Hurricane Irene Prepares to Leave the Bahamas and Head for the US

By: Dr. Jeff Masters , 7:51 AM GMT on August 25, 2011

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As of 2AM EDT, Hurricane Irene was located at 24.2N, 76.0W, 105 miles east-southeast of Nassau or 760 miles south of Cape Hatteras. It was moving northwest at 12 mph with maximum sustained winds of 115 mph, making it a Category 3 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 950 mb. Hurricane force winds can be found up to 70 miles from Irene's center, and tropical storm force winds can be found out to 255 miles from the storm's center.

Hurricane warnings are in effect for all of the Bahamas. Hurricane and tropical storm watches will likely be posted for the Carolina coastlines later this morning. At this time, Dare County Emergency Management has issued a mandatory evacuation order for all visitors in their county. Dare County Schools will also be closed Thursday and Friday.

Satellite Views
Figure 1 is the infrared satellite image of Irene at 135EDT. The convection is a bit unbalanced around the storm center, which is going to cause Irene to wobble like an unbalanced clothes washer (Analogy courtesy of Angela Fritz) over the next few hours. At the time this image was taken, the convection around Irene's center appears to be getting more vigorous, as cold cloudtops are starting to increase around the storm center. This is important to note because microwave satellite imagery from Wednesday evening suggested Irene was starting an eyewall replacement cycle. Figure 2 shows passive microwave imagery from a Air Force DMSP polar-orbiting satellite. The two concentric green/yellow bands in the image suggest that two eyewall features are present in Irene, and Hurricane Hunter observations confirm this. This has important consequences for Irene's intensity, because in an eyewall replacement cycle, as the inner eyewall weakens, the storm's intensity drops. However, once the inner eyewall is gone, and the outer eyewall contracts to replace it, the storm intensity will increase again.


Figure 1 IR satellite view of Irene taken at 113AM EDT, August 23, 2011


Figure 2 DMSP F18 microwave overpass of Irene at 824PM EDT, August 24, 2011. Image courtesy of the Naval Research Laboratory

Track Forecast

Irene is forecast to move to the northwest, passing over the northwest Bahamas by Thursday evening, then curving to the northeast. Irene then makes landfall in the US near or at the Outer Banks Saturday afternoon, then traveling along the mid-Atlantic coastline of the US. Sunday, Irene may make secondary landfall anywhere from New Jersey to Long Island and the southern New England coastline. In my opinion, New York City may be significantly impacted by Irene. It is also important to note that the windfield of Irene is expected to be large, affecting areas distant from the immediate track of Irene's center. Tropical storm forces winds are expected to be found out to at least 150 miles away from Irene's center on Friday afternoon.

NHC is forecasting for Irene to become a Category 4 storm (winds faster than 130 mph) by Thursday morning. As Irene moves northward into cooler water, the intensity is expected to drop slowly to a Category 2 storm before making landfall in the Outer Banks.


Figure 3 Official track forecast of Irene at 2AM EDT.

Forecast models and today's planned flights
The different forecast models are still in fairly good agreement about Irene's track through the Bahamas and along the east coast of the US. The 00Z GFS run is in close agreement with the 12Z ECMWF run, but the 00Z ECMWF run (shown in figure 4) is continuing the ECMWF's trend of shifting the track westward with each run. NHC forecasters have been placing emphasis on the ECMWF's forecast track when making their forecasts for IRene, so it is possible that the NHC track will shift westwards at the 5AM update.

Looking at the plan of the day valid for today, it will be a busy day for airborne reconnaissance. Three flights for the Air Force hurricane hunters, two flights for the Gulfstream IV (Gonzo), and two flights for NOAA 42, a WP-3D (Kermit). They may have to give NOAA a littering permit for all of the dropsondes used to monitor Irene and her environment, but the forecast improvements they generate are worth the effort.


Figure 4 Plot of the maximum sustained winds in mph over the next week from the 00Z ECMWF forecast.

Impacts

Hurricane force winds will arrive in the northwestern Bahamas today. Storm surge near the center of Irene will be 7-11 feet above tide level. The Bahamas can expect 6-12 inches of rain over the next day or so, and it looks like the Turks and Caicos islands will receive a total of 6-12 inches from Irene. Large, swells from Irene will start landing on the southeastern US coastline later today. Please don't go in the water, as these swells can cause dangerous rip currents. Dr. Masters has catalogued the worst-case storm surge surge scenarios as a function of storm intensity here.

