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 TropicalAnalystwx13:
Severe damage reported in the Bahamas, near Crooked Island.
Link
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Quoting vortextrance:



.FLIGHT-LEVEL AND SFMR-OBSERVED SURFACE WIND DATA
SUPPORTED A CURRENT INTENSITY OF NO MORE THAN 100 KT...AND THIS IS
PROBABLY GENEROUS.

That wasn't weakening, that was keeping current intensity.....
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394. MahFL
Quoting WxLogic:


That's not the correct steering... this one would be:




So on that steering it's going to Florida ?
Member Since: June 9, 2004 Posts: 0 Comments: 3850
might ride right up elbow cay abaco islands. nnw
Member Since: September 11, 2010 Posts: 1 Comments: 5006
Quoting tatoprweather:
TD # 10



Jose could be named later today.
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Quoting Dunkman:
I mean if it goes inland at Wilmington there isn't going to be a hell of a lot left other than some rain and gusty winds once it gets to NYC.


If it is going inland to wilmington, they need to sound the alarm NOW. Landfall would be in give or take 48 hours most likely, and we are under a tropical storm watch...

Hopefully thats not the case, but this is coming dangerously close for my liking. People here ARE NOT prepared for a major hurricane and probably wont think they need to be unless they atleast issue a hurricane watch
Member Since: August 4, 2011 Posts: 0 Comments: 631
Quoting tatoprweather:
TD # 10

98L is fluctuating between 10% or 20% is it?
Member Since: August 11, 2010 Posts: 0 Comments: 784
Quoting islander101010:
still waiting for gilbert to hit galveston
x. Not time to be like that. I believe models confirm and nhc will follow...ignorance is bliss I guess
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Quoting 2003FXDWG:


8 blocks from a potential hurricane landfall is a very dangerous place to be. I have seen +12" trees snapped in half over 90 miles inland from Rita. Please take a look at these pictures of Bolivar Peninsula before and after Ike (the last storm to make US landfall). http://coastal.er.usgs.gov/hurricanes/ike/photo-co mparisons/bolivar.html

Also here is an article detailing the fates of people who stayed because they had been lucky in the past. The man from Port Neches (where I grew up) was 100 miles east of Ike's landfall. http://www.chron.com/neighborhood/baytown-news/art icle/Grisly-finds-put-Houston-area-Ike-death-toll- at-32-1583737.php

Please follow all your local emergency authorities' recommendations.


You are absolutely correct! In Ike, we had barges..huge barges and whole houses 5 miles inland. We rescued animals from homes miles inland that had "never" flooded before. In Katrina the force of the water bent railroad tracks like they were cooked spaghetti. The wind is bad, but the storm surge is even worse.

Play it safe and leave early! During Gustave it took 16 hours to get from New Orleans to Panama City Florida! We couldn't even get into Sabine Pass TX after Ike (and they didn't even take a direct hit!) for 5 days due to the water still rushing our from being so far inland and by the time we got there, we only found 2 goats (they climbed on top of the school roof (two storied up!) and 2 cats alive (the climbed into an attic of the two story house). It's just too sad for words.

Just go! If nothing happens, consider it great practice for the future and if you have pets, you really need to leave early! When you evacuate, take your pets with you!! Never, ever, ever leave them behind!!!
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Quoting snotly:
in addition to ewrc is there some shear from the SSW?


Her anticyclone is now off the southern Cuba coast, moving west in tandem? The shear is to her NE.LinkCIMMSShearMap
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Tropical Depression 10, if not for anything else, is a convection-maker. Has always had it...Should be Jose soon.

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Quoting gilby715:
Wrong map for Irene currently.
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2nd fleet ordered to sea 26 more ships to sea out of Norfolk VA. to protect the fleet from damage. as per wflx news
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Quoting aimetti:
say this thing hits me in SE CT , is 9 miles inland far enough from the coast? obviously surge wouldnt be an issue but in general.


Depends...I'm at least 150 miles from where Charlie made landfall and we had strong winds and heavy rain. Lots of trees and limbs down, some flooding, etc. Best thing to do is follow your local authority's recommendations. If they say to leave, find a nice place to spend the weekend.
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TD # 10

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Quoting gilby715:


That's not the correct steering... this one would be:

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378. Vero1
For those that are into interactivate graphics a good page is: http://www.stormpulse.com/
Member Since: July 21, 2008 Posts: 4 Comments: 2233
Quoting yonzabam:
If Irene hits NYC, I wonder how many windows will get blown out? There are a LOT of windows in NYC. Good business for someone, but I wouldn't want to be underneath all that falling glass.
How about clean-up?
Member Since: August 11, 2010 Posts: 0 Comments: 784
I mean if it goes inland at Wilmington there isn't going to be a hell of a lot left other than some rain and gusty winds once it gets to NYC.
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This image captures Irene's decaying small eye, and the newer large eywall.

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looks like Irene is going for the Gulf Stream and ride that up the coast ?
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in addition to ewrc is there some shear from the SSW?
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370. 900MB
Funk finding some green again
Link
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Good morning!

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Quoting vortextrance:


Weakening. She will have to strengthen some to reach her current listed max winds of 115. The NHC mentioned that estimate as generous.

