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Hurricane Katia


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Some quick thoughts:

1. Yesterday, I noted that the stronger storms that developed in the region in which Katia formed had less chance of recurvature than the weaker ones, noting that none of the storms that failed to recurve were tropical storms. The 12z Euro is depicting a markedly weaker storm. Not too surprisingly, it turns the storm much more quickly than the 0z run did (around 64°W vs.71°W on the earlier run).

I didn't catch that yesterday, but it's interesting since it bucks the conventional wisdom that a stronger system would move poleward faster. I wonder what makes this sample do the opposite.

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I didn't catch that yesterday, but it's interesting since it bucks the conventional wisdom that a stronger system would move poleward faster. I wonder what makes this sample do the opposite.

Maybe the wishcast theory about strong cyclones outflow and subsidence poleward enhancing the ridge and "making their own weather" isn't completely invalid.

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I didn't catch that yesterday, but it's interesting since it bucks the conventional wisdom that a stronger system would move poleward faster. I wonder what makes this sample do the opposite.

On that front, I'm going to guess that shear/dry air from westerlies further south may have something to do with it, whereas the stronger storms had a better Bermuda High north of it.

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The TVCN, GFDL, GFDN, HWRF, and NOGAPS are the only ones to support your observations.

Not exactly the Hall of Fame for Hurricane Modeling, there.

huh.gif

Okay, the consensus track (TVCN) is probably one of the best pieces of guidance out there. And the GFDL and HWRF are solid hurricane models. Trends are trends

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huh.gif

Okay, the consensus track (TVCN) is probably one of the best pieces of guidance out there. And the GFDL and HWRF are solid hurricane models. Trends are trends

You do realize that both the GFDL and HWRF are worthless in terms of projecting long range synoptic features, right?

If you really want to try to figure out if there is any remote threat to the US, look at the GFS, Euro, CMC, and UKMET... only one of which you showed.

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You do realize that both the GFDL and HWRF are worthless in terms of projecting long range synoptic features, right?

If you really want to try to figure out if there is any remote threat to the US, look at the GFS, Euro, CMC, and UKMET... only one of which you showed.

Agree...however, just a note....with Irene 4-5 days out, the models were certainly demonstrating a much more westward track, yet in the end, the storm barely made LF south of 35N....and here we are, some week or so from any potential LF concerns....in model word things can change quite drastically at these leads. IMO, the value of model changes and swings this far out (either west, east, slower or faster) is minimal, due to the fact that the overall longwave pattern over the US, the eventual evolution and trasition of the GOM system, and the STR all can still (and probably will) verify much differently than what is depicted by model consensus today. That said, chances for a US LF, IMO are a few percentage points below climo at this point.....and frankly, any TC 6-10 days out can only be forecasted better than climo by a few percent at best even with models and pattern recognition skills. Of course, climo loses it's muscle quite quickly at shorter leads....

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Katia is ready to take off, potentially catastrophic hurricane in her infancy stages. Perhaps the NE Lesser Antilles Islands the main landfall location in danger of a landfall potential with Katia, not good as she could be nearing category 4/5 status by that time.

Its current heading strongly argues against even a Lesser Antilles hit.

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1700 NHC disco staying south of Euro track - for now...

NEAR THE END OF THE FORECAST PERIOD...A WEAKNESS

IN THE RIDGE PRODUCED BY A TROUGH OVER THE WESTERN ATLANTIC IS

EXPECTED TO INDUCE A GRADUAL TURN TO THE RIGHT WITH A DECREASE IN

FORWARD SPEED. THE OFFICIAL TRACK FORECAST IS CLOSE TO THE

MULTI-MODEL CONSENSUS AND SOUTH OF THE LATEST ECMWF SOLUTION.

