Latest from the GFS not looking good

[Huckster]

00z run of the GFS is trying to keep most of the moisture out in the Gulf. Hopefully (for the snow seekers) this won't pan out. Maybe it will flip flop back. This most recent run is trending with the last couple in reducing the chance of frozen precip. Someone please contradict this post, with facts and hard science

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/images/gfs_slp_096m.gif

[Sean in New Orleans]

It wouldn't surprise me if this panned out...it's a fairly typical pattern...but, then, again, we are looking at a computer model that's on to something...Keep in mind it still has the moisture there...it's just missing the overrunning...on the other hand, with such a strong front, we could be looking at this very situation..

[ktulu909]

Being as Im no meteoriologist and cant even read these maps from chinese writing,Im going to go out on a limb here and say that I think Im still on the very edge of that map Does the light light green still mean a possible dusting?

[Sean in New Orleans]

Being as Im no meteoriologist and cant even read these maps from chinese writing,Im going to go out on a limb here and say that I think Im still on the very edge of that map Does the light light green still mean a possible dusting?

Spend a little time here and you'll be reading them in no time...Welcome to the board...

[TS Zack]

You shouldn't look exactly where the moisture is progged.

The big key is the models are still picking up on an area of SLP. We won't know where that SLP will form until Thursday but for now we will have a snowstorm somewhere just don't know where.

Trends.......

[SouthernWx]

but for now we will have a snowstorm somewhere just don't know where.

Trends.......

Not neccesarily my friend. I've done a great deal of research into major southern winter storms of the past, and the axis of heaviest snowfall is normally found about 230 nautical miles (265 statute mi) NW of the surface cyclone track.

During the record breaking February 1973 snowstorms which dropped 17" of snow at Columbia, SC....16.5" at Macon, GA and 14" at Columbus and Augusta, GA....the deepening surface low pressure tracked across Florida on a line from just north of Tampa to near Daytona Beach (with a corresponding heavy snowband from coastal Mississippi across southern/ east central Alabama....central Georgia into central South Carolina). Every school system in north Georgia was closed...yet NOT A FLAKE of snow fell in metro Atlanta or points northward to the Tennessee line.

If both the 12z ECMWF and 00z GFS are correct....progging the eventual low pressure storm track from just north of the Yucatan to near Key West then across south Florida (near PBI)....that would place the heaviest precip band from the middle Gulf to near Cedar Key, Florida to Jacksonville...then staying offshore the Georgia/ South Carolina coasts.

The problem with that? The 850 mb freezing line (freezing level at 5000' feet) is progged from near New Orleans to central Georgia...then INLAND west of Charleston and Myrtle Beach. There will be NO snowfall south of the 850 mb 0° C line.

What will we end up with? A chilly rain event for the immediate Gulf coast from SE Louisiana to southeast Georgia/ northern Florida and the coastal Carolinas with possibly some light sleet mixed in....and a milder rain across the remainder of central/ south Florida (poss. t-storms in Miami/Fort Lauderdale and the Keys).

In this scenario....which I'm very afraid we're trending toward tonight would mean the cold air never meets up with the precip...thus no snowstorm for anyone.

This isn't December 1989....while the air mass progged to be in place on Christmas Eve into Christmas is very cold, it's NOT anywhere close to the bitter arctic air of fifteen Decembers ago. During that outbreak, lows here in metro Atlanta were 3-6° with highs in the mid-upper TEENS for three days.

LOW temps for this outbreak are progged in the 12-17° range in this area....not even close to the 1989 levels.

I hope I'm wrong...because even if I don't witness a white Christmas in Atlanta, I'd love to see one for my many wx buddies located farther south (Macon, Charleston, Savannah, Dothan, Mobile, New Orleans, etc), but unless there are major model shifts in a hurry, I'm afraid I'm correct (and model data in the 96-120 hour range is normally pretty accurate).

After looking over the 00z model data...and using past winter storms & climatology, I currently rate the odds of a white Christmas in Atlanta and Birmingham at less than <1%.....and less than 10% across central/ southern Alabama, Georgia, Mississippi, or Louisiana

As DT says...the trend is your friend. Well, the model trend all day (every run) has been less impressive and farther south (and more depressing

[Sean in New Orleans]

Well, you see, this is where I differ...I'm inclined to the chance of snow, but, I'm more inclined to frigid temperatures. On Christmas morning, I expect the Central City of New Orleans to be around 20F...maybe even upper teens. I think the Northern side of Lake Pontchartain could be as low as 12F...I would not be surprised, at all, to see Birmingham and Atlanta in single digits temps without the wind chill...

[SouthernWx]

Well, you see, this is where I differ...I'm inclined to the chance of snow, but, I'm more inclined to frigid temperatures. On Christmas morning, I expect the Central City of New Orleans to be around 20F...maybe even upper teens. I think the Northern side of Lake Pontchartain could be as low as 12F...I would not be surprised, at all, to see Birmingham and Atlanta in single digits temps without the wind chill...

Sorry, but I've seen no model support for such frigid temps in northern Alabama or Georgia later this week. The GFS has been cold biased all month, and progs 12° in metro Atlanta; based on the last two cold snaps, it will likely be 2-4° degrees warmer than that.