ATL: KATIA - Post Tropical - Discussion

[GCANE]

A ridge will be building over the Great Lakes and could set up a Bermuda High when this gets close to VI / PR area.

I don't think it is a given that the EC is in the clear at this point.

[Nightwatch]

it's already TS Katia

Says who?

My mistake, forgot the questionmark in it. Sorry

[Swimdude]

Joe Bastardi tweets that the models will trend west and we may have another east coast threat in 10-15 days.

1) Keep in mind that JB very often says this kind of thing. How often do you hear him say the opposite? Also, all he says is that it MAY then be a threat. That's not really committing to anything, regardless.

2) JB was not as much of a guru on Irene as he leads us to believe. Initially, he had it as a big FL
threat per his tweets.

In his defense, the NHC also had Irene going straight up the spine of Florida.

But I also can't count how many times I've heard this over the years from JB...

[RL3AO]

Lets keep it on topic. This isn't he "Complain about JB thread".

[alan1961]

Yes certainly evidence of easterly shear with exposed centre
and the convection to the west of the circulation.

[GCANE]

Yes certainly evidence of easterly shear with exposed centre
and the convection to the west of the circulation.

Its half naked.

http://rammb.cira.colostate.edu/products/tc_realtime/loop.asp?product=1kmsrvis&storm_identifier=AL122011&starting_image=2011AL12_1KMSRVIS_201108290745.GIF

[perk]

Not to mention its at total odds with the GFS/ECM, which at this range tend to be the two models that need to be most closely watched.

Agreed. The CMC is generally an inferior model. I'm still going with a 90% chance of a recurve east of the continental U.S. The western Atlantic is forecast to be pretty void of the high pressure needed to bring a TC far enough west.

90% recurve 10 days out, i think you're over shooting the runway.

[Aric Dunn]

Actually, I do think this will be at least a NE carrib islands threat. The models continue to show this mid to upper level low moving developing then moving west well to the north of TD 12. however I am questioning the strength and the duration this feature will last. The euro keeps bouncing between this feature being stronger and weaker. 00z last night had it a little stronger and thus td 12 turned more WNW towards the end of run 12z yesterday had it weaker and the turned less. the nogaps barely keeps the feature around for more than a couple days as is very weak. I believe that due to the easterly shear forecast for the next few days this mostly mid and upper level feature will have little affect and td 12 should stay on a more westerly track.

I also think the models are way over doing the the duration of the weakness over the western atlantic due to Irene. So as for a east coast threat its not out of the question.

[gatorcane]

Latest SFWMD plot. Notice that the models want to bring it WNW now even though it is moving west (see XTRP line):

[gatorcane]

Aric good points. This retrogading upper-low the models are latching onto is quite an interesting feature and the strength of that low will be key as to how much the ridge breaks down. Also, considering how far out in the east Atlantic this system is, it is too early to say whether the CONUS will be impacted. For now, models are suggesting a recurve, but will not put much faith in them right now being so far out.

The Central Atlantic ridge does look weaker than normal, but if this system continues to move west over the next couple of days without gaining much lattitude as models suggest, the threat to the NE Leewards does increase.

[painkillerr]

Looking at the set-up aloft it looks like a big risk down the line to Bermuda...I suspect anywhere else other then maybe E.Canada should be *ok*.

As I said in the model thread, its a track that probably the NE Caribbean needs to keep a close eye on, I think it should clear the islands to the north but then again the models thought the same with Earl last year and that had a mighty close call.

I expect a slightly further west version of Danielle from last year.

I agree with the Earl analogy. It was forecasted to recurve but it kept moving west and finally passed just north of St. Thomas and slammed us with 75mph wind and rain. It was a very close call.

[SouthFloridawx]

[BigA]

Looks like as of now, the models suggest recurve, but do not necessarily scream it.

Here is the tropical atlantic model plot linked. I can't find a way to post an image of it

http://tropicalatlantic.com/plots/12-googlemaps.shtml

[gatorcane]

Looks like as of now, the models suggest recurve, but do not necessarily scream it.

Here is the tropical atlantic model plot linked. I can't find a way to post an image of it

http://tropicalatlantic.com/plots/12-googlemaps.shtml

[southerngale]

BigA... it opens up as a blank map, but anyone can easily add the models they want to see. Thanks.

If you want to post an image of something that you can't right click and save, take a screen shot (print screen button usually in top right of keyboard), open your Paint program, press CTRL + V to paste it into paint, then crop it to take out excess clutter from your screen, save it, and upload it. I do this all the time and it's really quick once you get used to doing it. Hope this helps.

[Aric Dunn]

Aric good points. This retrogading upper-low the models are latching onto is quite an interesting feature and the strength of that low will be key as to how much the ridge breaks down. Also, considering how far out in the east Atlantic this system is, it is too early to say whether the CONUS will be impacted. For now, models are suggesting a recurve, but will not put much faith in them right now being so far out.

The Central Atlantic ridge does look weaker than normal, but if this system continues to move west over the next couple of days without gaining much lattitude as models suggest, the threat to the NE Leewards does increase.

Yeah notice some of the consensus tracks continuing the WNW and almost west motion at the end of run. Dont think the models have a very good handle on the evolution of this weakness left over by Irene. the models are all spitting out multiple lows out of the same area effectively keeping that weakness. Not sure that is likely to occur.

[Aric Dunn]

Also notice the almost complete lack of any Sal. The last few systems that came off africa had a good deal of moisture that was well north to the southern desert.. not if there was measurable rainfall lol but its sure stopped the flow of dust. Dry air wont be a problem with the next few waves ... at least not from the SAL

[jhpigott]

Is that TD12 just entering the picture on the right side of the frame?

http://rammb.cira.colostate.edu/ramsdis ... 4km_visir2

[Riptide]

Is that TD12 just entering the picture on the right side of the frame?

http://rammb.cira.colostate.edu/ramsdis ... 4km_visir2

Indeed.

[wxman57]

Also notice the almost complete lack of any Sal. The last few systems that came off africa had a good deal of moisture that was well north to the southern desert.. not if there was measurable rainfall lol but its sure stopped the flow of dust. Dry air wont be a problem with the next few waves ... at least not from the SAL

http://tropic.ssec.wisc.edu/real-time/sal/splitEW.jpg

I think that SAL graphic demonstrates that the Bermuda High to the north of 12 is considerably weaker than it was as Irene moved through the same area. I saved that image:



While I think that "Katia-to-be" will most likely pass a few hundred miles north of the eastern Caribbean, I wouldn't turn my back on it if I lived there. Kind of like staring down train tracks at an approaching train and having someone tell you not to worry because they're pretty sure the switch had been thrown to turn the train.

Long-term, it's way too early to be very confident in a recurve near Bermuda or any east U.S. threat. Recurve is most likely, maybe, possibly, but I'm not confident of that.