In my opinion, people living from the Carolinas to Cape Cod should pay close attention to Irene and prepare for a wide range of impacts. I think that there is a 75% chance of Irene's secondary landfall will be somewhere between JFK airport and Cape Cod. That said, Irene's size will cause significant impacts for people living far from it's center.

Dr. Masters will have a new blog entry this morning, and Angela Fritz will be covering the afternoon. I'll be back on third shift tonight.

Thanks for reading,

Dr. Rob Carver

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Quoting Vero1:
You own a boat or canoe?


That's not nice -- If you flood easily, think about the worst storm you've ever had and plan for more. Its been my experience that once they get into this area the rains are the most devastating part.

And if that doesn't happen, at least you were ready.
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Quoting CarolinaHurricanes87:
Thanks Tampa. Wilmington... Hopefully it doesnt shift west because no one here is prepared at all for a major hurricane


Incorrect! I live in Wrightsville Beach and have friends and family over the bridge in Wilmigton. Plenty of people are ready for a major hurricane....should it hit here!Maybe it is you who is not. Hazel, Bertha, Fran, Floyd...once you go through them, you have a good idea of what to expect and what to do.
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unenhanched IR

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843. beell
click to enlarge



"This graphic shows storm surge heights, in feet above normal tide level, which have a 20% chance of being exceeded during the next 3 days. The graphic is based upon an ensemble of SLOSH model runs using the current National Hurricane Center (NHC) official hurricane advisory. There is a 20% chance that 7 foot surge will be observed along the southern coast."

Hurricane Irene Briefing August 26-28, 2011
Eastern North Carolina
Threat Assessment
Hurricane Irene
National Weather Service
Newport/Morehead City, NC
Member Since: September 11, 2007 Posts: 142 Comments: 16295
Quoting TampaSpin:



Never said anything about dying.......a nice shower that is warm would have been nice tho......think about no water coming into your house as the water plants shut off the water and not online for days. One kinda might stinch after a while.


Don't forget about cooking (even if on camp stove), cleaning (how do you clean baby bottles w/o water?) and FLUSHING. It is about SANITATION, too!
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In Fayetteville? I'm no weather man, but the NHC wind probability map shows a pretty good chance of TS force winds. I'd say a couple inches of rain on that and you have a miserable weekend in store.
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840. Vero1
.
Member Since: July 21, 2008 Posts: 4 Comments: 2233
Quoting hotrods:
Winds starting to kick up here in Palm Bay, no rain yet,but it looks like it will be moving in.
I was just staying in Indialantic beach for the past week and was disappointed to have to leave yesterday before the swell arrived.
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i live about an hour directly north of NYC. How much rain do you think i should expect? my town floods pretty easily and i am trying to figure out what i am going to have to deal with. Are we talking 10" or more like 20"? i really don't know, any advice is appreciated.
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Quoting MahFL:


Can you name one person who died due to a lack of water after a hurricane in the USA ?
I very much doubt it.....


I live in Florida and been through several Hurricanes. If you run out of water you're not very smart. Days before a storm hits you know it's coming. Start filling up jugs from water faucet, buy the kind of water jugs you take camping that hold 2.5 - 5 gallons of water. People who buy water aren't very bright either, why would you buy water when you have ALL the clean tap water you want before the storm arrives. After the storm water is brought in by Red Cross and other agencies within 2-3 days so nobody every goes very long without water. Just make sure you have at least a 4 day supply of free tap water and you should be good.
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Quoting MahFL:


Can you name one person who died due to a lack of water after a hurricane in the USA ?
I very much doubt it.....



Never said anything about dying.......a nice shower that is warm would have been nice tho......think about no water coming into your house as the water plants shut off the water and not online for days. One kinda might stinch after a while.
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Quoting snotly:
the satellite presentation looks like the storm is weakening is this still the EWRC? even so, the wind radii will expand...
I was wondering if the islands and upwelling may be having some effect on Irene..She was moving quite slow there for a while..
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Quoting MahFL:


Can you name one person who died due to a lack of water after a hurricane in the USA ?
I very much doubt it.....


They dropped like flies in New Orleans from lack of water and heat exhaustion.

Don't be a fool.
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This hurricane is right in the middle of those little islands which are no higher than maybe 20 ft above sea level - where are all the people sheltering? I have not heard any news coverage about the human loss and/or material loss regarding to this disaster.

Irene just passed Puerto Rico about five days ago and we still have thousands without electricity and water, even in shelters because they lost their houses due to the tropical storm winds. It was not even a hurricane when it went over us!
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Quoting surfsidesindy:


by all models AND the NHC, or just the models?



everyone knew it was coming well in advance. the high to the north of andrew was so strong it began moving west early am the 22nd at 22 mph and never stopped til it crossed florida. storms moving that quick rarely deviate. there is a great series on you tube that chronicles the 50 hours leading up to the storm from the weather channel's and the local news perspective. erie stuff cause i was there... just search Hurrican Andrew
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Quoting mojofearless:


All excellent advice. May I add baby wipes (for spot bathing), hand sanitizer, bleach, bug spray and a baseball bat to fend of the loose dogs? Dog bites are the most common post-hurricane injury - not that FEMA has ever mentioned that. I love dogs - but have seen some nasty bites from loose, terrified dogs after storms.
I second the warning about loose dogs post-storm. We had a few incidents in my neighborhood during post-Ike cleanup.
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826. MahFL
She's still moving wnw/nw.
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Winds starting to kick up here in Palm Bay, no rain yet,but it looks like it will be moving in.
Member Since: October 22, 2009 Posts: 0 Comments: 89
Now that Florida is out of the woods ya'll start bashing the NY-NJ crowd, just as they're about to get the worst storm many of them have ever seen in their lifetime?

Stay classy, Florida.
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(24.2n76.0w has been re-evaluated&altered for H.Irene's_12pmGMT_ATCF
24.1n75.9w, 25.4n76.6w are now the most recent positions
Starting 24August_12pmGMT and ending 25August_12pmGMT

The 4 shorter line-segments represent HurricaneIrene's path
and the northernmost line-segment is the straightline projection.

Using straightline projection of the travel-speed&heading derived from the ATCF coordinates spanning the 6hours between 6amGMT then 12pmGMT :
H.Irene's travel-speed was 17.2mph(27.6k/h) on a heading of 338.8degrees(NNW)
H.Irene was headed toward passing near GreatAbaco,Bahamas ~2&1/2_hours from now

Copy&paste 22.7n74.3w-23.5n75.1w, 23.5n75.1w-24.1n75.9w, 24.1n75.9w-25.5n76.5w, atc, cel, rsd,ghb, elh, 24.1n75.9w-mhh, tcb, wkr, 24.1n75.9w-30.9n78.97w, jax into the GreatCircleMapper for more info

For EastCoast watchers...
H.Irene was headed toward passage over Mt.Pleasant,SouthCarolina ~1day5hours from now

Copy&paste 21.9n73.3w-22.7n74.3w, 22.7n74.3w-23.5n75.1w, 23.5n75.1w-24.1n75.9w, 24.1n75.9w-25.5n76.5w, jax, 24.1n75.9w-32.8n79.9w, chs into the GreatCircleMapper for more info

The previous mapping (for 25August_6amGMT)
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822. hamla
for those who never been thru a cane or a ts a little info
just because the storm gets below hurricane strength wind wise dont think its over.
allison was a t.s and moved back and forth from tex-la-tex and dropped so much rain on houston,lake charles la major flooding,major cost.andrew,betsy,camille,hugo,katrina,rita,ike,wi lma,ETC were major canes and caused major damage cost=$$$$$$$$$$$$$$$$$$$$$$$$$$$$
related deaths from those canes was mostly from FLOODING.IF THEY TELL YOU TO GET OUT OF DODGE GO do not try to out do Mother Nature you will loose
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Quoting klaatuborada:


All well and good, but there's no place to go to. If the storm tracks West, then we'll going right into the worst of it. I went through Bob. I know what's up. Only a two lane highway on and off Cape. But Martha's Vineyard and Nantucket are our bumper.
Gloria was bad for that area too...Fast mover though..
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largeeyes what effects could I see here in Fayetteville, NC?
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the satellite presentation looks like the storm is weakening is this still the EWRC? even so, the wind radii will expand...
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Quoting mojofearless:


All excellent advice. May I add baby wipes (for spot bathing), hand sanitizer, bleach, bug spray and a baseball bat to fend of the loose dogs? Dog bites are the most common post-hurricane injury - not that FEMA has ever mentioned that. I love dogs - but have seen some nasty bites from loose, terrified dogs after storms.


