ATL: KATIA - Post Tropical - Discussion

[DESTRUCTION5]

Difference here is GFS takes "Lee" NE making a weakness on east coast and 12Z EURO Pushes his but into the Rio grande...Thus keeping high pressure off the east coast...Model war time..or in this case "timing"...

[stewart715]

2PM models westward movement. I have zero confidence in late cycle GFS.

Just for clarification, it looks like all of those are 12z model runs (e.g. starting at 8 a.m. EDT). The "interpolated to 2 p.m." means that they took the 12z model runs and looked at the 6 hours forecasts. In other words, those aren't "2 pm models" as much as they are the 12z / 8 am models that start at the 6 hour forecast (which itself is valid at 2 pm EDT).

I understand, I was more interested in the change of GFS and others-- a slight, but noticeable, change westward.. Here is previous from 8AM today.

[otowntiger]

2PM models westward movement. I have zero confidence in late cycle GFS.


Just for clarification, it looks like all of those are 12z model runs (e.g. starting at 8 a.m. EDT). The "interpolated to 2 p.m." means that they took the 12z model runs and looked at the 6 hours forecasts. In other words, those aren't "2 pm models" as much as they are the 12z / 8 am models that start at the 6 hour forecast (which itself is valid at 2 pm EDT).

Thanks for your input WxGuy!! I'm not sure I got all of what you just said, nevertheless, in your professional opinion does it look like a trend to the west that we need to be concerned about?

[gatorcane]

Still looks like it's not going to have any significant impact on the NE Caribbean, and it will probably recurve well east of the U.S.

You're not concerned with some of the models bending Katia westward at the end of their runs?

Looks like Wxman wrote this before the 12Z Euro came out, though one still thinks it will find a way to recurve before reaching the U.S East coast.

[SouthFloridawx]

Jevo,

Something that I noticed about Ridges and Troughing is that when you have a strong shortwave trough... butted up against it is an equally strong ridge. As seen here:

What I am saying is that the system in behind Katia, has a much greater potential for impact on the Islands and the Conus. Though this is a long way out... it's something that I've noticed over time.

[RL3AO]

Thanks for your input WxGuy!! I'm not sure I got all of what you just said, nevertheless, in your professional opinion does it look like a trend to the west that we need to be concerned about?

Basically those aren't the 18z runs of the models, they are the interpolated runs of the 12z models. It just takes the 6hr forecast from the 12z and uses that as the current forecast. So that map just shows the 6 to 126 hr runs of the models. Hopefully that makes sense.

[CrazyC83]

60 kt seems reasonable. Seems to be an eye forming, but not enough confidence to call it Hurricane Katia yet.

[Jevo]

What we can take away from this is that the NHC will probably not shift at all since it appears that even after all the kooky twists and turns that the Euro just spit out the storm ends up where it did in previous runs: Heading fast and furious for Greenland!

I think we all learned from "The Perfect Storm" that all hurricanes go staraight for the Flemish Cap once they recurve ..... Cause thats where the fish are

[stewart715]

Thanks for your input WxGuy!! I'm not sure I got all of what you just said, nevertheless, in your professional opinion does it look like a trend to the west that we need to be concerned about?

Basically those aren't the 18z runs of the models, they are the interpolated runs of the 12z models. It just takes the 6hr forecast from the 12z and uses that as the current forecast. So that map just shows the 6 to 126 hr runs of the models. Hopefully that makes sense.

It does, thank you...

[WxGuy1]

2PM models westward movement. I have zero confidence in late cycle GFS.


Just for clarification, it looks like all of those are 12z model runs (e.g. starting at 8 a.m. EDT). The "interpolated to 2 p.m." means that they took the 12z model runs and looked at the 6 hours forecasts. In other words, those aren't "2 pm models" as much as they are the 12z / 8 am models that start at the 6 hour forecast (which itself is valid at 2 pm EDT).

