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 An upper-level outflow channel that was open to the south is gone, and has been replaced by shearing winds from the west and southwest that are ripping into the hurricane.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 PensacolaDoug:
When He booked the flight to Tampa the strorm was forecast to come to Florida. He had to make the call Monday where to fly to or the fares would go up.


Hmmm...That's roughly $150 in gas one way...

Looks like Irene is taking a little jog to the East. Also moving very slowly it seems the past few hours. Sign of a more northern and maybe NNE motion?
Member Since: August 17, 2005 Posts: 26 Comments: 16874
Quoting P451:


Doomed.

True that. Why I asked. Probably rate a neg number on the DOOM:CON@ scale.
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Hmmm

Extrap. Sfc. Press: 937.2 mb (~ 27.68 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 130° at 22 knots (From the SE at ~ 25.3 mph)
Air Temp: 19.8°C* (~ 67.6°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 26 knots (~ 29.9 mph)
SFMR Peak (10s) Sfc. Wind: 24 knots (~ 27.6 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
(*) Denotes suspect data
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Quoting Tazmanian:
omg re call my last post when i said it could go too 937mb on the next pass and look what recon found


937.2 mb
(~ 27.68 inHg)

Bingo, Taz...great call dude!
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is it just me, or it looks like Irene has been nearly stationary for nearly an hour?

Could that just be her wobbling due to the eyewall problems?
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Quoting Sflabuck:
trust me, this is a fish storm .. stop panicking ...
i wasted monies on beef jerky and red wine here in Boca to ride out this fishy


Money spent on red wine and beef jerky is never a waste.
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Quoting Tazmanian:
omg re call my last post when i said it could go too 937mb on the next pass and look what recon found


937.2 mb
(~ 27.68 inHg)



OUCH...........CAT 4 coming for sure tonite.......that CAT 5 i was talking about may not be that far off....
Member Since: September 2, 2007 Posts: 179 Comments: 20448
Quoting Cat5Hurricane250:
937.2 mb
(~ 27.68 inHg)


Well, that caught my eye!
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Quoting gulfbreeze:
Ivan had waves over 90 ft. in the Gulf!
Allright, let's not make this into a "my wave is bigger than your's" contest. Each storm is different, and the one we're dealing with right now is the one to talk about. It's history, bad history, happening right in our face, at hurricane speed. And this one looks to be intensifying and on-track for disaster. Let's do our best to get that word out to anyone we know, and any newcomers from the NE that may find themselves here, as we saw with many new and scared people around NOLA before Katrina. We did ok, but not our best, as a blog, to help them. Let's do better this time.
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Quoting P451:


I know the difference no need to point it out. I doubt there is a single person on this blog that doesn't know the difference.

Thanks though, I guess, lol.



I don't. Can you please define it for me?! ;-)
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1431. JonClaw
Quoting aislinnpaps:
With the 'current path' would the Catskills in upstate NY be affected?



Rain and some winds at most, IMO.
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Quoting reedzone:


For Irene or the Western Pacific storm?


