Irene continues to weaken

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

Share this Blog
25
+

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

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: 652 - 602

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 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44Blog Index

Quoting wunderweatherman123:
just notice some deeper convection starting to form around the center.. look like she will maintain cat 2 status until landfall but levi now that there is less than 24 hours before landfall, do you see irene right now at this moment becoming a 3 or that appears unlikely.



I'm not Levi but imo, Category 3 won't happen - if Irene could cycle out more dry air tonight, and I think it will, it could increase 5/10 mph since pressure still remains low... but it only has about 18 hours left before landfall in North Carolina.

But Levi knows more about this than I do.
Member Since: Posts: Comments:
Quoting Levi32:
Last pass by recon shows Irene's pressure remains steady. We're seeing proof of how resilient Irene is, in the face of all the dry entrainment and virtually no eyewall, she refuses to fill up with air.


She seems to have an usually large temperature gradient as well. Very impressive for her current lack of organization. Although the air inside her "eye" is still pretty saturated.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
650. bwat
Quoting CosmicEvents:
Well, I mean every offense I can make towards JB. Look at him and look at Dr. Masters. Both professional mets, let's say both have equal skills and knowledge. Dr. Masters makes money on a site that's presenting weather as it is. Bastardi makes his money by hyping every storm, with the tendency to forecast landfalls in heavily populated($$$$$$$) areas.
I agree 100%. but to each his own, if some like him, that's their call. i aint gonna lose any sleep tonight.....then again, I might considering Irenes current track takes her over me about noon tomorrow!
Member Since: August 18, 2009 Posts: 0 Comments: 353
Quoting Patrap:
Wilmington, WunderMap®
No other radar map compares!!!!
Member Since: September 20, 2008 Posts: 0 Comments: 293
648. bwi
Looks from the long range radar like the center is nearly due south of Atlantic Beach. I think that's a good thing -- possibly a little bit right of the forecast line. My hunch is that Irene will maintain 950-960mb for quite a ways north, perhaps further north than people expect. Big storm with a lot of energy spreading out over a wide area.
Member Since: Posts: Comments:
Quoting Gorty:


So... NNE now is her movement. What does that mean for the dry air and for New England now since she will be interacting with land less?


It's probably not going to make much of a difference either way whether Irene is 50 miles farther east in the outer banks. The center may get pretty close to or over the Jersey coast, but whether it's offshore or not only makes a difference in the specifics of the storm surge near New York. The water off of Long Island is cold, down to 23C, so having the center over water won't mean much.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting presslord:


Joe Bastardi


Frightening.
Member Since: Posts: Comments:
Quoting presslord:


Joe Bastardi

lmao
Member Since: Posts: Comments:
644. Remek
Quoting WeatherNerdPR:
Rainfall graphic is up for PR:


I remember watching that one wide feeder band that just stayed in place for hours and hours without shifting. :P
Member Since: Posts: Comments:
7:53 PM 73.9 °F - 72.0 °F 93% 29.52 in 2.5 mi NNE 27.6 mph 44.9 mph 0.26 in Rain Heavy Rain

Wilmington, NC
Member Since: Posts: Comments:
Quoting weatherwart:


Oh lordy. What is THAT? That first picture.


Joe Bastardi
Member Since: Posts: Comments:
Quoting wunderweatherman123:
its expected to be neutral postive until september



After Irene's passing, as stated in my post, the atmosphere will take time to settle and respond which will put us at about the first couple days of September.
Member Since: Posts: Comments:
Quoting presslord:
Who ya gonna trust?

This:



or

This:




Oh lordy. What is THAT? That first picture.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting ConnecticutWXGuy:


that's what I was thinking.... I don't see any even in the right side of the storm nevermind the right front quadrant. Maybe there is buoys that we don't all have access to though?


It wouldn't surprise me - Navy or something like that. But I can't see anyone else who would have something like that.

