Irene slightly weaker, but still very dangerous

By: Dr. Jeff Masters , 8:59 PM GMT on August 25, 2011

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An Air Force Reserve hurricane hunter aircraft investigating Irene has found a slightly weaker storm. As of 4pm EDT, the strongest surface winds seen by the aircraft with their SFMR instrument were 91 mph in the storm's northeast eyewall. Highest winds measured at their flight level of 10,000 feet were 114 mph. Assuming the aircraft missed sampling the strongest winds of the hurricane, it's a good guess that Irene has fallen to Category 2 strength with 100 - 105 mph winds, even though the official advisory is higher. The aircraft noted that the eyewall was missing a large chunk on it southwest side, but the central pressure was about the same as early this morning, 950 mb. Satellite imagery from late this morning and early this afternoon showed a distinctly lopsided appearance to Irene's cloud pattern, with not much heavy thunderstorm activity on the southwest side. This was due to moderate wind shear of 10 - 20 knots due to upper-level winds out of the southwest. This shear was able to disrupt Irene's circulation while it was attempting to complete an eyewall replacement cycle, resulting in dry air getting wrapped into the core, which can be seen as a streak of darker clouds in this morning's MODIS satellite image (Figure 1.) satellite loops show that Irene is beginning to recover from this adversity, with a respectable amount of heavy thunderstorms beginning to wrap around to the southwest side from the north. An upper-level wind analysis from the University of Wisconsin CIMSS site shows that Irene's upper-level outflow is much more restricted than was the case 24 hours ago. An upper-level outflow channel that was open to the south is gone, and has been replaced by shearing winds from the west and southwest that are ripping into the hurricane. I think it is 30% likely that Irene will have trouble recovering from this setback, and will not reach the peak intensity of 120 mph winds it had earlier. However, it is more likely that the hurricane will be able to re-establish its upper-level outflow and overcome the shear, based on the latest satellite loops, plus forecasts from the various hurricane models such as the GFDL, HWRF, and ECMWF, which all show Irene at Category 3 strength as it approaches North Carolina on Saturday afternoon.


Figure 1. MODIS satellite image of Hurricane Irene taken at 11:50 am EDT Thursday August 25, when Irene was a Category 3 hurricane with 115 mph winds. The eye of the storm was just off the coast of Abaco Island in the Bahamas. Note the rather squashed appearance of the hurricane, with less heavy thunderstorms on its southwest side. Upper level winds of 10 - 20 knots out of the southwest were eating away at the clouds on this side, and you can see that this shear helped drive some dry air into the hurricane, which can be seen as a darker strip of cloud spiraling into the center from the south, around the east side, then into the center along the northwest side of the storm. Image credit: a href=http://rapidfire.sci.gsfc.nasa.gov/gallery/ NASA.

Irene likely to bring destructive fresh water flooding
In this morning's post, I highlighted the threat from storm surge flooding, but flash flooding and river flooding from Irene's torrential rains are also a huge threat. The hurricane is expected to bring rains in excess of 12" to 100-mile 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. At Philadelphia, rainfall so far this August has been 13 inches, not far from the record for rainiest month of all-time, the 15.82" that fell in August 1867. This record will almost certainly be broken when Irene's rains arrive. 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. 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 Tuesday August 30, as issued by NOAA/HPC.

Latest forecast for Irene
The latest set of model runs don't show any major changes to Irene's track or intensity. Irene will bring damaging winds, torrential rains, and an extremely dangerous storm surge to the coast, affecting a huge area of the mid-Atlantic and New England. Take this storm seriously! Expect widespread disruptions to electric power, transportation, and water systems. Be prepared for many days without power, as utility crews will be overwhelmed with the damage. Irene is capable of inundating portions of the coast under 10 - 15 feet of water, to the highest storm surge depths ever recorded. I strongly recommend that all residents of the mid-Atlantic and New England coast familiarize themselves with their storm surge risk. The best source of that information is the National Hurricane Center's Interactive Storm Surge Risk Map, which allows one to pick a particular Category hurricane and zoom in to see the height above ground level a worst-case storm surge may go. If you prefer static images, use wunderground's Storm Surge Inundation Maps. If these tools indicate you may be at risk, consult your local or state emergency management office to determine if you are in a hurricane evacuation zone. Mass evacuations of low-lying areas along the entire coast of New Jersey, Delaware, Maryland, and Virginia are at least 50% likely to be ordered by Saturday. The threat to the coasts of New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, and Maine is less certain, but evacuations may be ordered in those states, as well. Irene is a very dangerous storm for an area that has no experience with hurricanes, and I strongly urge you to evacuate from the coast if an evacuation is ordered by local officials. My area of greatest concern is the coast from Ocean City, Maryland, to Atlantic City, New Jersey. It is possible that this stretch of coast will receive a direct hit from a slow-moving Category 2 hurricane hitting during the highest tide of the month, bringing a 10 - 15 foot storm surge.

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.

Jeff Masters

Irene Rainband from downtown Ft. Lauderdale (pho)
8/25/11 0910 local time.
Irene Rainband from downtown Ft. Lauderdale
HurricaneIreneIsOutThere! (trigirl)
Early at the beach to snap the waves from Hurricane Irene east of our coast, the wind was unreal with thunderclouds rolling in with lots of rain for the day.
HurricaneIreneIsOutThere!

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Quoting Walshy:
Eight people on a jetty are injured by rough surf in Florida.


Missed a Darwin.. by just that much....
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739. HadesGodWyvern (Mod)
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Quoting Landfall2004:



Is Cantore ever in the RIGHT place? If he's there, it isn't coming.
Not so true for Katrina. Still have the video of him on the beach in Biloxi telling everyone to take a last look at everything behind him because it wouldn't be there after the storm. That was the truest statement I have ever heard. Everything I have ever known was GONE!!
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BREAKING NEWS: Dedication of Martin Luther King Jr. memorial postponed due to Hurricane Irene
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Quoting TomTaylor:
Other things to note about the latest vortex message...

Winds have yet to increase (in fact, they've dropped slightly lol), pressure continues to drop, the eyewall has contracted slightly, and the temperature difference between the inside and outside of the eye has increased.


Radar also shows the weakness/opening in the eyewall was on the south side during the time of this vortex message (2306z, 7:06 EDT) and is now on the east side of the eye.




nothing weakening about irene right now.. thats a given pressure down to 946 you new to this?
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735. DFWjc
720. NOWORRIES 11:50 PM GMT on August 25, 2011
This storm is starting to look quite beaten up. It is looking less likely to be the wind event in New England people are saying and more of a rain event and beach erosion event for US east coast areas. The conus is likely to be east of forecast tracks for several reasons, but one being the increased shear from the west.

Member Since: October 24, 2005 Posts: 0 Comments: 97

719. poknsnok 11:50 PM GMT on August 25, 2011
irene is a stregthening storm fellas

Member Since: August 17, 2008 Posts: 0 Comments: 195


WOULD YOU MAKE UP YOUR MIND,lol, it can't do both
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Eight people on a jetty are injured by rough surf in Florida.
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Quoting 1900hurricane:

Wow...

very impressive...

Irene take notes, this is what an eye/eyewall region should look like
Member Since: August 24, 2010 Posts: 19 Comments: 4358
Quoting Squid28:


If it makes you feel any better, the same issue happens regardless of where ever you may live with an approaching storm. I understand that some folks are limited financialy and what not, but it is aggravating to try and convince folks that they need to prepare (even when you give them serious advance noticed) and they do nothing until the 11th hour and then some.

