Irene continues to weaken

By: Dr. Jeff Masters , 8:46 PM GMT on August 26, 2011

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Satellite data and measurements from the Hurricane Hunters show that Irene continues to weaken. A 1:32 pm EDT center fix by an Air Force Reserve aircraft found that Irene's eyewall is still gone, and the central pressure had risen to 951 mb from a low of 942 mb this morning. The winds measured in Irene near the surface support classifying it as a strong Category 1 hurricane or weak Category 2. Satellite imagery shows a distinctly lopsided appearance to Irene's cloud pattern, with not much heavy thunderstorm activity on the southwest side. This is due to moderate southwesterly wind shear of 10 - 20 knots. This shear is disrupting Irene's circulation and has cut off upper-level outflow along the south side of the hurricane. No eye is visible in satellite loops, but the storm's size is certainly impressive. Long range radar out of Wilmington, North Carolina, shows that the outermost spiral bands from Irene have moved ashore over North Carolina. Winds at buoy 41004 100 miles offshore from Charleston, SC increased to 47 mph, gusting to 60 mph at 3 pm EDT, with significant wave heights of 25 feet.


Figure 1. MODIS satellite image of Hurricane Irene taken at 11:50 am EDT Friday August 26, when Irene was a Category 2 hurricane with 105 mph winds. The eyewall collapsed several hours before this image was taken, and no eye is apparent. Image credit: a href=http://rapidfire.sci.gsfc.nasa.gov/gallery/ NASA.


Figure 2. Distribution of Irene's wind field at 3:30 pm EDT Friday August 26, 2011, as observed by the Hurricane Hunters and buoys. The right front quadrant of the hurricane had about 90% of the storm's hurricane-force winds (yellow and warmer colors, bounded by the heavy black line between the "50" and "60" knot thin black lines.) Tropical storm-force winds (heavy black like bounding the light blue area) extended out 290 miles from the center of Irene. Image credit: NOAA/AOML/HRD.

Forecast for Irene
With its eyewall collapsed and just 18 more hours over water before landfall, Irene does not have time to build a new eyewall and intensify. The storm is too large to weaken quickly, and the best forecast is that Irene will be a strong Category 1 hurricane at landfall in North Carolina on Saturday. Based on the latest wind analysis from NOAA's Hurricane Research Division (Figure 2) and Irene's continued weakening trend, I predict that the 80-mile section of North Carolina coast to the right of where Irene makes landfall will receive sustained hurricane-force winds of 75 - 85 mph on Saturday at landfall; the 80-mile section of coast to the left will receive 55 - 75 mph winds. High wind shear of 30 knots will begin ripping into Irene Sunday morning when it is near Southern New Jersey, and more rapid weakening will occur. By the time Irene arrives on Long Island Sunday afternoon, it will probably have top sustained winds in the 65 - 75 mph range. However, since Irene is such a huge storm--tropical storm force winds extend out up to 290 miles from the center--it has set a massive amount of the ocean's surface in motion, which will cause a much larger storm surge than the winds would suggest. At 3:30 pm EDT this afternoon, a wind analysis from NOAA/HRD (Figure 2) indicated that the potential storm surge damage from Irene still rated a 5.0 on a scale of 0 to 6. This is equivalent to the storm surge a typical Category 4 hurricane would have. While this damage potential should steadily decline as Irene moves northwards and weakens, we can still expect a storm surge one full Saffir-Simpson Category higher than Irene's winds when it impacts the coast. Since tides are at their highest levels of the month this weekend due to the new moon, storm surge flooding will be at a maximum during the high tidal cycles that will occur at 8 pm Saturday night and 8 am Sunday morning. Wherever Irene happens to be at those times, the storm surge damage potential will be maximized. I continue to give a 20% chance that a 3 - 4 foot storm surge high enough to over-top the Manhattan flood walls and swamp the New York City subway system will occur on Sunday. The latest 11 am probabilistic storm surge map from NHC shows a 20 - 30% chance of a storm surge in excess of 3 feet in New York Harbor (Figure 4.) Keep in mind that these maps are calculated for normal tide level, and this weekend's high tides will be nearly 1 foot above normal.

