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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Despite the weakening, I hope New Englanders are still taking her seriously.
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951mb is the pressure of irene still maintaining herself.....
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1450. ncstorm
Tornado warning in onslow county..Jacksonville, NC
Member Since: August 19, 2006 Posts: 13 Comments: 15313
1449. GatorWX
Quoting Patrap:


I just got home, so haven't been looking at maps and loops, but judging from that wilmington long range, she really looks to be unraveling. I suppose this is good for intensity, but is certainly making her windfield larger.
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Quoting ecupirate:
Significant Tornado damage in Bellhaven, NC :-(


ok, that kinda redefines misery. I've been in a tornado, I can't imagine being in one and being left with a hurricane after it passes.
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Quoting padirescu:


Seriously? You actually expect me to justify a response to this comment?

What's the average commute volume in and out of Manhattan each day and how many deaths are there on a daily basis? I'll leave it at that.


Wow, padirescu, you beat me to it. I was thinking the exact same thing. And right now, the subways, the trains and the buses are all working. Grab a few things, head to Penn Station or the Port Authority Bus Terminal and grab the first seat you can. I'm sure you can make it to Philly or even Syracuse way before this thing hits.

I live in South Louisiana. Trust me, evacuating is not rocket science. Its common sense.
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1446. j2008
Quoting oracle28:
I'm so glad this storm is weakening, by the time it crosses North Carolina, it should be only TS strength at most.

Hate to break it to you but shes not weakening. Her strength is exactly the same and an eye may possibly be reforming. That doesnt spell out good for the east coast.:(
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Quoting NJcat3cane:


very strong words...ill be fine i think..im with three other storm fanatics


Famous last words
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img src="
Watch live streaming video from breakinglivenow at livestream.com">
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We got the game in with our victory of 63-6 O_O Anyway, the sunset was beautiful with Irene's clouds coming toward us. Now it's getting windy here.
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I am sure someone has posted this info the past 45 minutes or so, but Irene is now 4-5 clicks east of the next Tropical Forecast Point.
http://www.ssd.noaa.gov/goes/flt/t2/flash-wv.html
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1441. beell
Quoting AllStar17:
Latest center fix: 951 mb.

Recon. also confirms a more eastward trend.


Yup, based on an amateur 500mb height analysis of recon-she will be east of OBX. No landfall in NC.

Crow standing by...!
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Call me suspicious, but with all the continous eyewall problems that seem to manifest themselves much more than the natural conditions would indicate on such a sizable/powerful storm, and the loss of outflow specifically on the southern portion of the storm....it makes me wonder about Peter Cordani's Claims that he can stop a hurricane, and that was 6 years ago, and he did get the pvt funding he needed since then. Just makes you go, hmmmmm....

Politically they could never admit they can control hurricanes(even a little bit), because it would fuel trememdous debates on everything from finger pointing, to drought recovery.

Sighs, back to the real world we know, lol.
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1439. 900MB
Quoting Levi32:
Extrapolated pressure still near 950-951mb:

023500 3231N 07655W 6969 02721 9506 +156 +125 339020 021 010 001 03


Do you think they nailed the center on that pass?
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Another of the River...easy to see it isn't where it is supposed to be

Member Since: September 16, 2007 Posts: 0 Comments: 3650
clearly on the downtrend from the last radar loops.

dierene
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link?
Quoting shadoclown45:
XD oz's streaam is priceless "My outside mic has a condom and some monkey fur on it... GREAT AUDIO :D"
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1435. MahFL
22k power outages in SC reported by Progress Energy.
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1434. Remek
Quoting oracle28:
I'm so glad this storm is weakening, by the time it crosses North Carolina, it should be only TS strength at most.


no, not nearly that much. Still at least a CAT1 (with CAT2 surge).
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Quoting PcolaDan:surge forecast


It seems like they are playing Russian roulette. I mean, hell, I'm all down for that type of fun but this seems unnecessary.

Especially since they are lucky enough to have many friends and family that live inland. They are moving out of the country for a year in exactly two weeks they have so many good things planned for the near future, why take such a risk now? It's not like you prevent damage to the house by staying in it!

... Er. Sorry. I didn't realize how frustrated I felt about them staying till now. I don't even know them that well. Just worried. Off to send them a message.

Thank you for the link! (This is the one that I was also looking for. Mid Atl Surge)
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Significant Tornado damage in Bellhaven, NC :-(

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I'm not very "link" oriented -- but if someone here is, it would be nice to do a blog and collect the links. That way people could just go to your blog for all the good links.

(I'm very good at volunteering other people...lol)
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1430. Remek
Quoting duajones78413:


Can someone give me the link to this cam?


scroll down. it's been posted at least a dozen times in the last 50 posts!
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1429. GatorWX
Jeez, Irene has been crawling towards N Carolina for the past couple hours. You can see a marked decrease in speed in a long range sat loop. She also seems to be quite a bit east of her official track. This does not appear to me to be simply a wobble where she will eventually meander back to the left and get "back on track" so to speak. Her heading seems to be, at least at the moment, a bit more east than the official heading. Windfield seems to be expanding a lot as well. Quite Ike-like! I can't help but compare the track and intensity to Floyd. I realize Floyd had a much stronger trough and thus much more wind shear, but I would imagine the impacts will be quite similar, although a bit more severe along the coast further north than was experienced from Floyd. I don't think inland flooding will be as sever, however this storm has a greater surge potential along the mid-Atlantic and Northeast as it should maintain a greater intensity and be moving at a slower pace.

