Category 2 Irene Approaches The Bahamas

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

Share this Blog
19
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1335 - 1285

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28Blog Index


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: Posts: Comments:
Quoting Matt1989:
This has to be the worste forecast I have seen from the models in years. They just keep shifting. And the blob off the Florida coast if it does develope would cause Irene to go farther out to sea.. Not closer to the us

x 100
Member Since: Posts: Comments:
I wonder what the low off the fla ne coast will impact the track of irene
Member Since: Posts: Comments:
1332. 7544
another wobble west going to 72 west soon ?



















/
Member Since: Posts: Comments:
Quoting alvarig1263:


I went through Charley and Wilma living here in SW FL. I know what Cat. 3's and Cat. 4's can do. Lol


Exactly why I said "although you should"
Member Since: Posts: Comments:
1329. Buhdog
Quoting rkay1:
Oh, here we go.  Is it that time already to be mentioning the 1 or 2 storms that are the exceptions to the rules?  Sure, some teams come back from 10 runs down in the 9th.  Guess what? Its rare, next to impossible.  Get over it. 



are you lucreto/stormtop? You are very combative...why spend so much time banging FL people or people in general that are claiming she is slightly south of the forecast point? Did you ask anyone of those people if they also thought it meant anything at all in relation to the path? It is going n and ne eventually...but a 100 miles is a big deal right now. Try tracking with less emotion, it will go a long way if possible.

Member Since: Posts: Comments:
1328. WxLogic
12Z GFS Init:

Member Since: Posts: Comments:
Quoting rkay1:
The FL casters in this blog remind me a lot of the low/middle income family that votes Republican.  When will you learn they don't give a hoot about you?  When will you accept Irene is not coming your way.  You may not even see a cloud from her.  Actually,  it might be sunnier than usual.
I suppose you support the new class we have created....The slavery class.
Member Since: Posts: Comments:
Quoting tiggeriffic:


lots of wind and rain...but still not takin my eyes off her


not even bettin' on that at this point
Member Since: Posts: Comments:
NEW BLOG!
Member Since: Posts: Comments:
1324. Patrap
Member Since: Posts: Comments:
That blob is just some thunderstorms firing at the end of a cold front, nothing much exciting, Irenw ill probably absorb it or push it aside 1 of the 2

The Low is forecast by the OPC to dissipate very soon btw
Member Since: Posts: Comments:
Quoting Matt1989:
This has to be the worste forecast I have seen from the models in years. They just keep shifting. And the blob off the Florida coast if it does develope would cause Irene to go farther out to sea.. Not closer to the us


Not necessarily. Interactions between lows are incredibly difficult to forecast, and as the new blob is moving south, it's difficult to say what effect this could have on Irene's track.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
Quoting Matt1989:
This has to be the worste forecast I have seen from the models in years. They just keep shifting. And the blob off the Florida coast if it does develope would cause Irene to go farther out to sea.. Not closer to the us


Latest TWD as of 12Z indicates it is dissipating, but who knows what's gonna happen next.
Member Since: Posts: Comments:
Quoting rkay1:
The FL casters in this blog remind me a lot of the low/middle income family that votes Republican.  When will you learn they don't give a hoot about you?  When will you accept Irene is not coming your way.  You may not even see a cloud from her.  Actually,  it might be sunnier than usual.


You know, you just have become the first person I have put on ignore in the whole bunch of years I have been a member here. As a matter of fact, now I think is a great time for me to start cleaning the house.
Member Since: Posts: Comments:
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?


Exactly, the NHC's job is primarily to save lives and protect property. It's not a contest on who can predict or forecast better.


NHC Mission Statement

The NHC mission statement is to save lives, mitigate property loss, and improve economic efficiency by issuing the best watches, warnings, forecasts and analyses of hazardous tropical weather, and by increasing understanding of these hazards.
Member Since: Posts: Comments:
Quoting alvarig1263:


Sorry, "picked up" by what?


