Powerful Category 3 Irene enters the Bahamas

By: Dr. Jeff Masters , 3:49 PM GMT on August 24, 2011

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Powerful Category 3 Hurricane Irene stormed through the Turks and Caicos Islands overnight, bringing hurricane-force winds, torrential rains, and storm surge flooding. On Providenciales in the Turks and Caicos Islands, where half of the population of these islands live, winds reached a sustained 65 mph at a personal weather station at Pine Cay, and the pressure bottomed out at 989 mb. The eyewall of Irene missed the island, with the center of the storm passing about 60 miles to the southwest. The center of Irene passed about 60 miles to the northwest of Grand Inagua Island, and Category 1 hurricane conditions were probably experienced on that island. Damage in the Turks and Caicos is likely to be much less than the $50 - $200 million wrought by Category 4 Hurricane Ike of 2008, since Irene's eyewall missed populated islands.


Figure 1. Morning satellite image of Irene.

Monday, Irene hit Puerto Rico as a tropical storm with 70 mph winds, but reached hurricane strength as it emerged into the Atlantic northwest of the capital of San Juan. One drowning death is being reported from the island, and the storm dumped up to 20 inches of rain in some areas. About 11% of the island was still without power this morning, and numerous roads were closed due to flooding and landslides. Irene did an estimated $17 million in damage to agriculture and $2 million to ports in Puerto Rico. Satellite estimates suggest that Irene has brought only 1 - 2 inches of rain to Haiti. With Irene now pulling away from Hispaniola, Haiti can expect only another 1 - 2 inches from the hurricane, and appears to have dodged a major bullet. Heavy rains of 3 - 6 inches were common across the Dominican Republic, where moderate flooding but no deaths occurred.


Track forecast for Irene
Continuing dropsonde missions by the NOAA jet have helped to significantly narrow the uncertainty in the 1 - 3 day forecasts from the computer models. Irene will track through the central Bahamas today, the northwestern Bahamas on Thursday, and approach the Outer Banks of North Carolina on Friday. However, the models still diverge considerably on their 4 - 5 days forecasts, and we don't know if Irene will plow up the mid-Atlantic coast into New Jersey, as the GFDL model is predicting, hit New England between Long Island, NY and Massachusetts, as the ECMWF, GFS, and HWRF models are predicting, or miss the U.S. and hit Canada, as the NOGAPS model is predicting.

Intensity forecast for Irene
Latest data from the Hurricane Hunters shows that Irene has paused in its intensification cycle. A gap has opened in the eyewall, and the central pressure has remained constant at 956 - 957 mb over the past few hours. However, the hurricane is embedded in a large envelope of moisture, and wind shear is expected to remain low to moderate, 5 - 20 knots, for the next three days. With water temperatures very warm, 28 - 30°C, these conditions should allow for intensification to a Category 4 storm sometime in the next two days. Satellite loops show that Irene is well-organized, with excellent upper-level outflow, and impressive spiral banding.

Irene's impact on the Bahama Islands
Irene is making a direct hit on Crooked Island (population 350) in the Bahamas, and will continue west-northwest and hit Rum Cay (population 80) and Cat Island (population 1700) late tonight. These unfortunate islands will bear the full brunt of Irene's 115+ mph winds and 8 - 13 foot storm surge, and suffer major damage that will take months to recover from. Major damage is also likely on Long Island (population 3000) and San Salvador Island (population 1000.) Shortly after midnight tonight, winds at the capital of Nassau, home to 70% of the population of the Bahamas, will rise above tropical storm force, and increase through the night. By late morning on Thursday, sustained winds will peak on Nassau at just below hurricane force, 60 - 70 mph. Nassau will miss the brunt of the storm, and I expect the airport should be able to re-open on Friday. Winds on Grand Bahama Island in Freeport will rise above tropical storm force late Thursday morning, and increase to a peak of 45 - 60 mph late Thursday afternoon. Grand Bahama will also miss the brunt of the storm, but Abaco Island to its east will likely experience Category 2 hurricane conditions Thursday afternoon. However, Abaco will probably miss the right front eyewall of Irene with the strongest winds and highest storm surge.


Figure 2. Wind distibution around Irene as of 1330 UTC (9:30am EDT) August 24, 2011. Irene was a Category 3 hurricane with 115 mph winds at the time. Hurricane force winds (yellow colors) extended over Crooked Island to the storm's northwest, and over Mayaguana Island to the east. Image credit: NOAA/AOML. Irene is a large storm, and its potential storm surge damage rated 3.9 on a scale of 0 to 6, with its wind damage potential rated at 2.5 on a scale of 0 to 6.

Irene's impact on the Southeast U.S.
Long-period ocean swells from Irene will reach the coast from Florida to North Carolina tonight, and continue to build as the storm approaches. The outermost rainbands of the hurricane will reach South Florida by Thursday morning, and spread over much of the eastern coastal portion of Florida during the day Thursday. If Irene follows the official NHC forecast through the Bahama Islands, the storm's expected radius of tropical storm-force winds of 130 - 170 miles will keep tropical storm conditions just off the east coast of Florida. Sustained winds of 20 - 30 mph can be expected along the coast of Florida during Irene's point of closest approach, and rainfall amounts of 1 - 2" will be common along the coast. Georgia, which could use the rain, will get very little. It is unlikely any airport in Florida or Georgia will need to close for Irene.

Late Friday night or early Saturday morning, Irene's outer spiral bands will move over the southern coast of North Carolina and the northeastern portion of South Carolina, and tropical storm-force winds of 39+ mph will arrive. Winds will steadily increase to hurricane force on the Outer Banks by Saturday night. The main damage from Irene in North Carolina will come from the storm's flooding rains of 4 - 12" that will fall in coastal areas. Fortunately, this region is under moderate to severe drought, so the damage will not be as severe as that experienced during Hurricane Floyd of 1999. Significant wind damage can be expected in the Outer Banks of North Carolina, and considerable storm surge damage may occur along the shores of Pamlico and Albemarle Sounds. If Irene's eye misses making landfall in North Carolina, total damage from the storm should be less than $200 million, and could be considerably less than that.


Figure 3. Sea surface temperatures for August 24, 2011. Temperatures of 26°C (79°F) are typically needed for a hurricane to maintain its strength (black line). This boundary lies just off the southern coast of New Jersey this year, which is much farther north than usual.


Figure 4. Predicted 5-day rainfall for the period ending Monday morning, August 29, at 8am EDT. Image credit: NOAA/HPC.

Irene's impact on the mid-Atlantic and New England
The impact of Irene on the mid-Atlantic and New England is highly uncertain at this point, because we don't know if the core of the storm will miss the coast or not. In general, the heaviest rains will fall along a 100-mile swath just to the west of where the center tracks, and the worst wind and storm surge damage will occur to the east. If the core of Irene stays offshore, the mid-Atlantic and New England may escape with a few hundred million dollars in damage from flooding due to heavy rains and storm surge. If Irene hits Long Island or Southeast Massachusetts, the storm has the potential to be a $10 billion disaster. Irene is one of those rare storms that has the potential to make landfall in New England as a Category 2 or stronger hurricane. It is difficult for a major Category 3 or stronger hurricane crossing north of North Carolina to maintain that intensity, because wind shear rapidly increases and ocean temperatures plunge below the 26°C (79°F) level that can support a hurricane. We do expect wind shear to rapidly increase to a high 30 - 50 knots once Irene pushes north of Delaware, which should knock the storm down by at least 15 - 30 mph before it reaches New England. However, this year sea surface temperatures 1 - 3°F warmer than average extend along the East Coast from North Carolina to New York. Waters of at least 26°C extend all the way to Southern New Jersey, which will make it easier for Irene to maintain its strength much farther to the north than a hurricane usually can. During the month of July, ocean temperature off the mid-Atlantic coast (35°N - 40°N, 75°W - 70°W) averaged 2.6°F (1.45°C) above average, the second highest July ocean temperatures since record keeping began over a century ago (the record was 3.8°F above average, set in 2010.) These warm ocean temperatures will also make Irene a much wetter hurricane than is typical, since much more water vapor can evaporate into the air from record-warm ocean surfaces. The latest precipitation forecast from NOAA's Hydrological prediction center shows that Irene could dump over 8 inches of rain over coastal New England.


Figure 5. Soil moisture profiles from yesterday show that a region of very moist soils ranking in the top 1% in recorded history (dark green colors) lie over northern New Jersey, Southeast New York, and Northeast Pennsylvania. Image credit: NOAA/CPC.