Insurance company AIR-Worldwide is estimating that insured damages from Irene in the U.S. will be $1.5 - $6 billion. They estimate losses in the Caribbean at $0.5 - $1.1 billion from Irene.


Figure 3. Storm surge heights, in feet above normal tide level, which have a 20 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. Image credit: NOAA.


Figure 4. Overall chance that storm surges will be greater than 3 feet above normal tide levels 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.  Storm surge probabilities depend on the historical accuracy of NHCs forecasts of hurricane track, and wind speed, and an estimate of storm size. Image credit: NOAA.

Links
For those of you wanting to know your odds of receiving hurricane force or tropical storm force winds, I recommend the NHC wind probability product.

Wunderground has detailed storm surge maps for the U.S. coast.

The National Hurricane Center's Interactive Storm Surge RIsk Map, which allows one to pick a particular Category hurricane and zoom in, is a good source of storm surge risk information.

Wunderblogger Mike Theiss is in Nassau, documenting the storm's impact on the Bahamas.

Internet radio show on Irene at 4:30pm EDT
Wunderground meteorologists will be discussing Hurricane Irene on a special edition of our Internet radio show, the Daily Downpour, today (Friday) at 4:30pm EDT. Shaun Tanner , Tim Roche, Angela Fritz, and Rob Carver will take your questions. The email address to ask questions is broadcast@wunderground.com.

Jeff Masters

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Wilmington animated, WunderMap®
Member Since: July 3, 2005 Posts: 427 Comments: 129411
801. 996tt
Quoting WeatherNerdPR:

Well, this is an area(the NE) that has had very little experience with significant cyclones. Irene is very large, and even if it's "only" a Cat1 in the Mid-Atlantic. Same thing happened with Igor in Newfoundland last year. Not to mention, the effects it could have in NC.


Get it, but F2 and F3 tornados have hit down town high rises in Atlanta and Dallas and no real loss of life. These strikes were much more intense and worse than cat 1 winds and perhaps TS winds by the time it even gets there. Again, if he is going to scare everyone, where does he expect them to go.

If they were intellectually honest, they would mention that high rises have sustained direct hits by tornadoes and survived. They just conveniently leave out objective details and play on the subjective.
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Quoting P451:


Not to mention the 25-30 foot waves that are rolling in Raritan bay just to the south....being pushed by S winds gusting to 90kt.

This would be what makes Irene historic. If we get 8 foot surge that means water 3 feet above the bulkhead there. That travels a few hundred feet up a slight incline and reaches the subway entrances there then we're talking about a serious problem with lasting effects.



I guess that just answered my question...
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Quoting presslord:


they just left with a body they fished out right across from my house @ 4East


Oh that is so sad. :(
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Time: 00:33:30Z
Coordinates: 32.3N 76.9833W
Acft. Static Air Press: 696.5 mb (~ 20.57 inHg)
Acft. Geopotential Hgt: 2,709 meters (~ 8,888 feet)
Extrap. Sfc. Press: 949.4 mb (~ 28.04 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 107° at 10 knots (From the ESE at ~ 11.5 mph)
Air Temp: 15.0°C (~ 59.0°F)
Dew Pt: 10.5°C (~ 50.9°F)
Peak (10s) Flt. Lvl. Wind: 16 knots (~ 18.4 mph)
SFMR Peak (10s) Sfc. Wind: 21 knots (~ 24.1 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)
(*) Denotes suspect data

That's the lowest pressure this pass. Very little change.
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Quoting victoriahurricane:


Can you wumail me those pictures as well or post them up here for everyone to see? TIA.


just now downloading from phone to photobucket...i had text em to press...inbox a cell # and i will send u them...
Member Since: September 16, 2007 Posts: 0 Comments: 3666
Quoting Patrap:
Once the surge inundates,,above ones ability to remain higher,,well...one may have a difficult time surviving the Surge and winds.

Mr Guerra explains it well during the last min of this one from 6 years ago Monday.

Video taken by Guerra Family during/after Hurricane Katrina. Chalmette, La.


Wow - that was amazing. Should be mandatory viewing for everyone who refuses to leave an evacuation area.
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795. P451
Quoting 900MB:
Okay, I downloaded Google Earth, Google Chrome, etc...Now how do I get the hurricane hunter recon again?
Thanks!!!


