pay their workers to take on additional risks. This data comes primarily from payroll statistics, but opinion surveys also play a role. In 2004, the Environmental Protection Agency (EPA) valued an American life at $8 million. EPA cut the value of a life by 8% that year, and a further 3% in May 2008, making the economic value of a life $6.9 million in today's dollars. The Department of Transportation gives a lower figure of a life as being worth $5.8 million. Using this number implies a savings of about $1.2 billion per year for the 200 lives saved per year by better hurricane warnings and evacuations. Today's decision by NHC to increase warning times should continue this trend of saving lives, which will also provide considerable monetary benefit. Despite the increased costs and dangers of "crying wolf" too often due to overwarning the coast, I believe that the double value of saving lives--for both the intrinsic and monetary value of a human life--makes NHC's move of increasing warning and watch times the right call.

References
Whitehead, J.C., 2003: "One million dollars per mile? The opportunity costs of Hurricane evacuation", Ocean and Coastal Management 46, 1069.

I'll have a new post on Thursday or Friday.

Jeff Masters

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589. IKE
I see the system now in the northern plains...dropping toward the ESE or SE.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
This is just wrong.You people down there are about the same temp as I am up here.49801
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587. IKE
LOL....freeze warning!

Hey...it kills the....spiders....I don't see any ants mulling around.

28 is cold.
Member Since: June 9, 2005 Posts: 23 Comments: 37858

Hey Ike, how do you like this low temp for c fl.
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585. IKE
My low has been 23.5.

Crestview's is a record low...

Crestview, Florida (Airport)
Updated: 10 min 27 sec ago
Clear
16 °F

Clear
Windchill: 16 °F
Humidity: 92%
Dew Point: 14 °F
Wind: Calm
Pressure: 30.33 in (Steady)
Visibility: 10.0 miles
UV: 0 out of 16
Clouds:
Clear -
(Above Ground Level)
Elevation: 210 ft
Member Since: June 9, 2005 Posts: 23 Comments: 37858
584. IKE
Crestview, Florida (Airport)
Updated: 47 min 2 sec ago
Clear
18 °F

Clear
Windchill: 18 °F
Humidity: 78%
Dew Point: 12 °F
Wind: Calm
Pressure: 30.33 in (Rising)
Visibility: 10.0 miles
UV: 0 out of 16
Clouds:
Clear -
(Above Ground Level)
Elevation: 210 ft
Member Since: June 9, 2005 Posts: 23 Comments: 37858
grumble, grumble...

no need for words, I think we're all suffering.
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Strangely warm up here. :) Iron Mountain, Michigan (Airport)
Updated: 2:54 AM CST on January 06, 2010
19 °F
Overcast
Windchill: 8 °F
Humidity: 74%
Dew Point: 12 °F
Wind: 9 mph from the NW
Pressure: 30.19 in (Steady)
Visibility: 8.0 miles
UV: 0 out of 16
Clouds: Overcast 1800 ft
(Above Ground Level)
Elevation: 1181 ft

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580. HadesGodWyvern (Mod)
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579. HadesGodWyvern (Mod)
Mauritius Meteorological Services
Tropical Cyclone Advisory Number EIGHT
TEMPETE TROPICALE MODEREE EDZANI (08-20092010)
10:00 AM Réunion January 6 2010
======================================

At 6:00 AM UTC, Moderate Tropical Storm Edzani (994 hPa) located at 12.7S 82.6E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The storm was reported as moving west-southwest at 10 knots.

Dvorak Intensity: T3.0/3.0/D0.5/12 HRS

Gale-Force Winds
=================
20 NM from the center extending up to 80 NM in the northeast sector

Near Gale-force Winds
======================
80 NM from the western semi-circle and up to 130 NM in the northeastern quadrant

Forecast and Intensity
=====================
12 HRS: 13.3S 80.9E - 50 knots (Forte Tempête Tropicale)
24 HRS: 13.8S 79.4E - 60 knots (Forte Tempête Tropicale)
48 HRS: 14.8S 76.3E - 80 knots (CYCLONE Tropical)
72 HRS: 16.0S 72.1E - 100 knots (CYCLONE Tropical Intense)

Additional Information
=========================
Last available microwave shows a banding eye feature. System has intensified rapidly within the last few hours. Vertical wind shear has weaken (CF, CIMSS data). Divergence is strengthening equatorwards. low level inflows and oceanic heat content are very good up to range 72HRS. System is expected to intensify at a climatological rate at least. The forecast is based on the available models, which are rather in good agreement.
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Gonna be interesting!!! i'm out nice posts to close my voyage into a new semester and into dreamworld. I hope the models do not further delay on development, its usually a sign of it not happening. NIGHT!
Member Since: September 6, 2009 Posts: 2 Comments: 3764
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Quoting Bordonaro:


This scenario, due to the cooler stable air present already, is not, I repeat, is not going to produce severe weather.

