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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I think the real killer from Irene will be river flooding. Much of the mid-Atlantic has already had a very wet August. River levels are well above normal. We may see catastrophic river flooding in the mid Atlantic from Irene like NC had with Floyd.
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Wilmington has been spared and I am safe. Wrightsville may have had worse impacts And I wish them good news tomorow but I'm shocked how weak Irene is here in wilmingon. I think the NE will be in for a big surprise they've evacuated for nothing. Just how I bought $150 of supplies for nothing.

Next time I'll trust my instincts and gut and live with what happens. I feel dumb and misled right now.
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Quoting beell:


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

Crow standing by...!


Like it matters. NC is getting hammered, either way.
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1599. MahFL
A wobble west :)
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Quoting hurricanejunky:
This is ridiculous but not surprising...
With Hurricane Bearing Down Eric Cantor Says Disaster Relief Should Be Paid For With Spending Cuts

That headline is like me saying, "I should be able to pay for that new big screen TV with my debts."
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1597. Levi32
Continuing to veer away...may only scrape the outer cape.

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Quoting weatherman321:
So I was just looking on Facebook when I saw a friend who lives in NYC post: "A hurricane can't hit NYC because it needs winds to cirrculate and there are too many tall buildings in NY.. So Sunday just gonna be another rainy day." I hope this isn't what most new Yorkers think..

Must be some stupid in the water up there...that's incredibly idiotic thinking. Makes my brain hurt just trying to understand that...
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Quoting PoconoLakefront:


Take the space out of the link and it works

Never Mind I'm only a page behind



i finally got em...posted like four of our area
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Sad news...
Quoting tiggeriffic:


think it was a different one...2 separate beaches... one i knew of was IOP/Sullivan's Island... they pulled em out in front of Press's house
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Hey Flood!

Good to see you my friend....
Tig - anxious to hear WindSurfer, Surfer?
Quoting Floodman:


Hi, Tigs...was the body the windsurfer they lost today?
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Quoting weatherman321:
So I was just looking on Facebook when I saw a friend who lives in NYC post: "A hurricane can't hit NYC because it needs winds to cirrculate and there are too many tall buildings in NY.. So Sunday just gonna be another rainy day." I hope this isn't what most new Yorkers think..


Oy.
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Quoting Floodman:


Hi, Tigs...was the body the windsurfer they lost today?


think it was a different one...2 separate beaches... one i knew of was IOP/Sullivan's Island... they pulled em out in front of Press's house
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So I was just looking on Facebook when I saw a friend who lives in NYC post: "A hurricane can't hit NYC because it needs winds to cirrculate and there are too many tall buildings in NY.. So Sunday just gonna be another rainy day." I hope this isn't what most new Yorkers think..
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1589. Skyepony (Mod)
Quoting Beachfoxx:
Hey Skye --- any idea how much the new moon will impact surge and tides combined with Irene?? Normally would make for higher tides... so I'd expect the same for surge & tides with Irene.


I'm seeing the difference from normal tide to the upcoming perigee & moon influence to be ~ 1 1/2' in NC & ~2' in the NE.
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1588. docrod
Quoting GatorWX:


I don't think it's working in firefox, and I don't know what browser you use, but you use Linux, correct?


I can switch to Linux - on Vista (sigh) right now. Maybe Levi could post the link and I can try to figure it out ... doggone, that center sure seems to have an east bias on the forecast track ...
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Quoting victoriahurricane:
Can one of the resident knowledgable bloggers here comment on the eastward jog for the past few hours? Does she have a chance to go out to sea or will this just make it worse for NY and NJ?


She's been traveling on a general NNE heading for about 4-6 hours and looking at the subtropical ridge still parked to her east its unlikely she moves anywhere east of that heading when averaging out the wobbles. Her track is pretty much setup at this point...she will move through the Outer Banks and then right along the east coast or a couple of dozen miles offshore until she reaches NE. Then the mid latitude trough in the Great Lakes and SE-ern Canada will send her off to the NE and ENE.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Quoting ShenValleyFlyFish:
Ok folks

Been playing around with the Storm Surge feature on the WUnderground map and it is not making me feel good at all. Am I missing something or are most of those NC barrier Islands supposed to go totally under water before this thing passes?


I'd expect the storm surge in NC to be comparable to Hurricanes Floyd and Isabel, which were about the same strength.
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1585. Levi32
Quoting GatorWX:


I don't think it's working in firefox, and I don't know what browser you use, but you use Linux, correct?