Start here: http://tropicalatlantic.com/recon/

Download the google earth file. Double click on it and it will install to google earth. Then you'll see a drop down menu appear on your left panel with the recon.

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Quoting presslord:


they were removed...my guess is Jeff did it himself...he's a class act...


Just kidding...how are you doing? Getting TS conditions I assume?
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Tornado Watch here...Rough night ahead.
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792. Gorty
Levi, looks like she is starting to look really good again. Do you think seeing her now your forecast will come true with her being 115 mph?
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Quoting tiggeriffic:


was that the kite boarder that was seen somewhere round Sullivan's/IOP ?


I dunno...but, yea, SJ...quite dead
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Quoting tiggeriffic:


the ones i sent of Edge water were at least an hour after high tide...and the water was still over the road


Can you wumail me those pictures as well or post them up here for everyone to see? TIA.
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789. P451
Quoting Levi32:
We've got to appreciate the outflow that is sustaining Irene as well. I mean look at the satellite loops - an 85kt outflow stream to the east of the storm, flowing south. That's amazing.



That's a whole lot of venting.
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Quoting CaneHunter031472:
Talking about long range predictions here we go GOMEX IS next.

GFS 18Z Could you link it please? Tks
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Quoting presslord:


they just left with a body they fished out right across from my house @ 4East


That sucks...I'm assuming by body you meant deceased. Goes to show it was one of those folks that did NOT know what they were doing. Only the experts should have been out there today.
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Quoting presslord:


they just left with a body they fished out right across from my house @ 4East


was that the kite boarder that was seen somewhere round Sullivan's/IOP ?
Member Since: September 16, 2007 Posts: 0 Comments: 3666
785. 900MB
Okay, I downloaded Google Earth, Google Chrome, etc...Now how do I get the hurricane hunter recon again?
Thanks!!!
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I can tell you right now that storm is going to hit hard....the winds may not be that fast, but they are well organized and widespread.....and I am afraid what that storm surge might look like, especially when all that water is pushed up against Long Island.
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Quoting presslord:


they just left with a body they fished out right across from my house @ 4East



One soul claimed by the Storm

Tragic and so easily preventable.
Member Since: July 3, 2005 Posts: 427 Comments: 129411
Quoting muddertracker:

Any chance that low is moving west?


With that high above it, it probably is.
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Quoting hurricanejunky:


same with those images Press...


they were removed...my guess is Jeff did it himself...he's a class act...
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780. P451
Quoting muddertracker:
Canttore in Battery Park..just said 4-8 ft. storm surge...for certain...


Not to mention the 25-30 foot waves that are rolling in Raritan bay just to the south....being pushed by S winds gusting to 90kt.

This would be what makes Irene historic. If we get 8 foot surge that means water 3 feet above the bulkhead there. That travels a few hundred feet up a slight incline and reaches the subway entrances there then we're talking about a serious problem with lasting effects.

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The webcam at Topsail Beach is showing some fairly high wave action. Lots of water being pushed on shore.
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Quoting 996tt:
Rookie blonds in TWC is still throwing dooms day message out. Sorry, cat 1 . . . I understand the targets are important, but seriously. If a cat 1 was heading toward Destin it would be completely different newscasting even though storm surge is a lot worse when trapped in the GOM.

Well, this is an area(the NE) that has had very little experience with significant cyclones. Irene is very large, even if it's "only" a Cat1 in the Mid-Atlantic. Same thing happened with Igor in Newfoundland last year. Not to mention, the effects it could have in NC.
Member Since: July 7, 2010 Posts: 0 Comments: 5725
Quoting NICycloneChaser:




There you go ;)

Any chance that low is moving west?
Member Since: August 16, 2007 Posts: 1 Comments: 2351
once she gets to the new england states, she might not be too strong but the trees will fall over, they are not flexible like palms. also the ground is allready saturated due to heavy rains in august so flooding will happen as well. Irene is no joke.
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I'm not familiar with New York, but if they get a 4-8ft storm surge in the city, how do they keep the water out of the subway system?
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No, Irene's not even close to that.

Tip, the biggest tropical cyclone ever, would fit in the distance between Lisbon and Berlin.
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Quoting CaneHunter031472:
Talking about long range predictions here we go GOMEX IS next.