Lol..Irene.
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Time: 01:57:00Z
Coordinates: 27.9N 77.3167W
Acft. Static Air Press: 752.9 mb (~ 22.23 inHg)
Acft. Geopotential Hgt: 1,990 meters (~ 6,529 feet)
Extrap. Sfc. Press: 937.2 mb (~ 27.68 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 130° at 22 knots (From the SE at ~ 25.3 mph)
Air Temp: 19.8°C* (~ 67.6°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 26 knots (~ 29.9 mph)
SFMR Peak (10s) Sfc. Wind: 24 knots (~ 27.6 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
(*) Denotes suspect data
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000
URNT15 KWBC 260158
NOAA2 2309A IRENE HDOB 37 20110826
014900 2817N 07654W 7521 02278 9759 +157 //// 138087 087 066 005 01
014930 2816N 07656W 7522 02269 9749 +157 //// 137085 086 066 006 01
015000 2815N 07657W 7522 02259 9737 +159 +162 134086 088 067 005 00
015030 2813N 07659W 7521 02248 9724 +158 //// 132088 088 068 006 01
015100 2812N 07700W 7518 02241 9707 +163 +165 132089 090 069 010 00
015130 2810N 07702W 7522 02222 9690 +166 +164 131089 091 069 020 00
015200 2809N 07704W 7517 02212 9672 +165 //// 133092 093 071 018 01
015230 2808N 07705W 7522 02190 9653 +167 //// 132092 092 072 010 01
015300 2806N 07707W 7520 02172 9631 +170 //// 132092 093 074 016 01
015330 2805N 07708W 7521 02154 9607 +173 +177 127092 093 072 008 00
015400 2803N 07710W 7516 02133 9580 +171 //// 128095 099 074 017 01
015430 2802N 07712W 7515 02107 9548 +176 +177 122093 095 077 025 00
015500 2801N 07713W 7499 02092 9513 +176 +178 116088 095 081 033 00
015530 2759N 07715W 7498 02066 9473 +184 //// 117069 080 084 021 05
015600 2757N 07716W 7524 02017 9433 +191 //// 121051 055 058 003 05
015630 2756N 07718W 7527 02001 9391 +197 //// 127035 039 036 002 01
015700 2754N 07719W 7529 01990 9372 +198 //// 130022 026 024 000 01
015730 2752N 07720W 7538 01981 9406 +203 +182 107018 020 019 000 03
015800 2750N 07721W 7535 01979 9423 +201 +176 102004 005 018 000 03
015830 2748N 07721W 7516 02002 9421 +203 +164 267004 007 019 000 00
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1426. will40
01:57:00Z 27.900N 77.317W 752.9 mb
(~ 22.23 inHg) 1,990 meters
(~ 6,529 feet) 937.2 mb
(~ 27.68 inHg) - From 130° at 22 knots
(From the SE at ~ 25.3 mph) 19.8°C*
(~ 67.6°F*) -* 26 knots
(~ 29.9 mph) 24 knots
(~ 27.6 mph) 0 mm/hr
(~ 0 in/hr) 20.3 knots (~ 23.4 mph) 92.3%
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Quoting MississippiWx:


Wow...


For Irene or the Western Pacific storm?
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1424. NCCANE
is it just me or does the continental high seem to be building in faster now to the north? If it is do you think it will influence the track any?
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With the 'current path' would the Catskills in upstate NY be affected?
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Quoting tpabarb:


I'm in Wilmington too, and I feel kind of like an idiot for leaving, but I don't really see what benefit staying has? I keep wavering. Now that it's going to hit us during the day I'm considering staying...but, what if a tree falls on the house? I'd rather be 2.5 hours west! I dunno...are you leaving?


Im staying... but I have no trees around my house, am not in a flood prone area of town, and am not close enough to the marshes for a storm surge to affect me. Only thing I am worried about is if power goes out, how long it will stay out for.
Member Since: August 4, 2011 Posts: 0 Comments: 631
Quoting P451:


I know the difference no need to point it out. I doubt there is a single person on this blog that doesn't know the difference.

Thanks though, I guess, lol.

just checking cause you were talking about open ocean waves and then said storm surge was nothing to mess with
Member Since: August 24, 2010 Posts: 19 Comments: 4358
No increase in winds found though.
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I haven't been able to find that 937mb reading...Where did you find that, Cat5?

Nevermind...found it.
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Quoting RedrumATL:


And I've asked the blog for a guesstimate of diameter on that eye. No response yet. Do you know? Thanks, Redrum
25 nautical miles on the last vortex message.
Member Since: August 24, 2010 Posts: 19 Comments: 4358
omg re call my last post when i said it could go too 937mb on the next pass and look what recon found


937.2 mb
(~ 27.68 inHg)
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1415. KEEPEROFTHEGATE (Mod)
Quoting FLdewey:
Unscheduled air show...

More than 200 military aircraft in SE Virginia preparing to depart for safe airfields ahead of Irene.
sortie time must issue sortie within 36 hrs of impact
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I was just watching if a major hurricane hit nycity special and now it is looking like it might just happen. People in nycity need to take heed and get out of the way of this storm. Damage will be in the millions down there. A direct hit would be devastating for nycity. Glad i live upstate where most models put the storm well east of me.
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937 mb? Unreal...
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Quoting TStormSC:

Calling for gusts 35-45 tomorrow afternoon.


Our local met just called for 40-50mph gusts for Jax tomorrow. But no worries...the storm isn't coming anywhere near us.
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Quoting MississippiWx:
Quoting ConnecticutWXGuy:


good for NC, bad for New England where there are more people.


Overall for the U.S. that would be worse as Irene could carry her storm surge all the way instead of being disrupted.
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Quoting MississippiWx:


Wow...


If that's correct - Taz was right!
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Quoting Cat5Hurricane250:
937.2 mb
(~ 27.68 inHg)



What...did they just MEASURE that? Is that a mistaken or true measruement?

I knew a sorta saw a pinhole-like eye trying to get its act together....
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Quoting flbeachgirl:


We were out on Jax Beach today watching the waves. We usually have a moderate-to-high risk of rip currents on a good day. The surfers were describing the water as a "washing machine".


I live near New Smyrna and they were talking about the rips on the local news. They said they were much worse than usual.
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Time: 01:58:30Z
Coordinates: 27.8N 77.35W
Acft. Static Air Press: 751.6 mb (~ 22.19 inHg)
Acft. Geopotential Hgt: 2,002 meters (~ 6,568 feet)
Extrap. Sfc. Press: 942.1 mb (~ 27.82 inHg)
D-value: -
Flt. Lvl. Wind (30s): From 267° at 4 knots (From the W at ~ 4.6 mph)
Air Temp: 20.3°C (~ 68.5°F)
Dew Pt: 16.4°C (~ 61.5°F)
Peak (10s) Flt. Lvl. Wind: 7 knots (~ 8.0 mph)
SFMR Peak (10s) Sfc. Wind: 19 knots (~ 21.8 mph)
SFMR Rain Rate: 0 mm/hr (~ 0 in/hr)
(*) Denotes suspect data
Member Since: September 8, 2005 Posts: 0 Comments: 3805
Quoting P451:


The Perfect Storm in 91 put 100 foot waves in the North Atlantic in the open sea.

We had 30 foot waves pouring over the sea wall in Sea Bright in New Jersey. Witnessed it first hand.

Storm Surge is nothing to fool with.

Ivan had waves over 90 ft. in the Gulf!
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Quoting ShenValleyFlyFish:

What's the land mass underneath?
Philippines
Member Since: August 24, 2010 Posts: 19 Comments: 4358
Quoting Cat5Hurricane250:
937.2 mb
(~ 27.68 inHg)



Wow...
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Quoting victoriahurricane:


Oh trust me I saw it, approaching 30 feet waves. Has the storm surge of a Cat 3/4, wow.


That graph kinda numbed me. As in we might be referring to the Outer Banks as Back When Banks in a couple days.

On the ? bright side, that buoy is apparently very close to the eyewall right now.
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1399. tpabarb
Quoting nccanewatcher:
I'm in Wilmington. It seems a lot of people aren't taking this serious enough. School was just cancelled, my guess is because Carolina Beach will call for a mandatory evacuation tomorrow morning, they need the shelters. A lot of people on Carolina Beach aren't going to leave because after Fran they weren't allowed back for a couple of weeks. A lot of people got mad and said they'd never leave again. I hope they decide to leave.


I'm in Wilmington too, and I feel kind of like an idiot for leaving, but I don't really see what benefit staying has? I keep wavering. Now that it's going to hit us during the day I'm considering staying...but, what if a tree falls on the house? I'd rather be 2.5 hours west! I dunno...are you leaving?
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1398. HiWay
Quoting Sflabuck:
trust me, this is a fish storm .. stop panicking ...
i wasted monies on beef jerky and red wine here in Boca to ride out this fishy


More like a beached whale.
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Quoting P451:
After some additional struggles this evening the eye has cleared back out and the CDO seems to be strengthening and wrapping around with colder tops.

AVN Color Enhanced IR


Water vapor


And I've asked the blog for a guesstimate of diameter on that eye. No response yet. Do you know? Thanks, Redrum
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1395. Zaphod
Hmmm....west side is still under shear it seems. Looks to be consistently a bit east of track for a change too. Too soon to see if it's a wobble or a deviation of track, though.
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937.2 mb
(~ 27.68 inHg)

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Quoting FLdewey:


The mother of all Charlie Foxtrots.


Roger that.
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1392. bassis
Quoting SPLbeater:
CAN SOMBODY PLEASE PLEASE GIVE ME THE LINK AND/OR POST THE STORM SURGE POTENTIAL FROM IREN IN NEW HANOVER COUNTY PLEASE? THANKS


I found this with a quick google. not good with posting links

http://www.nhc.noaa.gov/psurgegraphics_at4.shtml? gm
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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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