Category 2 Irene Approaches The Bahamas

By: Dr. Jeff Masters , 7:51 AM GMT on August 23, 2011

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As of 2am EDT, Hurricane Irene was located at 20.1N, 69.7W, 135 miles southeast of Grand Turk Island. It was moving west-northwest at 12 mph with maximum sustained winds of 100 mph, making it a Category 2 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 978 mb. Hurricane warnings have been issued for the northern coast of the Dominican Republic from the Haiti board to Cabo Engano, the southeastern and central Bahamas, and the Turks and Caicos islands. Hurricane watches have been posted for the north coast of Haiti from Le Mole, St. Nicholas to the Dominican border and the northwestern Bahamas. Tropical storm warnings are in effect for all of Haiti and the southern coast of the Dominican Republic from Cabo Engano to Santo Domingo.

5AM Update
As of 5am EDT, Hurricane Irene was located at 20.3N, 70.1W, 105 miles southeast of Grand Turk Island. It was moving west-northwest at 12 mph with maximum sustained winds of 100 mph, keeping it a Category 2 storm on the Saffir-Simpson scale. Irene has a minimum central pressure of 978 mb.

Figure 1 shows that Irene is maturing into a vigorous storm, with apparent waves in the western edge of the cirrus outflow.


Figure 1 IR satellite view of Irene taken at 135AM EDT, August 22, 2011

Track Forecast

Irene is forecast to move to the north-northwest, passing over all of the Bahama islands by Thursday evening, at which points it starts curving to the north. Irene is forecast to make landfall in the US near Wilmington, NC Saturday evening. However, it is important to note that this is not a definitive forecast, the average forecast error for day 5 is 250 miles. The timing of Irene's recurvature depends on how quickly several small troughs of low pressure in the Northeastern US move to the east. After Saturday, Irene may pose a threat to the mid-Atlantic coastline and locations further north, but it is too early to make a skillful forecast for those regions.

NHC is forecasting for Irene to become a major hurricane (winds faster than 110 mph), within 24 hours, then reaching peak intensity at 130 mph (Category 4 storm) by 8pm EDT Thursday evening.

Forecast models and adaptive observations
The different forecast models are in rough agreement until Irene nears the Carolinas. The dynamical hurricane forecasting models, GFDL and HWRF, have Irene making landfall near Charleston, SC. NGFDL (a variant of the GFDL that uses NOGAPS for background conditions) has landfall near Morehead City, NC, and the GFS has Irene crossing the Outer Banks. The UKMET forecast track splits the difference, placing Irene near Myrtle Beach, SC at landfall.

To reduce the model spread, and improve the track forecast error, the NOAA Gulfstream IV and an Air Force WC-130J have been flying dropsonde missions north of Irene. A dropsonde is an meteorological instrument package dropped from a plane that can tell you the vertical profile of temperature, pressure, moisture, and winds. By flying these missions, the dropsondes can improve all of the numerical weather prediction models initial picture of the atmospheres, which improves the forecast. Also, NHC has asked NWS offices in the southeastern US that launch weather balloons to do so every 6 hours instead of the normal 12 hour frequency.


Figure 2 Official track forecast of Irene as of 2am.

5AM update
The 00Z ECMWF forecast is available and Figure 3 shows the maximum wind speed over the next week for the eastern coast of the US. Green indicates tropical storm force winds, while yellow and orange are hurricane-force winds. The important thing is not to fixate on the predicted landfall location, but to see that Irene's winds will affect areas far away from landfall. The GFS, not shown, agrees with ECMWF that Irene will have a large area of tropical-storm force winds associated with it.

Figure 3 Maximum wind-speed in mph from the 00Z August 23 ECMWF forecast for the next week.

Impacts

In the immediate future, Irene is expected to have a significant impact on the Bahamas and surrounding islands. Hurricane force winds are forecast to reach the southeastern Bahamas and the Turks and Caicos sometime this afternoon or evening. These locations can also expect 5-10 inches of rain. Three to six inches of rain are forecast over northern Hispaniola, with isolated areas receiving up to 10 inches. This could lead to flash flooding and mudslides in mountaineous terrain. NHC is predicting a storm surge of 9-13 feet above normal tide level for the southeastern Bahamas and the Turks and Caicos.

Outside of the islands immediately impacted by Irene, it is my judgement that everybody living on the eastern coast of the US should monitor Irene and review their hurricane preparations over the next few days.

