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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Quoting NJcat3cane:
im sticking it out here in Atlantic City even with mandatory evac here..should be crazy


Is it the storm that will be crazy or you?? Do you realize when the storm arrives those conditions will last 18-21 hours? Are you really ready for that? I hope you'll reconsider your decision. No one is going to help you out once this gets rolling.
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isnt the rain in a hurricane a fine mist that falls extremely fast aided by winds, and also i live on staten island on top of grimes hill the second tallest area on staten island i have a view of the hudson/bay area looking torwards sandy hook if i could get a live stream up would anyone watch it?
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yea they just took off though. I think the last wave got a little to close
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1299. Patrap
..some always tempt fate,

Dat's a bad way to Live.
Member Since: July 3, 2005 Posts: 428 Comments: 129909
1298. snotly
people on the pier @ topsail....!!!!!??
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things have gone way down hill tonight in NC
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
1295. Walnut
Quoting cindyker:
Are there people on TS Pier!?
Not for long.
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Quoting Levi32:
Radar storm total estimates are exceeding 4 inches already along the NC coast and over 6 inches south of Wilmington.



Levi I feel like its moving way east of forecast, are we off the major hook here in hampton roads?
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1293. Patrap
Wilmington LIVE animated WunderMap®
Member Since: July 3, 2005 Posts: 428 Comments: 129909
1292. Skyepony (Mod)
Awesome TRMM pass of Irene today. Click pic for the quicktime animation. This is a 3-D view of the precipitation in the storm.
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1291. Levi32
Quoting WeatherNerdPR:

Have you noticed that the rain has been just sitting over Eastern NC? Might see some worsening flooding overnight.


That is likely. I can't believe that some streets there are already underwater based on the picture posted here earlier. I would like to know whether that was ocean water flooding a sea-side street or fresh water. I would think it was more likely to be the ocean.
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1290. hahaguy
Woah there are 2 people on the pier!
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My God, people are on the Topsail pier
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Quoting QacarXan:
OMG two people just walked on the pier at Topsail I think. Why?! See that or just me?


no, I saw it too!
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1287. jdjnola
There are people on the pier! Crazy people!
Member Since: August 4, 2008 Posts: 0 Comments: 238
1286. 900MB
Quoting Levi32:


She might be trying to fill in the dry slot northwest of the eye a little bit, but it looks like too little too late for a Cat 3. My prediction of 115mph will end up a bit high, but Irene, from all appearances and recon data, is holding steady near the 950mb mark, which normally is characteristic of a strong Cat 3. There is no solid SFMR support for Cat 2 winds at the surface, but the stronger flight-level winds of 80-90kts could easily start mixing down to the surface due to turbulent mixing as the core moves close to the outer banks of North Carolina.


Well the "forecast maximum wind" forecast from the 5pm advisory for 2am this morning is 90mph. I think we will come in at 100mph or better, so we would be 10mph over forecast. She just looks much better than she did at 5pm when she looked like she was on death's door. Hunter is hooking left back towards the eye, this pass will be interesting!
Member Since: June 11, 2006 Posts: 0 Comments: 684
Are there people on TS Pier!?
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Quoting WeatherNerdPR:

Have you noticed that the rain has been just sitting over Eastern NC? Might see some worsening flooding overnight.


:\
Member Since: July 6, 2010 Posts: 113 Comments: 32877
OMG two people just walked on the pier at Topsail I think. Why?! See that or just me?
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1282. zawxdsk
NCStorm - this is a stupid question but give me some help here because I need to get a couple of people out of your area.

Brother and Sister and law live in Wilmington, right on the beach. They were going to go inland as of this morning. I just now heard that they are still there.

Assuming I can't convince them to go - how bad do you expect it there right on the beach?
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1280. hahaguy
Quoting TropicalAnalystwx13:


How much more rain? :(


Trust me there will be rain for the next 12hrs at least.
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1279. Levi32
Gusts now over 40kts at a couple of locations along North Carolina:

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1278. nymore
Quoting cindyker:


You need to build your beach home like, Dome of a Home. This picture is after Ivan ran over it.
Nice construction incredibly strong design
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Quoting Levi32:
Eye moving just a hair east of due north, right towards the outer banks.


