07/05/05 -- TALK: Hurricane Dennis

[Ben Cotton]

The 11AM discussion of TD Four bumps it up to TS Dennis. This is the first one to form outside of the GoM this year. I'm not too hip on my tropical history...is it common for the Gulf to dominate the early part of the season? This is also the earliest the Atlantic basin has had 4 named storms, per TPC. If you'll recall 2004, Danielle didn't come around until August (nor did Bonnie and Charley), so this year is well ahead of last year's pace.

Right now, the offical forecast strengthens Dennis to a hurricane and then takes him over Cuba. It looks like, at this point, Dennis will head for the FL panhandle area...but that's a good week out, at least. Dennis' track is a little east of Charley's last year...so time may bring him closer to the Florida peninsula. Barring thermonuclear war, this will be the first tropical system with enough time and water to really get cranked up, so it should be a good one to watch.


Ben

 

[Thomas Loades]

It's looking rather interesting already; there's much sharper outflow than Cindy's (more shear?) and you can already see a kind of eye. This one ought to be interesting, indeed.

 

[MClarkson]

its july 5 and we are on D. Thats pretty unusually, I believe.

Dennis has time over moderatly warm water and low shear, so its prospects of organizing into a hurricane are better than the previous storms. This is really the first interesting storm of the year. I'll be watching this one... although I still think its too early in the season for anything large.

 

[Glen Romine]

its july 5 and we are on D. Thats pretty unusually, I believe.

First time since close records began, apparently.

TROPICAL STORM DENNIS DISCUSSION NUMBER 3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT TUE JUL 05 2005

BANDING FEATURES ARE BECOMING BETTER DEFINED AND...BASED ON A DVORAK CLASSIFICATION OF T2.5 FROM TAFB...THE CYCLONE IS BEING NAMED. THIS IS THE EARLIEST DATE EVER TO HAVE FOUR NAMED TROPICAL CYCLONES IN THE ATLANTIC BASIN.

 

[Owen Shieh]

Last time there were 4 named storms before July 15 was 1959. However, this says nothing about this season being more active. For example, 1997: 4 named storms by the end of July, but a really quiet season overall. Of course, that was during an El Nino year, so naturally, Atlantic tropical cyclone activity would be supressed. This year, we don't have that, so chances are, we will have an active season. Overall convective activity over the tropical Atlantic and the Caribbean have been abnormally high for June and July. If it weren't for harsh upper-winds, we would have gotten even more storms already. You can see a hint of the Saharan Air Layer in the deep Atlantic right now, so that indicates an inversion, something equivalent to a giant cap over that area right now (hence, not much activity between the Leeward Islands and Africa).

Dennis is sitting under the upper-level Sub Equatorial Ridge, which is very favorable for development, and the TUTT low just north of it is helping with the outflow. However, if it moves too fast, it may get under the Subtropical Ridge over Cuba/Florida that is subsident, so it would tend to inhibit rapid development. But for now, Dennis has the greatest potential out of all the storms that we have seen this year. It could very well be our first hurricane within a couple days.

And yes, the Gulf and northwest Caribbean are normally most active in June. In July, you get some development to the east of Florida and the east of the Leeward Islands, but new research has shown that the northwest Caribbean temporarily quiets down in July. The Gulf still remains active in this month.

 

[Kyle Masters]

Well according to my statistical search, it appears that in the July calendar month, there is on average 1 HURRICANE (not tropical storm) that forms outside of the Gulf every 1 or 2 years, so it's not horribly unusual, but there wasnt one last year, so it's on the outside of those stats.

 

[Alex Lamers]

18Z GFDL takes Dennis' 950 mb winds to category 4 strength before it hits cuba...might be overdoing the weakening as it crosses Cuba (its rather thin after all). NHC is forecasting it to reach major hurricane status now as of 10 PM advisory with category 3 strength invof Cuba.

...Alex Lamers...

 

[Owen Shieh]

Yeah, Dennis is about ready to take off. There's nothing going against it right now. Cuba's affect on it would depend on where it ends up hitting the country. Eastern Cuba is mountainous, so that would do more to disrupt the circulation. If it crosses western Cuba, then yeah, nothing much in the way of a disruption would happen, and it would continue plowing along as a major hurricane. This could be bad news for Florida residents......again. I'm imagining either an Ivan or a Charley track with this thing.

 

[Mike Hollingshead]

http://www.rap.ucar.edu/weather/model/gfs1...2hr_850_wnd.gif

Hmmm, why am I even considering this? Not a good forecast for New Orleans.

 

[Kyle Masters]

Heh...gotta love this from the recent discussion:

DENNIS IS EXPECTED TO REMAIN IN A VERY LOW SHEAR AND HIGH SST ENVIRONMENT..WHICH UNFORTUNATELY ARE PRIME CONDITIONS FOR PRODUCING INTENSE HURRICANES.

Looks like they are really playing this one up, with a steady intensification with the reorganization of the deep convection at the core of the system. Looks like 72 hrs will be the max (relatively, forecasts only go 120 hr) of 100 KT sustained surface winds. Ouch.

Yeah, New Orleans isn't going to be too happy...lol

 

[Kyle Masters]

Ooohhhh...

Looks like the first look at an organized eye on the IR imagery. Really tight right now, so expect it to widen as the circulation increases.

 

[MClarkson]

Id imagine the layer of warm water cant be all that deep since it is early. I wonder how long an intense cane could last this time of the year before its waves mix up too much cooler water. Its moving pretty good now but it will likely slow down when the steering currents decrease as the ridge weakens for its turn towards the north.

the 06/00Z gfdl keeps it pretty intense the whole way... if that plays out it this one might be worth the long chase(im in boston not florida right now).

 

[Chris Hayes]

5 AM discussion has it becoming a Cat 3 in 72 hours. Possibly reaching cat 4 strength after that. Anyone know what the Gulf of Mexico water temperatures are like?

 

[Thomas Loades]

The waters are consistently warm, around the 80s; you can check the image here.

Dennis certainly looks more organized — there look to be concentric rainbands developing now; the latest discussion is calling for it to slow down, so I'd say we'll have a hurricane on our hands by the end of the day.

 

[Brett Adair]

Dennis is looking very organized this morning with symmetrical convection already wrapping around a tightly stacked cyclone SE of Jamaica. I still like the NHC track a bit, but I do believe due to the ridge being cut a bit that this track will move further west as Dennis crosses into the Gulf of Mexico. Looks like I will definately be feeling the effects of Dennis here early next week in my Central Alabama location.