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

[Sam Sagnella]

TD 9 has formed in the eastern atlantic and should continue generally to the W or WNW over the next few days. All models bring the system north of the islands but now that we have a closed low they should have a much better handle on the track. As the NHC mentions in their 5pm discussion, the depression is forecast to remain in a low-shear environment at least thru the next 48h so strengthening to tropical storm status and eventually hurricane status seems inevitable.

EDIT- There have been too many friggin status changes on this system!

 

[MClarkson]

durring the record year of 1933(21 storms), TS#9 formed on august 24th.

 

[bill mudd]

any hope of monsoon spin off from this fella? havent checked the models yet

 

[Jeff Snyder]

Re: 08/04/2005 TALK: Tropical Depression Nine

the depression is forecast to remain in a low-shear environment at least thru the next 48h so strengthening to tropical storm status and eventually hurricane status seems inevitable.

If there is one thing about tropical forecasting, it's that it is very unreliable. This isn't a comment on the actual forecasts (or the forecasters), but on the "nature of the beast". There is so little data collected over the Atlantic that models are hardy reliable. Through in the fact that tropical system genesis is hardly well understood, and you have the making of a very unreliable beast. Looking at the shearing that is currently taking place of the system, I'd wouldn't be surprised to see it never reach T.S. status.

 

[Anthony Silver]

NHC Quote "...TROPICAL DEPRESSION FIGHTING A HOSTILE ENVIRONMENT..."

I agree with Jeff's statement. Based on what I've seen over the last 24 hours...I don't see very much potential for intensification. If anything it looks like it may crap out or remain at depression status throughout it's lifespan. Jeff stated it very well...these things are very unreliable and can also be unpredictable so things could change in the next couple of days...but right now I don't see that happening.

 

[Jeff Snyder]

Doh! Well, I guess this goes to show just how little I know about tropical system intensity forecasts as well! LOL T.S. Irene was just named.

 

[Sam Sagnella]

NORMALLY BY THIS DATE ONLY TWO NAMED STORMS
HAVE FORMED.

TD 9 has been upgraded to TS Irene as of the 15z advisory. Relatively cool SSTs and moderate shear should hinder strengthening for at least a couple days. I really don't see this strengthening beyond 45kts or so and, given the current environment, I'm actually surprised it attained TS status.

 

[Dan Dawson]

If there is one thing about tropical forecasting, it's that it is very unreliable. This isn't a comment on the actual forecasts (or the forecasters), but on the "nature of the beast". There is so little data collected over the Atlantic that models are hardy reliable. Through in the fact that tropical system genesis is hardly well understood, and you have the making of a very unreliable beast. Looking at the shearing that is currently taking place of the system, I'd wouldn't be surprised to see it never reach T.S. status.

I would agree for the most part, especially for the intensity part of forecasting, which we have very little skill in. You are right, the further out you get in the Atlantic the less reliable the track forecasting is, particularly in cases where you have changing steering flow patterns. Overall, however, track forecasting for Atlantic TC's is pretty darn good nowadays as compared to even 10 years ago.

I'm not sure what to think about Irene right now. These sheared TC's tend to be rather tenacious, taking a long time to completely dissipate, and this one obviously still has a vigorous LLC. As long as it can hang on to that and keep periodic bursts of convection going over its center, as it is right now, it could stand a chance. It's likely to turn north into the weakness in the ridge caused in part by Harvey.

I recall that the models did a pretty good job in forecasting cyclogenesis with Irene. The UKMET and GFS both were consistently developing it when it was still a wave just coming off the African coast, while the NOGAPS never showed much. As a general rule of thumb, when at least 2 models are forecasting development of a wave in the 2-3 day range, it vastly increases the likelihood that they are right.

Dan

 

[Steve Miller]

Irene is sure not looking healthy in the near term with persistent shear but with a little time she might just get going...
The past few runs of the ECMWF show Irene to develop into a tiny hurricane as it moves westward into warmer SST's, then stall the low hanging out in the Bermuda Triangle.
Looks like a Eastern US landfall just north of Florida is possible at this time.
Question still remains - hurricane, tropical storm/depression or rain shower?

 

[Jesse V. Bass III]

Irene is sure not looking healthy in the near term with persistent shear but with a little time she might just get going...
The past few runs of the ECMWF show Irene to develop into a tiny hurricane as it moves westward into warmer SST's, then stall the low hanging out in the Bermuda Triangle.
Looks like a Eastern US landfall just north of Florida is possible at this time.
Question still remains - hurricane, tropical storm/depression or rain shower?

Yep. the ECMWF has started to be consistant on bringing it westward.. The GFS did in the 6z and the 12z seems to loose it but showed a trend westward.. As long as Irene stays weaker, it should continue to come westward.. As a weak sheared storm it will be driven along by the trade winds instead of the mid and upper level steering currents.. Could be interesting come next week..

Jesse V. Bass III
http://www.vastormphoto.com

 

[MClarkson]

Im not to optimistic about this storm. In addition to the decent chance of it just dissipating or staying weak, I think its allready got way too much latitude... and will probably recurve away from the US.

 

[Brett Adair]

I'm still very optimistic of any chance of this thing nearing US soil by about 1200 miles. Don't think it will undercut the trough....looks like a fish to me.

 

[Michael Auker]

The Chesapeake-Potomac Hurricane in 1933 came in at a high latitude. Hurricane Felix in 95 was also a storm that traveled westward at a high latitude. It might be a trait more common in very active seasons?

 

[Steve Miller]

Interesting point on high latitude storms Michael. Both the Chesapeake-Potomac Hurricane in 1933 and Hurricane Felix in 95 were within six days of each other in August. Felix was the 17th and Chesapeake-Potomac was on the 23rd. Interesting timing...
It appears now that Irene will climb in latitude a little over the next 24 hours according to a statement I just read. Storm movement is WNW @ 17kts.

 

[Jesse V. Bass III]

Well the 11 am continues to shift westward. The through also is by passing Irene to the north and east. East coast threat is looking a little more like a reality than not. Could be a hurricane by late weekend..

Jesse V. Bass III
http://www.vastormphoto.com