Tropical storm-force winds and heavy rains will move into Eastern Virginia Saturday afternoon, and push northwards to Delaware and coastal Maryland by late Saturday night. Tropical moisture through a deep layer of the atmosphere will also stream well ahead of Irene into New England on Saturday afternoon and evening, bringing what is called a "Predecessor Rain Event" (PRE). The Washington D.C., Baltimore, and Philadelphia airports will be right at the edge of the heavy rain and high wind area, and it currently appears they will not have to close for an extended period. The Philadelphia and New York City airports may not be as lucky, and it is possible they will suffer extended closures Sunday morning and afternoon. By late Sunday night, Irene's rains will move north of New York City, allowing the airports to re-open. The highest potential for damaging fresh-water flooding is in northern New Jersey, Southeast New York, and Northeast Pennsylvania, where soil moisture is near record high levels, and there is nowhere for the rain to go (Figure 5.) Heavy rains of 4 - 12" are likely across all of coastal New England if Irene passes within 100 miles of shore.

Links
For those of you wanting to know your odds of receiving hurricane force or tropical storm force winds, I recommend the NHC wind probability product.

Wunderground has detailed storm surge maps for the U.S. coast.

Elsewhere in the tropics
A tropical wave far out in the eastern Atlantic about 200 miles southwest of the Cape Verde Islands, Invest 90L, is showing signs of organization. NHC is giving this disturbance a 50% chance of developing into a tropical depression by Friday. Several of our models do develop 90L into a tropical storm by early next week, but long-range models are showing that this system will not be a threat to any land areas over the next seven days, and will probably move too far north to ever be a threat to land.

Internet radio show on Irene at 4:30pm EDT today
I'll be discussing Hurricane Irene on a special edition of our Internet radio show, the Daily Downpour, today (Wednesday) at 4:30pm EDT. Fellow wunderground meteorologists Shaun Tanner, Tim Roche, and Angela Fritz will also be there. Listeners can email in or call in questions. The email address to ask questions is broadcast@wunderground.com.

Jeff Masters

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490. hamla
winds now 120 mph and gom blocking high moving west via wx channel
Member Since: August 29, 2008 Posts: 0 Comments: 165
Yes, there are wishcasters, but anyone who has lived in Florida or other coastal areas know that even though a system does not make a direct impact on their area, there are indirect impacts even from weak hurricane. Hurricane Francis is the best example. Here is a little excerpt from Francis. Even though it never came that close to extreme south Florida, and made a direct hit much North from here, there were massive power outages for days and very high winds, and she was only a Category 2, way before it made landfall. Yes, a Category 4 is very much of a concern, because of the indirect effects of such a powerful system.


Excerpt
On September 3, Frances passed into the vicinity of Abaco Island and directly over Grand Bahama while continuing to slowly weaken. The storm regained Category 2 hurricane intensity prior to passing over Grand Bahama Island and also slowed in forward speed due to a weakness in the subtropical ridge to its north. Parts of South Florida began to be affected by squalls and the outer rainbands of the hurricane at this time. Gusts from 40 miles per hour (64 km/h) to as high as 87 miles per hour (140 km/h) were reported from Jupiter Inlet to Miami.[12]

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Quoting Beachfoxx:
ROFL - gone underground low!


When I saw the crowd hanging out here now I kind of figured you had gone into hiding with Smcdavid, I think that was her handle, from Houston area if I remember right!
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...IRENE A LITTLE STRONGER...EYE OVER CROOKED ISLAND...


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...22.7N 74.3W
ABOUT 65 MI...105 KM SE OF LONG ISLAND BAHAMAS
ABOUT 250 MI...405 KM SE OF NASSAU
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...954 MB...28.17 INCHES
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monster hole sebastian inlet is towable
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Quoting tiggeriffic:


like back in the cone and hitting that 78W or closer mark close?


This close:
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Now that is a scary thought!
More scary than a direct hit from Irene!
Quoting presslord:


Oh God...don't say that...now it can only get worse
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wake up people. what happens if this becomes a Gilbert or Andrew? ummmm.....it will IGNORE the pull north...and maintain it's general heading.

In physics....any object in motion tends to stay in that general motion. and since Irene is getting stronger and stronger...the models may miss that fact, and she will in fact..maintain the wwnw heading....kick slightly wwnw..

and take out Miami....

