ATL: SANDY - Models

[jlauderdal]

NOGAPS as folks pointed out continues to show a near SE Florida direct hit:

http://moe.met.fsu.edu/cgi-bin/ngptc2.c ... =Animation

its not a near this time... landfall

seems odd, sandy is really going to head 3 degrees west from her current position, unlikely unless some ridging sets up quick...nogaps had a good run on this storm

[boca]

What would cause Sandy to move NNW once it moves north of Cuba?

[StormingB81]

Crazy looking at most of the models it seems to curve around the carolina coast.

[Aric Dunn]

NOGAPS as folks pointed out continues to show a near SE Florida direct hit:

http://moe.met.fsu.edu/cgi-bin/ngptc2.c ... =Animation

its not a near this time... landfall

[img]https://www.fnmoc.navy.mil/wxmap_cgi/dynamic/NGP/2012102406/ngp10.usf.048.troplant.gif[/ig]

seems odd, sandy is really going to head 3 degrees west from her current position, unlikely unless some ridging sets up quick...nogaps had a good run on this storm

from looking at the loop it appears there a reformation offshore cuba as the center gets disrupted. the euro does something similar too just the nw jog is farther to the north. so its quite plausible

[gatorcane]

What would cause Sandy to move NNW once it moves north of Cuba?

Upper-level low/trough just to the NW of Sandy...as Sandy moves north and is positioned NE of that upper-level low/trough, the trough could nudge her a bit more NNW....the NOGAPs is likely too far west but that is what I think could do it. The trough is clearly seen over Western Cuba/NW Caribbean on WV imagery.

[Bocadude85]

Based upon some of these models (Euro and NOGAPs) I would be surprised if the TS Watches on the SE FL Coast are not upgraded to warnings with even an outside shot at Hurricane Watches going up.

I do not think there is any chance of us going under a hurricane watch unless the models really shift west. Im thinking we will see top winds in the 40-50mph range. Of course I am not a expert and there is a likely chance that I could be wrong.

[SootyTern]

Silly question, perhaps, but what does 'Phase with the front' exactly mean?

(sorry for posting this in model thread)

Vorticity of front and cyclone combine - a process in extra-tropical cyclone development.

Analogous to when two waves combine to reinforce each other into a bigger wave.

Thanks GCANE, and for the further reading. I thought it meant something like that but wanted to be sure.

[Laplacian]

I was looking at the 06Z GFS forecasts of 500-mb heights and absolute vorticity and noted the unusual journey of a vort max over the North Atlantic at 114 hours (circled in blue on the link to the 114-hour forecast below). It has nothing to do with Sandy, but I thought it was unusual and interesting (please forgive me for this digression).

https://www.e-education.psu.edu/worldof ... otated.png

Here's the loop from the 06Z GFS; it should be good for five days. Quite an unusual journey indeed.

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

[HurricaneFrances04]

I believe the GFDL shows a NNW track, although north of the Bahamas, but towards Jax before turning towards the NE.

[AdamFirst]

I was looking at the 06Z GFS forecasts of 500-mb heights and absolute vorticity and noted the unusual journey of a vort max over the North Atlantic at 114 hours (circled in blue on the link to the 114-hour forecast below). It has nothing to do with Sandy, but I thought it was unusual and interesting (please forgive me for this digression).

https://www.e-education.psu.edu/worldof ... otated.png

Could that be the ghost of TS Tony, or that's a separate entity?

[Laplacian]

As a follow-up to my earlier post, I should point out that the 06Z GFS taking Sandy to the east now seems incorrect. Indeed, a classic Rex blocking high developing near Greenland and the Canadian Maritimes (see the link below to the 06Z GEFS ensemble consensus for 500-mb heights and normalized spread (bottom panel) valid at 06Z Sunday evening) will interrupt the normal west-to-east progression of weather systems, producing a wide swath of easterly flow in the middle troposphere (remember the crazy vort max I pointed out).

https://www.e-education.psu.edu/worldof ... notate.png

With a strong mid-latitude trough also arriving and setting up shop over the Appalachians (see 06Z GEFS ensemble consensus for 500-mb heights and normalized spread (bottom panel) valid at 18Z Monday afternoon), there is now greater confidence of a hybrid storm (Sandy and the mid-latitude system) impacting the Northeast States.

https://www.e-education.psu.edu/worldof ... 00H-23.gif

Real blocking highs (not the slow-moving long-wave ridges some people erroneously elevate to blocking status) are often associated with bizarre weather, and it's looking more and more that there's greater confidence in this evolving forecast scenario.

