Category 2 Irene Approaches The Bahamas

By: Dr. Jeff Masters , 7:51 AM GMT on August 23, 2011

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As of 2am EDT, Hurricane Irene was located at 20.1N, 69.7W, 135 miles southeast of Grand Turk Island. It was moving west-northwest at 12 mph with maximum sustained winds of 100 mph, making it a Category 2 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 978 mb. Hurricane warnings have been issued for the northern coast of the Dominican Republic from the Haiti board to Cabo Engano, the southeastern and central Bahamas, and the Turks and Caicos islands. Hurricane watches have been posted for the north coast of Haiti from Le Mole, St. Nicholas to the Dominican border and the northwestern Bahamas. Tropical storm warnings are in effect for all of Haiti and the southern coast of the Dominican Republic from Cabo Engano to Santo Domingo.

5AM Update
As of 5am EDT, Hurricane Irene was located at 20.3N, 70.1W, 105 miles southeast of Grand Turk Island. It was moving west-northwest at 12 mph with maximum sustained winds of 100 mph, keeping it a Category 2 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 978 mb.

Figure 1 shows that Irene is maturing into a vigorous storm, with apparent waves in the western edge of the cirrus outflow.


Figure 1 IR satellite view of Irene taken at 135AM EDT, August 22, 2011

Track Forecast

Irene is forecast to move to the north-northwest, passing over all of the Bahama islands by Thursday evening, at which points it starts curving to the north. Irene is forecast to make landfall in the US near Wilmington, NC Saturday evening. However, it is important to note that this is not a definitive forecast, the average forecast error for day 5 is 250 miles. The timing of Irene's recurvature depends on how quickly several small troughs of low pressure in the Northeastern US move to the east. After Saturday, Irene may pose a threat to the mid-Atlantic coastline and locations further north, but it is too early to make a skillful forecast for those regions.

NHC is forecasting for Irene to become a major hurricane (winds faster than 110 mph), within 24 hours, then reaching peak intensity at 130 mph (Category 4 storm) by 8pm EDT Thursday evening.

Forecast models and adaptive observations
The different forecast models are in rough agreement until Irene nears the Carolinas. The dynamical hurricane forecasting models, GFDL and HWRF, have Irene making landfall near Charleston, SC. NGFDL (a variant of the GFDL that uses NOGAPS for background conditions) has landfall near Morehead City, NC, and the GFS has Irene crossing the Outer Banks. The UKMET forecast track splits the difference, placing Irene near Myrtle Beach, SC at landfall.

To reduce the model spread, and improve the track forecast error, the NOAA Gulfstream IV and an Air Force WC-130J have been flying dropsonde missions north of Irene. A dropsonde is an meteorological instrument package dropped from a plane that can tell you the vertical profile of temperature, pressure, moisture, and winds. By flying these missions, the dropsondes can improve all of the numerical weather prediction models initial picture of the atmospheres, which improves the forecast. Also, NHC has asked NWS offices in the southeastern US that launch weather balloons to do so every 6 hours instead of the normal 12 hour frequency.


Figure 2 Official track forecast of Irene as of 2am.

5AM update
The 00Z ECMWF forecast is available and Figure 3 shows the maximum wind speed over the next week for the eastern coast of the US. Green indicates tropical storm force winds, while yellow and orange are hurricane-force winds. The important thing is not to fixate on the predicted landfall location, but to see that Irene's winds will affect areas far away from landfall. The GFS, not shown, agrees with ECMWF that Irene will have a large area of tropical-storm force winds associated with it.

Figure 3 Maximum wind-speed in mph from the 00Z August 23 ECMWF forecast for the next week.

Impacts

In the immediate future, Irene is expected to have a significant impact on the Bahamas and surrounding islands. Hurricane force winds are forecast to reach the southeastern Bahamas and the Turks and Caicos sometime this afternoon or evening. These locations can also expect 5-10 inches of rain. Three to six inches of rain are forecast over northern Hispaniola, with isolated areas receiving up to 10 inches. This could lead to flash flooding and mudslides in mountaineous terrain. NHC is predicting a storm surge of 9-13 feet above normal tide level for the southeastern Bahamas and the Turks and Caicos.

Outside of the islands immediately impacted by Irene, it is my judgement that everybody living on the eastern coast of the US should monitor Irene and review their hurricane preparations over the next few days.

