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: 602 - 552

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

602. Gorty
Not good for New England, shes going NNE now which means LESS interaction before New England.
Member Since: Posts: Comments:
Anyone have a link to the New GFS coming in? TIA
Member Since: Posts: Comments:
Quoting NOLALawyer:
If she rebuilds her eye and strengthens I am going to be thrilled that the college kid from Alaska had the better forecast than the extremely experienced and educated PhD holder and former H.H. who runs this blog. It is getting to the point where I find Levi to be the best, and least sensational, voice available on the internet regarding tropical systems.


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.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Rainfall graphic is up for PR:
Member Since: Posts: Comments:
Quoting RitaEvac:
WTH is this...



A hurricane ;)
Member Since: October 16, 2008 Posts: 0 Comments: 544
(Though, it's coming from the same American media which proudly presents 'World News'... which happens to usually be about America.)
Member Since: Posts: Comments:
Quoting WXHEAD:


Sorry! No, well it didn't used to be. You'd think he would learn. But no "cha-ching" down to 5 lives now.

How many lives does Irene have left?


Probably not as many as that cat.
Member Since: Posts: Comments:
Quoting NICycloneChaser:
LOL, TWC just said Irene was the size of Europe.


Did the Russians invade when we weren't looking?
Member Since: Posts: Comments:

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 800 PM EDT...0000 UTC...THE CENTER OF HURRICANE IRENE WAS LOCATED NEAR LATITUDE 32.1 NORTH... LONGITUDE 77.2 WEST. IRENE IS MOVING TOWARD THE NORTH-NORTHEAST NEAR 14 MPH...22 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE TONIGHT AND EARLY SATURDAY.

ON THE FORECAST TRACK...THE CORE OF THE HURRICANE WILL APPROACH THE COAST OF NORTH CAROLINA TONIGHT AND PASS NEAR OR OVER THE NORTH CAROLINA COAST ON SATURDAY.

THE HURRICANE IS FORECAST TO MOVE NEAR OR OVER THE MID-ATLANTIC COAST SATURDAY NIGHT AND MOVE OVER SOUTHERN NEW ENGLAND ON SUNDAY.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 100 MPH...160 KM/H...WITH HIGHER GUSTS. IRENE IS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE.

LITTLE CHANGE IN STRENGTH IS FORECAST BEFORE IRENE REACHES THE COAST OF NORTH CAROLINA. SOME WEAKENING IS EXPECTED AFTER THAT...BUT IRENE IS FORECAST TO REMAIN A HURRICANE AS IT MOVES ALONG THE MID-ATLANTIC COAST ON SUNDAY.

Everyone should be in prepare mode by now if not prepared.
Member Since: Posts: Comments:
Quoting BiloxiBlues:
Maybe, at least, Irene will extinguish the Great Dismal Swamp fire.


There are bunch of fires in NC and VA near the coast that need extinguishing. This should do it!
Member Since: Posts: Comments:
Got some short video of the conditions here...If it will ever upload, lol.
Member Since: Posts: Comments:
is irene french or spanish ? i am sure twc will have a half hour special on her real origins . btw just on the edge of irene her in joco nc
Member Since: Posts: Comments:
Quoting breald:


I think Brian Williams, who is reporting live from NJ made that comparison. TWC was just talking to him. :)


Yeah, it was. Poetic license.
Member Since: Posts: Comments:
Pains Bay fire too, burning since May
Member Since: Posts: Comments:
Quoting wolftribe2009:


Yea I believe the GOM is a sitting duck this year. I just can't imagine a hurricane season like this one without one in the gulf. The pattern changed in mid august which has opened the door more for the eastern gulf. I expect the Texas high to back westward in September and that is when I think we will have to watch the GOM.
Correct. CC got hours of drizzle rain yesterday. First since Mid-January.
Member Since: Posts: Comments:
Quoting NICycloneChaser:
LOL, TWC just said Irene was the size of Europe.


I think Brian Williams, who is reporting live from NJ made that comparison. TWC was just talking to him. :)
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
I think she'll pop just before landfall. Dynamo effect.
Member Since: Posts: Comments:
Maybe, at least, Irene will extinguish the Great Dismal Swamp fire.
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:
Yeah, well, I went outside to get video of the wind and it decides to stop.

:\
It'll pick up again. This is likely your first storm.
There's pauses between bands even when you're in the eye-wall, though the pauses then are much briefer. You've got a good 24-36 hours of weather to look forward to, on and off.
Member Since: Posts: Comments:
Quoting WXHEAD:


I think that maybe, sometimes, they might exaggerate the size of things there at TWC. For Jim Cantore it all started when he was a young man...