Dr. Masters will have a new blog entry this morning, and Angela Fritz will be covering the afternoon. I'll be back on third shift tonight.

Thanks for reading,

Dr. Rob Carver

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485. Skyepony (Mod)
Good morning everyone.. Nice cone shift. My biggest concern about it..the models (gfs for example) have 98L fly across the Atlantic helping to weaken & erode the high. 98L decoupled overnight & is a naked swirl.
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484. 900MB
Quoting sullivanweather:
Irene, a storm 190 years in the making.

img src="">


Quite a map. Don't forget these, directly grifted from Wiki:

Before the 1938 hurricane it had been several decades since a hurricane of any significance adversely affected the northeastern Atlantic coastline. Nevertheless, history has shown that several severe hurricanes have affected the Northeast, although with much less frequency in comparison to areas of the Gulf, Florida, and southeastern Atlantic coastlines.

* The Great September Gale of 1815 (the term hurricane was not yet common in the American vernacular), which hit New York City directly as a Category 3 hurricane, caused extensive damage and created an inlet that separated the Long Island resort towns of the Rockaways and Long Beach into two separate barrier islands.

* The 1821 Norfolk and Long Island Hurricane, a Category 4 storm which made four separate landfalls in Virginia, New Jersey, New York and southern New England. The storm created the highest recorded storm surge in Manhattan of nearly 13 feet and severely impacted the farming regions of Long Island and southern New England.

* The 1869 Saxby Gale affected areas in Northern New England, decimating the Maine coastline and the Canadian Outer Banks. It was the last major hurricane to affect New England until the 1938 storm.

* The 1893 New York hurricane, a Category 2 storm, directly hit the city itself, causing a great storm surge that pummeled the coastline, completely removing the Long Island resort town of Hog Island (New York).

The years spanning 1893 to 1938 saw much demographic change in the Northeast as large influxes of European immigrants settled in cities and towns throughout New York and New England, many of whom knew little, if anything, about hurricanes. Most people at the time associated hurricanes with the warmer tropical regions off the Gulf Coast and southern North Atlantic waters off the Florida coastline, and not the colder Atlantic waters off New York and New England. The only tropical storms to affect the area in recent years had been weak remnant storms. A more common weather phenomenon was a noreaster, which is a powerful low-pressure storm common in the Northeast during fall and winter. Although Noreasters can produce winds that are similar to those in hurricanes, they do not produce the storm surge that proved to be the 1938 storm's greatest killer. By 1938, most of the earlier storms were hardly remembered.
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Quoting ironbanks:
Always amazes me how much the track shifts 4-5 days out. Local weatherman says you want to see the models aimed at your location that far out. His logic, it likely will go somewhere else. Hate to agree but seems to happen more often then not.
That does often seem to be the case, here it is illustrated.


There is a javascript version of all the graphics archives available online here: IRENE Graphics Archive
Here is the latest animated Doom Cone




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ATCF 1200z update:

AL, 09, 2011082306, , BEST, 0, 201N, 697W, 85, 978, HU, 64, NEQ, 45, 30, 20, 35, 1010, 300, 15, 0, 0, L, 0, , 0, 0, IRENE, D,
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481. HCW
Quoting 900MB:


NYC to Long Island :)



Here you go . Now on with the countdown

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479. 900MB
Quoting NICycloneChaser:


A few of the models have the shortwave troughs moving down and through, then out again a little faster than before. As of current predictions, all that would do is move Irene further east, likely staying just off shore. However, if that trend continues, we could actually have the opposite effect, with the troughs moving in and out before Irene is far enough north, then the ridge building back in to the west and pushing Irene towards the coast.


Hmmm, thanks. Not exactly music to my ears.
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Irene, a storm 190 years in the making.

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Quoting SLU:
POOR LITTLE IRENE IS GOING TO GET HER NAME RETIRED :(


Looks like it may.
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I know that everyone is focused on Irene right now and rightly so but here is some grim news from Texas.

Good Luck and God Bless to everyone in Irene's path.

Link

As historically bad as this summer's drought has been, we may not have seen the worst of it.

There's growing concern among some scientists that Texas' drought could linger through another dry winter and return next summer to more deeply ravage an already water-stressed state.

"I've started telling anyone who's interested that it's likely much of Texas will still be in severe drought this time next summer, with water supply implications even worse than those we are now experiencing," said John Nielsen-Gammon, the state climatologist and a Texas A&M University professor.

