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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1383. RukusBoondocks
8:51 PM GMT on August 23, 2011
we doomed
Member Since: February 13, 2011 Posts: 0 Comments: 294
1382. RM706
6:08 PM GMT on August 23, 2011
5.8 Earthquake in Virginia, DC and New York.
Member Since: May 30, 2007 Posts: 0 Comments: 227
1381. Cybereagle
5:45 PM GMT on August 23, 2011
Quoting DellOperator:



http://www.insmet.cu/asp/genesis.asp?TB0=PLANTILL AS&TB1=RADAR&TB2=../Radar/06Gran%20Piedra/gpdMAXw0 1a.gif


Got it
Member Since: August 25, 2008 Posts: 0 Comments: 0
1380. DellOperator
5:43 PM GMT on August 23, 2011
Link

Click on a radar site in the map.
Member Since: May 31, 2007 Posts: 0 Comments: 209
1379. DellOperator
5:40 PM GMT on August 23, 2011
Quoting SPLbeater:
Got the cuban radar up,but cant find an available loop. Anybody got a link to a Cuban loop radar? Patrap er Levi?



http://www.insmet.cu/asp/genesis.asp?TB0=PLANTILL AS&TB1=RADAR&TB2=../Radar/06Gran%20Piedra/gpdMAXw0 1a.gif
Member Since: May 31, 2007 Posts: 0 Comments: 209
1378. jonelu
5:23 PM GMT on August 23, 2011
Quoting Patrap:
wow...look at all the dry air over Tx...thats awful.
Member Since: October 31, 2007 Posts: 2 Comments: 884
1377. SPLbeater
4:47 PM GMT on August 23, 2011
North side of eye visible, south side seems to have a thunderstorm up over top of it seen on visible...
Member Since: August 4, 2011 Posts: 46 Comments: 4487
1376. SPLbeater
4:37 PM GMT on August 23, 2011
Quoting BA:


Are you serious? ...margin of track error > 5 days out is extremely large...nobody is going to be any different with any sort of consistency. You have to realize that nobody can truly predict what all the patterns will do, when it changes, all forecasters have to change with it.


Yes i do know that, but they have shifted way further then 250 miles...going up a third of the Eastern Seaboard is a large shift
Member Since: August 4, 2011 Posts: 46 Comments: 4487
1375. sunlinepr
4:16 PM GMT on August 23, 2011
Member Since: August 2, 2010 Posts: 21 Comments: 9825
1374. sunlinepr
4:15 PM GMT on August 23, 2011
Member Since: August 2, 2010 Posts: 21 Comments: 9825
1373. BA
4:14 PM GMT on August 23, 2011
Quoting SPLbeater:
I am getting fed up with the NHC, all this shifting. go from South Florida to barely scraping the NC coast! really wish they would admit they dont know where its going, geez...Irene is looking good though.


Are you serious? ...margin of track error > 5 days out is extremely large...nobody is going to be any different with any sort of consistency. You have to realize that nobody can truly predict what all the patterns will do, when it changes, all forecasters have to change with it.
Member Since: July 15, 2005 Posts: 0 Comments: 156
1372. AllStar17
4:13 PM GMT on August 23, 2011
11:00am Advisory
Click image for enlarged view
Member Since: June 29, 2009 Posts: 13 Comments: 5313
1371. cynvision
4:13 PM GMT on August 23, 2011
The main event this evening! Clash of the Atlantic fluffies! In this corner, a tough young lady from across the sea-- Irene!! And in this corner, a local girl, a spinner off the old front The Nameless Newbie-- *DING DING!* And there's the bell!
Member Since: May 28, 2008 Posts: 8 Comments: 42
1370. BahaHurican
4:01 PM GMT on August 23, 2011
Bahamian officials are expecting hurricane Irene to be near New Providence by Thursday, and out by Friday morning.

Arthur Rolle, our head wx guy, also said the track should bend sufficiently to the East to prevent the Northwest Bahamas from experiencing the worst of the storm.

Talk about track confidence!

I am wondering if people remember that today is the anniversary of Andrew's trek through The Bahamas.
Member Since: October 25, 2005 Posts: 19 Comments: 22359
1369. saylo2mylilfren
3:56 PM GMT on August 23, 2011
Quoting kflhuds05:
Was that a jog to the W and WSW close to the end of the frames of Irene...

NOAA Link

..if so, that may change a bit of the course some!
Hudson, FL weather


hard to tell without a radar but it looks like it
Member Since: June 27, 2010 Posts: 0 Comments: 13
1368. kflhuds05
3:54 PM GMT on August 23, 2011
Was that a jog to the W and WSW close to the end of the frames of Irene...

NOAA Link

..if so, that may change a bit of the course some!
Hudson, FL weather
Member Since: February 27, 2004 Posts: 85 Comments: 17
1367. HurricaneNewb
3:52 PM GMT on August 23, 2011
Quoting Floodman:


They plot their track as a consensus of model track and model track changes as the conditions change; what were your thoughts on how they did it? Should they stick to a track despite the fact that it's wrong? Or do you have a way of making a storm conform to a specific track?
Ya really its not like its a Magnet with the track being metal lol.
Member Since: July 15, 2008 Posts: 0 Comments: 197
1366. HurricaneHunterJoe
3:48 PM GMT on August 23, 2011
Quoting rkay1:
SPECIAL UPDATE: The only way FLORIDA will be effected is if it detaches from America and floats about 250-300 miles East.

Who died and left him GOD?
Member Since: September 18, 2010 Posts: 0 Comments: 5234
1365. SPLbeater
3:48 PM GMT on August 23, 2011
Got the cuban radar up,but cant find an available loop. Anybody got a link to a Cuban loop radar? Patrap er Levi?
Member Since: August 4, 2011 Posts: 46 Comments: 4487
1363. OracleDeAtlantis
3:45 PM GMT on August 23, 2011
Quoting WxLogic:
Wide open for any northerly fluctuations:

You mean wide opening to weakening, which means further West.
Member Since: August 27, 2009 Posts: 0 Comments: 525
1362. FLWaterFront
3:44 PM GMT on August 23, 2011
It looks as if the Florida-casting will not stop until Irene has officially entered the history books.

I predict the Florida-casts for Irene should begin to taper down sometime around mid-October. It's silly though.

Imagine it's late May or early June, and a storm system is threatening to produce a major tornado outbreak in and near Minnesota and Wisconsin. Then imagine that a bunch of people from Kansas and Missouri get on a blog and insist that the tornado threat is really going to be in Kansas and Missouri. That would be rather uncool would it not?

Please give the wishcasting for Florida a rest. Plenty of major hurricanes have plowed into Florida in the past and it will surely happen again. You will have your day, though you may regret it. This is not your day, however, and I for one and relieved about that. On the other hand, I am worried for those further north. 'Nuff said.
Member Since: October 15, 2010 Posts: 0 Comments: 727
1361. NICycloneChaser
3:44 PM GMT on August 23, 2011
NEW BLOG NEW BLOG
Member Since: August 10, 2010 Posts: 2 Comments: 1971
1360. charlottefl
3:44 PM GMT on August 23, 2011
Motion over the past couple of hours has definitely been more towards the West. We'll have to see what if any changes that has on long term track.
Member Since: December 18, 2006 Posts: 7 Comments: 2686
1359. dipchip
3:43 PM GMT on August 23, 2011
TWC says the storm is rapidly intensifying. The central pressure is down 1 milli-bar in the past 15 hours. What is slow intensification? 15 to 20 knts of SW shear. Their reporters may need extra sun shield for a few more days.
Member Since: September 20, 2005 Posts: 0 Comments: 73
1358. Waltanater
3:43 PM GMT on August 23, 2011
Quoting wolftribe2009:
"blob" not going to go north of Irene from what i see. It looks like the two will collide which that would be interesting. I think Irene would suck up the blob creature and eat it from dinner. Yet if the blob becomes a low and moves far enough west over Florida it would be the door open to turn the storm into the Carolinas.