I finally have given up on trying to convince anyone about what they need to do or when , I might mention it once, but I mainly look out for my family and that's it


It's like Christmas time, everyone shops the day before.
Member Since: October 16, 2008 Posts: 0 Comments: 544
Many Long Island peeps seem to still think it is a joke saw one idiot actually post that " It won't be anything storms up here dissipate" I mena really how often does the Gov of NJ tell you that you need to prepare and if he orders an evacuation "YOU BETTER EVACUATE!!" I mean New York City is already trying to get those that would take a long time to leave out of the area are opening shelters. Sad but also angering when you see people making jokes about stuff that could get them and their friends and family killed.
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Quoting NOWORRIES:
This storm is starting to look quite beaten up. It is looking less likely to be the wind event in New England people are saying and more of a rain event and beach erosion event for US east coast areas. The conus is likely to be east of forecast tracks for several reasons, but one being the increased shear from the west.


Dude, you handle is NOWORRIES... that just says it all.
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Quoting MississippiWx:
Lol...I can't believe Timmer said it...

Reed Timmer
@reedtimmerTVN Reed Timmer
Hurricane Irene has a pin hole eye! Becoming very well organized at the worst time for the East Coast fb.me/15UlYnxu6
eye isn't even closed yet lol
Member Since: August 24, 2010 Posts: 19 Comments: 4358
Quoting MississippiWx:
Lol...I can't believe Timmer said it...

Reed Timmer
@reedtimmerTVN Reed Timmer
Hurricane Irene has a pin hole eye! Becoming very well organized at the worst time for the East Coast fb.me/15UlYnxu6

PINHOLE
lol
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...EYE OF IRENE GRADUALLY MOVING AWAY FROM ABACO ISLAND IN THE BAHAMAS...
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BULLETIN
HURRICANE IRENE INTERMEDIATE ADVISORY NUMBER 22A
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011
800 PM EDT THU AUG 25 2011

...EYE OF IRENE GRADUALLY MOVING AWAY FROM ABACO ISLAND IN THE
BAHAMAS...


SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...27.7N 77.4W
ABOUT 530 MI...855 KM SSW OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NNW OR 335 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...946 MB...27.93 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

NONE
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This storm is starting to look quite beaten up. It is looking less likely to be the wind event in New England people are saying and more of a rain event and beach erosion event for US east coast areas. The conus is likely to be east of forecast tracks for several reasons, but one being the increased shear from the west.
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irene is a stregthening storm fellas
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Quoting TomTaylor:
Latest Vortex says it's still open to the south

000
URNT12 KNHC 252337
VORTEX DATA MESSAGE AL092011
A. 25/23:06:10Z
B. 27 deg 28 min N
077 deg 20 min W
C. 700 mb 2629 m
D. 76 kt
E. 114 deg 17 nm
F. 205 deg 87 kt
G. 126 deg 55 nm
H. 947 mb
I. 8 C / 3046 m
J. 16 C / 3045 m
K. 6 C / NA
L. OPEN S
M. C25
N. 12345 / 07
O. 0.02 / 1 nm
P. AF306 2109A IRENE OB 21
MAX FL WIND 100 KT NE QUAD 20:52:20Z
MAX OUTBOUND FL WIND 91 KT NW QUAD 23:12:10Z
Other things to note about the latest vortex message...

Winds have yet to increase (in fact, they've dropped slightly lol), pressure continues to drop, the eyewall has contracted slightly, and the temperature difference between the inside and outside of the eye has increased.


Radar also shows the weakness/opening in the eyewall was on the south side during the time of this vortex message (2306z, 7:06 EDT) and is now on the east side of the eye.

Member Since: August 24, 2010 Posts: 19 Comments: 4358
717. GoWVU
Just got back in from dinner, what is the latest movement? Is Irene approaching the number 78 yet?
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Quoting MississippiWx:


You are post #666. DOOM.


Patrap had is 96,666th post on the last blog...
Member Since: October 16, 2008 Posts: 0 Comments: 544
Quoting aislinnpaps:
Anyone seen Keeper or have a copy of his list? I have some friends who want it. They've never experienced a hurricane and asked me what to get and do. Keeper's is very good and I know I won't forget something important.


It is probably on his blog
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714. HCW
Quoting MississippiWx:
Lol...I can't believe Timmer said it...

Reed Timmer
@reedtimmerTVN Reed Timmer
Hurricane Irene has a pin hole eye! Becoming very well organized at the worst time for the East Coast fb.me/15UlYnxu6


That's shocking to hear Weed Trimmer say that
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Quoting MississippiWx:
Lol...I can't believe Timmer said it...

Reed Timmer
@reedtimmerTVN Reed Timmer
Hurricane Irene has a pin hole eye! Becoming very well organized at the worst time for the East Coast fb.me/15UlYnxu6

Wow, really? Just...wow.....
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Quoting JamesSA:

I heard on the radio last night at 10pm that Atlantic Beach was being evacuated at that time. That is probably why we haven't heard from him. Hopefully he left and is safe because it looks as if his home is right at ground zero on a barrier island.


He wasn't at Atlantic beach, he was at Topsail Island. I was wondering about him myself.
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77.3 was the latest longitude point if the 8pm advisory has it the same that means irene is heading due north
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709. Gorty
Quoting MiaZoomom:
Is there any word out of Eleuthra since Irene made her direct hit there? I have a good friend w/a home on the no. end of the island...would appreciate any info - tks!


Sorry to hear that. Hope he or she is ok! :)
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708. HCW
Quoting 900MB:


4 miles from my apartment, surreal! I knew there was a reason I didn't want to live in Battery Park City!


That means that you are 100% safe from Irene due to the Cantore 5'2 storm shield
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Quoting SCwannabe:
Cantore is in the wrong location-NC is going to get hammered...will be a few rainshowers in NYC



Is Cantore ever in the RIGHT place? If he's there, it isn't coming.
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Quoting CycloneUK:
Nanmadol:



Don't see many storms as perfect as this.

Wow...

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Quoting robj144:
Are the models more accurate now since they NOAA launched just about everything they had to collect data?


I was wondering about this. What is the turn around for replacing these dropsondes and balloons? We are only at the beginning of the peak and they seem to have released a plethora of devices.
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Lol...I can't believe Timmer said it...

Reed Timmer
@reedtimmerTVN Reed Timmer
Hurricane Irene has a pin hole eye! Becoming very well organized at the worst time for the East Coast fb.me/15UlYnxu6
Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting 900MB:


4 miles from my apartment, surreal! I knew there was a reason I didn't want to live in Battery Park City!


I think he was reporting from Ma yesterday.
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What is the latest longitude measured by HH?
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Cantore is in the wrong location-NC is going to get hammered...will be a few rainshowers in NYC
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Well it looks like our year of crazy weather continues.
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Is there any word out of Eleuthra since Irene made her direct hit there? I have a good friend w/a home on the no. end of the island...would appreciate any info - tks!
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Anyone seen Keeper or have a copy of his list? I have some friends who want it. They've never experienced a hurricane and asked me what to get and do. Keeper's is very good and I know I won't forget something important.
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696. 900MB
Quoting Stormchaser2007:
Cantore is in NYC...

Pretty crazy.


4 miles from my apartment, surreal! I knew there was a reason I didn't want to live in Battery Park City!
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Quoting presslord:


I was referring to our Portlight crew and trailer...but thanks for the sentiment...


I know but wanted to express my thoughts..hell, I knew that you weren't going down there to play in the water - maybe go to the bar - but not play in the water..lol
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unenhanched IR

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Quoting Patrap:


Looks like a wonderful organization. Will have to check them out online. I have several charities and "causes" I support--may have found something new.
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Quoting TropicalAnalystwx13:


We do not have a Tropical Storm, unless you meant Tropical System. It is still Tropical Depression #10.


I think he was inferring it was a tropical storm by its appearance on satellite... which of course makes it a tropical storm. :)
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Quoting NICycloneChaser:

Just to clarify, the pressure is likely 946mb, not 944mb. Extrap pressures on the HH aircraft have been 2/3 mb below the actual minimum consistently. The NOAA 'Kermit' Plane just passed the centre, reported extrap pressure of 946mb. Still, pressure is falling.



Meh, close enough. Lol.
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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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