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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The only good news from this storm is the possibility that the cast of Jersey Shore may be washed out to sea.
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They need to knock it off with this 'Local on the 8s' nonsense
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Quoting WeatherfanPR:
Can someone tell Irene it's time to recurve North because it's getting closer to Florida and is not funny !!!!!


I just sent her a text. She said another 12 hrs and 32 mins. It'll happen.
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So glad this witch isn't in the Gulf...She's a beast. Feeling terrible for the Bahamas, though.

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Happy 29th anniversary Hurricane Andrew down in Homestead, FL...as we are all fixated on another monster in the region...Hurricane Irene, who shall leave her own trail of destruction and scary stories for decades to come and go!

Hudson, FL weather


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Last time I watched TWC it was Lyons & I think Carver with a cameo by Hope

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Quoting Jedkins01:


Hey don't worry, Irene isn't going to Florida, current steering currents would have to change drastically for that to happen.

By the way, since you live in Tampa now, how was that squall line for your area yesterday? I unfortunately was in Calc 2 class, so I couldn't experience it, but it produced a 51 mph gust at my house.


Jedkins, that line looked nasty on radar what kind of weather station do you have there?
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Quoting Hoynieva:
Quite disappointed that I'm going to be out of town for the only possible hurricane in NYC in many years and long before I lived here.


This is how I felt till I moved to Fl. and meet Wilma. It changed my thoughts about wanting to be in town for any cat1 or higher.
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1281. Levi32
Quoting wxobsvps:


you have source for that? been looking for that kind of product. thanks


Decoded Recon Data
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1280. Zaphod
TAwx -- dry air may be there, but it's 100 miles from the center now, rather than wrapping the core. Or so it looks to me.
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Quoting BobinTampa:
just checking in. Is Tampa in the clear now?


Yes it is, it would take some extreme changes in steering for Tampa to be hit.
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Quoting Jax82:


Cant believe anyone would ride out the cane on Crooked island, that had to be a wild ride.
They live there. You're right about the ride. A guy in Mayaguana called in to the radio this a.m. and you could hear the wind howling in the background. He had somebody else's roof in his yard. It was eerie from 400 miles away.
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Irene has moved 1.4W and 1.0N since 10:45 UTC.


What is that? A mixture between WNW and NW?
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Looks like an EWRC is underway. When it clears out again we could see a move down to Cat 4. Probably another 8 to 12 hours before the eye fully rebuilds but with it will likely come another round of deepening. This would be most unfortunate if it palys out that way because Irene will then be approaching the most populated and developed of the Bahamas chain as a strengthening major hurricane.
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1275. Levi32
Quoting Bluestorm5:
Storm still threat to Mrytle Beach to Wilmington? Right now, it look like it'll hit Morehead City...


SC is out of the NHC cone, but with these storms, you always want to keep a close eye on it until you see it physically passing east of you. South Carolina should keep their eyes peeled until it is obvious that they are safe. Right now, a major hurricane moving up the length of the Bahamas is not something to just ignore.
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Quoting Levi32:


I like this morning's NHC track, though slightly farther west over the outer banks. That would have a shot at bringing Wilmington tropical storm conditions, though it will depend on how much the western side expands before then, as the largest part of the wind field is still to the east.
and you answered my question answering someone's question lol.
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Quoting WeatherfanPR:
Can someone tell Irene it's time to recurve North because it's getting closer to Florida and is not funny !!!!!


Hey don't worry, Irene isn't going to Florida, current steering currents would have to change drastically for that to happen.

By the way, since you live in Tampa now, how was that squall line for your area yesterday? I unfortunately was in Calc 2 class, so I couldn't experience it, but it produced a 51 mph gust at my house.
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just checking in. Is Tampa in the clear now?
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1270. Brock31
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"I'm freakin out man!"

...
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"yes"
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"you are freakin out"
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"man"
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I am evacuating from the Virginia Beach area tomorrow afternoon to the Lynchburg area. I hope that keeps us far enough out of harms way..... (too bad its closer to earthquake epicenter) but that is neither here nor there.... LOL
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Quoting ProgressivePulse:



Highly Unlikely it makes it to FL, however, 78W is the mark for bringing TS winds inland, it "could" get there based on what I am seeing.



I have family living in Boynton Beach,FL
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Ok I am in southeast florida ft lauderdale area about 1 mile from the beach why does this thing look like it is headed straight for us it looks like it is going west northwest not north west the wind has picked up steady 6 to 7 mph with gusts of about 12 to 13 mph i am just a bit concerned can anyone enlighten me please?
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1265. Levi32
Quoting TropicalAnalystwx13:
Levi, what is your latest forecast track for Irene? Still got me in the TS force winds?


I like this morning's NHC track, though slightly farther west over the outer banks. That would have a shot at bringing Wilmington tropical storm conditions, though it will depend on how much the western side expands before then, as the largest part of the wind field is still to the east.
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Quoting TropicalAnalystwx13:


Ok, maybe it was an exaggeration, but still...A lot of people watch TWC.


I watch now and then but not in the morning. Can't handle Stephanie Abrams at all!!
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Quoting Levi32:


If the storm reaches the forecasted position off the SE US coast on Friday morning and the track still takes the storm over New England, then watches would be issued 48 hours in advance by the NHC.
Storm still threat to Mrytle Beach to Wilmington? Right now, it look like it'll hit Morehead City...
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Quoting Bluestorm5:
Joplin Tornado holds the record for the most TV viewers during a certain time period at 50 million people. Katrina may have more people watching it (1/2 of USA maybe?) but not at the same period of time.


Half the people that really wanted to watch TV couldn't because we had no power or were evacuating. Imagine if ALL of us were able to watch!
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1261. JNCali

Quoting presslord:
This could be a nightmare scenario for new England!!!!! My God...it's just horrifying to think about!!!! Seriously!!! This could do damage to a whole generation!!!! Has someone warned them FEMA is coming?!?!?!?!?!
Brutal Funny!!!   +100000000000000
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1260. tea3781
Why do I feel so nervous here in East Central Florida. I know what the models say...but I remember what the models said for Charley too and they were all wrong.
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1258. stexram
Quoting Abacosurf:
Yea. I helped build the pool and the new double decker decks there with the new kitchen in 98-99.

Just talked to Michael Roberts. Johnnys dad. He said they are ready.


I hope so, they are really exposed to the wind right there. You all be safe!
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Quoting wxgeek723:
Living in South Jersey I'm a little apprehensive about the forecast calling for a category 2 off our coastline.


LOL. Same here
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Quoting BiloxiBlues:
NHC is not always right. They had Katrina landing in the middle of the Florida panhandle.

http://www.nhc.noaa.gov/archive/2005/KATRINA_grap hics.shtml
They are not always wrong either. I'm pretty satisfied they got this Irene forecast right. Always had it coming up or through most of the Bahamas.

10 or 12 days out. [not counting the other times when they had it in Houston or the GA Sea Islands.]
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Quoting tinkahbell:
I was calm until I started watching TWC.

Cantore downing the 5 hour Energy drinks every 2 hours now I see?
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Irene is still having a little dry air problem...You can see the outflow boundaries on the western side of the storm.

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Quoting trHUrrIXC5MMX:


Raleigh in orange, Clayton on the borderline between orange and red.
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Shhhhh. Nobody tell the cast of Jersey Shore......
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I was calm until I started watching TWC.
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Quoting ChrisDcat5Storm:
she going west!!!


Stair stepping... Track it over the last 6 hours, Irene is going almost exactly NW.
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Quoting WeatherfanPR:
Can someone tell Irene it's time to recurve North because it's getting closer to Florida and is not funny !!!!!



Highly Unlikely it makes it to FL, however, 78W is the mark for bringing TS winds inland, it "could" get there based on what I am seeing.
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Quoting AllStar17:



Yes. He is the hurricane specialist. Dr. Rick Knabb is the hurricane expert.


On Sunday, the woman in the studio in the afternoon called Irene "Ilene" and also had so many grammatical errors in her speech, I couldn't believe she had a job on television! I watch TWC because I don't have another station to watch. If there was an alternative, I would be all over it.
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1246. snotly
Its about to make landfall at Long Island now.

Quoting westernmob:
If Irene stays offshore long enough for a Long Island landfall, does this have the potential to be stronger than Gloria in 1985?
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1245. Levi32
Quoting Fotograffa:


So would you guess they should have issued watches/warnings by Friday for the northeast? Of course, no one needs to wait for watches or warnings to get prepared.


If the storm reaches the forecasted position off the SE US coast on Friday morning and the track still takes the storm over New England, then watches would be issued 48 hours in advance by the NHC.
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Quoting trHUrrIXC5MMX:
Will the TWC go to storm alert mode?

Im pretty afraid now


Well usually they do it for storms that pose a significant threat to the United States. I'm guessing that this storm fits that billing.
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i am really concerned for those up north.. southerners are used to hurricanes but those up north kinda shrug it off.. I just talked to my Mom and son whose in college in NJ.. they have this wait n see.. might get a little rain and some wind..the NJ beaches are really vulnerable too.. they are barrier islands which flood from the ocean and back bays.. and the local tv channels up there are not making much about it either.. not trying to be an alarmist but they should at least be getting some supplies in and such.. they think im overreacting.. im just worried..is there any chance this could possibly veer out and miss the northeast? i do appreciate your input.. thank you.
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Quoting TropicalAnalystwx13:


What are you talking about? Millions to Billions of people watch the Weather Channel.
Joplin Tornado holds the record for the most TV viewers during a certain time period at 50 million people. Katrina may have more people watching it (1/2 of USA maybe?) but not at the same period of time.
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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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