I'm in windows today because I need Microsoft Silverlight to view some of the live streams.

I apologize guys....apparently WU doesn't like HTML5 lol.
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is it turning to the east
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1583. DFWjc
Quoting GatorWX:


I don't think it's working in firefox, and I don't know what browser you use, but you use Linux, correct?


I had to update flash for Firefox yesterday, clear your cache and reopen the browser...
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Quoting tiggeriffic:


what time? it was closed some of the day with the power pole and lines in the road, we were DT at high tide...wasnt going near folly at that time...plus, they pulled a body from the water this evening too over there...didn't want to get in all that


Hi, Tigs...was the body the windsurfer they lost today?
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lurking and reading but i thought i would jump in for two quick questions. What do you mean when yoou sa "extrapolated" presure and the weather man here just said the ridge is here in Texas is "breaking down and booking out" next week for a while. Ia that correct? He better not be teasing me! LOL
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1580. nymore
Looks like java not flash to get Levi's post I got it
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Quoting OceanMoan:


We got there around 4pm and left around 8. Traffic was awful, heard emergency worker sirens several times. Saw a house starting to fall in the ocean, and several decks and walkways destroyed.


no way i would have been there at high tide, you are brave...heard early this morning the waves were at the 10th step of the crossovers...i dont think ive seen them past 2-3
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1577. beell
This quick-sketch graphic was originally not intended for "publication" so it is a little rough-but maybe showing enough weakness to allow the center to miss landfall in NC. Have to emphasize I am talking about the center. Not the effects of Irene's large circulation. A turn to the NNE has been in the forecast for quite a while so the turn itself is not a surprise. Maybe just a little more of a turn than expected.

Soundings along the east coast (NC and VA)support stronger ridging to the storm's west leaving just enough weakness to squeeze by.
Approaching trough is plenty strong enough to promote the miss also.

click to enlarge



click for loop

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1576. 2ifbyC
Just a 'hats off' to Levi for being here with his knowledge and explanations!

I don't mean to overlook the others that post useful info, but I've been a long time Levi admirer and follower. Having him here online should mean a lot for those who are not familiar with his talents.

Thanx, Levi!
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Quoting victoriahurricane:
Can one of the resident knowledgable bloggers here comment on the eastward jog for the past few hours? Does she have a chance to go out to sea or will this just make it worse for NY and NJ?

The way I see it, it would make it worse as Irene will be out over the water rather than hugging the coast, which will allow her to be stronger than she otherwise would be. Also, the only way Irene is going out to sea will be after it slams into New England as an 75-80mph hurricane.
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Quoting tiggeriffic:
high tide charleston, sc at the battery

http://s1209.photobucket.com/albums/cc390/maryalo vestigger/?action=viewt=082611185529.jpg&ev t=user_media_share

ok...trying to copy the pic didn't work...hope this does


Take the space out of the link and it works

Never Mind I'm only a page behind

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1573. GatorWX
Quoting Levi32:


Strange, it should have worked if you had flash.

IR loop of Irene moving towards the outer banks. The core is maintaining itself at a disorganized level, but this disorganized hurricane is still very dangerous.



I don't think it's working in firefox, and I don't know what browser you use, but you use Linux, correct?
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its size is just as big as Katrina just not as strong...gonna still plague havoc whereever she goes.
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Ok folks

Been playing around with the Storm Surge feature on the WUnderground map and it is not making me feel good at all. Am I missing something or are most of those NC barrier Islands supposed to go totally under water before this thing passes?
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Quoting GTcooliebai:
I take it NYC is still in play here for the center to pass right over it?


Yes correct. Still more likely to pass 30-40 miles to the E of the city, but that won't make much of a difference when all is said and done. It will not free the area from 6-10 inches of rain and potentially destructive storm surge.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Quoting Levi32:


Strange, it should have worked if you had flash.

IR loop of Irene moving towards the outer banks. The core is maintaining itself at a disorganized level, but this disorganized hurricane is still very dangerous.





can you plzs stop with that
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Quoting Levi32:


Strange, it should have worked if you had flash.

IR loop of Irene moving towards the outer banks. The core is maintaining itself at a disorganized level, but this disorganized hurricane is still very dangerous.


I'm in IE, Levi and not seeing it.
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1565. GatorWX
Quoting GatorWX:
Levi,

What do you think of what the gfdl is hinting in that the current trough wont be strong enough to keep her on her current track all the way up the coast and pull away (trough), allowing her to bend back to the left a bit?


