Irene's eyewall collapses; further intensification unlikely

By: Dr. Jeff Masters , 3:14 PM GMT on August 26, 2011

Share this Blog
25
+

Satellite data and measurements from the Hurricane Hunters show that Irene is weakening. A 9:21 am EDT center fix by an Air Force Reserve aircraft found that Irene's eyewall had collapsed, and the central pressure had risen to 946 mb from a low of 942 mb this morning. The highest winds measured at their flight level of 10,000 feet were 125 mph, which would normally support classifying Irene as a Category 3 hurricane with 115 mph winds. However, these winds were not mixing down to the surface in the way we typically see with hurricanes, and the strongest surface winds seen by the aircraft with their SFMR instrument were just 90 mph in the storm's northeast eyewall. Assuming the aircraft missed sampling the strongest winds of the hurricane, it's a good guess that Irene is a mid-strength Category 2 hurricane with 100 mph winds. 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 wind shear of 10 - 20 knots due to upper-level winds out of the southwest. 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 Wlimington, North Carolina, shows that the outermost spiral bands from Irene are now beginning to come ashore along the South Carolina/North Carolina border. Winds at buoy 41004 100 miles offshore from Charleston, SC increased to 36 mph as of 10 am, with significant wave heights of 18 feet.


Figure 1. Distribution of Irene's wind field at 9:30 am 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 and storm surge potential for Irene
With its eyewall collapsed and just 24 more hours over water before landfall, it is unlikely Irene will 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 Category 2 hurricane at landfall in North Carolina on Saturday, and a rapidly weakening Category 1 hurricane at its second landfall in New England on Sunday. 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 9:30am EDT this morning, a wind analysis from NOAA/HRD (Figure 1) indicated that the potential storm surge damage from Irene rated a 5.1 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 gradually decline as Irene moves northwards and weakens, we can still expect a storm surge one full Saffir-Simpson Category higher than Irene's winds. 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. A surge rivaling that experienced during Hurricane Isabel in 2003 is likely in northern NC, southern Maryland, and up Chesapeake Bay on Saturday night. Coastal New England from New York City to Massachusetts may also see storm surges characteristic of a Category 1 hurricane during Sunday morning's high tide, even if Irene has weakened to a tropical storm. I continue to give a 20% chance that a storm surge high enough to over-top the Manhattan flood walls and swamp the New York City subway system will occur on Sunday.

Wind damage
I don't think Irene is going to do a lot of wind damage to the mid-Atlantic states, since the eye of the storm will be just offshore, and the I-95 corridor from Virginia to New Jersey will be on the weak (left) side of the hurricane. The current wind distribution of Irene (Figure 1) shows almost all of the hurricane's winds are on the right side of the storm, and by the time the storm reaches Virginia, there will be likely be no hurricane-force winds on the left side of Irene. Sustained winds should stay below 74 mph (hurricane force), and wind damage will be similar to that wrought be some of the strongest Nor'easters of the past 20 years, from Virginia northwards to New York City. Since Irene will be steadily weakening as it approaches its second landfall on Long Island, I give a 50% chance that no mainland U.S. surface station in New England will record sustained hurricane-force winds. I do think it likely that one or more of the offshore islands--Block Island, Nantucket, and Marthas Vinyard--will get Category 1 hurricane winds. Though the wind damage to buildings will be similar to what the Northeast has seen during some of the more severe nor'easters of the past 20 years, tree damage will be much worse. The trees are in full leaf during hurricane season, and catch the wind much more readily than during the winter. Tree damage will very heavy, and we can expect trees in regions with saturated soils will fall over in high winds onto power lines. Irene is likely to cause one of the top-five most widespread power outages in American history from a storm. The record power outage from a Northeast storm was probably the ten million people that lost power during the great Blizzard of 1993. I don't think Irene's power outages will be quite that extensive, but several million people will likely lose power.

Irene likely to bring destructive fresh water flooding
In addition to storm surge, flash flooding and river flooding from Irene's torrential rains are the main threats. The hurricane is expected to bring rains in excess of 8" to a 100-mile-wide swath from Eastern North Carolina northwards along the coast, through New York City. The danger of fresh water flooding is greatest in northern New Jersey, Southeast Pennsylvania, and Southeast New York, where the soils are saturated from heavy August rains that were among the heaviest on record. New Jersey has had its 6th wettest August on record, with most of that rain falling in the past two weeks. Expect major river flooding throughout New Jersey the Delmarva Peninsula, and regions near New York City, as Irene's rains run off the saturated soils directly into the rivers. In general, the heaviest rains will fall along the west side of the hurricane's track, and the greatest wind damage will occur on the east side. I don't think flooding from heavy rains will be a huge concern in North Carolina, which is under moderate to severe drought. Irene's rains are likely to do some good in Southeast Virginia, where a fire triggered by lightning from a thunderstorm on August 4 sparked a fire in the Dismal Swamp that is burning out of control. Right now, it does not appear that tornadoes will be a major concern, but there will probably be a few weak tornadoes. Hurricane Bob of 1991, the last hurricane to affect New England, spawned six tornadoes, most of them weak F-0 and F-1 twisters.


Figure 2. Predicted rainfall for the 5-day period ending at 8 am EDT Wednesday August 31, as issued by NOAA/HPC.

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 there, and I will be available if my schedule permits. Listeners can email in or call in questions. The email address to ask questions is broadcast@wunderground.com.

Portlight mobilizes for Irene
The Bahamas have been hit hard by Irene, and unfortunately, it appears that the Northeast U.S. may have its share of hurricane victims before Irene finally dissipates. My favorite disaster relief charity, Portlight.org, is mobilizing to help, and has sent out their relief trailer and crew to North Carolina. Check out this blog to see what they're up to; donations are always needed.

Jeff Masters

Hurricane Irene's Wrath ! (MikeTheiss)
A shot of the Palm Trees at Nassau, Bahamas being thrashed by high winds during Irene's closest approach !
Hurricane Irene's Wrath !
Aftremath of Hurricane Irene in Nassau, Bahamas (ktbahamas)
Utility pole with street light snapped in half by Irene's winds on a busy street in New Providence.
Aftremath of Hurricane Irene in Nassau, Bahamas
Irene Response (presslord)
Portlight deploying to North Carolina
Irene Response

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1279 - 1229

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28Blog Index

Quoting IceCoast:


Euro shows another system in the long range on the 12Z. Pretty far north, but a long ways out.



Yeah, I posted it a few posts back.
Member Since: July 15, 2006 Posts: 17 Comments: 10244
Quoting MrstormX:


Yah, the flooding in PR is crazy...of course why am I telling you this, you know it first hand. :)
Quoting P451:


People don't even know that as a Tropical Storm she raked Puerto Rico. They don't even know. So how they're laughing about a 100mph Hurricane that has grown to incredible size I just don't know.

But, whatever, you can't fix stupid as they say. And as I say I can only control what I do and know - not what other people do.


Well, half of the damage was to the Bahamas, but still a big load of damage.
Member Since: Posts: Comments:
Quoting Levi32:


And it will be weakening, but a Cat 2 to a Cat 1 from North Carolina to New England is not rapid, or as rapid as usual.


Wrong.

Dr. Masters said: "With its eyewall collapsed and just 24 more hours over water before landfall, it is unlikely Irene will 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 Category 2 hurricane at landfall in North Carolina on Saturday, and a rapidly weakening Category 1 hurricane at its second landfall in New England on Sunday.

See above.
Member Since: Posts: Comments:
Quoting MississippiWx:
If this setup holds true, the East Coast could be under the gun again in 10-15 days. Long way out, of course.



Euro shows another system in the long range on the 12Z. Pretty far north, but a long ways out.

Member Since: Posts: Comments:
it is sad that people expecting a strong hurricane and will not believe forcast too much future storms
Member Since: Posts: Comments:
Quoting MississippiWx:
If this setup holds true, the East Coast could be under the gun again in 10-15 days. Long way out, of course.

what about the gulf coast? theyve been protected ever since the beginning of the season. will they be protected the entire season?
Member Since: Posts: Comments:
Quoting Bluestorm5:
People, watch this video of storm surge and you'll see how dangerous storm surge is... btw, that cameraman is an idiot.....

Youtube:
Link


NOT IRENE'S STORM SURGE. THE COMMENT HAD BEEN EDITED.
Member Since: Posts: Comments:
Quoting BobinTampa:


no, but the storm will reach New York on Sunday and that IS the day after tomorrow. What say you now???!!

hahahahahhahahahahaha LMFAO!!!!!!
Member Since: Posts: Comments:
1270. CCkid00
Quoting AllStar17:


Dr. Masters predicts it will weaken rapidly (up in the blog entry).


no, actually he says...."the storm is too large to weaken quickly."
Member Since: Posts: Comments:
1269. Dennis8
4:13 PM 77.0 °F - 71.6 °F 83% 29.81 in 8.0 mi East 11.5 mph 21.9 mph 0.04 in Rain Light Rain
History for Hatteras, NC
Member Since: August 15, 2008 Posts: 0 Comments: 446
Quoting DontAnnoyMe:


You really need to stop with the misinformation.

"Brought to you by extreme storm chaser/cameraman Jim Edds and his famous "surge cam," included here, in sequence, are Hurricanes Rita (Key West 2005), Fabian (Bermuda 2003), Katrina (2005), Isabel (2003). "
I EDITED IT. I AM NOT MISINFORMATING PEOPLE ON PURPOSE!!!
Member Since: Posts: Comments:
Quoting WeatherNerdPR:

And the $1.1 billion in damage caused so far.


Yah, the flooding in PR is crazy...of course why am I telling you this, you know it first hand. :)
Member Since: Posts: Comments:
Quoting Levi32:


And it will be weakening, but a Cat 2 to a Cat 1 from North Carolina to New England is not rapid, or as rapid as usual.


Well, what if it weakens to a Cat 1 as it passes North Carolina? Does that then mean a Tropical Storm for New England?
Member Since: Posts: Comments:
im not really concered with the wave the euro and gfs develop. both take it out to see in all of their runs most likely our first BIG cape verder that recurves.
Member Since: Posts: Comments:
If this setup holds true, the East Coast could be under the gun again in 10-15 days. Long way out, of course.

Member Since: July 15, 2006 Posts: 17 Comments: 10244
1262. Gorty
It could just brush the outer banks that and combined with her being further away from the dry air... watch out.
Member Since: Posts: Comments:
ISS latest pass of irene seen in the pick iss her eye and the dry air
Member Since: Posts: Comments:
Quoting MrstormX:
Irene will probably be retired just because of all the evacs she has caused, and NYC shutting down....

And the $1.1 billion in damage caused so far.
Member Since: Posts: Comments:
Latest radar is showing the beginning of a more northeastward turn.
Member Since: Posts: Comments:
1257. KEEPEROFTHEGATE (Mod)
09L/H/I/C1
RI FLAG (off)
RD FLAG (off)
MARK
33.32n/76.92w forecast point





ALWAYS FOLLOW NHC/TPC FORECASTS FOR ALL WARNINGS REGARDING THIS STORM
Member Since: July 15, 2006 Posts: 171 Comments: 53808
1256. Dennis8
4:32 PM 80.6 °F 88.1 °F 78.8 °F 94% 29.72 in 2.5 mi East 15.0 mph 24.2 mph 0.07 in Rain Heavy Rain

History for Beaufort, NC
Member Since: August 15, 2008 Posts: 0 Comments: 446
Quoting Bluestorm5:
People, watch this video of Irene's surge (idk where) and you'll see how dangerous storm surge is... btw, that cameraman is an idiot.....

Youtube:
Link


You really need to stop with the misinformation.

"Brought to you by extreme storm chaser/cameraman Jim Edds and his famous "surge cam," included here, in sequence, are Hurricanes Rita (Key West 2005), Fabian (Bermuda 2003), Katrina (2005), Isabel (2003). "
Member Since: Posts: Comments:
Quoting Levi32:


It takes a lot of air to fill up a 950mb low that is 800 miles wide. Baroclinic influence also looks favorable to keep the storm from weakening quite as rapidly as usual.


Can you dive into this a little bit further. I've heard a few people say it but don't really understand it. Does it have to do with the storms forward motion? Another feature in the atmosphere that will keep the pressure gradient strong?
Member Since: Posts: Comments:
Been out all day, so I'm behind on my model runs. Just realized the Euro develops an African wave about 96-120 hours out into this at 240...



Also has a TS in the Bay of Campeche.
Member Since: July 15, 2006 Posts: 17 Comments: 10244
Just began raining and thunder in central Raleigh.
Member Since: Posts: Comments:
1251. Levi32
Quoting AllStar17:


Dr. Masters predicts it will weaken rapidly (up in the blog entry).


And it will be weakening, but a Cat 2 to a Cat 1 from North Carolina to New England is not rapid, or as rapid as usual.
Member Since: Posts: Comments:
is Irene still moving due north & is she gonna make landfall further south and west now?
Member Since: Posts: Comments:
I see NHC says storm is weakening, and not forcast to increase again. must be like a strong tropical storm or something because of no
eye. never seen a cane without an eye.
Member Since: Posts: Comments:
Quoting 900MB:
Despite potential dry air intrusion from the NW, the Funktop, Rainbow, IR presentations are getting more organized.
Anyone have latest recon data?



Getting close...

20:28:30Z 31.267N 77.883W 696.7 mb
(~ 20.57 inHg) 2,860 meters
(~ 9,383 feet) 967.5 mb
(~ 28.57 inHg) - From 329° at 76 knots
(From the NNW at ~ 87.4 mph)


Link
Member Since: Posts: Comments:
People, watch this video of storm surge and you'll see how dangerous storm surge is... btw, that cameraman is an idiot.....

Youtube:
Link
Member Since: Posts: Comments:
Irene will probably be retired just because of all the evacs she has caused, and NYC shutting down....
Member Since: Posts: Comments:
1245. KEEPEROFTHEGATE (Mod)
09L/H/I/C1
RI FLAG (off)
RD FLAG (off)
MARK
33.32n/76.92w forecast point





ALWAYS FOLLOW NHC/TPC FORECASTS FOR ALL WARNINGS REGARDING THIS STORM
Member Since: July 15, 2006 Posts: 171 Comments: 53808
Quoting Walnut:
Cantore doesn't decide where to go - the mets at TWC make the assignments. He is just operating as an onsite reporter. Is he overly dramatic? Maybe - but last night Irene looked to be looking to put a real hurting on NYC - and still may do so. People take him seriously.


TWC is a bunch of drama queens. I used to like them until they became part of NBC.
Member Since: Posts: Comments:
Quoting LowerCal:
Live video of Irene from the International Space Station coming up.


Thanks for posting that! Incredible.
Member Since: Posts: Comments:
Quoting Tazmanian:



i no you guys no that am the real me but do the admins no

I'm sure Keeper has told them Taz I put #4 on ignore earlier like alot of us did. We knew he was a troll
Member Since: Posts: Comments:
1240. wpb
recon crew what happened to irene the other day she had makeup on. today she forgot
Member Since: Posts: Comments:
Quoting 53rdWeatherRECON:
Picture Irene as a plow, from her storm surge, then picture the entire time 60+ mph winds keeping all that water out in front of the "plow" from escaping.

This effect, combined with the size of the system, slow forward speed, abnormally high tides.

There is no over hyping this system, it is as they say, "Once in a lifetime".
Love that analogy! They should use it on the weather channel
Member Since: Posts: Comments:
Quoting Levi32:


It takes a lot of air to fill up a 950mb low that is 800 miles wide. Baroclinic influence also looks favorable to keep the storm from weakening quite as rapidly as usual.


Dr. Masters predicts it will weaken rapidly (up in the blog entry).
Member Since: Posts: Comments:
Quoting NICycloneChaser:
For anybody doubting what a Category 2 hurricane can do:

Ike, 2008:





It ain't the wind...it's the water...Irene is a big girl..she'll be pushing a lot of water.
Member Since: Posts: Comments:
Quoting NoVaForecaster:


When my cat ran to the basement right before the earthquake a few days ago in VA I became a firm believer in animals knowing that stuff will happen before we do.


After Gustav I saw this same thing happen...only with horses and tornadoes. My husband and I were outside securing our back porch roof when I noticed about 20 of our neighbors horses run to the middle of the field and stand in a tight bunch.
I came in and took our daughter to the laundry room (safest room in our house). About 3 minutes later my husband, who thought I was nuts and was still outside, saw three tornadoes come over the top of the trees, split in the air over our pasture, and take out the neighbors barn and horse trailers, my elderly neighbors roof, and a storage building across the road.
Member Since: Posts: Comments:
Quoting NOLALawyer:


I am going with Levi. Hurricane all the way to New England.


Even if it's not...the NHC will say it's so the people up there won't let their gaurd down.
Member Since: Posts: Comments:
1232. Dennis8
Quoting NICycloneChaser:
For anybody doubting what a Category 2 hurricane can do:

Ike, 2008:





Lived through it....12 hours TS winds 6 hours Hurricane force winds 2weeks no electricity..2 miles north downtown Houston. I have been in 12 Tropical systems and this would had a Howling wind Like I have never heard and Celia in 1970 was 161 mph.
Member Since: August 15, 2008 Posts: 0 Comments: 446
Quoting Landfall2004:


I hate to even try to compare the two--but personally, I would rather be out of power after a hurricane than out of power in the FREEZING weather of an ice storm.


Ya it definitely was not pleasant at that time of year. Funny thing was I had just flown back into Boston home for School vacation and i was back for no more then 2 hours before the power went out for 2 weeks lol! A nice welcoming back the Northeast..
Member Since: Posts: Comments:

Viewing: 1279 - 1229

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.