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?
Member Since: Posts: Comments:
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 :)


I went through Charley and Wilma living here in SW FL. I know what Cat. 3's and Cat. 4's can do. Lol
Member Since: Posts: Comments:
Ugh. Poor timing on the first Wilmington, NC hit in ages. My family is visiting and my house is filled with babies!
Member Since: Posts: Comments:
Quoting JimboUSMC17:


I just don't see how they are plotting the next point that much further north than what Irene is currently positioned at and heading towards.

Think about it this way, yesterday the XTRP had the straight tajectory aimed at Miami-Dade county. Today, the XTRP is south of that. It leads me to beleive that its forward motion is slightly more West than WNW. Maybe somewhere in between. However, according to their next forcast point, they have it maving in between WNW and NW. I agree it is still generally moving WNW, but closer to West than NW.

Hope it makes sense. Until I see that turn more the NW, I still beleive the models should be slighlty West of their current positions.


want another "chilling" statement. The GFDL has been the best model over the last couple years from what i have heard. It kept insisting that the storm would move into Florida for the longest time before finally shifting over the past few hours.

Member Since: Posts: Comments:
Quoting cchsweatherman:


Will be interesting to see what the NHC does with this new data showing significant weakening and deterioration of the inner structure of the hurricane in the next update.


First they will wait to see more of the recon data, only one pass throught the center, there will be several more in the next few hours. No data yet in the SW or NW quads.
Member Since: Posts: Comments:
This has to be the worste forecast I have seen from the models in years. They just keep shifting. And the blob off the Florida coast if it does develope would cause Irene to go farther out to sea.. Not closer to the us
Member Since: Posts: Comments:
1310. Patrap
Member Since: Posts: Comments:
1308. RM706
000
NOUS42 KNHC 231500
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1100 AM EDT TUE 23 AUGUST 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 24/1100Z TO 25/1100Z AUGUST 2011
TCPOD NUMBER.....11-084

I. ATLANTIC REQUIREMENTS
1. HURRICANE IRENE
FLIGHT ONE -- TEAL 72 FLIGHT TWO -- NOAA 49
A. 24/12Z,18Z A. 25/00Z
B. AFXXX 1409A IRENE B. NOAA9 1509A IRENE
C. 24/0930Z C. 24/1730Z
D. 22.3N 73.8W F. 41,000 TO 45,000 FT
E. 24/1130Z TO 24/18Z
F. SFC TO 15,000 FT FLIGHT FOUR -- TEAL 73
A. 25/00Z,06Z
FLIGHT THREE -- NOAA 42 B. AFXXX 1709A IRENE
A. 25/00Z C. 24/2115Z
B. NOAA2 1609A IRENE D. 23.6N 75.2W
C. 24/20Z E. 24/2330Z TO 25/06Z
F. SFC TO 15,000 FT F. SFC TO 15,000 FT

FLIGHT FIVE -- NOAA 49 FLIGHT SIX -- TEAL 71
A. 25/12Z A. 25/09,12,15Z
B. NOAA9 1809A IRENE B. AFXXX 1909A IRENE
C. 25/0530Z C. 25/0600Z
F. 41,000 TO 45,000 FT D. 24.8N 76.0W
E. 25/0830Z TO 25/15Z
FLIGHT SEVEN -- NOAA 42 F. SFC TO 15,000 FT
A. 25/12Z
B. NOAA2 2009A IRENE
C. 25/08Z
D. SFC TO 15,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 3-HRLY FIXES,
P-3 AND G-IV MISSIONS EVERY 12 HRS.