In the short term, there's little relief in store. Houston topped 100 degrees (101) again Monday, beating the record of 32 total days with temperatures reaching the century mark set in 1980 (not consecutive).


I would recommend reading the entire article as it really summarizes how bad it really is down here.


I am about to become a SERIOUS WISHCASTER.

This drought and heat wave are making people crazy! There are no green lawns, tree's are dying and it just continues........
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Morning All.

Fully expect Eastern FL to be out of the cone @ 11am, welcome news :-). Unfortunately, business is way down and we can't afford to leave right now. My rule is to get out of dodge for a 4 and above so that would have put us in a precarious situation. However, still can't let the guard down, Jeanne taught us that hard lesson.

Not so lucky for T&C and the Bahamas however, prayers are with you.
Member Since: August 19, 2005 Posts: 5 Comments: 5458
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472. BDAwx
Ok now I'm confused, what do we all mean by "direct impacts" from hurricane Irene?

I would say Florida is out of the woods for a landfall from Irene but it could still see direct impacts. Direct impacts being wind, rain, and surf generated by the storm. Just a reminder that the storm is huge and is likely going to get bigger as it pulls more northward (away from any inhibiting factors of hispaniola's mountains, and natural increase in size from latitudinal gain) so the storm needn't make landfall on you to give you hurricane winds.
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Quoting cat5hurricane:

Yep. Focus not so much on the intensity with this one, but with the expanded wind field about to take shape. It should be incredible.


Cat 5: Not a scientist, but I can appreciate and be scared of the energy bomb that is just about to explode as soon as the south clears the big islands. The size bothers me, a lot, since even CAT 1 Isabel did a number on two tide cycles in my favorite fishing towns. It has been a very long time since a major hurricane cut this path and a big major hurricane is big time bad news with the growth in population and property.
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Quoting nrtiwlnvragn:


Here is a crude animation that will give you a broad, general idea of steering with various trofs (lows) over the CONUS and high pressure in the Atlantic.


Thanks for link. Been looking for a down and dirty explanation how highs and lows affect a storm's path.
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Quoting nash28: I remember Charley very well. It was Tampa, Tampa and TAMPA for days! Then at the last minute (damn near) he turned and missed us by over 100 miles.



Oh me too, I was living in St. Pete then, on the water (the bay) - evacuated in a total panic (first hurricane).
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Quoting alvarig1263:



Nice of you to join us


Thanks!
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466. MahFL
Pump the ridge !....westcast !
Member Since: June 9, 2004 Posts: 0 Comments: 3805
Quoting stillwaiting:
sooo flloridas officially out of the woods for direct impacts from irene,the west coast of fl 100% clear no???


This product is designed to address those kinds of questions;

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464. 900MB
Quoting HCW:


I can make a new one just for you showing your location P:)


NYC to Long Island :)
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anyone got the cimms maps? i would like to see the current and projected high. yesterday it showed the high building back in and the trough lifting out. wonder what it is showing now? tia!
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Quoting 900MB:


T&C just can't catch a break these last few years. Prayers and wishes for all!


Everybody's talking about NC and how it's going to strengthen over the next couple of days.
Guess what it's going to strengthen over?
Good grief. Where's Baha?
Grandpato4 in Atlantic Beach says his car is filled up and he's loading Mama in the car and heading out today or tomorrow.
So many people, so little time.
If you've ever been through hurricane prep you know how things escalate. You don't want to be one of those running around at the last minute. People aren't even looking at traffic lights anymore...It's quite strange as the distraction takes over.
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AL, 90, 2011082306, 122N, 190W, 25, 1008
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Quoting SeanyBoy:
Hey Everyone! Just a young mind with plenty of knowledge looking to learn more!!! No Trolling from me. Lol.



Nice of you to join us
Member Since: September 2, 2008 Posts: 0 Comments: 744
459. MahFL
The new invest is LARGE.....doom !
Member Since: June 9, 2004 Posts: 0 Comments: 3805
I think with this storm being so close to shore timing becomes a huge factor. The models starting to agree on the genaral movement of Irene. We've Seen this many times an early turn shes out to sea late and FL, GA, SC, and NC could all get a serious impact.
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457. SLU
POOR LITTLE IRENE IS GOING TO GET HER NAME RETIRED :(
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Quoting KeyWestwx:
What is a Dominator? Is that the Terminators nagging wife telling him to take out the trash and mow the lawn? LOL!
LOL!
Member Since: May 16, 2010 Posts: 0 Comments: 1472
Hey Everyone! Just a young mind with plenty of knowledge looking to learn more!!! No Trolling from me. Lol.
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454. HCW
Quoting 900MB:


Do you have one of those model maps that doesn't cut off the Northeast?


