Powerful Category 3 Irene enters the Bahamas

By: Dr. Jeff Masters , 3:49 PM GMT on August 24, 2011

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Powerful Category 3 Hurricane Irene stormed through the Turks and Caicos Islands overnight, bringing hurricane-force winds, torrential rains, and storm surge flooding. On Providenciales in the Turks and Caicos Islands, where half of the population of these islands live, winds reached a sustained 65 mph at a personal weather station at Pine Cay, and the pressure bottomed out at 989 mb. The eyewall of Irene missed the island, with the center of the storm passing about 60 miles to the southwest. The center of Irene passed about 60 miles to the northwest of Grand Inagua Island, and Category 1 hurricane conditions were probably experienced on that island. Damage in the Turks and Caicos is likely to be much less than the $50 - $200 million wrought by Category 4 Hurricane Ike of 2008, since Irene's eyewall missed populated islands.


Figure 1. Morning satellite image of Irene.

Monday, Irene hit Puerto Rico as a tropical storm with 70 mph winds, but reached hurricane strength as it emerged into the Atlantic northwest of the capital of San Juan. One drowning death is being reported from the island, and the storm dumped up to 20 inches of rain in some areas. About 11% of the island was still without power this morning, and numerous roads were closed due to flooding and landslides. Irene did an estimated $17 million in damage to agriculture and $2 million to ports in Puerto Rico. Satellite estimates suggest that Irene has brought only 1 - 2 inches of rain to Haiti. With Irene now pulling away from Hispaniola, Haiti can expect only another 1 - 2 inches from the hurricane, and appears to have dodged a major bullet. Heavy rains of 3 - 6 inches were common across the Dominican Republic, where moderate flooding but no deaths occurred.


Track forecast for Irene
Continuing dropsonde missions by the NOAA jet have helped to significantly narrow the uncertainty in the 1 - 3 day forecasts from the computer models. Irene will track through the central Bahamas today, the northwestern Bahamas on Thursday, and approach the Outer Banks of North Carolina on Friday. However, the models still diverge considerably on their 4 - 5 days forecasts, and we don't know if Irene will plow up the mid-Atlantic coast into New Jersey, as the GFDL model is predicting, hit New England between Long Island, NY and Massachusetts, as the ECMWF, GFS, and HWRF models are predicting, or miss the U.S. and hit Canada, as the NOGAPS model is predicting.

Intensity forecast for Irene
Latest data from the Hurricane Hunters shows that Irene has paused in its intensification cycle. A gap has opened in the eyewall, and the central pressure has remained constant at 956 - 957 mb over the past few hours. However, the hurricane is embedded in a large envelope of moisture, and wind shear is expected to remain low to moderate, 5 - 20 knots, for the next three days. With water temperatures very warm, 28 - 30°C, these conditions should allow for intensification to a Category 4 storm sometime in the next two days. Satellite loops show that Irene is well-organized, with excellent upper-level outflow, and impressive spiral banding.

Irene's impact on the Bahama Islands
Irene is making a direct hit on Crooked Island (population 350) in the Bahamas, and will continue west-northwest and hit Rum Cay (population 80) and Cat Island (population 1700) late tonight. These unfortunate islands will bear the full brunt of Irene's 115+ mph winds and 8 - 13 foot storm surge, and suffer major damage that will take months to recover from. Major damage is also likely on Long Island (population 3000) and San Salvador Island (population 1000.) Shortly after midnight tonight, winds at the capital of Nassau, home to 70% of the population of the Bahamas, will rise above tropical storm force, and increase through the night. By late morning on Thursday, sustained winds will peak on Nassau at just below hurricane force, 60 - 70 mph. Nassau will miss the brunt of the storm, and I expect the airport should be able to re-open on Friday. Winds on Grand Bahama Island in Freeport will rise above tropical storm force late Thursday morning, and increase to a peak of 45 - 60 mph late Thursday afternoon. Grand Bahama will also miss the brunt of the storm, but Abaco Island to its east will likely experience Category 2 hurricane conditions Thursday afternoon. However, Abaco will probably miss the right front eyewall of Irene with the strongest winds and highest storm surge.