That is what I am looking at. Wow the weather is unpredictable. Where was this blob yesterday lol?
Wouldn't this "blob" actually HELP the forecast for Irene!? Wouldn't the troughs have the same affect on this blob as it would with Irene, only earlier? It could help the timing of it all.
Member Since: May 16, 2010 Posts: 0 Comments: 1472
1357. alvarig1263
3:43 PM GMT on August 23, 2011
NEW BLOG!!
Member Since: September 2, 2008 Posts: 0 Comments: 744
1356. alvarig1263
3:42 PM GMT on August 23, 2011
NEW BLOG!!!!!!!
Member Since: September 2, 2008 Posts: 0 Comments: 744
1355. kshipre1
3:42 PM GMT on August 23, 2011
is the bermuda High still supposed to build into the western atlantic this Friday?
Member Since: July 12, 2010 Posts: 0 Comments: 1130
1354. SCwannabe
3:42 PM GMT on August 23, 2011
Quoting 69Viking:


He made #5 on my list!


I love your Picture...Go Vikes!!
Member Since: August 14, 2007 Posts: 0 Comments: 535
1353. 69Viking
3:41 PM GMT on August 23, 2011
Quoting SCwannabe:


amen to that one!!


He made #5 on my list!
Member Since: August 25, 2006 Posts: 1 Comments: 3060
1352. TropicalBruce
3:40 PM GMT on August 23, 2011
I'm of the opinion that Irene also won't affect Florida too much except some gusty winds/rain, primarily on the eastern half of the peninsula, plus high seas along the east coast. That said, Floridians should still watch Irene carefully until it passes their latitude on a N to NW heading.
Member Since: May 10, 2009 Posts: 0 Comments: 115
1351. stormpetrol
3:40 PM GMT on August 23, 2011
Link

First time the eye is really starting show up on visible , Irene is intensifying not weakening imo.
Member Since: April 29, 2007 Posts: 0 Comments: 7935
1350. kmanislander
3:40 PM GMT on August 23, 2011
Good morning.

A couple of quick posts for the morning.

Visible imagery shows significant outflow boundaries on the NW side of the circulation which confirms that dry air has been ingested by Irene yet again. This has been a recurring problem from before it was even classified as a TD.

The source of this dry air is probably downsloping winds from the mountains of Hispaniola that are warming and drying and then being sucked into the SW side of the system and then being ejected on the NW side after traversing the entire flow inside Irene.

This will probably result in a steady state for the hurricane for the next several hours until it pulls far enough away from Hispaniola to only have moist ocean air as the power source for the internal hear engine. By tonight Irene should start to strengthen and expand.
Member Since: August 19, 2006 Posts: 0 Comments: 15842
1349. SPLbeater
3:40 PM GMT on August 23, 2011
Member Since: August 4, 2011 Posts: 46 Comments: 4487
1348. smartinwx
3:40 PM GMT on August 23, 2011
Quoting TropicalXprt:


Wow.....You have zero knowledge of fluid dynamics.


But he did stay at a Holiday Inn Express last night.
Member Since: September 22, 2010 Posts: 0 Comments: 88
1347. OracleDeAtlantis
3:40 PM GMT on August 23, 2011
Quoting cat5hurricane:
Irene continuing to entrain dry air into her center from her southern semi-circle, ultimately breaking down her southern and eastern eyewall and thus exposing her inner core to dry air. I expect a slight downgrade to 95mph at the next update from the NHC, at 11am EDT.

However, this does not change the longer-term intensity forecast. The intensification expected may be halted a little, but I still expect this to top out at low-end category 4, with a strong cat 2 or weak cat 3 upon landfall...if she makes landfall anywhere in the U.S.

Prayers and thoughts for those in the Bahamas.

click image for animation
It does, however, potentially shift the track further to the West, agreed?
Member Since: August 27, 2009 Posts: 0 Comments: 525
1346. j0nd03
3:40 PM GMT on August 23, 2011
Wouldn't the cut off low fight the bridging of the bermuda and texas high pressure? This would create more weakness towards the bermuda high allowing Irene to move a little more west?

My first question, sorry if it isn't worded correctly.
Member Since: July 27, 2011 Posts: 0 Comments: 18
1345. libertygirl
3:39 PM GMT on August 23, 2011
Quoting SeanyBoy:
IMO Floridians have every right to be on this blog right now and they should. Models are "Best Guesses" and that is all; NO MODEL IS PERFECT. Obviously, things are looking much better for Florida, but to many wobbles to the West and Florida might get unlucky.