Have you noticed that the rain has been just sitting over Eastern NC? Might see some worsening flooding overnight.
Member Since: July 7, 2010 Posts: 0 Comments: 5725
Quoting Levi32:
Radar storm total estimates are exceeding 4 inches already along the NC coast and over 6 inches south of Wilmington.



How much more rain? :(
Member Since: July 6, 2010 Posts: 113 Comments: 32877
1275. K8eCane

Quoting ncstorm:
Someone reporting Lightening on a community facebook page that lives in Castle Hayne..isnt that a sign of strengthening?
Im in Castle Hayne and I saw that lightening! My friend and I were in my back bedroom smoking a cigarette with the window raised and we saw it...lights flickered a bit
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ooopppsssie....forgot who I was for a moment there...
Member Since: August 13, 2007 Posts: 0 Comments: 10492
1273. Levi32
Radar storm total estimates are exceeding 4 inches already along the NC coast and over 6 inches south of Wilmington.

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Quoting tiggeriffic:


i took the pics...they are on my puter, asked several times for people to tell me how to get a pic up but no answers...tell ya what...inbox me your number and i will send it to ya that way


e mail them to yourself...open the email..open the pic...right click on 'copy picture location'.....paste into 'image' below...voila!...oh yea...click 'post comment'
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Quoting DallasGumby:
Those people all have a place to go and public transportation to get them there. You're advocating 5 million people leaving the city, with public transportation ceasing at noon, when many of them have nowhere to go - and, basing that on a hypothetical that there will be hundreds or thousands of deaths in high-rises caused not by the storm, but by secondary emergencies for which the authorities will not be able to respond.

I have no opinion whether areas of NYC should be evacuated. I do have an opinion about people assuming there is no risk in an evacuation.


Ok, last comment regarding this topic then it's back to focusing on Irene and letting those that think they're safe in high rises in Zone A to make their own decisions.

My original argument was specific to Michael Bloomberg's comments around the risks of staying in a high rise in the Zone A mandatory evacuation areas of the 5 burroughs. Somehow it got twisted into some mass evacuation of 5 million people by noon tomorrow when mass transit shuts down.

The 5 burroughs of New York City have a population anywhere from 8-10 million depending on your source of information. Zone A only consists of a small portion (<10% in all likelihood) of the broader New York City area so at best we're only talking about 1 million evacuees. Furthermore, the mandatory evacuation was ordered close to 24 hours before the shutdown of the mass transit system. Considering there are well over 1 million commuters via mass transit to and from NYC on a daily basis I'm sure they gave them plenty of time to evacuate via all available methods of transport.

Now back to our regularly scheduled programming of Irene and good luck to all those stubborn New Yorkers that don't heed the warnings of their own elected leadership.
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1270. hahaguy
Tigger you got mail.
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no what you think is a floating piece of dock, is actually the shadow notice how it stays in the same place
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1268. Levi32
Eye moving just a hair east of due north, right towards the outer banks.

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1267. Gorty
Anyone, is she still going NNE?
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1265. Levi32
Quoting atmosweather:


Great point to consider about the length of time spent enduring strong TS or Category 1 winds. Many older and vulnerable structures cannot withstand even these winds for any length of time. As any of us that rode out Hurricane Frances will tell these folks...18-24 hours of constant battering by 50 mph winds takes its toll in a big way.


A note of comfort though from an official that Cantore interviewed is that the structures that have been around for over 100 years, have been around for over 100 years, after all, and had to go through the 1821 hurricane, as well as others that went through the northeast. Chances are they can handle a strong TS or Cat 1, even if it is for a long duration. Hopefully that holds true and the winds don't do any real structural damage to the NYC area.
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1264. Dennis8
Quoting zoomiami:


Was just trying to figure the time they will be under those conditions. If the eye is still approximately 10 hours away & the winds are already sustained at 45-50 miles, then by time the hurricane has pulled away, they will have had almost 20 hours of the winds and the rains.