Thanks for your input WxGuy!! I'm not sure I got all of what you just said, nevertheless, in your professional opinion does it look like a trend to the west that we need to be concerned about?

Hi Otowntiger -- I wouldn't lose sleep over it yet. The large-scale environment just isn't forecast to be very supportive of a landfall in the U.S. given Katia's current location. Looking at the GFS forecast, if Katia does end up farther west, it'll also end up under stronger winds aloft (15,000 - 30,000 feet above sea level), which will create some shear that may end up weakening the storm. It's very common to see shifts left or right when different models come in, but there are times when the next result of these shifts are more or less significant. If we didn't have this trough in the eastern U.S. that's forecast by both the ECMWF and GFS, then I'd be more worried about whether these shifts end up having a meaningful impact on the area of location.

Here's the 250 mb map (which is about 30,000 feet above sea level) valid at the end of next week. Katia, in this run, is located on the far right part of the image. This trough is forecast to move eastward into the western Atlantic, causing Katia to move NNW and eventually lose tropical characteristics:



As noted, the ECMWF is a little different, and it may be because of the interaction between any possible future Lee in the Gulf of Mexico. The GFS has future-Lee farther east in teh extreme northeastern Gulf of Mexico; the ECMWF generally has had future-Lee farther west, closer to Texas. It's quite feasible to think that the location of Lee will affect how the "weather" at 15,000-30,000 feet "looks", which in turn could easily affect the path of Katia. That said, even the ECMWF indicates that a U.S. landfall is unlikely.

GIST: If you live on the east coast, I wouldn't lose much sleep. Of course, this time of year, it always pays to keep aware of the situation. This is doubly true when there's a name soon-to-be-hurricane in the tropical Atlantic heading west-northwestward. So, don't let minor changes in model forecasts cause you any stress, but just check into the NHC website at least once a day to make sure there haven't been any major changes to the forecast. Long range forecasts for tropical cyclones can be very poor at times, so just keep an eye on the situation.

Post-Gist: You should always use the NHC for official forecasts related to tropical cyclones in the tropical Atlantic and northeastern tropical Pacific. These people tend to be the best of the best, and it's their entire job this time of year to make forecasts such as that for Katia. You'll find a lot of different opinions on this forum, and you should take all of them (mine included) with a grain of salt. You'll find that some folks tend to jump on any shift on any model in any run that lets look it might perhaps lead to a slightly higher chance of land impact. To be fair, you'll also run into folks who tend to prematurely dismiss storms as "fish" (e.g. with no significant impacts to land). Stick to the NHC for the official forecasts, and use opinions and forecasts on this forum as supplemental information, at most.

[meriland23]

I just woke up. From the looks of it, more models are coming into agreement on a more westerly track. This track is sounding more and more like Andrew.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[clfenwi]

Latest microwave iamge:

[cycloneye]

The latitude position at 11 am was 14.2N.By looking at the microwave image,it looks like it has not gained a lot of latitude in the past 4 hours.

[Jevo]

I just woke up. From the looks of it, more models are coming into agreement on a more westerly track. This track is sounding more and more like Andrew.

You're pretty new here so you don't yet know.. but anytime you compare a storm to Andrew.. Dr. Bob Sheets comes to your house and visits you while you sleep... the rest is too horrific to describe on these forums..

Hehe that being said there are a lot of uncertainties late in the model runs before we compare this track to any previous storm.. WxGuy makes some good points about synoptic setup late in the forecast period that still gives a better than even chance of Katia becoming a viking

[SouthFloridawx]

Decent convection over the center occurring now...

[meriland23]

I just woke up. From the looks of it, more models are coming into agreement on a more westerly track. This track is sounding more and more like Andrew.

You're pretty new here so you don't yet know.. but anytime you compare a storm to Andrew.. Dr. Bob Sheets comes to your house and visits you while you sleep... the rest is too horrific to describe on these forums..