I am wondering if the initial trough will be powerful enough to really draw her NE or if she'll continue a more northerly route as it seems the initial trough is looking a bit stretched horizontally. I'm no expert, but it would certainly seem possible ridging could push her a bit further west as the trough clears out as the gfdl has been indicating. This should also keep her speed in check. She isn't going to race off to the northeast like 99% of the storms in this scenario do. She is certainly a curious storm to witness and study, at least at home from a computer in Florida. It will be interesting to see the type of damage she can bring. I think the media is overhyping her a bit at this point as she will be considerably weaker at her North Carolina landfall than was predicted yesterday, but as I stated above, she seems to be quite a bit east of her forecast points and appears to be on a more easterly heading, so she may avoid a long period over mainland. Definitely a big wait and see with this one.
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1428. Gorty
Look at that, shes looking good (not good for people), images and what not of her power in the US so far, her shear size, shear and dry air lessening some, and hugely impacts and widespread of wind and rain for the NE, and the downcasters are non-existent.
Member Since: November 8, 2008 Posts: 12 Comments: 1058
1427. Remek
Quoting tiggeriffic:
one more time to try lol...

Charleston SC Battery High tide...water is higher than the road, thank goodness there is a WALL


You did it! Yay!

(thx for the pix!)
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This is the Ashley River...the water is supposed to be BEHIND the trees to the left...
Member Since: September 16, 2007 Posts: 0 Comments: 3650
Quoting PTXer:
That Topsail Pier cam is indeed amazing.....


Can someone give me the link to this cam?
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If anyone cares, I did a blog on Irene.
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Latest center fix: 951 mb.

Recon. also confirms a more eastward trend.
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I'm so glad this storm is weakening, by the time it crosses North Carolina, it should be only TS strength at most.
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Quoting Levi32:
Extrapolated pressure still near 950-951mb:

023500 3231N 07655W 6969 02721 9506 +156 +125 339020 021 010 001 03
maintaining herself quite nicely. a cat 2 at landfall is now the likely scenario
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Quoting tiggeriffic:
one more time to try lol...

Charleston SC Battery High tide...water is higher than the road, thank goodness there is a WALL


Yea Tigger!
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Time: 02:34:00Z
Coordinates: 32.5333N 76.85W
Acft. Static Air Press: 696.6 mb (~ 20.57 inHg)
Acft. Geopotential Hgt: 2,720 meters (~ 8,924 feet)
Extrap. Sfc. Press: 951.2 mb (~ 28.09 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 137° at 3 knots (From the SE at ~ 3.4 mph)
Air Temp: 14.5°C (~ 58.1°F)
Dew Pt: 11.9°C (~ 53.4°F)
Peak (10s) Flt. Lvl. Wind: 7 knots (~ 8.0 mph)
SFMR Peak (10s) Sfc. Wind: 6 knots (~ 6.9 mph)
SFMR Rain Rate: 1 mm/hr (~ 0.04 in/hr)
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Quoting wolftribe2009:
do any of you know where I can get some webcam of the storm conditions in NC right now? I can't seem to find any.

Reposting for those asking: Topsail Webcam , NC
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Quoting wunderweatherman123:
does this mean irene is maintaining her stregnth?


Looks like it from the HH plane data.

And as I type they penetrate the center once more and find minimum pressures between 950 and 951 mb extrapolated. She hasn't really changed in strength at all in the last 6 hours.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
1416. K8eCane

Quoting Patrap:
 looks like the eye is falling apart to me!
Member Since: April 26, 2006 Posts: 5 Comments: 3153
1415. hahaguy
Quoting Remek:


I edited the link in the post. Try it again.


It worked
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one more time to try lol...

Charleston SC Battery High tide...water is higher than the road, thank goodness there is a WALL
Member Since: September 16, 2007 Posts: 0 Comments: 3650
1413. zingo
5 years ago I lived at Sneeds Ferry, right down the road from Topsail Beach. We moved and ended up at Santee, where there is fresh water fish. We dont worry about the storms like we use to. After doing adjusting for Ike storm victims we have never regreted the move.
Member Since: September 1, 2008 Posts: 0 Comments: 17
Based on vortex fixes unless it straightens up it he north it will miss NC all together.
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1410. Levi32
Extrapolated pressure still near 950-951mb:

023500 3231N 07655W 6969 02721 9506 +156 +125 339020 021 010 001 03
Member Since: November 24, 2005 Posts: 635 Comments: 26647
1409. Remek
Quoting hahaguy:


nope


I edited the link in the post. Try it again.
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Quoting atmosweather:
Now this is a little better...dropsonde ENE of the eye finds 90 mph surface winds and 120 mph winds at just below 3,000 feet.
does this mean irene is maintaining her stregnth?
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Quoting zoomiami:


Shows the expense for those in the affected area. At 3.50 per gallon that's 35.00 per day just for the generator. There are a lot of people out there who don't have that kind of extra cash.
or even a generator !
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1406. Patrap
Member Since: July 3, 2005 Posts: 424 Comments: 128347
Quoting NoVaForecaster:


Link

Link


Uh-Oh... Definite eye forming! NOT GOOD!!


Are we going to be hearing the phrase 'unexpected strengthening' before long?
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1404. ncstorm
Quoting muddertracker:
Cantore just used the term "ground zero" when he knows that he has an unusually large NY audience...I KNOW he didn't do that on purpose...that would be tacky.


very tacky
Member Since: August 19, 2006 Posts: 13 Comments: 15313
Quoting NoVaForecaster:
Latest Dvorak showing increased organization with banding showing up, and hot towers appearing at the center.



View full animation: Link

Definitely looks like a restrengthening system IMO.



I see what you mean.

Link
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Thinking ahead... How's the wave train looking? Any thoughts on the areas the models keep developing about 7 days out (cmc, gfs, and no gaps)?
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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.