ATL HANNA: Models Discussion

[Frank2]

Actually, the cirrus outflow from Hanna is already streaming to the N and NE, so, the lee side of the trough is already having an effect...

I agree that it might move N then NW - we shall see...

Frank

P.S. I like this topic - much friendlier than that "all purpose Hanna" thread...

LOL

[Sanibel]

If the High is oriented SW-NE then Hanna would move west. But the ULL's pull would make Hanna want to go north. So a compromise NW and up the coast of Florida results.

[Frank2]

Si - I agree...

Sanibel, is that your Gustav "Weather Warrior" photo I keep seeing on TWC - it was taken on the causeway...

P.S. That wouldn't be so bad, really, since the west side of the storm or hurricane is the weaker one - I recall during David (1979), which featured a NNW track from about the same location as Hanna is now, our weather was about the same as it was here on Saturday - mild, overcast and breezy with scattered showers - nice, actually, since most of the clouds were strato-cu...

[DESTRUCTION5]

12Z Euro anyone?

[Bocadude85]

yea i do not think S FL has much to worry about maybe a few gusts to 40 to 45mph

[deltadog03]

I don't know - their scenario doesn't sound right...

It seems Gustav only sharpened the trough that is impinging on Hanna, and, since the flow in the trough is still diving south, it seems the influence will only be more, not less...

Per the WV the trough is moving southwest (slowly), so, once the axis passes Hanna, as it's doing now, it seems that Hanna will possibly begin to move north, in response to the trough...

You make great points, but here is the thing...Sure the trof can effect her. IMO the only thing this trof might do to her is help vent her on the the eastern side.

[captain east]

I don't know - their scenario doesn't sound right...

It seems Gustav only sharpened the trough that is impinging on Hanna, and, since the flow in the trough is still diving south, it seems the influence will only be more, not less...

Per the WV the trough is moving southwest (slowly), so, once the axis passes Hanna, as it's doing now, it seems that Hanna will possibly begin to move north, in response to the trough...

You make great points, but here is the thing...Sure the trof can effect her. IMO the only thing this trof might do to her is help vent her on the the eastern side.

Meaning a more W NW track?

[NEXRAD]

The 18Z NAM is just starting to roll in. It looks well-initialized from the little bit I peeked at. Before anyone tosses a tomato, yes I know the NAM is not well regarded for tropical systems. I tend to be the "dark horse" since I use it to some degree, and the RUC, too.

- Jay

[deltadog03]

What concerns me is there will be a nice little upper ridge over the top of this and florida....Stewart still made mention to dual outflow channels as being possible.

[TreasureIslandFLGal]

d-dog,

Doesn't it also depend at what layers the trough is exerting it's influence? Sometimes if it is a shallow one, there isn't as much affect, especially if the storm is weaker and exists mostly at the lowest levels, correct?

[Frank2]

Thanks for your comment - coming from a meteorologist, I appreciate your comments...

I'll never say I was one - a map plotter for the NHC, and, a person who'd handle calls from TWC ("Where's our selected cities"?), but, forecaster, no...

My job was similar to a nurse's role with a physician, or a paralegal with an attorney - I think they call it paraprofessional...

Still, the folks I worked for were many of the pioneers in tropical meteorology, so, certainly we all learned a great deal from working for them...

I see what you mean about the venting - well, let's see what happens...

Thanks for letting me vent (LOL)...

Frank

[deltadog03]

And believe me...I like your comments as well. Thats why a good forum always works. Initially, I think we all thought that the trof would have some pulling power, but I am not so sure anymore. If hanna stays a bit east, she could eat more shear, but closer to the western bahamas she could have a fairly good outflow pattern.

[NEXRAD]

Feel free to correct me if I'm wrong, but per the NAM and GFS outputs, these models seem to handle the Atlantic ridge as approaching a possible merger with ridging over the Ern US for the general Thursday period. The actual models drastically scale-back the NW extent of this ridge, seemingly in a response to a stronger, more north situated, Hanna. That said, given Hanna's location more to the S today and depending on how the upper trough plays out, I'm watching for a possible greater NW extent of the ridging to the north of Hanna. Such a set-up would translate to the storm maintaining a NW heading.

Note, in the NAM/GFS outputs I mentioned I am looking at the H50 ridge/trough setup rather than Hanna's actual reflection.

- Jay

[DESTRUCTION5]

12 Z EURO Shifts W...Lines up with the HWRF and NOGAPS..

http://www.ecmwf.int/products/forecasts ... 8090212!!/

[Bocadude85]

Feel free to correct me if I'm wrong, but per the NAM and GFS outputs, these models seem to handle the Atlantic ridge as approaching a possible merger with ridging over the Ern US for the general Thursday period. The actual models drastically scale-back the NW extent of this ridge, seemingly in a response to a stronger, more north situated, Hanna. That said, given Hanna's location more to the S today and depending on how the upper trough plays out, I'm watching for a possible greater NW extent of the ridging to the north of Hanna. Such a set-up would translate to the storm maintaining a NW heading.

Note, in the NAM/GFS outputs I mentioned I am looking at the H50 ridge/trough setup rather than Hanna's actual reflection.

- Jay

and in terms of landfall this means further north or south

[NEXRAD]

Feel free to correct me if I'm wrong, but per the NAM and GFS outputs, these models seem to handle the Atlantic ridge as approaching a possible merger with ridging over the Ern US for the general Thursday period. The actual models drastically scale-back the NW extent of this ridge, seemingly in a response to a stronger, more north situated, Hanna. That said, given Hanna's location more to the S today and depending on how the upper trough plays out, I'm watching for a possible greater NW extent of the ridging to the north of Hanna. Such a set-up would translate to the storm maintaining a NW heading.

Note, in the NAM/GFS outputs I mentioned I am looking at the H50 ridge/trough setup rather than Hanna's actual reflection.

- Jay

and in terms of landfall this means further north or south

I wouldn't draw this out into a landfall projection, but a more NW track would increase the Florida risk while still keeping Georgia and at least South Carolina in the cone (this is a comment, not a forecast).

- Jay

[KWT]

Yep the models now shifting south towards central Florida, that ECM wouldn't be great for the areas that had such bad flooding with Fay, esp given Hanna is a chunky system.

does anyone have the plots for Hanna that have all the better models on it?

[captain east]

These are from 2:00 PM today, but it's just so everyone can see the models.

click for full size image

[Bocadude85]

These are from 2:00 PM today, but it's just so everyone can see the models.

click for full size image

that hwrf plot is wrong hwrf has landfall in FL

[caneseddy]

These are from 2:00 PM today, but it's just so everyone can see the models.

click for full size image

It's funny looking at that plot and seeing the UKMET being the easternmost outlier, while up to yesterday it was the westernmost outlier. Shows you how models change constantly