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Latest 18z Early Hurricane Models:

Track:

aal12_2011083018_track_early.png

Intensity:

aal12_2011083018_intensity_early.png

I find it really great that there are so many pro mets on this forum. I want to ask you guys a lot of questions, but I don't want to bug all of you too much. I'm still new to this forum, but how can you Personally Message someone, if you can, and can you message anyone?... Thanks

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Agree...however, just a note....with Irene 4-5 days out, the models were certainly demonstrating a much more westward track, yet in the end, the storm barely made LF south of 35N....and here we are, some week or so from any potential LF concerns....in model word things can change quite drastically at these leads. IMO, the value of model changes and swings this far out (either west, east, slower or faster) is minimal, due to the fact that the overall longwave pattern over the US, the eventual evolution and trasition of the GOM system, and the STR all can still (and probably will) verify much differently than what is depicted by model consensus today. That said, chances for a US LF, IMO are a few percentage points below climo at this point.....and frankly, any TC 6-10 days out can only be forecasted better than climo by a few percent at best even with models and pattern recognition skills. Of course, climo loses it's muscle quite quickly at shorter leads....

This is an excellent point, and I think goes to why trends of even good models only have so much applicability. About a week ago there was a lot of gnashing of teeth about the eastward trend of the models and how it was starting to look like Irene might even miss SNE. This is still a long way out, and the EC ensemble is quite a bit SW of the operational run and from what I have seen others post the GFS EnKF is pretty good guidance and it is quite a bit SW of the EC as well. As you say, the odds are probably a bit below climo at this point, but it is way too far out to call anything definitively.

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This is an excellent point, and I think goes to why trends of even good models only have so much applicability. About a week ago there was a lot of gnashing of teeth about the eastward trend of the models and how it was starting to look like Irene might even miss SNE. This is still a long way out, and the EC ensemble is quite a bit SW of the operational run and from what I have seen others post the GFS EnKF is pretty good guidance and it is quite a bit SW of the EC as well. As you say, the odds are probably a bit below climo at this point, but it is way too far out to call anything definitively.

I agree. At this time, I'm thinking that there is probably a greater than 60% chance of recurvature (possibly between 65W-70W), but a landfall threat remains a possibility. Katia's tracking close to 280° since 11 a.m. has put it somewhat south of some of the earlier guidance. FWIW, it looks like NHC made a subtle shift in its forecast track somewhat to the south.

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It had better curve by 70W or it's going to be crazy along the entire East coast, since Katia is going to be AT LEAST a cat. 3 by then. The other scary thing is that the current position and 5 day track of Katia is very close to the tracks of:

Sept. 1944

Donna 1960

Gloria 1985

Andrew 1992

Floyd 1999

Isabel 2003

Frances 2004

The key may be whether the strong trough that will bring the cold front through by Labor Day will pick up Katia. If not, the big high building in behind the front could start curving Katia back more to the west for at least a while. That's what happened with Andrew. It looked like the trough was going to pick it up (it was only a TS at 25/65), and many forecasters in Florida had given up on it. One VERY well-known and popular met in Miami even said on Friday: "go enjoy your weekend". Then it turned west, strengthened like mad, and the rest is history. Let's hope that sort of thing doesn't happen again.....ever.

Glenn

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It had better curve by 70W or it's going to be crazy along the entire East coast, since Katia is going to be AT LEAST a cat. 3 by then. The other scary thing is that the current position and 5 day track of Katia is very close to the tracks of:

Sept. 1944

Donna 1960

Gloria 1985

Andrew 1992

Floyd 1999

Isabel 2003

Frances 2004

The key may be whether the strong trough that will bring the cold front through by Labor Day will pick up Katia. If not, the big high building in behind the front could start curving Katia back more to the west for at least a while. That's what happened with Andrew. It looked like the trough was going to pick it up (it was only a TS at 25/65), and many forecasters in Florida had given up on it. One VERY well-known and popular met in Miami even said on Friday: "go enjoy your weekend". Then it turned west, strengthened like mad, and the rest is history. Let's hope that sort of thing doesn't happen again.....ever.

Glenn

Not to derail the thread but that is funny - haha: "go enjoy your weekend". I wonder what his post-mortem analysis featured.

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