I can make a new one just for you showing your location P:)
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Quoting ironbanks:
Always amazes me how much the track shifts 4-5 days out. Local weatherman says you want to see the models aimed at your location that far out. His logic, it likely will go somewhere else. Hate to agree but seems to happen more often then not.


Yes it does. My area, Sarasota/Tampa, was the bulls eye on Sunday and look how much has changed in 2 days.
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Quoting TropicalXprt:
You know, it use to be that the NHC made actual weather predictions. Clearly they are so consumed in their models now. I think they are wrong on this track, and have it way to far east. Mark my words this storm will be south of there projected target later today.

The accuracy of NHC predictions has improved tremendously. They are off by an average of 200 and 250 miles at days 4 and 5. That would not be possible without the models.
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Quoting 900MB:
Wow, what a beast!

Looks like a major major coming up the coast.

Our only chance here is that it somehow moves off the coast and stays off the coast. Saw a couple models this morning that have it head-faking out to sea, and then coming back in at NYC.

Anyone have any hot theories on how the troughs and high pressure will be steering on Sun-Mon?


A few of the models have the shortwave troughs moving down and through, then out again a little faster than before. As of current predictions, all that would do is move Irene further east, likely staying just off shore. However, if that trend continues, we could actually have the opposite effect, with the troughs moving in and out before Irene is far enough north, then the ridge building back in to the west and pushing Irene towards the coast.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
450. 900MB
Quoting Chicklit:


As is my nature, I am crying for the Turks, Caicos and Bahamian Islanders.
It's gonna be rough.
On the upside, they are experienced at such things and will be able to bear these conditions better than most.


T&C just can't catch a break these last few years. Prayers and wishes for all!
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Lookin' good...Which is bad.

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"...Quoting howtheweather:

WRONGAAIN , WHAT GARBAGE WERE ALSO MY OLD NAMES I KEPT GETTING BANNED SINCE 2 WEEKS AGO BECAUSE OF RUNNING MY MOUTH..."

And another gets added to your list of banned names because of you running your mouth.

Think about what all those banned names have in common.

You and your attitude...
Member Since: May 18, 2007 Posts: 289 Comments: 1639
Quoting ironbanks:
Always amazes me how much the track shifts 4-5 days out. Local weatherman says you want to see the models aimed at your location that far out. His logic, it likely will go somewhere else. Hate to agree but seems to happen more often then not.


Not lately.
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446. HCW
I can provide the expected winds and duration for your location


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Always amazes me how much the track shifts 4-5 days out. Local weatherman says you want to see the models aimed at your location that far out. His logic, it likely will go somewhere else. Hate to agree but seems to happen more often then not.
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444. 900MB
Quoting HCW:
IRENE update



Do you have one of those model maps that doesn't cut off the Northeast?
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442. 900MB
Wow, what a beast!

Looks like a major major coming up the coast.

Our only chance here is that it somehow moves off the coast and stays off the coast. Saw a couple models this morning that have it head-faking out to sea, and then coming back in at NYC.

Anyone have any hot theories on how the troughs and high pressure will be steering on Sun-Mon?
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Recon not updating, Back later...
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Quoting weatherguy03:


Yes watch my video and blog update this evening.



Thanks Bob! I definitely will
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No updates from Recon? What's up?
Member Since: September 2, 2008 Posts: 0 Comments: 744
437. HCW
IRENE update

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No such thing as 100% when it comes to weather or Hurricanes.  I would still keep an eye on it.  I am and Im in Central FL.  If the models and forecasters have predicted every storm and there path for a year then I would say 100% but that is not the case.
Quoting stillwaiting:
sooo flloridas officially out of the woods for direct impacts from irene,the west coast of fl 100% clear no???

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Quoting weatherguy03:


Yes. I say that carefully..LOL I said a few days ago that Irene was not going into the Eastern GOM and I almost got crucified by the Tampa Wishcasters!..LOL

Indirect affects along the East Coast of gusty winds, beach erosion and high surf.


I wish the wishcasters could have the damn thing!
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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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