The computer models are having a hard time placing the event, since this occurance is RARE to start with. I believe these are numerical models, going by what happened in the past, how and where. When these events happen, on average, once every, say 6-10 yrs, the computer sees the set up, and quite frankly, they do not know to make of it!

The atmospheric sounding taken across the region, within 12-24 hrs before the event, will tell the "whole story".

Not to spoil anyones dreams here, but snow/sleet/freezing rain events along the Gulf Coast, near Florida, are very, very rare. Once every 10-15 yrs?

That being said, this "go around" may produce a wintry precip event. Everyone needs to watch and wait.


I hear sumtimes past repeats itself like in a cycle.. lol but ya i know what ya mean.. its very rare to have freezing rain, sleet, or snow down in FL..
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Quoting FLPandhandleJG:


thanks again.. but if that L forms like we think it will and just depends how south or north it goes.. so with L forming will bring colder temps then a warm front or ridge that will climb towards the north.. Or its just what u need with the artic air clashing in with a L?


This scenario, due to the cooler stable air present already, is not, I repeat, is not going to produce severe weather.

The computer models are having a hard time placing the event, since this occurance is RARE to start with. I believe these are numerical models, going by what happened in the past, how and where. When these events happen, on average, once every, say 6-10 yrs, the computer sees the set up, and quite frankly, they do not know to make of it!

The atmospheric sounding taken across the region, within 12-24 hrs before the event, will tell the "whole story".

Not to spoil anyones dreams here, but snow/sleet/freezing rain events along the Gulf Coast, near Florida, are very, very rare. Once every 10-15 yrs?

That being said, this "go around" may produce a wintry precip event. Everyone needs to watch and wait.
Member Since: August 25, 2009 Posts: 20 Comments: 6785


looks like some moisture is tryin to form with unknown L that we talking about.. ;)
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Quoting TampaSpin:
I am out for the nite.......good nite everyone.


Night Tim.. thanks for ur imput sir.. c ya later
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I spect I can maybe get pics at Audubon Park tomorrow of the freeze areas,and again Friday Morn when we go down to near 20F.Single digit wind chills are forecasted here.


Should be a Hockey rink somewhere near the Golf Course Lagoons.
All the Ducks,Egrets,wrens and other Plumage Birds and Water fowl have hunkered down here.
Member Since: July 3, 2005 Posts: 426 Comments: 128767
I am out for the nite.......good nite everyone.
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Quoting TampaSpin:


The further south the low moves anything to the north of it will get snow....the south side would be less likely until it moves north and one would get the wrap around cold and moisture together.


Okay gotcha.. i was going to say doesnt matter which is the best side.. but how far the jet stream is goin to last if the L is goin to develop, if u have image or map?
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to me, i think that L will form.. just depends where and where it will go, thats the question of now..
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Quoting FLPandhandleJG:


thanks again.. but if that L forms like we think it will and just depends how south or north it goes.. so with L forming will bring colder temps then a warm front or ridge that will climb towards the north.. Or its just what u need with the artic air clashing in with a L?


The further south the low moves anything to the north of it will get snow....the south side would be less likely until it moves north and one would get the wrap around cold and moisture together.
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Quoting Bordonaro:


The Low will form. It is a question of where, how close and where the Arctic air is. There are several scenarios possible, from very cold and dry, a wintery mix, or all rain.

In the NE US, forecasting snow/sleet/freezing rain is easier. Why? Less variables, the Atlantic influence normally keeps snow events at a moderate number, along the NE and Mid Atlantic, due to to the Atlantic Ocean, bringing in slightly milder air above the surface, creating the snow to sleet to rain transition.

Down South, it is another ball game altogether, You have the Gulf of Mexico, with warmer water temps in the upper 50's to mid 70's. Arctic air intrusions are rare, this is some of the coldest air the South has seen in 10-20+ yrs. Atmoaggie gave a good example of a Tampa, FL atmospheric sounding.

The inversion, due to the warmer air above the Arctic air makes is very hard to pinpoint what will happen. It would take a whole slew of evaporational cooling to make snow possible, it would bring the lower atmosphere to the point where it probably would not precipitate anything.

It will take the proper amount of cold Arctic air at the surface, the right amount of lift and cooling of the first 10,000 ft of the atmosphere, before snow or a snow/sleet event will occur. Is it possible some areas will see snow/sleet &/or freezing rain in Florida? The answer is, "Yes".

HOWEVER, we have to wait and see where the Low develops, how much Arctic air is present from the ground to 10,000 ft. Patience training :0)!


thanks again.. but if that L forms like we think it will and just depends how south or north it goes.. so with L forming will bring colder temps then a warm front or ridge that will climb towards the north.. Or its just what u need with the artic air clashing in with a L?
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The 00Z CMC has backed off of the GOM low forming this weekend.
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Quoting Bordonaro:


The Low will form. It is a question of where, how close and where the Arctic air is. There are several scenarios possible, from very cold and dry, a wintery mix, or all rain.

In the NE US, forecasting snow/sleet/freezing rain is easier. Why? Less variables, the Atlantic influence normally keeps snow events at a moderate number, along the NE and Mid Atlantic, due to to the Atlantic Ocean, bringing in slightly milder air above the surface, creating the snow to sleet to rain transition.

Down South, it is another ball game altogether, You have the Gulf of Mexico, with warmer water temps in the upper 50's to mid 70's. Arctic air intrusions are rare, this is some of the coldest air the South has seen in 10-20+ yrs. Atmoaggie gave a good example of a Tampa, FL atmospheric sounding.

The inversion, due to the warmer air above the Arctic air makes is very hard to pinpoint what will happen. It would take a whole slew of evaporational cooling to make snow possible, it would bring the lower atmosphere to the point where it probably would not precipitate anything.

It will take the proper amount of cold Arctic air at the surface, the right amount of lift and cooling of the first 10,000 ft of the atmosphere, before snow or a snow/sleet event will occur. Is it possible some areas will see snow/sleet &/or freezing rain in Florida? The answer is, "Yes".

HOWEVER, we have to wait and see where the Low develops, how much Arctic air is present from the ground to 10,000 ft. Patience training :0)!


Could be one heck of a sleet storm rather than snow? It is very hard to tell.
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So where do you recommend ice skating Patrap?
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.DAY ONE...THIS AFTERNOON AND TONIGHT

.FREEZE WARNINGS... ANOTHER FREEZE IS EXPECTED TONIGHT. A HARD FREEZE IS ANTICIPATED ONCE AGAIN IN SOUTHWEST AND COASTAL MISSISSIPPPI...THE FLORIDA PARISHES...RIVER PARISHES AND SOUTH SHORE PARISHES WELL AWAY FROM THE TIDAL LAKES. A LIGHT FREEZE OF LONG DURATION IS EXPECTED IN THE NEW ORLEANS METRO AREA AND LOCATIONS ALONG THE IMMEDIATE LOUISIANA COAST. A HARD FREEZE WARNING IS IN EFFECT FOR TONIGHT.

THE PEARL RIVER AT PEARL RIVER WILL FALL BELOW FLOOD THIS EVENING. THE ATCHAFALAYA RIVER NEAR MORGAN CITY WILL REMAIN ABOVE FLOOD STAGE. PLEASE REFER TO THE LATEST RIVER FLOOD STATEMENTS AND RIVER FORECASTS FOR SPECIFIC DETAILS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY AN ARCTIC AIR MASS WILL PROVIDE HARD FREEZE CONDITIONS THURSDAY NIGHT...FRIDAY NIGHT AND SATURDAY NIGHT. THERE IS A SLIGHT CHANCE OF LIGHT WINTRY MIX THURSDAY AS THE COLD AIR ARRIVES PRIOR TO THE PRECIPTATION ENDING. SOME LOCATIONS...MAINLY WELL NORTH OF THE TIDAL LAKES...MAY EXPERIENCE A BRIEF PERIOD OF RAINFALL MIXING AND TRANSITIONING TO LIGHT SLEET AND LIGHT SNOW BEFORE ENDING THURSDAY AFTERNOON.

SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED AGAIN AT THE END OF THE WEEK THURSDAY NIGHT AND FRIDAY. A GALE WARNING MAY BE NEEDED THURSDAY NIGHT INTO EARLY FRIDAY MORNING.