Hehe that being said there are a lot of uncertainties late in the model runs before we compare this track to any previous storm.. WxGuy makes some good points about synoptic setup late in the forecast period that still gives a better than even chance of Katia becoming a viking

Lmfao, yeah I am new and just woke up. I best lock my doors... what is done can not be un-done LOL. Anyway, it is kind of scary that the more time has lapsed, the more westward this track evolves. But it is way too far out at sea still. Still at 65 mph from what I understand, which I never expected considering the rapid intensification it had gone through yesterday.

[otowntiger]

[

Hi Otowntiger -- I wouldn't lose sleep over it yet. The large-scale environment just isn't forecast to be very supportive of a landfall in the U.S. given Katia's current location. Looking at the GFS forecast, if Katia does end up farther west, it'll also end up under stronger winds aloft (15,000 - 30,000 feet above sea level), which will create some shear that may end up weakening the storm. It's very common to see shifts left or right when different models come in, but there are times when the next result of these shifts are more or less significant. If we didn't have this trough in the eastern U.S. that's forecast by both the ECMWF and GFS, then I'd be more worried about whether these shifts end up having a meaningful impact on the area of location.

Here's the 250 mb map (which is about 30,000 feet above sea level) valid at the end of next week. Katia, in this run, is located on the far right part of the image. This trough is forecast to move eastward into the western Atlantic, causing Katia to move NNW and eventually lose tropical characteristics:


As noted, the ECMWF is a little different, and it may be because of the interaction between any possible future Lee in the Gulf of Mexico. The GFS has future-Lee farther east in teh extreme northeastern Gulf of Mexico; the ECMWF generally has had future-Lee farther west, closer to Texas. It's quite feasible to think that the location of Lee will affect how the "weather" at 15,000-30,000 feet "looks", which in turn could easily affect the path of Katia. That said, even the ECMWF indicates that a U.S. landfall is unlikely.

GIST: If you live on the east coast, I wouldn't lose much sleep. Of course, this time of year, it always pays to keep aware of the situation. This is doubly true when there's a name soon-to-be-hurricane in the tropical Atlantic heading west-northwestward. So, don't let minor changes in model forecasts cause you any stress, but just check into the NHC website at least once a day to make sure there haven't been any major changes to the forecast. Long range forecasts for tropical cyclones can be very poor at times, so just keep an eye on the situation.

Post-Gist: You should always use the NHC for official forecasts related to tropical cyclones in the tropical Atlantic and northeastern tropical Pacific. These people tend to be the best of the best, and it's their entire job this time of year to make forecasts such as that for Katia. You'll find a lot of different opinions on this forum, and you should take all of them (mine included) with a grain of salt. You'll find that some folks tend to jump on any shift on any model in any run that lets look it might perhaps lead to a slightly higher chance of land impact. To be fair, you'll also run into folks who tend to prematurely dismiss storms as "fish" (e.g. with no significant impacts to land). Stick to the NHC for the official forecasts, and use opinions and forecasts on this forum as supplemental information, at most.

[/quote]

Thanks WXGuy for the detailed and straightforward reply! I will keep an eye out (will do either way since I'm a tropical weather junkie!). I'm not going to get too excited at this point.

[gatorcane]

The latitude position at 11 am was 14.2N.By looking at the microwave image,it looks like it has not gained a lot of latitude in the past 4 hours.

yeah I noticed that an Aric Dunn mentioned it may push more West today given the steering. Looks like that is happening.

The CMC and NOGAPs keep her pretty much due west for the next day or so

[Aric Dunn]

little better resolution....

still fiind the ridging that was north of her ( that turned her west) disappearing a little weird. being that within 24hours its replaced by a trough and its moving N then within 36hrs is accelerating out to see ... but it is very far out still its the euro it normally pretty straight forward..

http://www.meteo.psu.edu/~gadomski/ECMW ... floop.html

[KWT]

Yep looks like the system has been moving fairly close to due west recently...