8/15/05 FCST: Tropical Storm Irene (extratropical)

[Charles Kuster]

Irene is still a tropical depression as of the 5pm advisory, but it seems to be trying to organize some. It is still moving west and NHC's current track takes it northwest and then turns it more to the WNW by Friday, towards the U.S. Hurricane Andrew did a similar thing (moved towards the north/northwest and then turned west) but Irene will probably be further to the north. I am not very good at forecasting but I think a landfall in Georgia or South Carolina is possible. :?:

 

[MClarkson]

hmm the latest global models... gfdl...nogaps...ukmet... have the trough bypassing the storm and leaving irene hanging out somewhere in the vicinity of bermuda with little forward speed in the 5 day range. I wonder why the NHC track is well south of this.

the high off florida... if that can grab hold of irene and loop her west...

 

[Mike Johnston]

Looks like NHC track is S of 3 of the models in their suite, but N of 2 others, and N of the extrapolation of current movement. Per latest forecast discussion, seems NHC is hanging their hat on maint. of Bermuda high; while the models diverge some on this solution, probably a good climatological call. Irene has been called an adolescent in some quarters, notably Hurricane Hollow Network, but a drifting tropical low entering decent environment for intensification over next 2 days bears watching. One of those Outer Banks close calls might yet be in the offing.

 

[Simon Brewer]

If Irene explodes in the next 4 days it will move more to the west and the Carolinas will take a hit by a potentially strong hurricane!

 

[MClarkson]

Things are starting to look interesting... Im in boston right now so a cape hateras landfall might be chaseable. Its a 12 hour drive or so.

 

[Mike Johnston]

Wow. I would encourage anyone at all interested to read the latest NHC discussion on Irene. Very insightful, and very interesting. To take a quote:

"THE GFS 10-MEMBER ENSEMBLE MODEL HAS
MADE A 450 NMI WESTWARD SHIFT AT 120 HOURS."

With the passing hours, concerns of too northerly latitude and entrainment w/ upper trough passages seems to diminish. True - the storm hasn't exactly gotten it's act together (can't even pinpoint the true position of the surface low!), but plenty of time left for spin-up given favorable environment....which position and forecast track indicate will be a very distinct possibility over the next few days. Any indication of approach near Carolinas, and I will be to the OBX or Charleston within hours.

 

[Doug_Kiesling]

Latest NHC forecast shows we may have another diaster by Monday or Tuesday of next week.

 

[Sam Sagnella]

Very happy with the prospects of a possible impact here in CT by Thurs or Fri of next week. Models suggest that the ridge centered near Bermuda will shift to the east allowing for Irene to make a northerly turn. If this holds true, New England will likely see its first tropical cyclone since Floyd in 1999.

 

[Mark Farnik]

Irene has become much better organized overnight and presents a pretty good Visible satellite presentation, even though convection is slighty elongated from NW to SE. Top winds are up to 50 mph, and minimum central pressure is at 1000 millibars. Current motion is west-northwest at 17 mph. At this point the NHC is forecasting Irene to become a hurricane by early morning on Saturday and then they have left the intensity forecast at 75 knots through 120 hours. The reason they give for not showing further intensification is that Irene will be passing through some dry air as it moves towards the Carolinas. From the NHC 11 A.M. discussion:
SSTS ARE EXPECTED TO REMAIN BETWEEN 28.5C AND 29C...AND VERTICAL
SHEAR IS FORECAST BY THE SHIPS MODEL AND THE VARIOUS GLOBAL MODELS
TO REMAIN 10 KT OR LESS THROUGH 120 HOURS. SO THE ONLY INHIBITING
FACTOR AGAINST SIGNIFICANT INTENSIFICATION IS THE VERY DRY
MID-LEVEL AIR THAT IRENE WILL BE NAVIGATING THROUGH. THE OFFICIAL
INTENSITY FORECAST IS SIMILAR TO THE SHIPS MODEL THROUGH 72 HOURS
...AND THEN IS SLIGHTLY HIGHER AFTER THAT WHEN THE SHEAR IS
FORECAST TO DROP TO ABOUT 5 KT WHILE THE CYCLONE WILL BE MOVING
SLOWLY NORTHWARD NEAR THE WARMER GULFSTREAM.

So aside from the very dry mid-level air, everything looks conducive to possibly significant strengthing of Irene. And looking at the forecast models, this air won't be nearly as dry as the air she was contending with for most of her lifecycle. She's a scrappy little storm, and I'm willing to bet that with the low shear and 28.5-29 degree SST's in the Gulfstream, she will overcome this dry air with no problem. Don't forget that Andrew was a tropical depression/storm for a good portion of his life east of the Bahamas, too. You all know what happened next.
The current NHC track takes her to about 200 miles southeast of Wilmington and then curves her north and has her just barely missing Cape Hatteras before she continues toward the Delmarva Peninsula. At this point I'm guessing landfall will be sometime on Tuesday or early Wednesday between Wilmington, North Carolina and Dover, Delaware. Unfortunately, this looks like another potential Isabel to me. And everyone remembers how much havoc Isabel wreaked. Except if Irene overcomes the dry air at mid levels, all the other factors are there for the potential for Irene to be a Cat 3 major hurricane at landfall.
Oh, and by the way, shouldn't we rename this thread Tropical Storm Irene, since she's regained her strength?

 

[Bryan Burkholder]

Irene is just starting to look like an organized tropical system this morning! Convection has been persistent overnight and seems to be exploding at the moment. It appears Irene moved far enough away from the upper level low to its SW that was shearing it apart the past day or so.

I am very skeptical that Irene will have enough time in the shear-free environment to become a major hurricane, as there appears to be an upper low 500 mi east of Miami or so (probably there partly due to the compact high off the GA/FL coast). The track will probably recurve before landfall in the US, though it is definitely not out of the realm of possibilities that it could hit the U.S. A shortwave moving through the northeastern US may weaken the ridge enough for Irene to make Irene drift north a bit. The curve away will most likely happen when the trough progged moving through the northern plains today makes its way east.

The GFDL intensity and track forecast is basically the NHC consensus, recurving Irene just off the coast of Cape Hatteras, NC. The UKMet continues to be further east than the consensus, but has been moving its forecast west with time.

Hopefully Irene will not make landfall, but if it does, it probably won't be much more than a low-end category 2 hurricane. (But that's just my opinion)

 

[Tyler Allison]

AllisonHouse has hi-res satellite images for IRENE for those who want to track the storm. We'll be moving the image rendering as the storm moves.

Links removed since IRENE is dead

 

[Gabe Garfield]

Although the cloud tops of Irene are not particularly cold, the outflow continues to be fairly impressive, especially in the NE Quadrant. It appears that outflow may be somewhat restricted in the future if the northerly shear present off the US coast continues. However, if the shear relaxes, I believe this developing hurricane could present a somewhat signifciant threat to the United States (depending on its storm track).

Gabe

 

[Mark Farnik]

Irene's winds are now at 60 mph, and central minimum pressure has dropped to 997 millibars. An interesting development is that the center has relocated slightly to the east of the previous advisory posistion:
DATA FROM SEVERAL MICROWAVE SATELLITES INDICATE THAT THE CENTER OF
IRENE IS SOMEWHAT TO THE EAST OF THE PREVIOUS ADVISORY POSITION.
The current 5 day track has Irene recurving to the north/northwest, but it appears the weakness in the high that will allow this to happen will fill in about 5 days from now and prevent Irene from recurving northeast and out to sea. The forecast now has the center of Irene about 400 miles southeast of Cape May, New Jersey by 2 AM Wednesday, and if it maintains it's heading from there, New York City might be paid a visit from Irene sometime around the Friday/Saturday time frame. My best guess now is for a Cat 1 hurricane making landfall between Cape May and Martha's Vineyard. This is if Irene is not forced westward into the Carolinas or the Tidewater of Virginia if the weakness fills in more rapidly than predicted. I say Cat 1 due to the uncertainty of whether the northerly shear currently present off the Atlantic seaboard will persist or weaken. This is going to be a very important factor in how strong Irene gets, like Gabe said. If the shear maintains its strength, Cat 1 or maybe even just a strong tropical storm would be a good bet. However, if the shear relaxes, Irene could be much stronger than currently forecast and possibly be a major cane if all the right conditions come together.

 

[B Ozanne]

I know its a little early to talk about chasing, but I am well positioned right now in Avalon, NJ (about 10 miles north of Cape May). I am here until next Saturday and am hoping the pace and course hold so I can see some action. If I am forced from NJ I'll retreat home to coastal Connecticut which is also a decent target.

Water temps in Avalon are in the upper 70's right now, with warmer water just offshore. We are supposed to be in the 90's for the next few days so water temps will continue to hold steady or rise slightly.

 

[MClarkson]

unfortunatly the gfdl is now showing a recurve and total miss... I never trust the BAM and the other models seem to lose the storm.