The storm is not weakening. Its central pressure is constant, and its outer eyewall is contracting as it spins up to speed and completes the EWRC. The very low pressure of this system - like some other unusually large and sprawling storms we've seen in the past few years - has never matched the observed windspeeds. The flight level winds simply haven't produced the usual surface-level reduction factors as verified by dropsonde or SFMR. So what we're seeing is less weakening than a belated acknowledgement of that pattern.
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Quoting Cotillion:


It's obviously broken, just look at the other readings:

Level Wind Direction Wind Speed
998mb (Surface) 345° (from the NNW) 30 knots (35 mph)
996mb 350° (from the N) 35 knots (40 mph)
991mb 350° (from the N) 31 knots (36 mph)
980mb 340° (from the NNW) 39 knots (45 mph)
979mb 335° (from the NNW) 35 knots (40 mph)
977mb 340° (from the NNW) 18 knots (21 mph)
975mb 15° (from the NNE) 37 knots (43 mph)
974mb 15° (from the NNE) 80 knots (92 mph)
973mb 355° (from the N) 41 knots (47 mph)
972mb 230° (from the SW) 58 knots (67 mph)
970mb 215° (from the SW) 184 knots (212 mph)
969mb 220° (from the SW) 103 knots (119 mph)
968mb 235° (from the SW) 49 knots (56 mph)
751mb 5° (from the N) 48 knots (55 mph)

If it wasn't broken, could've ended up in a vortex embedded in the eyewall.


Thanks for correcting me .
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Quoting OminousCloud:
Thanks Taz.



your welcome
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VOILA! eye apparent
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Severe damage reported in the Bahamas, near Crooked Island.
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Quoting Vero1:
BULLETIN
HURRICANE IRENE INTERMEDIATE ADVISORY NUMBER 20A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
800 AM EDT THU AUG 25 2011

...IRENE POUNDING THE NORTHWESTERN BAHAMAS...


SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...25.5N 76.5W
ABOUT 65 MI...105 KM ENE OF NASSAU
ABOUT 670 MI...1085 KM S OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...950 MB...28.05 INCHES


Shes getting closer to NNW,
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360. Mikla
No... 9 miles is very small... the center of the eye would still be offshore by the time the eyewall passed over you. I have lots of family in CT (near Hartford) and I told them to act as if their house is on the beach.
Quoting aimetti:
say this thing hits me in SE CT , is 9 miles inland far enough from the coast? obviously surge wouldnt be an issue but in general.
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Quoting Hhunter:
Bastardi shifted his path west. Now to hit just and I mean just east of Wilmington and a litter West of new York city...yikes be aware folks..bad to NC and the big city...
still waiting for gilbert to hit galveston
Member Since: September 11, 2010 Posts: 1 Comments: 5006
Quoting Bobbyweather:
Oh my...

970mb 215° (from the SW) 184 knots (212 mph)


It's obviously broken, just look at the other readings:

Level Wind Direction Wind Speed
998mb (Surface) 345° (from the NNW) 30 knots (35 mph)
996mb 350° (from the N) 35 knots (40 mph)
991mb 350° (from the N) 31 knots (36 mph)
980mb 340° (from the NNW) 39 knots (45 mph)
979mb 335° (from the NNW) 35 knots (40 mph)
977mb 340° (from the NNW) 18 knots (21 mph)
975mb 15° (from the NNE) 37 knots (43 mph)
974mb 15° (from the NNE) 80 knots (92 mph)
973mb 355° (from the N) 41 knots (47 mph)
972mb 230° (from the SW) 58 knots (67 mph)
970mb 215° (from the SW) 184 knots (212 mph)
969mb 220° (from the SW) 103 knots (119 mph)
968mb 235° (from the SW) 49 knots (56 mph)
751mb 5° (from the N) 48 knots (55 mph)

If it wasn't broken, could've ended up in a vortex embedded in the eyewall.
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last few frames are starting to look like the north turn has happened.
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If Irene hits NYC, I wonder how many windows will get blown out? There are a LOT of windows in NYC. Good business for someone, but I wouldn't want to be underneath all that falling glass.
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342. wxobsvps 11:58 AM GMT on August 25, 2011 +0
GFDL


That is not pretty.
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354. Vero1
BULLETIN
HURRICANE IRENE INTERMEDIATE ADVISORY NUMBER 20A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
800 AM EDT THU AUG 25 2011

...IRENE POUNDING THE NORTHWESTERN BAHAMAS...


SUMMARY OF 800 AM EDT...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...25.5N 76.5W
ABOUT 65 MI...105 KM ENE OF NASSAU
ABOUT 670 MI...1085 KM S OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NW OR 325 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...950 MB...28.05 INCHES


Member Since: July 21, 2008 Posts: 4 Comments: 2233
Quoting Tazmanian:



this be come recon is in there dos not mean the rader can show a little W jogs from time to time so this be come recon says NNW dos not mean that the rader may be showing that this storm has take in a little W jog
Thanks Taz.
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The question is is how much does she move west before making a due north turn. its really crucial
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Quoting Bobbyweather:
Oh my...

970mb 215° (from the SW) 184 knots (212 mph)


LOL
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Quoting Bobbyweather:
Oh my...

970mb 215° (from the SW) 184 knots (212 mph)



where that from
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Quoting Bobbyweather:
Oh my...

970mb 215° (from the SW) 184 knots (212 mph)


LOL. SFMR is having problems, there is no way Irene is even a little tiny bit close to that.
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Quoting Bobbyweather:
Oh my...

970mb 215° (from the SW) 184 knots (212 mph)


Category 10 DOOMicane.
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Quoting robert88:
Turning NNW earlier than expected makes me think Irene's track will be on the E side of the models. It's still way too early but this may be a blessing for the EC.


Not yet...
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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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