Didn't realize you'd already responded
Quoting KoritheMan:
Personally, I think too many people are focusing on the wobbles. They will be critical for North Carolina, certainly, but again, she's NOT recurving. Erratic wobbles are to be expected for hurricanes of Irene's intensity.

She is east of the track, but should soon stabilize.


I think the "wobble" may be her feeling less of an influence from the trough and more of an influence from the atl high. This is what has me thinking she could possibly resume a more northerly track until the next trough becomes close enough for her to feel the effects from it. She is moving much slower than most storms we see jet up the east coast and these troughs are very shallow and weak.
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Quoting tiggeriffic:


what time? it was closed some of the day with the power pole and lines in the road, we were DT at high tide...wasnt going near folly at that time...plus, they pulled a body from the water this evening too over there...didn't want to get in all that


We got there around 4pm and left around 8. Traffic was awful, heard emergency worker sirens several times. Saw a house starting to fall in the ocean, and several decks and walkways destroyed.
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Hey Skye --- any idea how much the new moon will impact surge and tides combined with Irene?? Normally would make for higher tides... so I'd expect the same for surge & tides with Irene.
Quoting Skyepony:

Here's a gage close to there. Tide is going out ..looks to be ~3ft above MSL at this moment.
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Quoting NoVaForecaster:
Wow looking even better on Dvorak in the new image



Recon should have an interesting next pass.
Looking a little better in symetry though the huge area of dry air to her west seems to be hindering any developement on the storm's western side, overall hindering any intesification. This is more of a question than a statement
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1561. Levi32
Quoting docrod:


Levi - Firefox .... no suitable plugin found ... ??? Looks like you were posting a flash? Not sure why it did not load. - take care


Strange, it should have worked if you had flash.

IR loop of Irene moving towards the outer banks. The core is maintaining itself at a disorganized level, but this disorganized hurricane is still very dangerous.

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Can one of the resident knowledgable bloggers here comment on the eastward jog for the past few hours? Does she have a chance to go out to sea or will this just make it worse for NY and NJ?
Member Since: October 16, 2008 Posts: 0 Comments: 544
Quoting thelmores:


Very unlikely there will be any "significant" strengthening..... or weakening for that matter...... I believe Irene will maintain her current approx strength into Long Island.......


Having said all that, even with all our technology, we struggle with the track........ we struggle even more with intensity!
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Levi32 can you plzs re move post 1521 thanks
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Hey Guys. I live up here in Portland Maine and though the worse seems to be hitting in New York and CT...we are expecting gusts up to 90 MPH here, should the storm miss the outerbanks and slam into CT. A little self promotion, I work for Delta and I apparently have to work Sunday. I'll be driving in, and I will have a live stream going on my drive, and I plan to check out the ocean. If you want to check it out bookmark me Link

I'll be live around 1pm Eastern. My drive is roughly an hour...I'll be near the ocean at 2pm Eastern.
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Quoting oceanbug:
Ooh, nice list! Hopefully Topstorm's got some of those things on hand!

Good pictures, too, Tigger!


thanks! i like this list cuz most people have at least one or 2 of them and if not, the dollar tree does lol
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Quoting P451:


With the way this storm has bounced around I wouldn't rule out anything. Including her bouncing back more northerly for a spell again overnight.

The eastward jog seems to be due to the core organizing more and tightening up some. Seems like her eye which has popped out from time to time jumped east in just a couple of frames. Quite a wobble. Also she has become oblong with her pressure gradient sagging towards the east south east. That is also having a hand in the center jumping east.

Always said we wouldn't know what to expect up north until Saturday morning when Irene began to interact with and cross the outer banks.

With the ridge expected to build back in I don't expect her to be heading out to sea and missing the NJ/NY area like so many before her.

We'll know much more about that in the morning.


Let me clarify the comment... I wouldn't rule out a miss on the Carols. It may be very close... but it does appear that they may not get a Direct hit.
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1553. docrod
Quoting Levi32:


Levi - Firefox .... no suitable plugin found ... ??? Looks like you were posting a flash? Not sure why it did not load. - take care
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Quoting GatorWX:


Thanks for the response. The GFDL is the only model hinting this scenario, and it certainly appears plausible. A brief ridge could push her a bit more westward before the next trough pulls her away again as she'll be much further north to really feel the tug.
I take it NYC is still in play here for the center to pass right over it?
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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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