I have a friend who is a contractor for the NDBC and he says that one bouy like these starts at $250k to build without considering tow, launch, and routine maintenance. I think he was saying $25k minimal for the tow when one goes out and can't be fixed on site.
Member Since: August 2, 2011 Posts: 0 Comments: 198
My nephew left NJ today and is driving up to my sister's. He is planning on returning. Ugh. I think now he is going to stay there. The main roads are all going into counterflow in NJ starting at seven tonight he heard on the radio. No one allowed back in.
Member Since: August 22, 2009 Posts: 0 Comments: 3167
How long has it been since the the aea in the trackpath has experienced hurricane or tropical force winds?

That will give you a good idea of the amount of damage we will see monday morning.
Member Since: Posts: Comments:
Re #563

@ daddyjames... Not knowing anything never stopped me from posting much.... lol

But this is a great place to learn if u r willing to put up with the background noise, aka the fun and jokes...

It's really great to be back in the blog. I never knew a hurricane passage could be so boring... no light and no phone and heavy shutters means u really have nothing to do but sleep [can't too hot] eat [can't no power] and talk [ everybody else is sleeping or eating].... lol
Member Since: Posts: Comments:
Quoting bwat:
Ouch, never claimed to, just call em as I see em. No offense ment.
Well, I mean every offense I can make towards JB. Look at him and look at Dr. Masters. Both professional mets, let's say both have equal skills and knowledge. Dr. Masters makes money on a site that's presenting weather as it is. Bastardi makes his money by hyping every storm, with the tendency to forecast landfalls in heavily populated($$$$$$$) areas.
Member Since: Posts: Comments:
Quoting atmosweather:


Out of all the remarkable bloggers we have here - and we have A LOT of amazingly knowledgeable people - he's the best in my mind. But please take nothing away from Dr. Masters, Dr. Carver and Dr. Fritz...they are all very experienced meteorologists and their advice will save many lives and educate everyone who reads their posts. They have been in the field this long for a very good reason.


RESPECT
Member Since: Posts: Comments:
629. AVL
Any one that would like to chime in on this it is appreciated.

Last night the issue was pressure drop and winds not catching up. The general concensus was that the storm was using the drop (Energy?) to increase in size. Now that she is smaller, injected with dry air, and pressure is dropping will it make it easier for the wind speeds to correlate with pressure drop?
Member Since: Posts: Comments:
This used to be a Tropical Depression.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Wilmington, WunderMap®
Member Since: Posts: Comments:
Quoting Levi32:
Last pass by recon shows Irene's pressure remains steady. We're seeing proof of how resilient Irene is, in the face of all the dry entrainment and virtually no eyewall, she refuses to fill up with air.
just notice some deeper convection starting to form around the center.. look like she will maintain cat 2 status until landfall but levi now that there is less than 24 hours before landfall, do you see irene right now at this moment becoming a 3 or that appears unlikely.
Member Since: Posts: Comments:
Quoting atmosweather:


Far from that...she may not restrengthen back to major hurricane status, but calling her a "flame out" storm is not doing justice to the immense power she still packs and the types of impacts she will have across the entire eastern seaboard.


Thanks for staying on top of this..good point
Member Since: Posts: Comments:
623. Gorty
Quoting Levi32:
Last pass by recon shows Irene's pressure remains steady. We're seeing proof of how resilient Irene is, in the face of all the dry entrainment and virtually no eyewall, she refuses to fill up with air.


So... NNE now is her movement. What does that mean for the dry air and for New England now since she will be interacting with land less?
Member Since: Posts: Comments:
IRENE IS A LARGE TROPICAL CYCLONE. HURRICANE-FORCE WINDS EXTEND OUTWARD UP TO 90 MILES...150 KM...FROM THE CENTER...AND TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 290 MILES...465 KM.

DURING THE PAST HOUR...A SUSTAINED WIND OF 52 MPH... 84 KM/H ...AND A GUST TO 62 MPH...100 KM/H WERE REPORTED AT THE JOHNNY MERCER PIER IN WRIGHTSVILLE BEACH NORTH CAROLINA.

from 8 p.m.
Member Since: Posts: Comments:
Storm Relative 1km Geostationary Visible Imagery


Member Since: Posts: Comments:
Quoting twincomanche:
Dr. M mainly so he can promote his hard left AGW message. The other two are great weather people. Levi is the best.
Science is not about politics.
Member Since: Posts: Comments:
Quoting zawxdsk:


I don't see any bouy in the Atlantic that could possibly be placed to find anything like this. I'm OKAY with that.


