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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What a well organized hurricane

Member Since: Posts: Comments:
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..

Member Since: August 2, 2010 Posts: 0 Comments: 34
Member Since: July 3, 2005 Posts: 428 Comments: 129841
Quoting FLdewey:
Start the generator...



Looks like she is spitting out the dry air the last couple of frames. 2:00 update will be interesting.
Member Since: September 8, 2008 Posts: 0 Comments: 423
Good morning all. Looks like it will be an active day for all the folks along the Eastern seaboard. I noticed on my drive to work today how high the seas are in Florida Bay. A combination of lunar tides and the winds from Irene coming from the NE, pushing the bay into the land. There is a salt water pond on the end of Duval. Unfortunately the City of Key West allows its storm water system to drain into the ocean, so when the seas are high the sea comes into the streets. I hope it stays dry and breezy for the Keys today so I can get my lawn cut this afternoon. It was way too hot last night and I know once this storm is past, it will become very hot and still again. I urge anyone who is on the Coastal target area to heed their Emergency Managers and evacuate when told. The force of the ocean is not to be under estimated. Stay safe everyone.
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Quoting presslord:


yep...and somebody'll die in the next two days out here at Folly screwin' around in the water...


You can count on it unfortunately....

Some yahoo who has never been in water higher than his bathtub is gonna go out there and drown. Sad but true.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
Quoting rkay1:
I love how TWC reads Tweets.  Does anyone ever get the feeling we're screwed as a country?


I'm surprised it took TWC so long to get into the fad that every media outlet is doing these days.
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IMA

Quoting Skyepony:
What is that on the SSE side there at the end of MIMIC?


Pretty sure they're those super-secret weapons used to destroy hurricanes. Damn, there goes my security clearance
!

must be using the haarp again so fl don't get hit...lol...lets just see if another earthquake happens again...don't believe those are planes being picked up in the shot either...and the end of the loop almost looks like fingers rolling it back to the north aftert that west jog..very odd...
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Quoting ecupirate:


Dubmest thing I have ever seen. They track what certain cities are "tweeting"

I haven't watched TWC in years and for the first time turned it on late last night and every 10 minutes they have a "tweet" trend update...


yeah, they should just have norcross, steve lyons and cantore talking about this 24/7... no one gives a rats ass about what cities are tweeting right now.
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535. Vero1
.
Member Since: July 21, 2008 Posts: 4 Comments: 2233
Quoting rkay1:
I love how TWC reads Tweets.  Does anyone ever get the feeling we're screwed as a country?


Dubmest thing I have ever seen. They track what certain cities are "tweeting"

I haven't watched TWC in years and for the first time turned it on late last night and every 10 minutes they have a "tweet" trend update...
Member Since: Posts: Comments:
Quoting nash28:


Yep. If Irene cooperates and stays on the current NHC track, we won't get too terribly pounded. Maybe sustained TS force winds for a few hours. Most likely just TS force gusts and heavy rains.

My biggest concern is she scoots her rear end closer to the coast and the heavier weather is able to get here... As in tornadoes, etc...


yep...and somebody'll die in the next two days out here at Folly screwin' around in the water...
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Quoting presslord:


apparently you're under a TS watch


Yep. If Irene cooperates and stays on the current NHC track, we won't get too terribly pounded. Maybe sustained TS force winds for a few hours. Most likely just TS force gusts and heavy rains.

My biggest concern is she scoots her rear end closer to the coast and the heavier weather is able to get here... As in tornadoes, etc...
Member Since: July 11, 2005 Posts: 190 Comments: 16972
529. ackee
I looking of shower NEAR windward EVEN with no model support CONDITON RIPE carrb this should be watch notice THAT TD#10 seem to be going more west guess we see
Member Since: July 15, 2008 Posts: 0 Comments: 1376
Quoting CarolinaHurricanes87:


patrap... is this not another shift slightly west for the dynamical models? Maybe im wrong but looks like a couple models now have direct hits on wilmington... beginning to wonder if they really will up our TS watch to hurricane watch


Seems somewhat likely that they will, probably wait for the 12z Euro and GFS.
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Quoting cat5hurricane:

I would prepare and anticipate hurricane force winds at this point.


Cat5, you give great advice!!
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Quoting leelee75k:


HAARP in action?

kidding of course, but it is an intriguing anomaly
Whatever it is, it doesn't seem to be doing anything.

Considering this thing is releasing the equivalent of a ten megaton nuclear weapon every 30 seconds, and will soon be delivering 3 a minute, it's hard to believe they could have much influence on that kind of system, unless they had alien help.
Member Since: August 27, 2009 Posts: 0 Comments: 525
Quoting nash28:


You and me both!


apparently you're under a TS watch
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Quoting tropicfreak:


Me neither and I am 50 miles or so west of you in Richmond. All local tv stations WTVR WRIC and WWBT have you getting 60-70 mph winds maybe a brief period of hurricane force winds. Here in Richmond we're expecting 40-50 mph winds.


tropicfreak-

I have property on Rappahannock-- in Tappahannock-- I'm in GA. Planning on coming that way next week storm or no storm to close the place for the winter.

