SnowGoose69

Dewpoints just seem too high right now. If those do no start dropping I don't see how any significant snow occurs there

I would not even bother with the GFS at this point for thermals. Use it for precip axis only and maybe storm track

The RGEM even shows the R/S line going north after 20Z in GA due to precip shutting off or slowing down.

RGEM snow maps make no sense. Seems to show significant snow at ATL but the ptype algorithm on TT shows mostly rain other than a brief 3 hour period

RGEM on ptype maps appears to be mostly rain at ATL other than from 15-18Z or so.

Don't use the HRRR that far out.

The 00Z NAM to me looks like it slide south across GA/AL. Thats purely looking at precip field...not thermals

I know last year that ATL got their first ever severe freezing rain event without a wedge so anything can happen

I'm sure people here know better than me but I want to say GA commonly snows with thicknesses over 540

Almost has ATL in rain now. Its definitely been coming north with time

I can’t tell really on the 12Z RGEM but it appears to be not as amped as the 18z NAM in your area either. The ukmet is darn close though. 850 is like -0.4C in ATL the entire event

It sucks not having the RGEM because it can really let you know if the NAM is out to lunch or not

Be real careful with the warm ground deal. I find that doesn’t work often. If you’ve got a December sun angle and you snow even one half inch per hour the warm ground deal doesn’t often hold up. Many places jn GA have been in the 40s now for 36 hours plus. I always bring up Albany NY being 85 degrees and then seeing 15 inches of snow the next day

The GFS didn’t see the warm nose in that storm. Unfortunately the nws and many forecasters bought into it partially and kept snow totals too high when it was evident the event was likely going to be mostly FZRA

I would be shocked if ATL got anything big from this. It’s possible but making a forecast here you really have to go just up to 2 inches on cold surfaces. This isn’t a closed low or dynamic system where intense rates are likely and it’s occurring at a bad time of day for accumulation. One factor I think that is killing this for ATL is what I call “early wet bulbing” where you get precip too early before dry air really works in and when you finally do start going to all snow you don’t have the potential you would have had if you stayed dry. If for whatever reason the precip from 23-07Z stays south of ATL and they can get to 23-24-25 on dewpointa this even becomes much more dangerous for them

That event had a lousier cold air supply and was more dynamic forcing mild air into the 750-900 layer

The Euro wasn’t similar to the GFS in AL/GA/MS really. More for areas north. The Euro had 4-5 inches of snow in ATL while the GFS had none

It was much wetter overall than the NAM

And the 18Z NavGEM looks more west than the 12. At least we know some models, even if it’s the bad ones aren’t giving in

Through late Friday afternoon it appeared like it was going to possibly came way west but then thereafter that it appeared to be flatter and more east. It was definitely more west for AL/GA on the precip but areas further up the MA region it was more east and drier

The new SREF definitely sort of hints what the Euro showed. Things looked better thru 54-57 then it wasn’t as good as the previous run after that especially more north

The Op Euro since the upgrade 2 winters ago in systems that aren’t overly strong at the surface has tended to have a flat bias. I think the ensembles are definitely going to be more north and west. The Euro also tends to make slow adjustments. Sometimes if models are catching onto the setup late the Euro can still be making adjustments inside 12-18 hours

Many cases where the low is above 995-998mb it’s happened

The last few years when the NavGem has been this far north and west at this range it’s rarely not led to the flatter models coming further west

It’s hard to know without details but the UKMET I’m guessing wouldn’t even be snow in ATL. That’s probably the more classic BHM-RMG-CHA snow track