Although speaking of bouys, we've got 14013 south of Wilmington at 43 kts gusting to 56 and 24ft waves. Not too shabby.
Member Since: August 2, 2011 Posts: 0 Comments: 198
7:51 PM 80.1 °F 85.8 °F 77.0 °F 90% 29.70 in 3.0 mi East 18.4 mph 31.1 mph 0.10 in Rain Heavy Rain

Hatteras, NC
Member Since: Posts: Comments:
Member Since: Posts: Comments:
To everyone in the possible path of Irene, I would stay on alert with this one. She might have figured out a way to block out the dry air, and with her going directly over the gulf stream until land fall...I just don't want to see anyone unprepared. She could intensify for all we know.
Member Since: Posts: Comments:
Last pass by recon shows Irene's pressure remains steady. We're seeing proof of how resilient Irene is, in the face of all the dry entrainment and virtually no eyewall, she refuses to fill up with air.
Member Since: November 24, 2005 Posts: 635 Comments: 26700
Quoting WXHEAD:


Irene comes from Irina = Slavic (Russian)


Actually Irene is Greek, meaning "Peace"
Member Since: Posts: Comments:
Quoting aislinnpaps:
Evening all. Talked to my sister who lives north of NYC. She hasn't begun to get any supples. She said she'd run out tomorrow morning. I convinced her she might want to do it tonight. According to what's she heard from those around her, Irene won't be too bad. I think I convinced her that while Irene 'may not be too bad', the time after with no electricity, no gas stations or stores may not be so much fun.
a good friend of mine in Manhattan ,this AM, tried to buy batteries, flashlights, etc at Kmart and the shelves were empty. She said there were plenty of halloween costumes ;) Seriously, everyone should have supplies 'cause you know the stores will run out
Member Since: September 20, 2008 Posts: 0 Comments: 293
Member Since: Posts: Comments:
Quoting zawxdsk:


I don't see any bouy in the Atlantic that could possibly be placed to find anything like this. I'm OKAY with that.


that's what I was thinking.... I don't see any even in the right side of the storm nevermind the right front quadrant. Maybe there is buoys that we don't all have access to though?
Member Since: Posts: Comments:
Quoting atmosweather:


Out of all the remarkable bloggers we have here - and we have A LOT of amazingly knowledgeable people - he's the best in my mind. But please take nothing away from Dr. Masters, Dr. Carver and Dr. Fritz...they are all very experienced meteorologists and their advice will save many lives and educate everyone who reads their posts. They have been in the field this long for a very good reason.


I'll 3rd that.
Member Since: Posts: Comments:
606. bwi
Looks to me like the latest HH passes finding flight-level winds up to 106kts. What impresses are the 70 and 80 kt readings well away from the center, where the extrapolated pressures are up in the 990s. Big storm.
Member Since: Posts: Comments:
Quoting JerseyShoreGirl:
I am curious to see what Irene will look like in the AM when I wake up. Mandatory evacuations all over the place here in southern coastal NJ -- Exit 98 and all exits south will be closed. All East and south bound traffic on Rt. 70, 72, 35, 34, 36 all closed. I already sent my children and their pets to a safer area. I will wait till morning to make my decision on myself.


How close are you to the ocean?
Member Since: Posts: Comments:
What is the forecast windshear for Irene until out banks landfall?

patrick
Member Since: Posts: Comments:
Quoting ConnecticutWXGuy:
I was watching one of the NC news channels about an hour ago via livestream and their met said a buoy reported surface winds sustained at 106MPH and a 111MPH gust. Haven't seen that confirmed anywhere else though.


I don't see any bouy in the Atlantic that could possibly be placed to find anything like this. I'm OKAY with that.
Member Since: August 2, 2011 Posts: 0 Comments: 198
602. Gorty
Not good for New England, shes going NNE now which means LESS interaction before New England.
Member Since: Posts: Comments:

Viewing: 652 - 602

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 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44Blog 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.

Local Weather

Overcast
29 °F
Overcast

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron