ATL: KATIA - Post Tropical - Discussion

[cycloneye]

Saved image.

[cycloneye]

That is why we dont change the title of threads when best track updates are released until is official because anything can happen. like this:

AT THE TIME OF THE SATELLITE FIXES AT 00Z...A LARGE CURVED
CONVECTIVE BAND WRAPPED ABOUT HALF WAY AROUND THE CIRCULATION...
WHICH RESULTED IN SATELLITE INTENSITY ESTIMATES OF T2.5/35 KT FROM
SAB AND T2.0/30 KT WITH A DATA-T NUMBER OF 2.5/35 KT FROM TAFB.
HOWEVER...SINCE THAT TIME THE CURVED BAND HAS DISSIPATED...AND THE
CONVECTIVE PATTERN HAS DEVOLVED INTO MORE OF A SHEAR PATTERN. A
SMALL BURST OF DEEP CONVECTION HAS DEVELOPED OVER AND JUST WEST OF
THE CENTER...BUT ONE THUNDERSTORM DOES NOT MAKE A TROPICAL STORM.
THEREFORE...THE INTENSITY IS BEING HELD AT 30 KT FOR THIS ADVISORY.

[HurricaneWarning92]

I found this passage from the discussion particularly interesting...

THIS CHANGE IN THE STEERING FLOW SHOULD
KEEP THE CYCLONE MOVING ON A WEST-NORTHWESTWARD TRACK FOR THE NEXT
4 DAYS...AND THEN SLOW DOWN AND POSSIBLY TURN MORE WESTWARD BY DAY
5 AS A NARROW RIDGE DEVELOPS TO THE NORTH AND WEST OF THE SYSTEM.

so if im not mistaken, at the end of the forecast cone, there may be a shift west later on? Cause right now until about Saturday, it heads on a wnw track but there is no westward turn...

[SouthDadeFish]

so if im not mistaken, at the end of the forecast cone, there may be a shift west later on? Cause right now until about Saturday, it heads on a wnw track but there is no westward turn...

I think the next few advisories might hint at a bending back to the west at the end of the cone. However, the question is how long will this bend back to the west last? What troubles me is they mention the ridge building into the North and WEST of "future Katia" if you will. If the ridge builds to the west that would imply a westward run for at least a few days. I definitely wouldn't call her a fish yet, thankfully we have plenty of time to keep an eye on her. This is just my opinion and not a professional forecast.

[hurricaneCW]

If the NHC is correct, then future Katia will at least give us another hurricane scare in 10-12 days.

[AnnularCane]

I don't understand. Didn't the data suggest this was a TS?

[HurricaneWarning92]

so if im not mistaken, at the end of the forecast cone, there may be a shift west later on? Cause right now until about Saturday, it heads on a wnw track but there is no westward turn...

I think the next few advisories might hint at a bending back to the west at the end of the cone. However, the question is how long will this bend back to the west last? What troubles me is they mention the ridge building into the North and WEST of "future Katia" if you will. If the ridge builds to the west that would imply a westward run for at least a few days. I definitely wouldn't call her a fish yet, thankfully we have plenty of time to keep an eye on her. This is just my opinion and not a professional forecast.

I was thinking the same thing about the ridge building to its north and west. Unless the ridge is VERY narrow, i think it would head more westward than expected.

[gatorcane]

The 12z ECMWF bends her some back more west some once north of the islands, so this wording really does not surprise me.

You can see that the are leaning on the ECMWF model rather than the GFS for the extended forecast which is what I would do right now also given the tendency of the latter model to erode ridges too quickly.

[SouthDadeFish]

I don't understand. Didn't the data suggest this was a TS?

At 8pm EST satellite estimates placed this at TS strength. However, the discussion stated that between that time and the time of 11pm advisory the satellite appearance degraded slightly, probably due to intake of dry air.

[hurricaneCW]

Since the ECMWF pretty much nailed Irene's track toward the Bahamas and even nailed it's northward turn up the coast instead of a more northeasterly turn the other models indicated a couple days before the storm hit, what it shows should be taken very seriously and what it shows is a potential threat to the U.S.

[HurricaneWarning92]

Looking forward for the 00z GFS... and well the Euro but thats in about 3 hours..

[abajan]

Has anyone considered the possibility of this degrading to an open T/W? I've seen that happen a few times in my lifetime. Of course, there have also seen systems that were downgraded to a wave, travel in a westerly direction across the Atlantic for a couple days and then re-intensify to a T/S.

[TwisterFanatic]

Has anyone considered the possibility of this degrading to an open T/W? I've seen that happen a few times in my lifetime. Of course, there have also seen systems that were downgraded to a wave, travel in a westerly direction across the Atlantic for a couple days and then re-intensify to a T/S.

From the looks of all the models, that's pretty unlikely.

[ROCK]

thats weird the CIMSS website is saying TS 12...whatever...

hard to discern movement but basically west IMO....

[cycloneye]

Has anyone considered the possibility of this degrading to an open T/W? I've seen that happen a few times in my lifetime. Of course, there have also seen systems that were downgraded to a wave, travel in a westerly direction across the Atlantic for a couple days and then re-intensify to a T/S.

From the looks of all the models, that's pretty unlikely.

And by satellite.



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[ROCK]

0Z GFS should be running now....aint staying up for the EURO...got plenty of days ahead before that is needed.....

[USTropics]

The waning of convection when TD 12 reached 30w was forecasted by WXman57 earlier today so it comes as no surprise. Here is his post and the graphical image detailing why:

I'm hearing through the grapevine that TD 12 may be passing beneath a region that might not be so favorable for development by tomorrow. Supposedly, a region of positive 200hPa (mb) vorticity anomalies will be passing over 12 for the next few days. Theoretically, this may suppress convection for a while. You can see this region on the graphic below. It's the reddish-brown area just reaching 30W now.

[ROCK]

GFS cranks this baby up right off the bat...


http://mag.ncep.noaa.gov/NCOMAGWEB/appc ... mageSize=M

[ROCK]

27 hours....nice ridging to the north....not gaining much lat either than previous runs....

http://mag.ncep.noaa.gov/NCOMAGWEB/appc ... mageSize=M

[ConvergenceZone]

I hope the islands are keeping an eye on these model runs, because even though it's forecasted to go North of the Islands at the moment, things can change quickly