That is going to add up to bad news for a lot of places.


Very good point..Ike gave us TS winds from 8pm until 10am and hurricane force from 1am until 8am and Irene is as large as Ike. We were 50 miles inland 3 miles north of downtown Houston. We got 11 inches of rain between 11pm and 9 am and that was measured in hurricane winds and my wireless gauge was on a fence that blew down! 28.29 on my Davis barometer as the eye cam just east of downtown at 5:30 am September 13, 2008.
Member Since: August 15, 2008 Posts: 0 Comments: 446
Quoting cindyker:


You need to build your beach home like, Dome of a Home. This picture is after Ivan ran over it.


That's really cool! I love seeing the types of structures that actually make it through these storms. So many lessons.
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Quoting Methurricanes:

1) Windows have nothing to do with any highrises intergety.
2) the Towers had damage alot deeper than windows, and to compare them to buildings that have a few blownout windows is insane.
Not to derail the conversation, but the engineers (if I remember) talked of the tremendous temperatures inside the towers generated from the burning jetfuel and other materials. This let to structural failures to beams and concrete supports.
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Quoting zoomiami:


Hi Tig-- do you have that link?


i took the pics...they are on my puter, asked several times for people to tell me how to get a pic up but no answers...tell ya what...inbox me your number and i will send it to ya that way
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Quoting violet312s:


An hour tops...if not gone already. HUGE waves hitting it


Seconded...one of those in the last minute was HUGE. Almost did the job then and there.
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Quoting K8eCane:

I still have power too but its been flickering....getting ready to shut the computer down


Stay safe.
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Quoting Dennis8:


Yes..It was NOT expected to rise so fast..some of my family members rode in helicopters off Bolivar to safety on Friday afternoon HOURS before the storm....This Irene has a TS wind field larger than IKE and water can be moved up in a hurry and this thing is moving water up the east coast already more than we know.


Glad to hear they made it off ok then. Seems to me people should be listening to what you have to say -- having been through a storm with the basic setup of this one. By that I mean the waters pushing in, and the huge windfield.
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Quoting dogsgomoo:
Thank you for your answers. You all are awesome.

I'm unsure of how to stress to them that they should leave because they are confident that everything will be fine. They have lived there all their lives. Their parents and grand parents as well.

They seem very confident that the 3 story house they are in will withstand because they are on the Bay side and not the Ocean side. Having seen it, I think it will as well, but...

I've lost the link to the surge reports for Irene and I'd like to post it on their face book page as a last ditch effort to get them facts. Does anyone have that handy?


Well, I am in a 3 story, 110 yr. old Dade-county pine (heart pine) house, about 3 ft. off the ground w/ a crawl space. It was my great-grandparents' home, has a hipped roof (good!) and shutters, and we are 2-3 miles from the inlet Frances and Jeanne came thru and Wilma left. The house didn't have a SCRATCH. It leaked like an old ship but soon the wood swelled up (and dried out just fine.) The yard was a wreck, though........
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Complete Update

TS BUSTED FORECAST ALIBI





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Quoting Dennis8:
Precipitation 2.81 in Wilmington rain so far..


1/5th of an inch of rain in 2 minutes? Wow that's heavy!
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...And that was over 60 MPH.
Member Since: July 6, 2010 Posts: 113 Comments: 32877
Quoting Levi32:
Here's another cam. I have no idea where it is though.




they are out morehead city
Member Since: May 21, 2006 Posts: 5091 Comments: 115456
For those who are oohing and aahing over the massive waves at the Topsail Pier, consider this: from tomorrow evening through Sunday night, similar waves will be atop a storm surge and battering billions of dollars in beachfront property from Maryland to Providence.

By way of comparison, here are a few links:

Topsail Beach

Seaside Heights, NJ
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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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