MAG5035

With a good snow column that doesn't have a warm nose in it and below freezing surface temps, it's more important what the temperature is where the best lift is occurring. Taking the Euro, temps are about -7ºC to -10ºC at 700mb where the big lift and heavy snowband is late in the storm. So not quite in the DGZ but it's definitely sufficient for good ratios.

I can't take credit for the December storm haha, @pasnownut made that one.

The early part of the storm where most of us spend likely the first several hours with a steady lighter snow probably won't have anything special in the ratio department... like an 11-12:1. Banding later in the event when the coastal starts cranking will be where we start seeing better ratios within heavier bands.. perhaps up to 15:1 or so. Euro generally had a 13-15:1 average going straight off of Kuchera amount divided by total QPF. Even the outlandish totals the RGEM have in the LSV are about a 12-13:1 average ratio with 15:1 out this way.

It's time guys, I did the thing.

Well here we go, I'm kicking this off now so we can have some of our last minute model guidance discussion organized together with an overall storm thread. Plus we're about 12 hrs from this getting into the region. Western PA folks are welcome too if they want to share their obs/discussion. Current Obs: Clearish, 32ºF. Snowboard deployed

That might be the best the GFS has looked overall for our region with this storm.

I retract my RGEM comment for now, I was looking at 12z. 18z hasn't ran yet. But still, a tremendous difference. This is why CTP is playing the slow but steady game with this.. although probably should've had the watches expanded more early today.

Yea, the 18z really lacked the organized intense CCB band that's going to be the determining factor for the eastern half of PA of having widespread excessive totals come to fruition or more like what the NWS is putting out with the 7-12" warnings. Still tremendous differences in the short range guidance. Check out the RGEM, the Mid-Atlantic folks probably fainted.

CTP also upgrading to warnings. Added some watches and there's a bunch of counties just got updated straight to warnings with no watches lol. Looks like all the warnings either 7-12 or 8-12".

Lol I went up this past Sunday before we got the freezing rain. I’m surprised they haven’t been making more snow like they could but there’s a decent amount of regular snow up there. They have a lot of their diamond terrain opened with only natural cover, which is probably better than frozen machine made snow but there was some pretty thin cover in spots. I did survive the opened top half of Extrovert lol.

I'm definitely making a Blue Knob trip day after this storm ends.

Euro throttles most of the state. LSV slots briefly but then is ground zero for the eventual intense CCB band.

Lol, I think I'm going to "start a fresh thread" to "kick off the second half of winter".. but probably not until tonight at 0z.

I don't know if I ever saw such a big area of 40"+ on even the Canadian, which can put out some crazy stuff. The ratio isn't crazy either. Harrisburg gets 3.38" of QPF for a pretty reasonable 12:1 average through the event. Is that much QPF reasonable? I dunno about that yet. But still.. you can get to two feet pretty easily with 1.5-2" and good ratios.

@Voyager 4 foot bullseye. He may need to travel to ORD via a snowmobile.

This escalated rapidly. Up until yesterday there weren't very many model runs with the big totals.. with only really the Euro having that run or two with the 30"+ (down in VA/DC). Everything's coming back to slowing/stalling that low closer to the coast right in the zone we need it. Add in that tremendous easterly flow and warmer than average Atlantic and suddenly we're burying folks on all the models.

It's like every time I thought I saw the craziest model runs ever leading up to a big storm in the last decade, the next big storm comes along with something crazier. This storm's starting in 24hrs or less guys.

Euro ensemble with a nod toward the op. Pretty good jump from 18z.

Yea, this hasn't been standard boilerplate Nina though. Not with that dominant -NAO/AO blocking pattern. I don't even know how effective taking an analog approach really is when trying to compare to past Nina's because you really can't find one quite like how this one is shaking out so far...imo anyways. With the storm I actually commented a couple times about the swath, as in how often to you see a Chicago to DC heavy snow swath.. or even a Chicago to NYC one? You don't have the established blocking regime and a system that cracks Chicago with a big snowstorm is probably causing p-type issues at best in the Mid-Atl/NE. Which was why I took pause with yesterday being as far south with the swath as it was.. with last night's 0z Euro being the "low water mark" so to speak. I'm not an expert on Long Island climo but I'd think if that coastal stalls/meanders off the Jersey Shore south enough the damage is probably done before you ever mix. Yea it may come north further, but this has stronger blocking and prime dead of winter climo compared to the December storm. That heavy swath is gonna probably be somewhere south of that one, which should bode well for NYC because they did okay in December.

I think models are finally starting to fill in this precip shield between the transferring lows in realization of that major easterly fetch off the ocean between the system and the blocking pattern. The setup's just too good with that established 850mb primary low tracking just under PA and transferring. Look at the 850mb jet just nosed right through PA. Couldn't ask for much better placement of that 850mb low.

Yup I'm cashing that one out right now, lol.

Well no one's gettin 30-40"+ but it's a straight up butt kicking across the whole state.

Euro's got a more expansive swath of heavier snows in most of the state so far through 57 hrs. Primary low presses right up to western WV with the transfer. Gonna be a pretty big one for everyone.

That part of the disco was updated at 9pm when only the NAM was starting to come out. I quoted it in one of my posts awhile ago.

Wow, a sizeable part of Lancaster County is literally a 4 foot bullseye. Finally relents after about Hr 96.