GFS 18Z T=384hrs






There you go ;)
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771. 996tt
Everyone is taking prudent safety measures. That's great. Okay, dude is trying to scare 90 percent of the population in NYC by telling them to get out of their high rise buildings. Seriously, those things could take a F2 o3 tornado hit. Is he trying to take about venturi effect? Everyone living in a big city knows this, but where does he expect all of these people living in high rise buildings to go?
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Quoting StormJunkie:
Evening all.

Hope everyone to the N stays safe. I will be very interested to see what kind of surge Irene brings with her along the N SC & S NC shorelines. From the pics press sent me; Irene was all Folly could take as far as water heights without creating significant problems.


they just left with a body they fished out right across from my house @ 4East
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Quoting CarolinaBeachGirl:
ncstorm; have you lost power? OUr is hanging on here---fingers crossed:-)


Yeah my power and cable still on..fingers crossed:)..I saw some pics of Carolina Beach..look like canal drive is getting it bad
Member Since: August 19, 2006 Posts: 13 Comments: 16208
Quoting Patrap:


Just some Friendly advice,..

Feel free to ignore it.


I know...I hear ya! And thanks...
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Quoting Patrap:
Once the surge inundates,,above ones ability to remain higher,,well...one may have a difficult time surviving the Surge and winds.

Mr Guerra explains it well during the last min of this one from 6 years ago Monday.

Video taken by Guerra Family during/after Hurricane Katrina. Chalmette, La.




I actually found this guy living in Shell Beach and I know the story....he and his wife had evacuated from Shell Beach to Chalmette, and was at his brothers house....the dog wasn't theirs....and it was lost after the storm. The family lost everything in Shell Beach....
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Member Since: July 3, 2005 Posts: 427 Comments: 129411
I give up no way I can post when drinking... No drinking and posting
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764. P451
Quoting NoVaForecaster:


How do you post the animation of that? It won't let me copy it from the NHC site.


Vidcapture and convert to gif then host elsewhere.

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Quoting presslord:


yes ma'am...lottsa water...the Ashley River was above Murray Blvd


the ones i sent of Edge water were at least an hour after high tide...and the water was still over the road
Member Since: September 16, 2007 Posts: 0 Comments: 3666
Hey guys I just heard something interesting on TWC and was hoping someone can confirm or dispute it. They say starting this year storm surge values given is how much the surge will go up on top of the land, not just how high the sea level will raise. Is this true? If so this 3 feet storm surge is actually pretty bad.
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Talking about long range predictions here we go GOMEX IS next.

GFS 18Z T=384hrs


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Quoting ShenValleyFlyFish:
Anybody done the math? How many sq mi/km is Europe? How many sq mi/km Emily. I could do it but it would be with pencil and paper. Some of you young guys out there ought to be able to do it in a flash. Give you something to do beside think up your next troll fart.


Well according to Wikipedia Europe is 3.93 million square miles in size. I'm almost positive, without doing the math on Irene, that she doesn't quite match up to that extent lol.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Evening all.

Hope everyone to the N stays safe. I will be very interested to see what kind of surge Irene brings with her along the N SC & S NC shorelines. From the pics press sent me; Irene was all Folly could take as far as water heights without creating significant problems.
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758. 996tt
Rookie blonds in TWC is still throwing dooms day message out. Sorry, cat 1 . . . I understand the targets are important, but seriously. If a cat 1 was heading toward Destin it would be completely different newscasting even though storm surge is a lot worse when trapped in the GOM.
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757. HCW
Live HH Recon Reports on TWITTER





Link
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Quoting hurricanejunky:


oh come now...with all the stuff that gets left up on this blog? is that better?


Just some Friendly advice,..

Feel free to ignore it.
Member Since: July 3, 2005 Posts: 427 Comments: 129411
Canttore in Battery Park..just said 4-8 ft. storm surge...for certain...
Member Since: August 16, 2007 Posts: 1 Comments: 2351
Quoting presslord:
junky...while I wouldn't disagree with that...I also probably wouldn't leave that up too long ;-)


same with those images Press...
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ncstorm; have you lost power? OUr is hanging on here---fingers crossed:-)
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Dry air still a problem, but Irene is looking a little better than she did earlier today.



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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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