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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Getting a good band here in WPB now..local mets last night called for only about 1-2" of rain though. School buses arent allowed to run in anything over 40mph gusts so I am wondering if i wont get a call from the school today to pick up the kids early..happened during Charley.
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645. CJ5
Quoting weld:
This storm has the potential to be disastrous for Florida if it does not turn. It could also be disastrous for the NHC.


You don't have to worry about that scenario.
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hey whos got the chart showing the curent num. of storms and the num. for 2010 2005 and I don't remeber the other but yes where is it
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Quoting presslord:
OK....I live in a favored vacation spot for New Jersey and New York folks....who come down here and 'try to cram lost years into 5 or 6 days'....they check in on Saturday afternoon....are drunk beyond functionality by about 10 Saturday night...and spend all day Sunday bar b queing themselves on the beach....on Sunday evening , we see them in the grocery store...looking about the color of a solar flare...with eyes that look like lunar craters....they're gonna have 'fun' if it kills 'em...throughout the next week they stumble frequently into the street in front of oncoming cars, drive like fools...and, not uncommonly, pee in my shubbery...

so my question is this:

Are these people smart enough to handle this?!


We want..........a shrubberrrrrrrry !!!
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Earth Scan Lab by LSU
Member Since: July 3, 2005 Posts: 426 Comments: 128668
Quoting presslord:
OK....I live in a favored vacation spot for New Jersey and New York folks....who come down here and 'try to cram lost years into 5 or 6 days'....they check in on Saturday afternoon....are drunk beyond functionality by about 10 Saturday night...and spend all day Sunday bar b queing themselves on the beach....on Sunday evening , we see them in the grocery store...looking about the color of a solar flare...with eyes that look like lunar craters....they're gonna have 'fun' if it kills 'em...throughout the next week they stumble frequently into the street in front of oncoming cars, drive like fools...and, not uncommonly, pee in my shubbery...

so my question is this:

Are these people smart enough to handle this?!


Those who arent will...well...It's Darwin's way.
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Quoting BeanTech:


You had a rain "event"?
I just say "it rained".



You're free to say as you please.

Have a great day!
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639. Vero1
Quoting ncstorm:
Does anyone know where I could find a weather map to show what type of conditions people should expect from Irene?

Inter-activate: http://www.stormpulse.com/hurricane-irene-2011
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Quoting cat5hurricane:

That's my thinking still. I think Myrtle Beach is out of the woods for a direct landfall, but hurricane force winds there along the coast are definitely not out of the question. At the very least, hurricane force gusts are possible there as she makes her way up the coast.

Still alot of time before all of this, and alot can change. But at the moment, anywhere between Wilmington, NC and Morehead City, NC is where I think approximately she can make a direct landfall. Until I see an almost due poleward motion within the next 12 hours, I would not be surprised to even see the NC/SC get a direct hit, as Nash alluded to earlier.

I say if she get's as far west as 78 degrees, that's a very bad sign for the NC/SC border. We won't know that for another 12-18 hours though.


Agree, never, ever discount the Hurricane magnet that is Cape Fear, NC, since last week I have been saying landfall in Bald Head Island, I still think thats a strong possiblity. Im in NMB and I have seen these things time and time again look like they are going to blast us and at the last second,head toward Cape Fear. Long Bay really saves our Butts here in Myrtle
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Quoting weld:
This storm has the potential to be disastrous for Florida if it does not turn. It could also be disastrous for the NHC.
We're ready and waiting...LOL
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Member Since: July 3, 2005 Posts: 426 Comments: 128668
Patrap - could you provide a link to where you obtained that last graphic from? I would like to nose around.

Thank you!
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634. GoWVU
Quoting weld:
This storm has the potential to be disastrous for Florida if it does not turn. It could also be disastrous for the NHC.


so true
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Meantime....

Trinidad weather now..
Temp 79F
Humid 89%
Wind WNW
Pressure 1016
Rain.

Sky is black and a constant drizzle since about 5:00 am.
Good weather, if you're a duck.
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Quoting presslord:
OK....I live in a favored vacation spot for New Jersey and New York folks....who come down here and 'try to cram lost years into 5 or 6 days'....they check in on Saturday afternoon....are drunk beyond functionality by about 10 Saturday night...and spend all day Sunday bar b queing themselves on the beach....on Sunday evening , we see them in the grocery store...looking about the color of a solar flare...with eyes that look like lunar craters....they're gonna have 'fun' if it kills 'em...throughout the next week they stumble frequently into the street in front of oncoming cars, drive like fools...and, not uncommonly, pee in my shubbery...

so my question is this:

Are these people smart enough to handle this?!



No, no and no, and give the order for them to exit immediately,under penalty of no Liqour or restrooms.
Member Since: July 3, 2005 Posts: 426 Comments: 128668
Quoting dmh1026:

Try this....http://www.nhc.noaa.gov/refresh/graphics_a t4+shtml/092237.shtml?5-daynl#contents


OK, so nothing's really changed...