My son has a CO2 powered Air Pistol that would come in handy for his! Won't leave any permanent damage but sure would leave a sting!
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Quoting Nimitz:


If it were me, I'd be getting the hell off the island. Keep this in mind: If I'm wrong, you can call me an idiot (and whatever words come to mind); if I'm right, you can say "Thank you!".

And if it was my family, I'd be packed and out already. If you wait too late, the roads will be packed and you'll ride the storm out in your car...if it doesn't flood and wash you away. I live in Florida and my back up plans involve high ground 150 miles away in Georgia...


All well and good, but there's no place to go to. If the storm tracks West, then we'll going right into the worst of it. I went through Bob. I know what's up. Only a two lane highway on and off Cape. But Martha's Vineyard and Nantucket are our bumper.
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Quoting poknsnok:



wrong answer. saturday early am 8-22-92 andrew began a bee line to S FL.. it was projected to hit s fl by almost all models for almost 48 hrs



Also computers models have come a long way in accuracy since 1992. Its not coming here and that is great news not sure why some want it to, must be kids wanting to have a day off from school!
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Quoting zoomiami:


I sympathize with everyone feeling this way, as I said last night, this was the utmost test of faith in the NHC.

I think that we have to recognize how much the forecasting has changed since Andrew. Even though there have been some issues, those forecasts usually say that there is a higher chance of uncertainty, where as this one did not.

It is absolutely true that 24 hrs prior to Andrew they did not believe it would hit South Florida. I believe what happened in that forecast was that they thought the high was going to back off, and it was going to turn out to sea. The high then "bridged" effectively cutting off the path. If you look at the track you will see that when it started west it never moved.


Almost exactly like they are thinking now! I'll just say this trough definitely doesn't look as strong as the last one! I'm pretty sure South Florida is safe as Irene would have to make a hard left trun to hit there but if she doesn't straighten out and go North soon North Florida could get a closer brush with Irene than they are planning on.
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Quoting Zaphod:
Colonial pipeline was down for a day or so from the earthquake, and gas supplies up the east coast were tight already. With everybody anywhere close to the coast filling up, shortages could happen, especially localized spot shortages.

With any major storm, the wind and water are the obvious and scary parts of the picture, but days and days without power, unable to travel due to tree-blocked streets, and with rotting food and too little water, make it really nasty.

If you're in the target zone and choose to stay, plan ahead. Not only should you have water, but a back-up plan to treat more. If you have a generator, get extra gas, oil, and filters. Get extra propane for the grill -- you can grill a LOT of foods that you'd normally cook on a stove or in an oven. Have plenty of extra canned and dried food. Most off all, if you have important meds get LOTS of extras. Not everybody will plan as well as you, so even when the pharmacy reopens they'll sell out of what you need most. Get plenty of cash too, as ATMs and credit cards will not work without power, yet some hardware stores will reopen surprisingly quickly for cash customers.

Lights, books, batteries -- all good things to keep busy with in your hot, dark house.

Chainsaws are valuable too, as you can't expect the city to clear streets, and you'll have to close up the hole where the tree hits your house. Tarps to cover gaping holes in roofs are good too.

Even if you don't need all of it or any of it, this is all good stuff to have. If you get lucky and the storm missed you, you can load up your new toys and join a volunteer group headed to where they need help.


All excellent advice. May I add baby wipes (for spot bathing), hand sanitizer, bleach, bug spray and a baseball bat to fend of the loose dogs? Dog bites are the most common post-hurricane injury - not that FEMA has ever mentioned that. I love dogs - but have seen some nasty bites from loose, terrified dogs after storms.
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Quoting poknsnok:



wrong answer. saturday early am 8-22-92 andrew began a bee line to S FL.. it was projected to hit s fl by almost all models for more than 48 hrs


by all models AND the NHC, or just the models?
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from Miami Radar sure looks like the center is moving just north of west...
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Cities Affected
Savannah, GA ; Fayetteville, NC ; Greenville, NC ; Jacksonville, NC ; New Bern, NC ; Raleigh/Durham, NC ; Wilmington, NC ; Charleston, SC ; Hilton Head, SC ; Myrtle Beach, SC ; Newport News, VA ; Norfolk, VA ; Richmond, VA

Travel ADvisory from US Airways for travel Aug 27-28.

