John1122

A half inch to 5+ is my modeled range 48 hours out. That's how crazy this system is.

Gonna choose to hug the HRRR for now. The higher the resolution the model, the better for mby. It may be finding the low atmosphere level snow better. These are simulated radar runs and snow will be falling from atmosphere levels lower than the radar can find in some cases.

The craziest thing to me is my high is predicted to be 6 Friday for the daytime, and 14 for Saturday but nothing below 0. Rare to get daytime highs in the single numbers and stay above 0.

I think a lot of models are slowing the cold up as it hits the western Plateau, just enough for the moisture to race away from the front.

MRX has been referring to this as December cold not seen in decades. 2014 and 2015 had -10s across a lot of the area. But that was Jan and Feb.

The NAM is working towards the GFS. The 12k is getting snow into East Tennessee now.

Euro was slightly better but not by a lot.

Hopefully it improves by this time tomorrow. If not, I expect the GFS will head its way.

RGEM wasn't good at all. Just bone dry except for a small bullseye around the central plateau. Barely gets .2 total qpf for most areas.

I'm not sure why the NAM loses the dynamics of the storm as soon as it hits the western Plateau. It looks healthy as all get out then just dies out.

They've got several mountains up to around 2300 feet. It actually looks similar to this area in spots.

It's at the very end of it's range but the RAP has most of it's moisture behind the front with the storm diving SE.

We are still maybe 24 hours from the NAMRGEM wheelhouse on these type of events. I expect the GFS to either throw in the flag or get others onboard in 36 hours or so.

Looking at the vort maps, the 500mb vort takes a similar path on the Euro/CMC/GFS it's just much more consolidated on the GFS and dips slightly further south.

It definitely looks like it on the GFS. Looks like it moves SE then back north across the Ohio Valley. You rarely see them attached to this potent a cold front. This is basically as Siberian express. Probably not as severe as the 1982 version though.

I've been including it here since the thread covers the winter threats from Dec 23rd to 30th. The Euro was closer to the CMC but very suppressed at 0z I believe.

The current OBS/Radar are a perfect example of how massively models struggle with the size of a precip shield. It's listed on the known biases of the GFS for areas just west of the Appalachians.

You're unlikely to ever see a low take that track that it does on the Canadian and have such a small precipitation shield. That's a big winter storm track for the Eastern half of the state especially.

Well the GFS drops SE than goes almost straight north as it strengthens. Still keeps the idea of being a nearly all anafrontal event.

The GFS looks like it's going full on clipper here with the LP moving SE.

06z GFS has pockets of very heavy snow being depicted behind the front now with almost all of the precip with it being anafrontal. Very little rain out ahead of it. Very similar to Christmas 2020.

The cold is insane on the RGEM. It has me at 1 degree at 1pm Friday.

06 NAM has heavy snow working across the state, laying down 1-3 inches but it just dies out as it reaches the western Plateau. The 0z RGEM did as well, but the 06z RGEM pushed snow into East Tennessee. We are still about 24 hours from really beginning to get into the wheelhouse of those two. The Euro is still completely Grinchy regarding backside snow, but as I've mentioned, it took until around 24-30 hours out before the Euro caught on that it was going to snow on the back side in 2020. Same for the UKIE. The GFS was steady until about 60 hours out and then it lost the 2020 storm for about a days worth of runs and came back around 30 hours out. The RGEM handled things the best. Hopefully it leads the way here. Euro is also grinchy on the second system the GFS and GGEM see.

I'd definitely take the 7 inches the Canadian gave me that run. You'll often see storms attack as the cold air leaves.

It may go down in flames but the GFS isn't backing down.