Do you have information and/or even opinions on whether I'll be closing it up or cleaning it up? I'm not finding much information on storm impacts regarding VA inland rivers.

edited to add: my profile is taken looking at the river from my porch for an idea of how close to the water.
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Quoting Skyepony:
We've seen majors move away from those MIMIC anomalies before..that is one of the more impressive ones I've seen.


Do you ever sleep? LOL
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Quoting cat5hurricane:

ATL high is stubborn. That needs to budge for me to breath a bit easier.


You and me both!
Member Since: July 11, 2005 Posts: 190 Comments: 16972
Quoting FLdewey:
My trash cans are skeerd.



Oh, I see that brief little shower about an hour ago was just a preview..........THX for the pic! With any stronger winds it is going to be raining avacadoes here, too! Tree is loaded--they are bigger than my hand. Guacamole, anyone?
Member Since: Posts: Comments:
Quoting Patrap:
12z Early Cycle NHC model tracks
Irene
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)



Dynamic Models (More sophisticated models)






patrap... is this not another shift slightly west for the dynamical models? Maybe im wrong but looks like a couple models now have direct hits on wilmington... beginning to wonder if they really will up our TS watch to hurricane watch
Member Since: August 4, 2011 Posts: 0 Comments: 631
518. ackee
LOOKING at wave coming off africa seeem like we about see the CV seasons KICK off again lets see where they will go fish or WEST only time will tell THE GFS seem very excited about these wave
Member Since: July 15, 2008 Posts: 0 Comments: 1376
475. HuracanKY
Report from the Turks & Caicos:
Well done. You really painted the picture of what was happening.
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515. Skyepony (Mod)
We've seen majors move away from those MIMIC anomalies before..that is one of the more impressive ones I've seen.
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Quoting Patrap:
12z Early Cycle NHC model tracks
Irene
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)



Dynamic Models (More sophisticated models)






Thats even further west for us in NC..... :-(
Member Since: Posts: Comments:
Quoting TruthCommish:


A little early, no?

No such thing...
Member Since: November 8, 2009 Posts: 4 Comments: 13800
The European model runs seem to have been on track for the couple of days and on the money so far with the high building back west and staying solid. It has had a Cat 2 hitting the Northeast. I hope it is wrong.
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Link



Radio station Nassau, Bahamas
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12z Early Cycle NHC model tracks
Irene
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)



Dynamic Models (More sophisticated models)




Member Since: July 3, 2005 Posts: 428 Comments: 129841
Can anyone explain why the NHC wind speed predictions look strange? The 5am data gives a predicted max wind for 24hrs at 135 mph (Cat 4), but also a 57% chance that the wind will be Cat 3 and only a 23% chance it will reach Cat 4. Is it just me, or shouldn't the forecast max wind and the most likely wind category match up?
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Quoting OracleDeAtlantis:
LOL What are they using, a ray gun?


Jawhumping big vaccuum set up on the top of the Blue Ridge. Gonna suck it right into Winston-Salem
Member Since: Posts: Comments:
Quoting Skyepony:
What is that on the SSE side there at the end of MIMIC?


HAARP in action?

kidding of course, but it is an intriguing anomaly
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Quoting FLdewey:
Time for a mojito.


A little early, no?
Member Since: September 4, 2009 Posts: 0 Comments: 158
Quoting kshipre1:
anyone have a link to see future waves coming off of Africa?

I know this is a good thing but for goodness sakes!!.... it is approaching September and only 1 yellow circle on the map!


There will be more. Be patient. IMO, we're going to need a break for a while so 1 yellow circle and TD-10 is a good thing.

BTW- if the track holds true TD-10 will be a danger only to shipping and thus would meet the criteria for the term "fish storm".

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Quoting spayandneuter:


Just remember, Irene can't read the weather maps or even knows what a "Cone" is! Neither could Charlie, the maps all said a Tampa Bay hit....many folks here evacuated south and just hours from when he was supposed to hit Tampa, he up and decided to take a hard right and hit Punta Gorda 100 miles to the south! These storms can be wily things and just do what they want!!


Charley is exactly what's on my mind about this - I lived in St. Pete then, right ON the water, and evacuated inland!
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Quoting wxobsvps:


So far it seems like the CONUS high has been the one willing to give ground for the trough.


Yep. I noticed that. You can clearly see how strong the ATL high is. Very robust. Every few hours it gives an inch, then takes an inch. Not budging much.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
Quoting CajunCrawfishhunter:
Should my Family in Fayetteville NC be worried?


Per local weatherman, anything west of 95 is safe even if the track shifts a little more west. They are setting up shelters all along I95 for those of us in the east.
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Quoting stormwatcherCI:
That is what I was looking at this morning and wondering how they expect TD 10 to go WNW. High is very strong and far west which if I am not mistaken should send it W or slightly WNW.

the ridge is not strong out in the east Atlantic and is forecast to break down even more resulting in TD 10 going NW.
Member Since: August 6, 2007 Posts: 0 Comments: 693
Should my Family in Fayetteville NC be worried?
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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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