ATL: KATIA - Post Tropical - Discussion

[Aric Dunn]

Ahh. now she has made a big turn on the 12Z ECMWF, bending W to even WSW....that makes more sense

Look at that big 500MB ridge overtop of her now...wonder how far west she goes this time???

[img]http://img683.imageshack.us/img683/4810/12zeurotropical500mbslpm.gif[/mg]

yeah seriously I was beginning to wonder.. lol

[SouthFloridawx]

[img]http://img820.imageshack.us/img820/969/gefsspagatlantic192mslp.gif

Lol, what is that? Looks like 1st grade art class?

COLORSSSSS

BTW thanks... I needed the laugh.

[gatorcane]

There doesn't appear to be any troughs left over the U.S or Canada, except if future Lee over the northern GOM amplifies a weakness and pushes it west.

Notice the High pressure cells building over the Great Lakes...

Trough is trying to lift out over SE Canada.

[Aric Dunn]

There doesn't appear to be any troughs left over the U.S or Canada, except if future Lee over the northern GOM amplifies a weakness and pushes it west.

Notice the High pressure cells building over the Great Lakes...

Trough is trying to lift out over SE Canada.

yeah was about to post that. but yesterday this happened and in the next 24hrs it was heading NNE and all the ridging was gone replaced by a large trough... lol

[gatorcane]

OK 168 hours, looks like she should start to turn...but look she got further west this time. Seems like each time the Euro bends her west, the farther west she is getting, after 168 hours, model guidance is quite inaccurate anyways.

[Aric Dunn]

OK 168 hours, looks like she should start to turn...but look she got further west this time. Seems like each time the Euro bends her west, the farther west she is getting:

[img]http://img694.imageshack.us/img694/2365/12zeurotropical500mbslpv.gif[img]

yeah see what I mean .. went from strong ridging with more building over great lakes .. then just 24 hrs later boom everything switches to a trough.. must be the fastest moving trough ever.. lol

http://raleighwx.americanwx.com/models/ ... _loop.html

[SouthFloridawx]

Holy Crap!

Someone used to do that...

[Meteorcane]

It is just me or does the ECMWF seem to be getting slightly closer to the Bahamas and the CONUS with each run.

[gatorcane]

OK 168 hours, looks like she should start to turn...but look she got further west this time. Seems like each time the Euro bends her west, the farther west she is getting:

[img]http://img694.imageshack.us/img694/2365/12zeurotropical500mbslpv.gif[img]

yeah see what I mean .. went from strong ridging with more building over great lakes .. then just 24 hrs later boom everything switches to a trough.. must be the fastest moving trough ever.. lol

http://raleighwx.americanwx.com/models/ ... _loop.html

Yeah something is not right. We go from High pressure across the Great lakes and Northeast and just 24 hours later, a huge trough along the Eastern seaboard as if it were December...hmmmmm, and its 192 hours so we know its inaccurate that far out.

But the trend is west, because yesterday's 12Z Euro was not this far west...

[Aric Dunn]

192 hours starts to turn..watch out carolinas.. if the trough misses it

http://raleighwx.americanwx.com/models/ ... _loop.html

[gatorcane]

Yep, its turning but alot closer to the United States this time probably misses Carolinas and heads NNE then NE, but what a shift from yesterday's 12Z run, more west.

Again where did that huge trough come fro SE Canada digging down the Eastern Seaboard of the U.S. Not following the Euro on that.

[Nimbus]

Her low level circulation seems to be running west out from under the convection. I was going to wait to see if that would bring her track through the northeast corner of the Caribbean Hebert box before speculating on any US landfall.

[ouragans]

Best track shows 15.8N 48.6W 65 knots... seems that she's back on WNW 285 deg 11kts

I was sure also Katia would be downgraded to TS by 18z

I wonder if the center has not been relocated NE of the previous location

[jhpigott]

Yep, its turning but alot closer to the United States this time probably misses Carolinas and heads NNE then NE, but what a shift from yesterday's 12Z run, more west.

How much further west are we talking about on the 12z run compared to the 00z run? 50, 100, 200 miles?

[gatorcane]

Shifted west about 150 miles it looks like?

12Z Euro yesterday, 216 hours:

12Z Euro today, 192 hours:

[SouthFloridawx]

That trough looks completely different in those two graphics. It's a lot more vertical and yesterday's was much more horizontal or zonal. Not sure what you would call a trough that is more vertical than one that is Zonal.

[Aric Dunn]

Ridging still building westward with katia.. explains the continued west motion.... looks like its build even more filling the gap a little as that trough lifts out.. also maybe some help from the outflow from 94L


low level steering..



mid to upper level when she is deeper... either layer indicates continued west to wnw motion.. no turn with that north of it.

[SouthFloridawx]

Gator, wouldn't you compare it to a frame that is 24 hours less. Let's say I wanted to compare and see how accurate yesterday's 12Z Euro was 24 hours later.

Ex:
Yesterday's graphic I would look at is the 8/31 12Z @ 24h.
Today I would look at the 9/1 12Z @ 00h.

So you would take yesterdays 216 Hour
and
Today's 192 Hour.

No offense intended btw

[Fego]

Oh well, according with RAMBB-CIRA, looks like Katia have gained some decimals.

[gatorcane]

Gator, wouldn't you compare it to a frame that is 24 hours less. Let's say I wanted to compare and see how accurate yesterday's 12Z Euro was 24 hours later.

Ex:
Yesterday's graphic I would look at is the 8/31 12Z @ 24h.
Today I would look at the 9/1 12Z @ 00h.

So you would take yesterdays 216 Hour
and
Today's 192 Hour.

No offense intended btw

Yeah that is what I intended, wrong graphic though. I just updated it.