I wish I could head home to New Bern this weekend.
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Quoting bingcrosby:
GFDL thinks it could be pretty windy inland




ECMWF agreed with the inland windiness. With a strong hurricane that is slowly losing strength and moving north you actually see a wind field expansion. Not going to be a fun day in Raleigh or Richmond.
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12 Z NAM so far not much different from 6 Z.
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Quoting SafeInTexas:


I went through Ike in Texas as a low end cat1... And we were over 100 miles inland. Many trees down and power was out for quite a while. If you're a good distance from the water, just make sure anything that can blow away is put up. Also get enough food for a few days that can be eaten if you don't have power. Don't expect anywhere around you to have power either. Gas up the car now (just like everybody else will be doing).


Good advice. I am in Houston and experienced Ike also. Just listen to the emergency news in New York and put together that emergency kit they are talking about. Be prepared for the storm to be loud for a very long time. I was surprised at the sound levels.

And remember when the power goes out the ATM's don't work.

Just follow what your news people will be telling you on the radio and TV.
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Quoting surfsidesindy:


And up until 24hrs beforehand, the NHC said Andrew wasn't going to hit you..



wrong answer. saturday early am 8-22-92 andrew began a bee line to S FL.. it was projected to hit s fl by almost all models for more than 48 hrs
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I think she's really feeling that upper low that is directly west of her and it's making her weaken. That would explain the ragged appearance on her west side.
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Complete Update

TS BUSTED FORECAST ALIBI





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Quoting FLdewey:
TS warnings are not needed for the Florida coast.

C'mon guys don't start with this again today.

We get worse weather in afternoon storms.
Just checked Al Huffmans model page. Storms cropping up all over...Link
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Colonial pipeline was down for a day or so from the earthquake, and gas supplies up the east coast were tight already. With everybody anywhere close to the coast filling up, shortages could happen, especially localized spot shortages.

With any major storm, the wind and water are the obvious and scary parts of the picture, but days and days without power, unable to travel due to tree-blocked streets, and with rotting food and too little water, make it really nasty.

If you're in the target zone and choose to stay, plan ahead. Not only should you have water, but a back-up plan to treat more. If you have a generator, get extra gas, oil, and filters. Get extra propane for the grill -- you can grill a LOT of foods that you'd normally cook on a stove or in an oven. Have plenty of extra canned and dried food. Most off all, if you have important meds get LOTS of extras. Not everybody will plan as well as you, so even when the pharmacy reopens they'll sell out of what you need most. Get plenty of cash too, as ATMs and credit cards will not work without power, yet some hardware stores will reopen surprisingly quickly for cash customers.

Lights, books, batteries -- all good things to keep busy with in your hot, dark house.

Chainsaws are valuable too, as you can't expect the city to clear streets, and you'll have to close up the hole where the tree hits your house. Tarps to cover gaping holes in roofs are good too.

Even if you don't need all of it or any of it, this is all good stuff to have. If you get lucky and the storm missed you, you can load up your new toys and join a volunteer group headed to where they need help.
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Quoting TruthCommish:


They were issued for coastal waters.


Maybe locally by the NWS but I don't get why the NHC didn't issue Tropical Storm Warniings for the coastline areas. These areas could easily see 50-70 mph winds and tornadoes as the storm goes by and this could happen inland a ways too, just watch the feeder bands on radar today.
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Quoting southbeachdude:
The first outer band of Irene is reaching SE Florida. The problem with not issuing any type of tropical storm watch is that trash cans are already flying around the neighborhood. Many did no preparation since we are not in the cone.


I made sure to bolt my trash cans and recycling bins to the curb. As I watch my neighbors bins turn into dangerous missiles, in these 6mph winds, I am reminded just how important it is to prepare ahead of time. :D

Seriously though, my trash can was over on my neighbors property, and I ended up bringing in the recycling because I don't feel like walking all over the neighborhood picking up my junk.
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They cost $600ea btw.
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Thanks Tampa. If the center of Irene really does shift west towards Morehead City... Wilmington will be very close not only to the hurricane force winds, but major hurricane force winds. Thats what scares me about the current scenario... still being under a TS watch. Hopefully it doesnt shift west because no one here is prepared at all for a major hurricane
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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