[Aric Dunn]

the nam has come a good deal west looks like a near landfall in SE FL and showing a much higher amount of rain possible. indicating the trough may not be as amplified by the time it reached florida. seems to be a ongoing trnd of this. the nam though not goo d with tropics does do well with large scale synoptics and being this scenario is both think we can give the NAM a little more credence for the time being.

http://mag.ncep.noaa.gov/GemPakTier/Mag ... precip.gif

[gatorcane]

Well the NAM and NOGAPS have a SE Florida hit (they are outliers) or near hit, fortunately for Florida the ECMWF/GFS (better models) are east of Florida. Still the NAM and NOGAPS are making it interesting where this will eventually end up! The setup is very complicated, models generally have a hard time with the interaction of tropical systems with upper-level lows/troughs (there is one in the NW Caribbean) in my opinion and the setup is going to be very complex once the system emerges north of Cuba.

[Laplacian]

I was looking at the 06Z GFS forecasts of 500-mb heights and absolute vorticity and noted the unusual journey of a vort max over the North Atlantic at 114 hours (circled in blue on the link to the 114-hour forecast below). It has nothing to do with Sandy, but I thought it was unusual and interesting (please forgive me for this digression).

https://www.e-education.psu.edu/worldof ... otated.png

Could that be the ghost of TS Tony, or that's a separate entity?

Good question.

No, that vort max comes from higher latitudes. Looks like Tony slides eastward, at least on the GFS forecasts. Here's the GFS forecast loop of 500-mb heights and absolute vorticity over the Atlantic. I'd lower the animation speed and you should be able to follow the 500-mb vorticity footprint of Tony and the crazy vort max from higher latitudes in time. The loop is good for five days:

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

[Aric Dunn]

Well the NAM and NOGAPS have a SE Florida hit (they are outliers) or near hit, fortunately for Florida the ECMWF/GFS (better models) are east of Florida. Still the NAM and NOGAPS are making it interesting where this will eventually end up! The setup is very complicated, models generally have a hard time with the interaction of tropical systems with upper-level lows/troughs (there is one in the NW Caribbean) in my opinion and the setup is going to be very complex once the system emerges north of Cuba.

although the euro is east of florida it has hurricane force winds all along the florida coast through central florida. the wind field is rather large by that time.

[artist]

Well the NAM and NOGAPS have a SE Florida hit (they are outliers) or near hit, fortunately for Florida the ECMWF/GFS (better models) are east of Florida. Still the NAM and NOGAPS are making it interesting where this will eventually end up! The setup is very complicated, models generally have a hard time with the interaction of tropical systems with upper-level lows/troughs (there is one in the NW Caribbean) in my opinion and the setup is going to be very complex once the system emerges north of Cuba.

although the euro is east of florida it has hurricane force winds all along the florida coast through central florida. the wind field is rather large by that time.

and they mention it is a tricky forecast at this point because of the baroclinic interaction.
This is important as well -
A GENERAL CONCERN SHOULD
BE FOR THE POSSIBILITY OF MINOR DAMAGE, INCLUDING SNAPPED TREE
BRANCHES, UPROOTING OF SMALL OR WEAK TREES AND DOWNED POWER LINES
RESULTING IN SCATTERED POWER OUTAGES.

[Aric Dunn]

gfs is rolling in.

[DESTRUCTION5]

12 Hr GFS

[DESTRUCTION5]

18 Hr....Posting every 6 till clears bahamas..

[MiamiensisWx]

Through 24hr the GFS is 30 n mi east of the 00Z run...showing much less of a threat to SE FL (in terms of TS winds south of Jupiter).