I read "nightmare turn" and I thought "due west track"...

We're in St Augustine, FL and we have all but stood down on our hurricane response..

Was thinking maybe we were gonna get caught flat-footed..

Thanx again for the link..


Michale....
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Quoting weld:
This storm has the potential to be disastrous for Florida if it does not turn. It could also be disastrous for the NHC.

lol.

Member Since: August 6, 2007 Posts: 0 Comments: 693
It's been unusually breezy here in Terra Ceia by the water this morning. I'm guessing its from Irene due to the winds out of the North. Thoughts
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Does anyone know where I could find a weather map to show what type of conditions people should expect from Irene?
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Quoting Chucktown:


Already turning - has gone from 285 heading to 325 in the last 24 hours.


Thanks for the answer! Then I guess for the moment I can breathe a sigh of relief for the Charleston area anyway! I am more concerned that if it does come in closer to (or makes a landfall near)the SC/NC border then we may see more action than we had anticipated. I was here for Hugo & the rest of them but I don't go out buying willy nilly without having cause. So, I was just wondering what everyone felt about this location needing to get supplies.
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625. weld
This storm has the potential to be disastrous for Florida if it does not turn. It could also be disastrous for the NHC.
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Quoting Brock31:


Has she lost here eye completley or is she going through a replacement cycle?

Last central pressure observation would indicate that she isn't weakening? Am I correct?


Looks to me as if IRENE is shaking off the last of some Continental Air from the west,and a tad bit of Land friction from the Islands impacted overnight.

But she has a well buit core and I expect her to ramp up this newer Inenner Wall with Warm SST's and low shear today.

Dr. Masters should be posting a mid morn update as Im sure he is scrutinizing the situ carefully.



Member Since: July 3, 2005 Posts: 426 Comments: 128668
Quoting DFWjc:


http://www.accuweather.com/blogs/news/story/54098 /hurricane-irene-to-slam-into-t.asp Link


Thanx... Much appreciated..


Michale
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Quoting Michale:
Drudge is reporting "NIGHTMARE TURN FOR IRENE"...

Any idea what is going on?? I can't find anything here or on NOAA...

Michale

Try this....http://www.nhc.noaa.gov/refresh/graphics_a t4+shtml/092237.shtml?5-daynl#contents
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Quoting Brock31:


Has she lost here eye completley or is she going through a replacement cycle?

Last central pressure observation would indicate that she isn't weakening? Am I correct?
Yes, Yes and Yes
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As more or less expected the models ceased their eastward march and have settled back to the west. Now, they'll vibrate around a fairly small area unless something really unusual happens, which won't given the hefty investment in dropsondes, air flights, and balloons.

The outcome for NYC and surrounding areas is going to very sensitive to the path through NC. It looks like Irene is going be large and powerful, so skirting the land or a short traversal isn't going to knock it flat. We're down to less than 72 hours from a NC landfall, and there is a LOT of data being collected, so those models should be unusually accurate. Still too far out from a NE landfall to know where that will be for sure.

The administration must be sweating this one, as would be the NHC. DC is in the target zone, and many more millions than have been in a potential evac zone perhaps ever before. When do you make the call to evac an area that has poor plans, little experience, and maybe not enough infrastructure? If you wait until the last minute, your options are limited. If you make the call early, you risk missing the right area or making the evac 5x larger than it needs to be. Any call you make is likely to be wrong for a large and influential group.

Maybe now the NHC will get the funding they need to improve predictions?
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617. DFWjc
Quoting Michale:
Drudge is reporting "NIGHTMARE TURN FOR IRENE"...

Any idea what is going on?? I can't find anything here or on NOAA...

Michale


http://www.accuweather.com/blogs/news/story/54098 /hurricane-irene-to-slam-into-t.asp Link
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Drudge is reporting "NIGHTMARE TURN FOR IRENE"...

Any idea what is going on?? I can't find anything here or on NOAA...

Michale
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Good morning! We are getting some wind and rain off a rain band here in Port Saint Lucie, FL. The NWS has issued a special statement for our area through 9:45AM until this band moves through.
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Quoting WatchingThisOne:


"What about us?"

- the Whales



Whales.....and anything else living underwater. LOL
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Link

first real squall approaching Miami Beach this AM.
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Miami
NEXRAD Radar
Velocity Azimuth Display Wind Profile


Member Since: July 3, 2005 Posts: 426 Comments: 128668
I don't know a whole lot about meteorology other than what I've observed over the years, so this is an honest question... looking at the satellite in the link below, which shows projected path as well...