I gotta the neighbor's cats on fire! Again!


Back up. Your neighbor's cat's on fire? Again? This is a regular occurance?
Member Since: Posts: Comments:
Quoting 900MB:
Recon, anyone? What's the latest?

Link

Open this in Google Earth and watch real time....
Member Since: Posts: Comments:
Quoting KennyNebraska:
Link


Thanks for the link...that's pretty cool. Goin' to see some interesting stuff when he starts driving in it when it makes landfall.
Member Since: Posts: Comments:
Quoting FLdewey:


She's lost an engine... flame out.


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.
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Evacuation orders covered 1 million people in New Jersey, 550,000 in New York, 315,000 in Maryland, 300,000 in North Carolina, 200,000 in Virginia and 100,000 in Delaware.

"This is probably the largest number of people that have been threatened by a single hurricane in the United States," said Jay Baker, a geography professor at Florida State University.

NBC, msnbc.com and news services
updated 42 minutes ago 2011-08-26T22:59:38

Member Since: Posts: Comments:
Quoting CybrTeddy:


I am not sure how to respond to this.. there's a hurricane about to hit the US coast. Your point is pretty much invalid.


ignore da troll
Member Since: Posts: Comments:
Time: 23:30:00Z
Coordinates: 32.0667N 77.1W
Acft. Static Air Press: 751.4 mb (~ 22.19 inHg)
Acft. Geopotential Hgt: 2,065 meters (~ 6,775 feet)
Extrap. Sfc. Press: 948.9 mb (~ 28.02 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 165° at 6 knots (From the SSE at ~ 6.9 mph)
Air Temp: 19.5°C (~ 67.1°F)
Dew Pt: 17.5°C (~ 63.5°F)
Peak (10s) Flt. Lvl. Wind: 7 knots (~ 8.0 mph)
SFMR Peak (10s) Sfc. Wind: 16 knots (~ 18.4 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
(*) Denotes suspect data
Member Since: Posts: Comments:
569. JLPR2
Quoting NICycloneChaser:
LOL, TWC just said Irene was the size of Europe.


Roflmao!
Member Since: Posts: Comments:
Quoting 996tt:
Seems to be jogging to NE or is that just convection close to the center. Is this precursor to shift East or is staying course due North.


Moving NNE @ 14
Member Since: Posts: Comments:
566. 996tt
Seems to be jogging to NE or is that just convection close to the center. Is this precursor to shift East or is staying course due North.
Member Since: Posts: Comments:
Quoting NICycloneChaser:
LOL, TWC just said Irene was the size of Europe.

XD
Member Since: Posts: Comments:
Quoting BahaHurican:
Sure and I've seen ur handle on the blog a few times....


Long time lurker, like to learn. Don't have the necessary qualifications to add to the discussion . . . except to parrot what others are already saying. Prefer to lurk and laugh. ;)
Member Since: Posts: Comments:
...IRENE TURNS TOWARD THE NORTH-NORTHEAST...TROPICAL STORM CONDITIONS SPREADING INLAND OVER SOUTHEASTERN NORTH CAROLINA...
8:00 PM EDT Fri Aug 26
Location: 32.1°N 77.2°W
Max sustained: 100 mph
Moving: NNE at 14 mph
Min pressure: 950 mb
Member Since: Posts: Comments:
LOL, TWC just said Irene was the size of Europe.
Member Since: Posts: Comments:
Quoting 900MB:
Recon, anyone? What's the latest?


Unremarkable still...90 kt winds the best they could find at flight level in the NE quadrant

233400 3309N 07519W 6963 03062 9962 +077 +055 154090 091 052 010 00
Member Since: September 24, 2005 Posts: 33 Comments: 9265
Quoting 900MB:
Recon, anyone? What's the latest?


Member Since: Posts: Comments:
Quoting NOLALawyer:
If she rebuilds her eye and strengthens I am going to be thrilled that the college kid from Alaska had the better forecast than the extremely experienced and educated PhD holder and former H.H. who runs this blog. It is getting to the point where I find Levi to be the best, and least sensational, voice available on the internet regarding tropical systems.


The kid's good, and getting better every season.
Member Since: Posts: Comments:








Live video from your Android device on Ustream
Member Since: Posts: Comments:
Wind has really picked up here in Wilmington, NC. Sideways rain. Finally getting some good action. Time to get the drinks flowing.
Member Since: Posts: Comments:

Viewing: 602 - 552

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.