Figure 2. Wind distibution around Irene as of 1330 UTC (9:30am EDT) August 24, 2011. Irene was a Category 3 hurricane with 115 mph winds at the time. Hurricane force winds (yellow colors) extended over Crooked Island to the storm's northwest, and over Mayaguana Island to the east. Image credit: NOAA/AOML. Irene is a large storm, and its potential storm surge damage rated 3.9 on a scale of 0 to 6, with its wind damage potential rated at 2.5 on a scale of 0 to 6.

Irene's impact on the Southeast U.S.
Long-period ocean swells from Irene will reach the coast from Florida to North Carolina tonight, and continue to build as the storm approaches. The outermost rainbands of the hurricane will reach South Florida by Thursday morning, and spread over much of the eastern coastal portion of Florida during the day Thursday. If Irene follows the official NHC forecast through the Bahama Islands, the storm's expected radius of tropical storm-force winds of 130 - 170 miles will keep tropical storm conditions just off the east coast of Florida. Sustained winds of 20 - 30 mph can be expected along the coast of Florida during Irene's point of closest approach, and rainfall amounts of 1 - 2" will be common along the coast. Georgia, which could use the rain, will get very little. It is unlikely any airport in Florida or Georgia will need to close for Irene.

Late Friday night or early Saturday morning, Irene's outer spiral bands will move over the southern coast of North Carolina and the northeastern portion of South Carolina, and tropical storm-force winds of 39+ mph will arrive. Winds will steadily increase to hurricane force on the Outer Banks by Saturday night. The main damage from Irene in North Carolina will come from the storm's flooding rains of 4 - 12" that will fall in coastal areas. Fortunately, this region is under moderate to severe drought, so the damage will not be as severe as that experienced during Hurricane Floyd of 1999. Significant wind damage can be expected in the Outer Banks of North Carolina, and considerable storm surge damage may occur along the shores of Pamlico and Albemarle Sounds. If Irene's eye misses making landfall in North Carolina, total damage from the storm should be less than $200 million, and could be considerably less than that.


Figure 3. Sea surface temperatures for August 24, 2011. Temperatures of 26°C (79°F) are typically needed for a hurricane to maintain its strength (black line). This boundary lies just off the southern coast of New Jersey this year, which is much farther north than usual.


Figure 4. Predicted 5-day rainfall for the period ending Monday morning, August 29, at 8am EDT. Image credit: NOAA/HPC.

Irene's impact on the mid-Atlantic and New England
The impact of Irene on the mid-Atlantic and New England is highly uncertain at this point, because we don't know if the core of the storm will miss the coast or not. In general, the heaviest rains will fall along a 100-mile swath just to the west of where the center tracks, and the worst wind and storm surge damage will occur to the east. If the core of Irene stays offshore, the mid-Atlantic and New England may escape with a few hundred million dollars in damage from flooding due to heavy rains and storm surge. If Irene hits Long Island or Southeast Massachusetts, the storm has the potential to be a $10 billion disaster. Irene is one of those rare storms that has the potential to make landfall in New England as a Category 2 or stronger hurricane. It is difficult for a major Category 3 or stronger hurricane crossing north of North Carolina to maintain that intensity, because wind shear rapidly increases and ocean temperatures plunge below the 26°C (79°F) level that can support a hurricane. We do expect wind shear to rapidly increase to a high 30 - 50 knots once Irene pushes north of Delaware, which should knock the storm down by at least 15 - 30 mph before it reaches New England. However, this year sea surface temperatures 1 - 3°F warmer than average extend along the East Coast from North Carolina to New York. Waters of at least 26°C extend all the way to Southern New Jersey, which will make it easier for Irene to maintain its strength much farther to the north than a hurricane usually can. During the month of July, ocean temperature off the mid-Atlantic coast (35°N - 40°N, 75°W - 70°W) averaged 2.6°F (1.45°C) above average, the second highest July ocean temperatures since record keeping began over a century ago (the record was 3.8°F above average, set in 2010.) These warm ocean temperatures will also make Irene a much wetter hurricane than is typical, since much more water vapor can evaporate into the air from record-warm ocean surfaces. The latest precipitation forecast from NOAA's Hydrological prediction center shows that Irene could dump over 8 inches of rain over coastal New England.


Figure 5. Soil moisture profiles from yesterday show that a region of very moist soils ranking in the top 1% in recorded history (dark green colors) lie over northern New Jersey, Southeast New York, and Northeast Pennsylvania. Image credit: NOAA/CPC.

Tropical storm-force winds and heavy rains will move into Eastern Virginia Saturday afternoon, and push northwards to Delaware and coastal Maryland by late Saturday night. Tropical moisture through a deep layer of the atmosphere will also stream well ahead of Irene into New England on Saturday afternoon and evening, bringing what is called a "Predecessor Rain Event" (PRE). The Washington D.C., Baltimore, and Philadelphia airports will be right at the edge of the heavy rain and high wind area, and it currently appears they will not have to close for an extended period. The Philadelphia and New York City airports may not be as lucky, and it is possible they will suffer extended closures Sunday morning and afternoon. By late Sunday night, Irene's rains will move north of New York City, allowing the airports to re-open. The highest potential for damaging fresh-water flooding is in northern New Jersey, Southeast New York, and Northeast Pennsylvania, where soil moisture is near record high levels, and there is nowhere for the rain to go (Figure 5.) Heavy rains of 4 - 12" are likely across all of coastal New England if Irene passes within 100 miles of shore.

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.

Elsewhere in the tropics
A tropical wave far out in the eastern Atlantic about 200 miles southwest of the Cape Verde Islands, Invest 90L, is showing signs of organization. NHC is giving this disturbance a 50% chance of developing into a tropical depression by Friday. Several of our models do develop 90L into a tropical storm by early next week, but long-range models are showing that this system will not be a threat to any land areas over the next seven days, and will probably move too far north to ever be a threat to land.

Internet radio show on Irene at 4:30pm EDT today
I'll be discussing Hurricane Irene on a special edition of our Internet radio show, the Daily Downpour, today (Wednesday) at 4:30pm EDT. Fellow wunderground meteorologists Shaun Tanner, Tim Roche, and Angela Fritz will also be there. Listeners can email in or call in questions. The email address to ask questions is broadcast@wunderground.com.

Jeff Masters

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1040. KEEPEROFTHEGATE (Mod)
09L/MH/I/C3
RI FLAG (off)
MARK
24.00n/75.00w forecast point





ALWAYS FOLLOW NHC/TPC FORECASTS FOR ALL WARNINGS REGARDING THIS STORM
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Quoting CybrTeddy:
Afternoon all! Irene is a monster, and 90L looks like it will become Jose.


Jose Wales? Sorry couldnt help it.
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Quoting portcharlotte:
I haven't seen a 295 or 310 heading since 10:15 AM..not sure which storm you are looking at




??? What do you have it moving? NHC has it at 310 as of right now. I just assumed all the jogs would be less down around 300 and 295, which was its previous heading.
Member Since: February 2, 2010 Posts: 0 Comments: 1456
no recon?
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1036. Ryuujin
Like I said in another post, if you want to get rid of 90% of the trolls make it a mandatory 24-48 hour wait for approval. That will keep most of the trolls away
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1035. 7544
we got another wobble west
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Afternoon all! Irene is a monster, and 90L looks like it will become Jose.
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Quoting RickWPB:
I've read a number of comments here that Irene is still heading WNW. Even the NHC advisory at 2PM is calling the direction NW... and the NHC is slow to make a change in direction.

Quote:
LOCATION...22.7N 74.3W
ABOUT 65 MI...105 KM SE OF LONG ISLAND BAHAMAS
ABOUT 250 MI...405 KM SE OF NASSAU
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...954 MB...28.17 INCHES


that is because it has averaged .4N to .5West...not quite WNW or NW...somewhere in between
Member Since: September 16, 2007 Posts: 0 Comments: 3650
Quoting RickWPB:
I've read a number of comments here that Irene is still heading WNW. Even the NHC advisory at 2PM is calling the direction NW... and the NHC is slow to make a change in direction.

Quote:
LOCATION...22.7N 74.3W
ABOUT 65 MI...105 KM SE OF LONG ISLAND BAHAMAS
ABOUT 250 MI...405 KM SE OF NASSAU
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...954 MB...28.17 INCHES


310 is not quite NW, but close (315)
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Quoting presslord:
WobbleCon Level 5!!!!!!!
LMAO
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Quoting wpb:
link


I removed it. The host website is having problems.
Link
Member Since: September 23, 2005 Posts: 14 Comments: 10876
Quoting hyperanthony:


Puerto Rico begs to differ.



Well discounting PR. I mean it's not going to hit the US East coast. Trust me on this.
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Quoting nigel20:
This is a large and extremely large and dangerous storm, so people in Irene's path must take extreme caution.


Thanks boss.
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Quoting Bluestorm5:
Grandpa, it's the trolls doing it. It get on my nerves sometimes and I don't see you doing anything wrong.


I think the whole karma thing needs to go. I personally think the blog should allow plus minus or report but it shouldn't contribute to some karma rating. Instead, each comment should stand on its own and a certain number of minuses auto removes it and reporting will alert admin and they can remove it or ban the user based on that. Beyond that, I think we can manage our personal preferences with the ignore list. The reason I say this is because there are many users who at times could become annoying (myself included) to some people but almost everyone on here, with a few exceptions, has something valuable to contribute to the discussion and I don't necessarily think it's a good idea to have certain people filtered out all the time based on the karma system. Just my thoughts...
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Quoting VieraChris:


Models and forecast are sticking with the turn but it is getting closer than I care to see with each hour. I'm thinking TS force winds for us. Be prepared just in case and keep watching.


believe me I am but I like the info I glean from this blog. quite a few knowledgeable ppl here. Rita posted that 77w is when we should really start to worry and another blogger said TS conditions bak in the forecast for central fl.
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Looks like another WNW wobble is occurring. Irene may go slightly south of the 8pm NHC position.
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Suggestion:

Do you think it's possible that Dr. Masters could
have it set up so that ONLY paid members would
see other paid members comments, and the non paid
members would only see other non paid members
comments? Hope you can understand what i'm saying.

Might stop alot of the trolling here!

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1023. Ryuujin
Quoting RickWPB:
I've read a number of comments here that Irene is still heading WNW. Even the NHC advisory at 2PM is calling the direction NW... and the NHC is slow to make a change in direction.

Quote:
LOCATION...22.7N 74.3W
ABOUT 65 MI...105 KM SE OF LONG ISLAND BAHAMAS
ABOUT 250 MI...405 KM SE OF NASSAU
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...954 MB...28.17 INCHES


Thing is, is that she is really not. She is really heading between wnw and nw, and they just err on the side of caution. Her wobbles have been decidedly wnw.
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1021. wpb
Quoting nrtiwlnvragn:
Experimental 12Z FIM. It is one of the models being developed for the HFIP. Just showing it as a p o s s i b i l i t y


link
Member Since: May 28, 2011 Posts: 0 Comments: 572
Quoting VieraChris:


Models and forecast are sticking with the turn but it is getting closer than I care to see with each hour. I'm thinking TS force winds for us. Be prepared just in case and keep watching.


I read the same exact posts when Emily was heading in a westerly direction and was forecast to turn. Irene is going to turn.
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1019. HarryMc
Quoting ILwthrfan:


Is the HH going to sample the atmosphere out ahead of Irene agian?


HH Plan for the day:

Link
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Quoting KEEPEROFTHEGATE:
i bet jfv is on the beach twirling around wrap in teh shower curtain crying


Yup
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WobbleCon Level 5!!!!!!!
Member Since: August 13, 2007 Posts: 0 Comments: 10479
1016. RickWPB
I've read a number of comments here that Irene is still heading WNW. Even the NHC advisory at 2PM is calling the direction NW... and the NHC is slow to make a change in direction.

Quote:
LOCATION...22.7N 74.3W
ABOUT 65 MI...105 KM SE OF LONG ISLAND BAHAMAS
ABOUT 250 MI...405 KM SE OF NASSAU
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...954 MB...28.17 INCHES
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1015. yoboi
Quoting MiamiHurricanes09:
Beautiful.





printed that photo out will frame it thanks........
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1014. hamla
the weather channel says the northeast corridor from nj to new england will be upgraded to extreme damage from high damage stay tuned
Member Since: August 29, 2008 Posts: 0 Comments: 166
On a side note its cool to see Taz, Rita, Reed, Flood, and some others on here....I wish Ike (although we didnt always see eye to eye I still liked the guy) and Storm were back on here.

Where is Dewey and DestinJ?
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Quoting KEEPEROFTHEGATE:
i bet jfv is on the beach twirling around wrap in teh shower curtain crying


teh..priceless!
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1011. NEwxguy
fingers are getting tired poofing so many people.
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Wish she would speed up at least..anyone on from the Exumas? Very concerned for the Bahamas.
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1009. KEEPEROFTHEGATE (Mod)
Quoting RitaEvac:
Telleconnections all point to a powerful hurricane moving up the east coast, this will be history in the making...lol
i bet jfv is on the beach twirling around wrap in teh shower curtain crying
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I haven't seen a 295 or 310 heading since 10:15 AM..not sure which storm you are looking at


Quoting ILwthrfan:
She's going to vary between 295 adn 310 around there until she gets her core well established and that ULL gets out of the way, until then she's gonna have a drunken walk up the Bahammas.
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...pinhole?
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Quoting reedzone:


Thanks for the info :) Will be interesting to see what the models show then.


Is the HH going to sample the atmosphere out ahead of Irene agian?
Member Since: February 2, 2010 Posts: 0 Comments: 1456
Quoting tropicalnewbee:
is it me or has she nto turned yet? I am in central florida brevard coast so the farther she tracks west the more interesting things will be for us. any help guys? thanks.


Models and forecast are sticking with the turn but it is getting closer than I care to see with each hour. I'm thinking TS force winds for us. Be prepared just in case and keep watching.
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1004. Titoxd
Quoting LavosPhoenix:
The blog is moving quickly as expected given the situation, so hopefully I can get an answer. IIRC, Irene has only dropped about 15 mb since last night/early this morning, but does anyone have a list of winds and pressures since she became a hurricane or for the past 24 hours?


Irene running best track, from the NHC.
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Quoting MiamiHurricanes09:
Beautiful.

She is indeed..
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she wobbled west again
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Edit: Removed origional post, host website can't handle the traffic.
Member Since: September 23, 2005 Posts: 14 Comments: 10876
Irenes' Central Dense Overcast has expanded over her again, looks better now. I love me a beautiful hurricane with high intensity to watch...but when it gets close to land i hate it!
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Quoting flasooner:
Is it just me, or are a number of models pushing back slightly to the west? I'm in West Palm Beach, so a slight westward move could spell the difference between simply a blustery day tomorrow or tropical storm conditions. Thoughts?


Not really that far west...I think what you will find is that there are a lot of people who really want this to pull farther and farther east - understandably so...I mean, who really wants death and destruction?

But I think that unless something just falls apart with the ridge over the US then Irene could be making a Wilmington / Outer Banks landfall. Just keep watching TWC.

No turn expected till early morning hrs tomorrow.
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Quoting zingo:
The city of Charleston, SC does not believe in trimming or cutting down trees. They have people on the city payroll that does nothing but map a tree for the city. You cut one, you pay dearly. Thousands of dollars. You can go to the city and ask permission to trim or cut down a tree. Go thought months of waiting and then getting a ruling. Power lines in this town are the worst I have ever seen. Hwy 17 trees downtown were trimmed last year some. It wouldn't take much of a storm to lose power there for some time. I have never understand why this city is that way.
I used to live in a home that had a 40 year old Mahogony tree in the front yard. Every couple of years we would "thin" it so if a storm comes, it will blow through, not blow the tree over. That is what needs to be done to large trees. A true arborist would know this needs to be done.
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Quoting tropicalnewbee:



so how long would she need to stay on this westerly path before I really need to be worried?


77W
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996. 7544
hmmm cetral fla ts conditions are back in the forecast interesting
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Quoting Tazmanian:



POOF


Hey Taz how are you today, ive begun bugging my father about this hurricane... Lol he got mad.
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994. HiWay
Quit worrying about "it's not turned yet". If you look at the forecast plots, WNW to NW to NNW to N will transition all the way through tomorrow evening and possibly Friday AM.
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This is a large and extremely large and dangerous storm, so people in Irene's path must take extreme caution.
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Beautiful.

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Quoting wxobsvps:
Thankfully Irene has come off its 295 heading and is now up to 310....every bit of latitude counts.
She's going to vary between 295 adn 310 around there until she gets her core well established and that ULL gets out of the way, until then she's gonna have a drunken walk up the Bahammas.
Member Since: February 2, 2010 Posts: 0 Comments: 1456

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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.