8/27/04 FCST: Frances (Atlantic)

[B Ozanne]

Mike, you're preaching to the quire here. I still think we should keep the forecast thread on topic...ranting and raving can commence over in Weather and Chasing. I've already started.

Back to the forecast, does anybody see that shear dying down? When?

 

[Mike Peregrine]

Per the latest forecast advisory just posted a few minutes ago ...

Movement is 295/05 kts ... estimated pressure is now up to 960 MB ...

The latest discussion mentions interpretation of the models' handling of the current shear pattern and entrainment, which is forecast to last another 18-24 hrs ... meanwhile the hurricane is trapped against the mid-level ridge to the north that is expected to keep it extremely slow moving over the next 36 hours. They are expecting only slight intensification as the storm passes over the Gulf Stream and now seem to be primarily concentrating on rainfall forecasts.

http://hurricane.terrapin.com/text/1094281...1US.TXT.html.en

 

[Jason A.C. Brock]

Well I am not good at hurricane forecasting at all lol. These things seem to be nearly impossible to forecast in all aspects. it did slow as I thought it would but weakening as much as it did I did not expect at all!
Still this storm will cause some very bad flooding due to its slow speed. I am about to call it quites on my hurricane forecasting lol.
The strike area is a tad further north thatn I thought but within my area I thought it might hit. I had expected a bit more of a left hand turn.
What I thought was the eyewall recycling was actually dry air intrusion trying to slowly choke the monster.
Still nothing to sneeze at but I would also be drawing my attention to Ivan which could take a more Southern Track and even go into to Gulf?
An interesting scenario nonetheless. T.A.S.C. has enjoyed tracking Frances and I think we will also begin tracking Ivan which should become a weak hurricane by tomorrow evening but a new thread should be made for that soon.
We still will have our Tropical weather page on the T.A.S.C. site until Ivan and Frances have dissipated. I added a position and projected storm track map which will update to our Hurricane Frances page for tropical storm Ivan. Just scroll to the rght to check them out.
Ill add more detailed maps on Ivan as Frances dies out over the weekend.
Again everyone stay safe and those chasing this thing be safe as well. I am interested to see f we get any Live feedback in the now thread.
http://www.texhomastormchasers.com
Click the hurricane Frances link page.

P.S. We have also added our summer time chase reports as well as astronomy pics to the T.A.S.G. page for those interested.

 

[Nick Smith]

I recall seeing the tops from thunderstorms over Cuba and adjacent waters blowing northeastward on Wed/Thurs. At first, I thought this was being created by the anticyclonic outflow of Frances, but it now appears that was southwesterly winds not related to the hurricane.

 

[Joel Wright]

I look for it to start to get stronger, possibly as high as a high end cat 4 before it begins to weaken while it makes the right turn towards the Carolinas. Hopefully it weakens to a cat 2 at least before it threatens there.

This is pretty much what I expected all along. Although I expected it to turn sooner and run up and hit the Carolinas. Major hurricanes that turn right weaken considerably almost every time..

 

[Kevin Scharfenberg]

A good indication of dry air in the area yesterday was the Miami observation of a dewpoint drop when some convection moved over (note the dewpoint fell to 68F from 77F after a shower). The convection appears to be wrapping more around the center of the storm based on radar, so perhaps there is still some window for strengthening. It still has 12-15 hours. Note that the AMX (Miami) radar is apparently not calibrated correctly (too "cold").

Based on a weaker hurricane, we are setting up one of the two SMART radars at Merritt Island airport, and the other at Space Coast airport. We're leaving the hotel shortly to begin ~24 hours of data collection. Good luck to all.

 

[Mike Peregrine]

It really seems like the dry air intrusion would have a greater weight on the hurricane's weakening than the shear issue ... where did the shear come from? - It wasn't the ridge to the north at the time - it was still too far away to have an effect by the time the hurricane really started to putter ... and the soundings from Florida ahead of the storm showed completely unidirectional winds out of the east Wednesday night (I'm sure the plots are still around somewhere to take a look at). So either the shear was the result of some localized phenomena or maybe the UL winds were entering the storm from the SW because of another ridge on the other side of the storm?

Either that, or shear shouldn't be focused on as the primary factor for the storm's weakening and instead it should be the dry air as Kevin and several others have mentioned.

There is still the possibility that the storm will strengthen a bit as the current situtation shear tapers off. The question remains if dry air will continue to evaporate moisture ahead of the system or whether there will be juice as it sits in a favorable environment for development.

 

[Thomas Loades]

The latest VIS image from 0715 EDT is interesting in that it shows fairly strong convection to the W of the center, somewhat less strong convection to the E, and a narrow "wedge" of subsidence between the two. I don't know whether that's another eye trying to form, or just more dry air being sucked in, but there is cloud in that "wedge."

NHC's latest advisory now speaks of "large hurricane Frances" — apparently no longer dangerous.

 

[B Ozanne]

I'm watching a radar loop right now and the "eye" hasn't budged an inch. It will be interesting to see what the TPC says at 11am.

Also, there is a clearing or lowering of cloud tops appearing within the eyewall...worth watching.

 

[Kevin Scharfenberg]

I'm at Merritt Island airport on a high speed internet connection. Sweet! Winds here have gusted as high as 60 kts so far. No water problems to speak of, and only a little rain. Looking at radar, it's only a short time before the fun begins.

 

[Bob Schafer]

The way she's reconstructing a distinct eye and becoming much more symmetrical, is upgrade to cat3 imminent?

[edit] From scanner: "Large blue crane about to fall at construction site"

What idiots left a crane standing??? Grrrrr

 

[B Ozanne]

I think an upgrade is a real possibility. The biggest indicator is that the eyewall appears to be constricting.

A side not, there has always been an eye, it is appearing to be more substantial because the eye is getting closer to the radar site. Before there was only half an eye wall because the radar was looking above the other half.

 

[B Ozanne]

Where is everybody? Let's get some more action on this site and the NOW thread.

YES...I am seeing ocean on the visible satellite in the eye!

 

[rdale]

"it is appearing to be more substantial because the eye is getting closer to the radar site. Before there was only half an eye wall because the radar was looking above the other half."

No, the southern end (which had limited convection) is closer to KAMX than the north side. You can clearly see on the loops that convection is filling in on the south side, which is nearer the radarsite.

- Rob

 

[Bob Schafer]

Gotcha...but I was referring to various sat imagery, but you're entirely correct. The way she's going, I wouldn't be surprised if we can see straight down to the sea on vis soon. That's very different from about the past 48 hours.