ATL: KATIA - Post Tropical - Discussion

[gatorcane]

Well things may be getting a little interesting here. The 12Z GFS did eventually recurve but way out in the long-range which is quite unreliable. From 120 to 168 hours, it is painfully moving every so slowly WNW to NW north of the Leewards, not recurving as quickly as it was in the previous runs, and there looks to be ridging trying to build in on top over Eastern Canada and the northern Western Atlantic.

The NOGAPs and CMC runs are quite interesting and are way west of the GFS and ECMWF right now. If the ECMWF shifts west on the 12Z significantly, watch out. Ironically enough a couple of days ago it was calling for NOGAPs-like track.

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[Swimdude]

She has to be a hurricane now.. the curved band has wrapped completely around the center and intermittent eye features keep popping out. actually as though she is about to start bombing out. with all the dry slots filling and overall CDO becoming more symmetrical.

http://www.ssd.noaa.gov/goes/flt/t2/loop-rgb.html

At least on visible, Katia is definitely MUCH more symmetrical than she was just 3-4 frames ago.

[Aric Dunn]

The evolution of Katia during days 3-5 is going to greatly hinge on those two troughs in the above mentioned text from the disco. Shear values look high and that trough doesn't look like it's going anywhere anytime soon.

if you look at the WV loop of that image you will already see the ULL your circled turning NW. that one is out of here the one near NC will follow suit once the east one starts moving N and NNE.. and the one you circled should also begin to weaken during this process as well.

[Aric Dunn]

She has to be a hurricane now.. the curved band has wrapped completely around the center and intermittent eye features keep popping out. actually as though she is about to start bombing out. with all the dry slots filling and overall CDO becoming more symmetrical.

http://www.ssd.noaa.gov/goes/flt/t2/loop-rgb.html

I actually have to disagree with you. It does still look well organized on vis, but IR doesnt look too pretty right now. After a couple hours it may be a different story though. I still wouldnt be at all surprised to see an upgrade at 5 or 11 tonight.

I agree this is the early stages but microwave images depict and eyewall forming and ir does not tell you if you have hurricane force winds.. look at IRENE it looked terrible most of the time but still have cat 3 winds. and when it first became a hurricane it really looked bad. you have to look to see if there is a curved bad that has wrapped all the way around and evidence of a eyewall forming. all of which exist now.

[stewart715]

She looks more organized than she is, but I believe at 5PM they'll make the Cat 1 declaration.

[Aric Dunn]

wow really.. CMC large ridging even more than the 00z run!!! west turn and likely after that straight west to florida.

12z
http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[stewart715]

Actually looking decent:

[AdamFirst]

I said a few pages back that these runs were reminding me of Frances even before a bend back to the west.





Let's see what KING EURO says.

[BigA]

wow really.. CMC large ridging even more than the 00z run!!! west turn and likely after that straight west to florida.

12z
http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

Yeah, the weakness looks to be closing up really fast at the end of the CMC run.

Also, FIM model running now. Turning back toward the west around 4 days, but the run is not done.

[gatorcane]

wow really.. CMC large ridging even more than the 00z run!!! west turn and likely after that straight west to florida.

12z
http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

Yeah Aric, I see that, it seems that weakness is closing up pretty quickly there and a huge ridge is moving in from the United States west towards the Western Atlantic. Seems like it would head into the Bahamas and Florida after that.

The CMC is usually good with synoptics, just need the GFS or ECMWF to jump on board before I start believing these westward shifts.

[Aric Dunn]

wow really.. CMC large ridging even more than the 00z run!!! west turn and likely after that straight west to florida.

12z
http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

Yeah Aric, I see that, it seems that weakness is closing up pretty quickly there and a huge ridge is moving in from the United States west towards the Western Atlantic. Seems like it would head into the Bahamas and Florida after that.

The CMC is usually good with synoptics, just need the GFS or ECMWF to jump on board before I start believing these westward shifts.

well to be honest. the gfs did shift west a lot and I bet when the ensembles come out that more take to the west again like the 00z and 6z ..

watching the spaghetti plots to update..

[fci]

Yeah, CMC and NOGAPS seem to be telling us not to write off Katia as a recurve just yet.......

[rainstorm]

i think it can be summed up this way. the models showing lee hitting texas/mx will have katia futher west. the ones showing lee headed into the SE and up the coast will show katia recurve.

[ouragans]

eye starting to show its self again....http://www.ssd.noaa.gov/goes/f ... p-rgb.html


also looks like its heading a little more on a 280 heading over the last couple hours... which would not surprise me given the strong ridging building in north of it..

http://tropic.ssec.wisc.edu/real-time/a ... g8dlm2.GIF

The above situation reminds me a lot 1998 with Georges, except that it was already a cat.4 when it got "stucked" on the ridge, then was "forced" to bend WSW for 36hrs to the northern Leeward Isl (righ over Sint Maarten. It even weakened during that process, but re-strengthened to cat.4 before reaching the islands.

EDIT: My bad, it was Luis in 1995, which hit hardly Sint Maarten

[Aric Dunn]

Yeah, CMC and NOGAPS seem to be telling us not to write off Katia as a recurve just yet.......

as well as the GFDL 6z had a slight westward bend at end of run. and now the GFS shift a lot to the west. so far today seems a trend west.. from yesterday

[SouthFloridawx]

There certainly is a big surface ridge. What about the 500mb ridging. Still a pretty healthy trough eroding the ridging.

[caribepr]

Off topic, but timely, I believe if you'd like a little humor with your weather (or not) prognosticating

http://www.cnn.com/2011/OPINION/08/29/o ... index.html

[Aric Dunn]

There certainly is a big surface ridge. What about the 500mb ridging. Still a pretty healthy trough eroding the ridging.

[img]http://img69.imageshack.us/img69/9522/595100.gif[img]

right but its the ridging that is sliding off the east coast. the atlantics erodes but the other ridge begins to fill in as that trough clearly lifts out ..

[fci]

Yeah, CMC and NOGAPS seem to be telling us not to write off Katia as a recurve just yet.......

as well as the GFDL 6z had a slight westward bend at end of run. and now the GFS shift a lot to the west. so far today seems a trend west.. from yesterday

Well, I am admittedly selfish and concerned about a possible similarity to a certain storm with an "A" name; and a possible effect where I live in South/Central Florida.
Of course, I worry about further up the coast still reeling from Irene, but I look selfishly at where I live first.
Just being honest............

[SouthFloridawx]

There certainly is a big surface ridge. What about the 500mb ridging. Still a pretty healthy trough eroding the ridging.
[img]http://img69.imageshack.us/img69/9522/595100.gif[img]

right but its the ridging that is sliding off the east coast. the atlantics erodes but the other ridge begins to fill in as that trough clearly lifts out ..

It's going to be interesting to see the actual evolution of those features and to see the eventual track of Katia. Will it be too far North in between those ridges or will it get caught underneath the one moving westward?