THE ATCHAFALAYA RIVER NEAR MORGAN CITY...WILL REMAIN ABOVE FLOOD STAGE THROUGH THE PERIOD. THE MISSISSIPPI RIVER AT RED RIVER LANDING IS EXPECTED TO RISE ABOVE FLOOD STAGE ON MONDAY. PLEASE REFER TO THE LATEST RIVER FLOOD STATEMENTS AND RIVER FORECASTS FOR SPECIFIC DETAILS.
Member Since: July 3, 2005 Posts: 426 Comments: 128767
Quoting FLPandhandleJG:
thanks for the input Bob and Tim.. I learn alot everyday :) I will be on here time to time.. But i wonder if that L will form.. i guess we will find out soon


The Low will form. It is a question of where, how close and where the Arctic air is. There are several scenarios possible, from very cold and dry, a wintery mix, or all rain.

In the NE US, forecasting snow/sleet/freezing rain is easier. Why? Less variables, the Atlantic influence normally keeps snow events at a moderate number, along the NE and Mid Atlantic, due to to the Atlantic Ocean, bringing in slightly milder air above the surface, creating the snow to sleet to rain transition.

Down South, it is another ball game altogether, You have the Gulf of Mexico, with warmer water temps in the upper 50's to mid 70's. Arctic air intrusions are rare, this is some of the coldest air the South has seen in 10-20+ yrs. Atmoaggie gave a good example of a Tampa, FL atmospheric sounding.

The inversion, due to the warmer air above the Arctic air makes is very hard to pinpoint what will happen. It would take a whole slew of evaporational cooling to make snow possible, it would bring the lower atmosphere to the point where it probably would not precipitate anything.

It will take the proper amount of cold Arctic air at the surface, the right amount of lift and cooling of the first 10,000 ft of the atmosphere, before snow or a snow/sleet event will occur. Is it possible some areas will see snow/sleet &/or freezing rain in Florida? The answer is, "Yes".

HOWEVER, we have to wait and see where the Low develops, how much Arctic air is present from the ground to 10,000 ft. Patience training :0)!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Didn't Crist just appoint himself our State Senator?
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Quoting TampaSpin:


The 00 GENS zdp Image Loop Just came out....looks like snow for Northern Florida for sure especially the Panhandle.


Very nice.. but its saying on the 8th and thats on friday.. so will they extend the forecast or wait til the last minute lol
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G'night WaterWitch11 ,..Sleep well
Member Since: July 3, 2005 Posts: 426 Comments: 128767
Quoting reedzone:


What new models?


The 00 GENS zdp Image Loop Just came out....looks like snow for Northern Florida for sure especially the Panhandle.
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Member Since: July 3, 2005 Posts: 426 Comments: 128767
Quoting TampaSpin:
The new models should be coming out very soon.


yay cant wait and c b4 i go to bed.. i need it since i had a rough time sleeping last night.. and plus i have to work in the AM.. boy its going to b cold when i leave.. im sure its going to be like that for most places.. eekkk
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Quoting TampaSpin:
The new models should be coming out very soon.


What new models?
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The new models should be coming out very soon.
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Quoting FLPandhandleJG:
thanks for the input Bob and Tim.. I learn alot everyday :) I will be on here time to time.. But i wonder if that L will form.. i guess we will find out soon


I believe it will....the models are being very consistent lately with the low forming.....
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thanks for the input Bob and Tim.. I learn alot everyday :) I will be on here time to time.. But i wonder if that L will form.. i guess we will find out soon
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Quoting PensacolaDoug:


Doug...its not that difficult to conclude that if moisture starts falling in those kind of temps and those temps will be in place....it won't be rain unless it is freezing rain...otherwise it would be sleet or snow.
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Hi Patrap!
well it's time for me to put the kid to bed, everyone have a good night and stay warm.
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Quoting Orcasystems:


He is acting really strange tonight.



Its not an act!!
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Quoting Bordonaro:
North Florida snow lovers! Just keep an eye on NAM/GFS for the next couple of days leading up to the actual event.

It will be that close to call until 12 hrs before the event!!


You are absolutely correct......heck that is the way it is up North when it comes with snow very often.
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Quoting Orcasystems:


He is acting really strange tonight.


Yes he is?
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Quoting TampaSpin:


Are we slightly being a butt head here...HUM..


He is acting really strange tonight.
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North Florida snow lovers! Just keep an eye on NAM/GFS for the next couple of days leading up to the actual event.

It will be that close to call until 12 hrs before the event!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
28*F in Macon right now headed down to 18*F with a 10*F wind chill. I am not a happy camper. RTLSNK

OMG Makes me want to cook up some pasta.


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Quoting ElConando:


And then in 12 days cats and dogs will be living together!!!


Are we slightly being a butt head here...HUM..
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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.