II. PACIFIC REQUIREMENTS......NEGATIVE/ JWP


Member Since: Posts: Comments:
Member Since: Posts: Comments:
GFS soon
Member Since: Posts: Comments:
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 :)
Member Since: Posts: Comments:
Quoting presslord:
tigger...it looks like a reasonably safe bet this won't be a Charleston event...in fact, I think the biggest impact we're gonna feel is some flooding...as we will have high astronomical tides this weekend...


lots of wind and rain...but still not takin my eyes off her
Member Since: Posts: Comments:
1302. 7544
this new low could throw a wrench in the models thay havent seen this yet

also if it gets close enough to irene it could distrupt her and we all know where she could wind up anyone getting dejeve lol
Member Since: Posts: Comments:
Quoting rkay1:
FLORIDIANS OF THE BLOG! Give it a damn rest. It's over. There is no West movement, no matter how much you pray to your raingods. Get over the denial already, its tiresome. Your like that team behind by 10 runs in the 9th inning with 2 outs and still thinking you have a shot.



I for take offense to the sports analogy. the storm may be over for Florida but never quit in sports.
Member Since: Posts: Comments:
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.
Member Since: Posts: Comments:
Quoting cat5hurricane:

Latest IR isn't very promising for Irene as well. I see a significant drop, but probably will retain minimal hurricane strength (80mph).

But if recon is indeed finding that, then that is not out of the question too.


Seems quite reasonable. Would not surprise me to see further weakening throughout the day as the current storm motion as shown by the last few Hurricane Hunter fixes shows the storm closer to Hispanola and moving slower.
Member Since: Posts: Comments:
Quoting Nolehead:

69Viking

Quoting Abacosurf:
That confirms the wobble to the WSW.


How does a storm go from 20.6N to 20.5N and the NHC in their advisory still says it's moving WNW??? Even if it's a wobble the movement from one advisory to the next was to the WSW, why lie about that? I'm goint to laugh if Irena misses the next trough, then who knows where she would end up. Not to mention that "thing" off the coast of Georgia, yep, this is getting to be a fun one to track
!


yes it does!!


maybe NHC just for got to put the S between the W's,since it's been wnw from the getgo pretty much
Member Since: Posts: Comments:
Quoting cchsweatherman:


Will be interesting to see what the NHC does with this new data showing significant weakening and deterioration of the inner structure of the hurricane in the next update.


I think they'll be reluctant to lower the wind speed, as it may make people complacent when in reality Irene could still strengthen a lot when it gets away from Hispaniola.
Member Since: August 10, 2010 Posts: 2 Comments: 1971
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?


It's the result of a pretty big thunderstorm complex that came off shore last night, but looks like it might have detached from the front.
Member Since: August 14, 2007 Posts: 0 Comments: 535
The next forecast point for Irene seems too far north.

The 7 PM track might have SC under the gun.
Member Since: Posts: Comments:
Looks like Irene is following in parallell the coastline of Hispaniola.

Member Since: August 4, 2010 Posts: 0 Comments: 140
Quoting SCwannabe:


I live in CHS and I'm still a bit nervous...


im in Chas too...and will not start feeling better untill she is due east of me and still trucking... worried that hispanolia is gonna cause more shifts...and not only that...this thing is pretty big...even if she ran the coast and was 60 miles out we would still get some vicious storms for a while
Member Since: Posts: Comments:
if she does weaken to a ts it would def effect the models as their expectingbher to be a major in the next 24hrs,big differnce in sterring a ts and a major,only time will tell,im guessing it wont happen and she'l go outto sea
Member Since: Posts: Comments:
I don't think the storm will hit S. FL unless it makes some crazy drastic move, but I do think it will skirt the coast closer than they are predicting with the forcast path.
Member Since: Posts: Comments:
1287. Patrap
Member Since: Posts: Comments:
Quoting rkay1:
SPECIAL UPDATE: The only way FLORIDA will be effected is if it detaches from America and floats about 250-300 miles East.


You, sir, obviously DIDN'T live thru JEANNE!
Member Since: Posts: Comments:
it should be noted that the "westward" motion is taking Irene into much warmer water. The area just east of south florida is extremely hot compared to areas further to the east.
Member Since: Posts: Comments:

Viewing: 1335 - 1285

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Overcast
29 °F
Overcast

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron