Bill intensifies to Category 4; globe has 5th warmest July on record

By: Dr. Jeff Masters , 3:28 PM GMT on August 19, 2009

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Category 4 Hurricane Bill is now the the fourth strongest tropical cyclone to appear on the planet so far this year, and may grow even stronger. Visible and infrared satellite imagery continue to show an impressive, well-organized, hurricane, with plenty of low-level spiral banding and upper-level outflow well-established on all sides except the west. On Bill's west side, upper-level winds from the west are creating a modest 10 knots of wind shear, which is giving the hurricane a bit of a squashed appearance there.

Wind shear is forecast to remain low to moderate, 5-15 knots, for the next four days. Sea Surface Temperatures (SSTs) will rise steadily from 28.5°C today to 29°C on Friday. Total ocean heat content is at a maximum today, and will gradually decline over the next four days. Bill should be able to take advantage of these favorable conditions a remain a major hurricane the next three days.


Figure 1. Visible satellite image from NASA's Aqua spacecraft at 12:40pm EDT Tuesday August 18, 2009. Image credit: NASA GSFC.

Water vapor satellite loops show a small "short-wave" trough of low pressure to the north-northwest of Bill, and this trough has turned Bill on a more northwesterly track over the past two days. Bill will miss the Lesser Antilles Islands, and the main impact of the hurricane on these islands will be high waves. The short wave trough (so called because it has a relatively small amplitude and wavelength) is not strong enough to turn Bill due north, and Bill is also expected to miss Bermuda. High waves and sustained winds of 20 - 30 mph are the worst that Bermuda is likely to get from Bill.


Figure 2. Visible satellite image of Bill's eye zoomed in, taken from NASA's Aqua spacecraft at 12:40pm EDT Tuesday August 18, 2009. Image credit: NASA GSFC.

An unusually strong "long wave" trough of low pressure (called long wave because of its large amplitude and wavelength) is expected to develop along the U.S. East Coast late this week. This trough will turn Bill to the north, and also bring high levels of wind shear in the 40 - 65 knot range on Sunday. Exactly where this turn occurs is still not clear. The models continue to be in two camps: an eastern camp (GFS, GFDL, HWRF, and ECMWF) that takes Bill 300 - 500 miles east of Cape Cod, and a more western camp (NOGAPS, UKMET) that bring Bill within 150 - 200 miles of Cape Cod. Both sets of models bring Bill ashore over the Canadian provinces of Newfoundland or Nova Scotia. Bill will be weakening rapidly as it makes landfall, and is likely to be a Category 1 hurricane if it hits Nova Scotia, or strong tropical storm if it hits Newfoundland.

Bill's big waves
Large swells from Bill will begin impacting the U.S. East coast from Florida to Maine beginning Friday night or Saturday morning. Seas will build to 5 - 10 feet in the offshore waters from central Florida northwards to South Carolina, and to 10 - 15 feet from North Carolina to Cape Cod. Near shore, waves will be about 40% less. This will cause a significant coastal erosion event along some portions of the coast. The latest run of the NOAA Wavewatch III model suggests that significant wave heights near Bill's center will reach 50 feet on Sunday. Since maximum wave height is typically about a factor of 1.9 greater than the significant wave height (which is the average trough-to-crest height of the top 1/3 largest waves), a few huge waves near Bill's center may reach 95 feet high.

Possible impacts to New England
The current set of computer model runs predicts that the center of Bill will pass Cape Cod, Massachusetts Sunday afternoon or evening. Tropical storm-force sustained winds of 39 mph or greater currently extend out 185 miles to the west of Bill's center, so that if Bill maintains its current wind distribution, Cape Cod could see sustained winds of about 40 mph Sunday night if the models predicting a more westerly path are correct. However, Bill will not keep this same radius of winds. The hurricane will weaken considerably beginning Sunday morning, once the storm gets caught up in the approaching long wave trough. High wind shear of 40 - 65 knots due to strong southwesterly winds aloft will act to compress the hurricane in the east-west direction, keeping the hurricane's strongest winds away from Cape Cod. The highest winds are likely to be no more than 30 mph on Cape Cod from Bill, if the storm follows the track of the western camp of models nearest to the Massachusetts. A few rain squalls may affect coastal Massachusetts, but the main impact of Bill on New England is likely to be coastal erosion from high waves.