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Last few GOES-13 images since 1pm ET showing a shift to the north.....
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Can someone post a link to the most recent model runs
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i can tell you this...sitting here in mobile around what they are calling the "weakness" between the bermuda ridge and the texas ridge it sure doesn't feel like low pressure or weakness to me. it's hotter than heck and my bones don't hurt, so there is no low....

by 10 p.m. c.s.t. crap is gonna start hitting the fan. weather stations throughout the eastern seaboard will have to start worrying big time..... when the eye reaches 75w 23n the best line will be a mess..... the trough was busted by the bermuda high over the past 40 hrs and there is no turning of Irene.
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478. DFWjc
Quoting cloudburst2011:



YOU JUST DONT GET IT THIS HURRICANE IS GROWING STRONGER BY THE MINUTE AND IS INCREASING IN SIZE..ALL THESE FLA PEOPLE ARE SAYING IF IT PASSES 150 MILES OFF THERE COAST THEY ARE GOING TO GET TROPICAL STORM FORCE WINDS 39-74 MPH...HOW DOES THAT MAKE ANYONE OF THEM A WISHCASTER...YOU DONT MAKE ANY SENSE..


i still say there's no such thing as wishcaster, because everyone is a guesscaster, because no one here, including computers can guess the proper future forecast..
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476. Jax82
Quoting VAbeachhurricanes:


CMC 12z brings it wayyyy to close for comfort to SC


Did you notice the other tropical storm to the East of Irene on that run? Interesting.
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Quoting presslord:


Oh God...don't say that...now it can only get worse


Not so sure about that, didn't we have rumors of porn on here today? I don't every remember that happening in the past!
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Quoting zoomiami:


shhh -- you weren't suppose to see that. How's it going with prep plans?


check out our blog...we're rollin'
Member Since: August 13, 2007 Posts: 0 Comments: 10458
The first Bahamian island Irene scored a bulleseye on only had a population of 400. The next in line, Long island, has a population 10X that.
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I think that NHC needs to get rid of the forecast points and just issue a cone with intensity at specific time periods but not specific locations.... then if you are in the cone people wont look at the center and think they are all clear
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Quoting presslord:


Oh God...don't say that...now it can only get worse


shhh -- you weren't suppose to see that. How's it going with prep plans?
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469. wpb
hmrf 12 z close to 6z
Member Since: May 28, 2011 Posts: 0 Comments: 572
468. GoWVU
Quoting NCSCguy:
What picture?


Irene coming closer to the SC coast line
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Quoting VAbeachhurricanes:


CMC 12z brings it wayyyy to close for comfort to SC


like back in the cone and hitting that 78W or closer mark close?
Member Since: September 16, 2007 Posts: 0 Comments: 3599
Quoting MississippiWx:
Good afternoon.

I see Irene has really consolidated her core today. The ring of red around the eye is a dangerous setup as that means she is in a solid position for further strengthening.



Although I know rationally that the storm will go up the coast and not across to us, it is not fun looking at that sitting just to the SE of Miami. Really would like for it to move on up and be gone.
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cuban radar on Crownweather isn't showing much of Irene beyond a rain band.
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Quoting miguel617:
I find it amusing how wishcasters watch a few frames of satellite images plus throw in some of their gut feeling and then make a prediction of how the hurricane is moving and then say the models are all wrong.

Folks, the models are generated using supercomputers, some being in the top 100 in the world. They take data from satellites, ocean buoys, air recon, global weather balloons, and after much processing, spit out their predictions.

Don't look like a fool thinking you can outdo a supercomputer using your armchair forecasting techniques.






Thank you! And you are exactly right. Hurricane forecasting is not a roll of the dice. The days when a storm such as this one could suddenly change direction and completely fool all of the forecasting tools are over.

In this day and age, the forecast track errors occur when a system is still an Invest and does not yet have an identifiable COC or enough strength to measure its future movements accurately with relation to the atmospheric dynamics. Once a storm is this large and powerful, the process becomes far more accurate and all possible solutions are factored into the forecast. This is why a sudden and completely unexpected, non-forecasted and drastic change in direction is all but impossible.
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Quoting NCSaint:


Interesting you say this Reed. What are your thoughts on the potential influencing low the NHS mentioned in the 1100 update? When do you suspect that to become a factor? Pre- or Post- OBX? These variables are the ones worrying me, living on the SE coast of NC. Even a "Jog" will have HUGE impacts on the crystal coast.