On the other hand if you are a Floridian and your wishcasting Irene to hit Florida you must be crazy. You obviously don't know what a Cat-3 or Cat-4 Hurricane can do, although you "Should".

- Seanyboy :)


Thank you for pointing that out. Having been through every storm since 1985...Georges and Wilma, down here in the Lower Keys - Key West...we have every right to comment and pay attention. Have you ever lost your home and cars to a hurricane and had to deal with FEMA? I have and 25% of the KW pop. when Wilma hit.
Member Since: December 10, 2007 Posts: 0 Comments: 195
1343. wolftribe2009
3:39 PM GMT on August 23, 2011
I am not taking Charleston out of it. I in fact have said they might be the eventual landfall. I am not buying the latest models shifting so far east. Now everybody is firing off fireworks and having parties over thinking it will miss the US now.

BEWARE! The trend this year goes like this. Just when NOAA starts to say something will happen and become convinced that it will; all hell breaks loose and the storm has a mind of it's own to do whatever it wishes that is the opposite of what is being predicted. I find it slightly amusing (Amusing because the weather continues to prove it does whatever it wants to do) that NOAA had the models come out shifting far to the east and then all the sudden Irene shifts west like she knows what they are saying. She is obviously playing with us. She is such a tease lol.

Case in point: Emily and Don
Member Since: July 22, 2010 Posts: 6 Comments: 752
1342. NasBahMan
3:39 PM GMT on August 23, 2011
Quoting wolftribe2009:
I swear the nest person to call IRENE a FISH STORM is going to have a bucket of crow thrown at you by ME! This ISN"T a Fish Storm because she already hit the isalnds in the eastern Caribbean and the Bahamas also are in serious trouble. All this talk of Florida and the Carolinas but no one is talking about Irene's first date partners in the Bahamas.

CAT 3-4 in the Bahamas=Disaster also=NO FISH STORM


Thanks, at least someone on here understands that there are actual people in the Bahamas whose live will be seriously disrupted.
Member Since: August 3, 2001 Posts: 0 Comments: 151
1341. SCwannabe
3:39 PM GMT on August 23, 2011
Quoting rushisaband:



exactly . LMAO ... reality show in the making ?


that's why we're all here...it's FUN
Member Since: August 14, 2007 Posts: 0 Comments: 535
1340. alvarig1263
3:38 PM GMT on August 23, 2011
Quoting rkay1:
Really? Really? You people just don't give up, do you? There's always a chance for it to come your way, right? Go play the lotto, your odds are better at winning than seeing any major changes with Irene.



We'll see, rkay
Member Since: September 2, 2008 Posts: 0 Comments: 744
1339. alvarig1263
3:38 PM GMT on August 23, 2011
Quoting RussianWinter:


I didn't see those things in the models. Those darn "pop-up" storms and unscheduled timings and miscalculations and other minor things that we can't see aren't in the models. They all play a big part in the grand scheme of things, will they always be there? Can we make them more predictable?


It definitely is pretty hard to predict them, but once they are noticed by the models then they can predict where Irene is going to go from there. But as this point anything can happen, and we just need to take Irene one hour at a time until it dissipates.
Member Since: September 2, 2008 Posts: 0 Comments: 744
1337. Orcasystems
3:38 PM GMT on August 23, 2011




BTW.. had a little rant in my Blog about the term FISH STORM, please feel free to look at it.. and give me some ideas. Comment #143
Member Since: October 1, 2007 Posts: 81 Comments: 26511
1336. rushisaband
3:37 PM GMT on August 23, 2011
Quoting TBird78:
I love watching people argue about the weather and predictions. It's like watching redneck cagefights!

It's ridiculous as hell but you can't turn away because it's hilarious!




exactly . LMAO ... reality show in the making ?
Member Since: August 15, 2011 Posts: 0 Comments: 107
1335. Nolehead
3:37 PM GMT on August 23, 2011

CaneHunter031472

The guys at HAARP are probably working overtime. Good job guys you saved Florida. If only this was real and they could also save the Bahamas and NC.


things that make you go hummmm...sometimes the unrealistic could be..just sayin..
Member Since: June 3, 2008 Posts: 0 Comments: 1932

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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.