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 HurricaneHunterJoe:
are the 12Z models out yet?


yes, for some oh them. the BAMS
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Quoting bocahurricane:


Think we are going to get any ts watches/warning down here?
NHC is waiting For the track to be very confident before issueing any watches for the US , but its likely SE fla would be under TS watches the wind field is going to be quite large , lets wait and see but i do not see a direct hit on S florida at all
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Quoting quakeman55:

Then it will run into the Philippines, then Taiwan, China, pop back off and hit Japan, then move across the north Pacific as an extratropical cyclone and slam into the Pacific Northwest, move across the US and move off the coast of New England, then a ridge of high pressure will push it southward, regains tropical characteristics, then rebuilding ridge pushes it west into the GOM, bombs into a Cat 5 and slams into New Orleans.

How's THAT suit ya? LOL


GRAPHIC or it won't happen. LOL [Sarcasm]
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932. DFWjc
Quoting gator23:


I have Patrap on ignore. He is always contradicting what I say even when he is wrong as he is now. Just ignore him.


I believe what Patrap is trying to say is there wasn't a VISIBLE eye on satellite, not a RADAR shown eye...
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931. 7544
morning everyone irene is looking good anysee the blob off the se of fla what role eill that play into irene could they meet as its moving south it just pop into the pic tia
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930. ackee
Quoting Seflhurricane:
IMO the slower she goes further west she may come and the Trof may be delayed in pulling her NW if she slows down.
agree seem to be slowing down means more threat to the us
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Quoting MoltenIce:
Impossible!

The gap created by dry air will steer Irene into the EPAC and then to the WPAC where it will live indefinitely.

(Sarcasm mode = on)

Then it will run into the Philippines, then Taiwan, China, pop back off and hit Japan, then move across the north Pacific as an extratropical cyclone and slam into the Pacific Northwest, move across the US and move off the coast of New England, then a ridge of high pressure will push it southward, regains tropical characteristics, then rebuilding ridge pushes it west into the GOM, bombs into a Cat 5 and slams into New Orleans.

How's THAT suit ya? LOL
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Quoting HurricaneHunterJoe:
are the 12Z models out yet?
not until 11:30.
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Irene inflow from the S.E. appears to being affected by the mountains now. This my lead to a little weakening and a more west trajectory in the short term, but I doubt any longer term consequences. It may make today interesting though.
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Quoting Patrap:


That file image of Katrina is as it appeareed still East of Fla as a Tropical Storm,,it never created a Eye feature till into the GOM.,,as a Hurricane
ok, thank you. It's funny people are saying you are wrong, but you did joined in June of 2005 before Katrina. These people are maybe been too young to remember Katrina.
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are the 12Z models out yet?
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The 0800 models appear further east again and the 1100 AM CPA for CONUS may now be Hatteras.
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923. zingo
I been through Floyd and Fran, parents lost their home. It seems once a hurricane sees the mouth of the Cape Fear River at the NC/SC border it just turns and goes up it. Now I am 50 miles from coast in SC and I'm not sure I need to worry about this one. Right now it is a toss up! Prayers to those that are dealing with her.
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IMO the slower she goes further west she may come and the Trof may be delayed in pulling her NW if she slows down.
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Quoting Seflhurricane:
looking at the projected windfield TS storm force winds would affect coastal SE Fla if the current track holds and so far she is on track , has the high pressure steering irene weakened at all ???? and the trofs have they been on time coming down or a bit delayed???


Think we are going to get any ts watches/warning down here?
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Quoting JGreco:


Trust me I'm concerned too. I have a sister in Charleston who is concerned that since her husband has to move the military aircraft from the area, it leaves her to evacuate by herself with her four children. To me he's not realist. A realist would want the models to trend further East and out of the region. He's a wishcaster who hopes to feel the brunt of the storm despite the millions who could possibly be affected.
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Quoting mcluvincane:


Best model around ECMWF

923 mb
whats that 135-140 mph ?
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Quoting Bluestorm5:
as I said, Carolinas are still in path... not over yet.


I figure tomorrow morning the mets will have a good idea of where and when. I'm near Charlotte and my sister is in Raleigh so my eye is tuned to the progress. It occurs to me that if we have a few more "poofs" this blog will start to slow right down.
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This year as the CV season has arrived,, the nose of the Atlantic Ridge is where the action will be. As in 05,08,,storms come around the nose of it,,or they ride under,expect a blend of both,with the nose being someones friend and another worst enemy as Canes round the edge and seek the coast.
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Quoting MahFL:


That radar is no use right now as the eye is too far east.


Worth bookmarking for tonight and tomorrow though.
Member Since: August 10, 2010 Posts: 2 Comments: 1970
Quoting SuperYooper:


Per Wiki-

In the terminology of the United States insular areas, a Commonwealth is a type of organized but unincorporated dependent territory.

The definition of "Commonwealth" according to current U.S. State Department policy (as codified in the department's Foreign Affairs Manual) reads: "The term 'Commonwealth' does not describe or provide for any specific political status or relationship. It has, for example, been applied to both states and territories. When used in connection with areas under U.S. sovereignty that are not states, the term broadly describes an area that is self-governing under a constitution of its adoption and whose right of self-government will not be unilaterally withdrawn by Congress".[1]

There are currently two United States insular areas classified with the status of commonwealth, the Northern Mariana Islands and Puerto Rico.

Of the current U.S. insular areas, the term was first used by Puerto Rico in 1952 as its formal name in English ("Commonwealth of Puerto Rico"). The formal name in Spanish for Puerto Rico is "Estado Libre Asociado de Puerto Rico,".

Despite the Spanish translation of the term "commonwealth", Puerto Rico's relationship with United States is not a Compact of Free Association (which is the case for the Federated States of Micronesia, Palau, and the Marshall Islands). As sovereign states, these islands have full right to conduct their own foreign relations, while the Commonwealth of Puerto Rico is part of the United States as a territory. ”[2]


And, if we're going to be picky about whether PR is a part of the U.S, what about the USVI (United States Virgin Islands)?

How close did Irene get to them?
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Quoting CaicosRetiredSailor:
Morning,

Still no classic "outer bands" have come through Provo, grey and blustry.
I don't expect to be on here a lot, but will update when I can.


I know you will stay as safe as possible - you're an old hand at this.

Thanks for the post - please continue to let us know when/ if you are able how things are going. Saying prayers for all.

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BTW, people on the radio are still saying "IF" Irene comes.... clear evidence that we haven't had a hurricane hit here for a while...
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912. MahFL
Quoting Patrap:
Eastern Cuba radar


That radar is no use right now as the eye is too far east.
Member Since: June 9, 2004 Posts: 0 Comments: 2906
Quoting Bluestorm5:
he's right, Carolinas are still not out. Models at 00z runs was directed at SC landfall. It usually shift east during the day, west at night with this storm.


Trust me I'm concerned too. I have a sister in Charleston who is concerned that since her husband has to move the military aircraft from the area, it leaves her to evacuate by herself with her four children. To me he's not realist. A realist would want the models to trend further East and out of the region. He's a wishcaster who hopes to feel the brunt of the storm instead despite the millions who could possibly be affected.
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Quoting Bluestorm5:
I wish I can answers that, but I haven't been around long... and others isn't here yet.


Hahahaha the grammar in this post is hilarious. Make it through high school first then come back.
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Quoting mcluvincane:


Best model around ECMWF


Per Dr. Masters..
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Quoting naplesdreamer28:
So are we safe to say at this point FL is out of it? I'm in SW FL and glad to see the cone gone, but sad to see where its heading for the Carolinas. From what I'm reading these troughs and influences are pretty well where they will be in terms for FL not to worry, correct?


I live here in Naples, and I don't believe there is any need to worry at this point, but just stay concerned and watchful incase of some sudden change in the forecast. I've already stocked up on stuff for the season so at least that's out of the way.
Member Since: September 2, 2008 Posts: 0 Comments: 744


Best model around ECMWF
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Quoting CaneHunter031472:


Saludos a ti tambien hermano. I'm in Mississippi (Go figure), but I love the people here in the south They remind me at my ppl back in the Island. They are proud, intelligent, and keep a smiley face even during Katrina. They are very strong as well and never feel sorry for themselves. I believe the hope of America is in the South.



que bien. exito por alla.
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Complete Update

HH almost there... and waiting for the model runs on 90L


TS BUSTED FORECAST ALIBI





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Quoting Zaphod:
Why the expected drop from Cat 4 to Cat 3 as it approaches land? A slow moving big storm will move a lot of water. Even if the wind intensity drops a bit, I'd imagine surge will be unusually significant.
shear and interaction with trough perhaps!?
Member Since: May 16, 2010 Posts: 0 Comments: 1418
hopefully,it looks like Haiti will be spared a major event
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looking at the projected windfield TS storm force winds would affect coastal SE Fla if the current track holds and so far she is on track , has the high pressure steering irene weakened at all ???? and the trofs have they been on time coming down or a bit delayed???
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So are we safe to say at this point FL is out of it? I'm in SW FL and glad to see the cone gone, but sad to see where its heading for the Carolinas. From what I'm reading these troughs and influences are pretty well where they will be in terms for FL not to worry, correct?
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Quoting TropicalXprt:


Are you kidding me? Local radar is the best tool there is. An eye is the center of circulation. Just because there are a few clouds covering the visibility of an eye, doesn't mean it doesn't exist. Hurricane and tropical storms CANNOT exist without an "eye", well defined or not.


I have Patrap on ignore. He is always contradicting what I say even when he is wrong as he is now. Just ignore him.
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Quoting Thoroside:
Where are the pros? Too much childs play on the board right now, too much getting buried. Grothar, Dak, Pat, Levi, PP, you know the good guys, can anyone offer insight to this?

Honestly here to learn, that said, can I ask about the pattern of the past two years. For two years now, we've heard from experts that the Atlantic Ridge will be firmly in place to push storms to the west on a beeline. We've heard that FL and the Gulf states are a sitting duck, etc etc.

Now, for the past two years, most every storm to approach we have now seen curve sharply north or a full re-curve. And in this case with Irene, I read from experts that, that was mostly due to the shortwaves skirting down, and not the deep East coast trough (which to an amateur myself would be more understandable). How is that, any little mild influence in the northern North American atmosphere is defeating this once proclaimed dominant Atlantic ridge?

I'd love to here some opinions and facts on the matter. Thanks guys.
I wish I can answers that, but I haven't been around long... and others isn't here yet.
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Quoting 69Viking:


Wow, go ahead and just insult people you don't even know, that will win you a lot of friends. So according to you the only TWO on here that aren't idiots are TampaSpin and NCStorm, wow!


Omgosh..I guess I can start doing tropical tidbits and make my own website with my vast knowledge..LOL..Blue, relax..time will tell soon enough what Irene will do..
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897. DFWjc
Quoting Vero1:


Yep still heading toward Dallas,TX


hey hey, no teasing us dried up folks up here!! LOL
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Quoting cruzinstephie:


Thanks for wishing that on us!


You gotta be kidding...I've been sweating bullets for the past week and my blood pressure isn't getting better. Thankfully I'm in Jacksonville which is the luckiest city in the US for 'canes' (check the records, least chance of getting direct hit, repeat, DIRECT hit) but it's still a big pain in the ass and there's always fall out from wind and rain.

Also, I'm scheduled to go in vacation Saturday. I've changed my sister in laws plans from flying here to flying to Baltimore and her brother picking her up, and now I'll have to leave Friday and run way inland to get away from not only the damn storm but the people who have evacuated. I'll be damn glad when we get to Cumberland, Md and I can forget all this crap.
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Quoting CaicosRetiredSailor:
Morning,

Still no classic "outer bands" have come through Provo, grey and blustry.
I don't expect to be on here a lot, but will update when I can.


Good luck... looks to be a rough ride... which is probably a gross understatement.
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Quoting FLdewey:
This blog needs an age filter.

Models are twitching... hopefully further East.


It needs an I.Q. filter.
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IRENE has good solid feeders in 75% of her inflow,

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Quoting ncstorm:
HPC Extended Discussion