Thanks in advance


Kind of wondering that myself... If I say something like it may have Irene head more west, I'd be called a wishcaster. I'm already getting attacked on here by people saying I disappeared after my forecast was pooped.. Not true. I originally had Irene NOT entering the GOM when others were sold on it. I wouldn't say my forecast of Irene being a EAST COAST problem would be off. Cut the crap guys and grow up. This NOT referring to the one I am quoting :)
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Hey MississippiWx! Been missing the fun this morning if you want to call it fun... How far west you think she'll get before she's head'n true North?
Member Since: February 2, 2010 Posts: 0 Comments: 1403
surferjoe5899, i misread your question sry about that :)
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ROFL - gone underground low!
Quoting zoomiami:


Beachie! long time -- picked a bad time to show up -- this blog has lowered itself to levels I didn't think were possible.
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Quoting zoomiami:


Beachie! long time -- picked a bad time to show up -- this blog has lowered itself to levels I didn't think were possible.


Oh God...don't say that...now it can only get worse
Member Since: August 13, 2007 Posts: 0 Comments: 10458
456. Gorty
Quoting Gorty:
I am getting increasing concerned that the models are going to shift west. GFS started, the NAM and looks like the cmc... not looking good.


I meant this for the New England/LI area.
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In about 5-6 hours, Long Island, Bahamas, and the little city of Clarence Town....will recieve cat 4 winds for approximately 3 hours.

and no where to hide.

and here we are, thinking its exciting. Imagine being in that city....with it's little airport...and you decided to stay.....how'd you be feeling right now.

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Ever so slightly to the left of NHC official track.
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452. Gorty
Quoting IceCoast:
Definitely concerned for my folks in Eastern Massachusetts. Sort of wish i could be home to witness this one if the track pans out. I let them know to start making preparations either today or tomorrow, when we should have a better handle on the track for the Northeast.

12Z HWRF


Damaging winds for me too in western Mass.
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Quoting 7544:



hmmmm cmc agrees with the nam thats two bringing irene more west over andors iasland island now gfdl is next might be closer to so fla now with these two new runs not for a landfall but for stronger effects


You'll get branded a westcaster ... LOL
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Quoting surferjoe5899:
Question
How does the warm water of the Gulf Stream effect the Hurricane's path?


The Gulf Stream won't affect the path (in the sense that a TS/HURR would follow it), but as you might know, it would affect the intensity assuming it stays long enough on the stream and the depth of the warm column of water.

Once you get into the Mid ATL regions the configuration of the westerlies would dictate where it might go, but not restricted to only that variable.
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If Irene has anything, it is a lot of spunk. This is a storm that strengthened while over PR. Not to mention that the mountains of Hispaniola were only a minor nuisance to it's development, in fact it doubled in size while dealing with inflow difficulties due to DR's mountains.

It is currently skirting the western periphery of it's forecast cone and dancing around with all of it's western wobbles regardless of the models saying that it should stop doing that.

Irene is like John Locke from Lost ,
Don't tell it what it can't do!
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448. GoWVU
Quoting tiggeriffic:


HUH? what did i miss on an F5???


look at #404 the CMC run
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Good afternoon.

I see Irene has really consolidated her core today. The ring of red around the eye is a dangerous setup as that means she is in a solid position for further strengthening.

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Quoting HurricaneLovr75:


Too many steroids! The guy has lost it. IS he ever right?


more often than not....lets see how this goes... what do you know about the roids? do tell
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Quoting GoWVU:


Just looked at that and dont like the picture....
What picture?
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there is no question that in the last few loops the storm has wobbled from a NW to WNW , these wobbles can make a significant difference in who gets the brunt of this hurricane, just saying....
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Quoting Beachfoxx:
Hey Viking! Long time no see...
and Yes, we did see flooding, beach erosion & damage on the Emerald Coast from Katrina & Ike which was ever further away... so Floridians ignore the nay-sayers and stay alert. : )


Beachie! long time -- picked a bad time to show up -- this blog has lowered itself to levels I didn't think were possible.
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Quoting tiggeriffic:


HUH? what did i miss on an F5???


CMC 12z brings it wayyyy to close for comfort to SC
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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.