Elsewhere in the tropics
The remains of Tropical Storm Ana are bringing scattered heavy rain showers to the Bahamas and Florida today. The remains are disorganized, and are not likely to re-develop. The only model calling for a new tropical cyclone to develop in the Atlantic over the next seven days is the GFS model, which predicts development off the coast of Africa about 7 days from now.

Fifth warmest July on record globally; a cold July in the U.S.
The globe recorded its fifth warmest July since record keeping began in 1880, according to NOAA's National Climatic Data Center. NOAA rated the period January - July 2009 as the sixth warmest such period on record. NASA's Goddard Institute for Space Studies rated July 2009 as the 2nd warmest July on record, behind July of 1998. For the second month in a row, global ocean Sea Surface Temperatures (SSTs) in July were the warmest on record, 0.59°C (1.06°F) above the 20th century average. This broke the previous July record set in 1998. The record July SSTs were due in part to an ongoing El Niño event in the Eastern Pacific, which has substantially warmed a large stretch of the tropical Eastern Pacific Ocean. As El Niño conditions mature during the coming months, near-record global ocean and land temperatures will probably continue. Now that El Niño conditions have been well-established for three months, the atmosphere has begun to heat up in response. It typically takes up to seven months for the atmosphere to heat up in response to ocean heating from an El Niño. This may explain why June of 2009, which independent assessments by NOAA, NASA, and the UK Hadley center agreed was the 2nd or 3rd warmest June on record at the surface, recorded only average satellite-measured temperatures in the lower atmosphere. In contrast, the July satellite-measured temperatures in the lower atmosphere were the 2nd or 3rd warmest on record, in agreement with the assessments that surface temperatures were the 2nd to 5th warmest on record.


Figure 3. Departure of temperature from average for July 2009. Image credit: NOAA/NCDC.

A cold July for the U.S.
For the contiguous U.S., the average July temperature of 23.1°C (73.5°F) was the coolest since 1994, and July temperatures were the 27th coolest in the 115-year record, according to the National Climatic Data Center. Ohio, Illinois, Indiana, Pennsylvania, Iowa, and West Virginia experienced their coolest ever July. Kentucky, Missouri, Michigan, and Wisconsin recorded their second coolest July in history. A strong trough of low pressure parked itself over the eastern portion of the U.S. in July, funneling down plenty of cold air from Canada. In the western U.S., a ridge of high pressure dominated, bringing unusually hot conditions. Arizona recorded its 3rd warmest July on record, and Seattle, Washington recorded its hottest day in history on July 28, notching a 103°F reading. This was 3°F above the previous record set in 1994.

U.S. precipitation was near average in July, with the month ranking 40th wettest in the 115-year record. U.S. tornado activity was above average in July, according to NOAA's Storm Prediction Center. However, no tornado deaths occurred in July.

At the end of July, 14% of the contiguous United States was in moderate-to-exceptional drought. This is a drop from the 19% figure observed at the beginning of the year. These extreme drought regions were exclusively in South and Central Texas.

I'll have an update Thursday morning.

Jeff Masters

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Quoting TropicTraveler:

Look at the nexrad (It's on the bar at the top of the blog - it's just about there. I also just heard there was just a tornado in Minneapolis. Unverified as yet by me.


Ya. I'm just north of the tornado watch, but close enough that it still counts. I have about 30 - 45 mins before it hits here.
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Quoting KimberlyB:


Im in northeastern IL waiting....should be...errr...interesting.

Look at the nexrad (It's on the bar at the top of the blog - it's just about there. I also just heard there was just a tornado in Minneapolis. Unverified as yet by me.
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Question. I was just looking at the 5 day forecast map and the 2am tomorrow looks like there is a faint cat5 shadow behind the cat4 icon. Is anyone else seeing this or do I need to go get my glasses checked?
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921. IKE
Red Sox/Patriot/Celtic nation.....