SFWMD Satellite Image

... it would seem that the path has shifted west twice in about 14 hours. I pretty much assumed that here in Charleston we were out of the woods, but does this mean that points south of the Outer Banks still have something to be concerned about or not? Or is it still too early to tell?
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Quoting wunderkidcayman:
wow hey guys I was still back on blog #1893 I did not know that we moved on but wow I can't belive I did that form blog #1893 to blog #1898 I feel bad
I hate when that happens LOL...
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Quoting mistified:
Please excuse my ignorance about these weather maps, directions, wobbles, ect... But, living near Charleston SC just how concerned should I be. I have been following along "lurking" for days and watching local TV about this storm. And although it does appear to be moving out & away from me, I'm not seeing this "big" turn yet. So, when should I start to really get concerned? Or should I just remain watchful but not go buy out the store yet.


Honestly, as someone who grew up in Florida and lived there for 25 years, here's what I suggest for any plan regarding hurricanes:

1. When hurricane season starts you should go buy some water to have on hand and a flashlight with some replacement batteries. That way if/when a storm comes you already have the bare necessities and you don't have to go battle other people for what's remaining in the store.

2. Pay attention to the storm track and if a Category 2 or higher storm looks like it will make landfall anywhere near you, pack up a few days worth of clothes,etc. and go take a trip inland. If you have friends in Asheville, Atlanta, Charlotte - anywhere a couple hundred miles away and in a direction where the storm is not anticipated to go, that's a good time to go visit. Don't stick around because you're afraid for your stuff. That's what your insurance is for. You don't want to be living in an area without power and no drinkable water for days (trust me), not to mention if it's a really powerful storm you don't want to be hiding in some closet all day/night.

If it's a Category 1 or tropical storm you can sit it out, which is where the water and flashlight/batteries come in.
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Quoting Patrap:
unenhanched IR



Has she lost here eye completley or is she going through a replacement cycle?

Last central pressure observation would indicate that she isn't weakening? Am I correct?
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604. PTXer
Quoting Plibster:
Link

Hope this works...nice webcam out of Palm Beach,FL.

Working well. Looks pretty gusty there!
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Member Since: July 3, 2005 Posts: 426 Comments: 128668
For the 2011 season NHC will be issuing "Probabilistic Hurricane Storm Surge greater than 2-25 feet" on www.nhc.noaa.gov when a hurricane watch or warning is in effect.


Probabilistic Hurricane Storm Surge

This graphic shows storm surge heights, in feet above normal tide level, which have a 10 percent chance of being exceeded during the next 3 days. The graphic is based upon an ensemble of Sea, Lake, and Overland Surge from Hurricanes (SLOSH) model runs using the current National Hurricane Center (NHC) official hurricane advisory. The exceedance heights depend on the historical accuracy of NHCs forecasts of hurricane track, and wind speed, and an estimate of storm size.




Link
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Quoting hang10z:
I have a serious question....

Currently my mother is in FL visiting. She lives on Long Beach Island in NJ, second house from the ocean. She is considering staying down here since her flight leaves friday night from Fort Lauderdale to Atlantic City Airport. Landing a little before midnight SAT. My brother lives outside of Philly but on the Jersey side of the river (Cherry Hill Area)

Should I have my brother head over to LBI, grab her car, get anything of value and bring it to his house 70 miles of so west of the coast? I figure if this thing hits NJ straight on LBI will be underwater.


He doesn't think its going to be that bad.. then again he doesn't really read this blog and watch model runs.. just listens to whatever the radio or TWC is saying.

He went to bed thinking a little rain and wind.. now it looks otherwise...


Thanks for your help..



It's better to be safe than sorry. I had a house 2 blocks from the beach in Ocean City, NJ when Bob came through in 91 and it was bad. Gutted the whole 1st floor. This looks like it is going to be much worse. Enjoy the extra time with your mom, and let your brother secure the house.
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Quoting Patrap:
unenhanched IR

I believe in NOAA I believe in NOAA *clicking heels togeather* That is a scary image to be able to watch and "know" that we are going to maybe get a little wind and some rain.
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599. ackee
Quoting chevycanes:

you must not have looked at the long range models then. plenty of weaknesses coming along and TD 10 will turn NW in the next day or 2.
notice THE 0ZGFS shift futher west with these wave not sure bet HIGH will be weak as yet guess we see
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598. Jax82
Crazy to see a hurricane so close to Miami, and no watches or warnings for them.
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Surf was pretty fun this morning here.

A big thanks goes out tho the NWS for your completely inaccurate forecast for the wind overnight and this morning. We were expecting moderate S to SSE winds here as forecast.

Woke up to light NW to NNW winds and a glassy ocean and a 13 second interval groundswell. I'm thinking this may have been our only window for any quality as far as surf goes for our area.

Looks like Irene's Hurricane force wind area has increased from a 50 mile radius yesterday to 70 miles today. She could essentially "miss" us by 100 miles and we would still get winds >74 mph here.
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Quoting chevycanes:

you must not have looked at the long range models then. plenty of weaknesses coming along and TD 10 will turn NW in the next day or 2.

and if you havent looked at the long range models too my frined you see jose going out a potential katia going out and lee heading towards the islands as a hurricane. there is going to be a gap for a week but after that it will be closing
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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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