THE LATEST NHC FORECAST IS
BETWEEN THE 00Z UKMET/ECMWF SOLUTIONS
...WITH THE 00Z GFS SLIGHTLY
FASTER UNTIL ABOUT DAY 6/MON WHEN THE GFS IS CLOSET. THUS...DUE TO
THE SIGNIFICANCE OF IRENE WILL LIKELY USE THESE 3 MODELS THE MOST
IN CONSTRUCTING THE PRELIMINARY PRESSURES/FRONTS FOR THE MEDIUM
RANGE PERIOD. EVEN WITH RELATIVELY CLOSE DYNAMICAL TRACK GUIDANCE
TO IMPLEMENT IN THE UPCOMING PROGS...NO SOLUTION OTHER THAN THE
00Z ECMWF IS EVEN REMOTELY CLOSE TO THE HURRICANE MODEL GUIDANCE
CENTRAL PRESSURES SUCH AS THE GHM/HWRF WHICH HAVE IRENE BOTTOMING
OUT AROUND 930 MB AND SHIFTING TO THE LEFT OF THE OFFICIAL NHC
TRACK ALONG THE SOUTH CAROLINA COAST. HOWEVER...WHEN CONSIDERING
THE ENTIRE SOLUTION SPREAD JUST BY DAY 4/SAT...TRACK DIFFERENCES
SPAN ABOUT 300 NM...SO THERE REMAINS MUCH TO RESOLVE FOR THE
SENSIBLE WEATHER DETAILS OF IRENE. FOR NOW...WILL INTERPOLATE
BETWEEN THE LATEST NHC POINTS FOR DAYS 3 AND 4 WHICH HAS IRENE
MAKING LANDFALL BETWEEN MYRTLE BEACH SC AND WILMINGTON NC LATE
SATURDAY. REFER TO THE NHC FOR THE OFFICIAL TRACK AND INTENSITY
FORECAST.

as I said, Carolinas are still in path... not over yet.
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Where are the pros? Too much childs play on the board right now, too much getting buried. Grothar, Dak, Pat, Levi, PP, you know the good guys, can anyone offer insight to this?

Honestly here to learn, that said, can I ask about the pattern of the past two years. For two years now, we've heard from experts that the Atlantic Ridge will be firmly in place to push storms to the west on a beeline. We've heard that FL and the Gulf states are a sitting duck, etc etc.

Now, for the past two years, most every storm to approach we have now seen curve sharply north or a full re-curve. And in this case with Irene, I read from experts that, that was mostly due to the shortwaves skirting down, and not the deep East coast trough (which to an amateur myself would be more understandable). How is that, any little mild influence in the northern North American atmosphere is defeating this once proclaimed dominant Atlantic ridge?

I'd love to here some opinions and facts on the matter. Thanks guys.
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Quoting WeatherfanPR:


a pues saludos hombre, yo soy natural de San Juan pero apenas hace 3 meses me mude para Tampa,FL.


Saludos a ti tambien hermano. I'm in Mississippi (Go figure), but I love the people here in the south They remind me at my ppl back in the Island. They are proud, intelligent, and keep a smiley face even during Katrina. They are very strong as well and never feel sorry for themselves. I believe the hope of America is in the South.
Member Since: August 1, 2007 Posts: 0 Comments: 163
Quoting cat5hurricane:

SC is definitely still under the gun. Very much so. Any halt in forward speed and/or intensification fluctuation could be all the world.

I am very on edge for my properties down in Isle of Palms and also some of my relatives near Goose Creek, SC.


Could be, might be, should be, will be, won't be, oughta be, ......
Member Since: October 26, 2003 Posts: 0 Comments: 363
Quoting TheMom:
Not so complicated it was cede to the US as an organized territory in the Spanish American War (think Teddy and the Rough Riders) They have a no vote representative as well in the US Congress


Just like the District of Columbia!
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Morning,

Still no classic "outer bands" have come through Provo, grey and blustry.
I don't expect to be on here a lot, but will update when I can.
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Quoting Bluestorm5:
it's sad that people don't realized that Irene is STILL going to hit Bahamas no matter what until it turns NE NOW... prayers for them.


Thanks. Sometimes it seems that most on this blog these days thinks the Bahamas are just a bunch of uninhabited rocks. Didn't use to be like this in the old days, back then most on here were a lot more knowledgeable about tropical weather and geography.
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This would be my message to the hurricane skeptics that always take the storm lightly and are the first we see on TV standing on their roof surrounded by walls of water from the ocean.

Hurricane Irene is going to be a dangerous storm and so anyone in it’s path need to stay tuned to the weather channel and the news. There are a lot of people that live in the Carolinas that talk about this storm or that one. They state that they have lived through them and so this one will be no different but the old saying goes, “It only takes one storm.” I bet that if you asked people in Katrina’s path in 2005 they would have made some of those same comments but talk to them after the storm and they give you a totally different answer. Oh and I am not just talking about people in New Orleans either because I bet some people in Missippi high tail it out from now on when a storm threatens their area.
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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.

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