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
522 PM EDT WED AUG 19 2009

.SYNOPSIS...
VERY WARM AND HUMID WEATHER WILL LIKELY CONTINUE INTO THE WEEKEND
AS PERSISTENT SOUTHWESTERLY FLOW CONTINUES ALONG WITH PERIODS OF
SHOWERS AND THUNDERSTORMS THURSDAY AFTERNOON THROUGH THE WEEKEND.
HOWEVER... THERE WILL BE MANY HOURS OF DRY WEATHER EACH DAY.
HURRICANE BILL IS LIKELY TO PASS WELL EAST OF NANTUCKET SOMETIME
SUNDAY.
ITS MAIN EFFECTS ON SOUTHERN NEW ENGLAND WILL BE IN THE FORM
OF HIGH SURF AND DANGEROUS RIP CURRENTS TO OCEAN BEACHES BEGINNING
LATE FRIDAY AND CONTINUING THROUGH THE WEEKEND.
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Quoting RitaEvac:
I'd rather be on Sable Island compared to New England right now


Really ... New England has a little more higher land to go to ... :c(
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Melagoo - Isn't sable island where all the fishing fleet got wiped out by an unexpected storm (I think around 1926 or 1927 - no satellite service then. There's a memorial in a museum in Nova Scotia (I think in Halifax) My fish logo comes from the Fisheries Museum there. It's a very moving memorial about what happened before we had good weather forecasting.
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Interesting to note from the 5PM Wind Speed Probabilities Bermuda has a 10% probability of hurricane force winds, Nantucket Ma has 7%.
Member Since: September 23, 2005 Posts: 14 Comments: 11215
still wondering myself how a hard turn at that speed is probable
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Bill will be going into some cooler waters, (the more north he goes) right?

So shoudn't he start to weaken soon? By the map I saw earlier he should be around a cat 2 at landfall.
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Quoting TropicTraveler:

I'm in Central Illinois ( a bit south of it) and so far so good. Hope it stays north of us.


Im in northeastern IL waiting....should be...errr...interesting.
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Pretty scary head of steam bill has.
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L8R Folks.
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I'd rather be on Sable Island compared to New England right now
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Quoting Melagoo:


Imagine Sable Island ...



Famous for the Wild Horses



Oh my gosh, I feel for the poor horses, then.
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910. IKE
Quoting RitaEvac:


Well...thats all folks! NYC in the clear, NEXT


Sorry....actually, I'm not sorry. I'm glad.
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Quoting RitaEvac:
If your Nantucket Island, you should be sweating bullets right now


Imagine Sable Island ...



Famous for the Wild Horses

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I have a son in DC...been telling him to watch...not like this continuous westward adjustment of the track...use to be bermuda in the center of that cone...now centered between bermuda and east coast...a little more to the left and the whole east coast could feel this one.
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NYC will sleep like a baby after that report, until the 6 hr mark comes knocking down the door
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Quoting lydine:
Central Illinois is getting slammed right now. Quite the system. It's on its way!

I'm in Central Illinois ( a bit south of it) and so far so good. Hope it stays north of us.
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damn, I missed Jerry by 3 minutes!!!!!
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#894 - Thanks! Can this turn into something down the road?
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Quoting SaoFeng:


Mariner's 1-2-3 rule has most of the east coast in the cone...

http://www.nhc.noaa.gov/refresh/graphics_at3+shtml/203116.shtml?basin#contents


according to this graphic we in wilmington nc are now technically in the danger zone
wow
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Quoting Floodman:


Yep...think about being in the Holland Tunnel when 18-20 feet of storm surge breaks over the end of Manhattan...hell, think about being in the Starbucks at 38th and Lex


Roll scenes from Independence Day, sans the spaceship. Large populations in panic mode is a horrific scene, whether it's New Orleans or New York. Therefore, I reside in the middle of nowhere. ;)
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Quoting IKE:
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
422 PM EDT WED AUG 19 2009

.SYNOPSIS...
-- Changed Discussion --
A WARM FRONT WILL LIFT NORTH ACROSS THE TRI-STATE AREA THURSDAY. A
TROUGH TO OUR NORTHWEST SHOULD PUSH A STRONG FRONT INTO THE REGION
FRIDAY NIGHT INTO SATURDAY. THIS FRONT IS EXPECTED TO KEEP THE
IMPACT OF HURRICANE BILL TO OUR EAST.
SUNDAY THROUGH TUESDAY SHOULD
BE DRIER BEHIND THE UPPER TROUGH.


Well...thats all folks! NYC in the clear, NEXT
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900. HadesGodWyvern (Mod)
Central Pacific Hurricane Center
Tropical Cyclone Advisory #31
TROPICAL DEPRESSION, FORMER GUILLERMO (EP102009)
21:00 PM UTC August 19 2009
====================================

At 18:00 PM UTC, Tropical Depression, Former Guillermo (1014 hPa) located at 30.8N 155.4W or 590 north-northeast of Honolulu, Hawaii has sustained winds of 30 knots with gusts of 40 knots. The depression is reported as moving northwest at 12 knots.

Forecast and Intensity
======================
12 HRS: 31.9N 156.9W - 30 knots (Tropical Depression)
24 HRS: 33.3N 158.3W - 25 knots (Low Pressure Area)
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Quoting DDR:
Hello everyone,carib. ppl...
Another lovely day in paradise(Trinidad)
Thanks Bill the sun is out in most of the island,but this wont last long after all it is august.


Hi T&T. I'm in BIM. Two of my sisters were born in your isle. Plus, my wife mom from there originally.
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flood!
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Okay folks, I'm out of here...going home
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896. slavp
I remember last year, Ike's landfall was 150 miles from us in SWLA and we still flooded...
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895. IKE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
422 PM EDT WED AUG 19 2009

.SYNOPSIS...
-- Changed Discussion --
A WARM FRONT WILL LIFT NORTH ACROSS THE TRI-STATE AREA THURSDAY. A
TROUGH TO OUR NORTHWEST SHOULD PUSH A STRONG FRONT INTO THE REGION
FRIDAY NIGHT INTO SATURDAY. THIS FRONT IS EXPECTED TO KEEP THE
IMPACT OF HURRICANE BILL TO OUR EAST.
SUNDAY THROUGH TUESDAY SHOULD
BE DRIER BEHIND THE UPPER TROUGH.
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Quoting TexasHurricane:


What is a ULL? Is this something that can turn into a concern later?


An Upper Level Low
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How do you change your current location, i was in Asia but now i am in Bethesda, MD. Thank you.
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Quoting CybrTeddy:


Starting to take on a more circular look, not as squashed as it was on the W side.


getting ready to hit his stride starting now and the next 24-36 hrs
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Opps! Sorry! I just noticed that Drak has posted the loop I was referring to.
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889. DDR
Hello everyone,carib. ppl...
Another lovely day in paradise(Trinidad)
Thanks Bill the sun is out in most of the island,but this wont last long after all it is august.
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Quoting BahaHurican:
It's the ULL that dropped South across the Bahamas and Cuba earlier this week....


What is a ULL? Is this something that can turn into a concern later?
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If your Nantucket Island, you should be sweating bullets right now
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Quoting Drakoen:


Starting to take on a more circular look, not as squashed as it was on the W side.
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Mariner's 1-2-3 rule has most of the east coast in the cone...

http://www.nhc.noaa.gov/refresh/graphics_at3+shtml/203116.shtml?basin#contents
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If that happened at all, I could imagine an instant state of emergency being declared in multiple states and immediate deployment of National Guard.

That would be too serious. As you know, it is not just winds, but storm surge, that will contribute to the threat.
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Quoting Floodman:


Yep...think about being in the Holland Tunnel when 18-20 feet of storm surge breaks over the end of Manhattan...hell, think about being in the Starbucks at 38th and Lex


United States is gonna start seeing more and more natural disasters, because on mother natures watch, it's just time
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Link
Look at this loop of Bill Notice how the "eye" is pointing at a westward angle , looks like borderline cat4/5 to me. I wonder if Bill's forward will change the track any.
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AT 500 PM AST...2100 UTC...THE CENTER OF HURRICANE BILL WAS LOCATED
NEAR LATITUDE 19.8 NORTH...LONGITUDE 57.6 WEST OR ABOUT 335 MILES...
535 KM...NORTHEAST OF THE LEEWARD ISLANDS AND ABOUT 970 MILES...1565
KM...SOUTH-SOUTHEAST OF BERMUDA.

BILL IS MOVING TOWARD THE NORTHWEST NEAR 20 MPH...32 KM/HR...AND
THIS GENERAL MOTION IS EXPECTED FOR THE NEXT DAY OR SO WITH A TURN
TOWARD THE NORTH-NORTHWEST FORECAST BY LATE FRIDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 135 MPH...215 KM/HR...WITH HIGHER
GUSTS. BILL IS A CATEGORY FOUR HURRICANE ON THE SAFFIR-SIMPSON
SCALE. SOME ADDITIONAL STRENGTHENING IS POSSIBLE DURING THE NEXT
COUPLE OF DAYS.

BILL IS A LARGE TROPICAL CYCLONE. HURRICANE FORCE WINDS EXTEND
OUTWARD UP TO 85 MILES...140 KM...FROM THE CENTER...AND TROPICAL
STORM FORCE WINDS EXTEND OUTWARD UP TO 230 MILES...370 KM.

THE LATEST MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE RESERVE
HURRICANE HUNTER AIRCRAFT WAS 947 MB...27.96 INCHES.

LARGE SWELLS ASSOCIATED WITH BILL WILL BE IMPACTING THE ISLANDS OF
THE NORTHEAST CARIBBEAN SEA DURING THE NEXT DAY OR TWO. LARGE
SWELLS ASSOCIATED WITH BILL SHOULD ALSO BEGIN TO AFFECT BERMUDA AND
PORTIONS OF THE EASTERN COAST OF THE UNITED STATES FRIDAY AND
SATURDAY.
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Quoting GeauxGirl:


There would be no point in trying to evacuate at that point. It would just be deadlock.
No pun intended.


Yep...think about being in the Holland Tunnel when 18-20 feet of storm surge breaks over the end of Manhattan...hell, think about being in the Starbucks at 38th and Lex
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Quoting kachina:
It appears that Bill is going to have a significant part of himself within the Hebert box unless I'm looking at the map totally wrong.


According to the NHC graphic of 5:00, its center wont pass through the box... which ends at 20 N and 60 W. And even if it did... "Hebert himself acknowledged that the boxes are not a guarantee of hurricane landfall either way"
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Quoting drg0dOwnCountry:
I wonder about the magnitude of impacts on europe weather. This is like temporarily stopping the flaw of the SAL(Saharan Air Layer) and subtropical jet stream?


Gosh, I was thinking about Bill making things better for the next tropical wave, but now that you mention it, you are right, all of the dust, dry air, that he is carrying North, not to mention disruption in airflows?

Interesting, unfortunately it will take someone of Dr.Masters expertise to give you an answer, I am just a layman, amateur.
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Blue skies all day and the dark clouds are just now starting to settle in with the rain. Will be interesting to see how much precipitation we get this evening, but wow were we lucky dodging this bullet.
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Quoting Nolehead:
guys can do that old ULL turn into anything that is spinnin on the west coast of cuba??? maybe that's what the models are pciking up on in the GOM???


I would like to know this too... Anyone?
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Quoting RMM34667:
That's a pretty sharp right turn forecast for Saturday. Bill is a big guy moving very fast, hope he tips over on that corner and falls flat on his face!



That's a POGO MINI!! Another Pogo'er on here. Cool.

Thanks for the graphic.
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Quoting stormwatcherCI:
I just looked at the vis in the Caribbean and if that is how you tell then it looks like a low between the w tip of Cuba and the Yucatan. Correct me if I am wrong as I am just trying to learn.
It's the ULL that dropped South across the Bahamas and Cuba earlier this week....
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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.