MAG5035

Light to moderate rate currently I got a uniform 2.5" on my measuring spots. I put a second board out to clear at 24 hrs tomorrow morning. A lot of this afternoon had pretty light snow but 2.5" in about 15 hrs is definitely playing the slow game lol.

Back to the discussion at hand, namely the ongoing storm... I still think the focus of the biggest totals will be that Lehigh Valley area of far eastern PA in northern half of NJ/NYC. And really the NAM still reflected that.. but the 0z run really hooked up with the major deform band reaching far back deep into C-PA. I'm a bit suspect of such a widespread area of a foot plus so far back like the 12k NAM has, but I do think the deform shield is probably being undermodelled on near term guidance like the HRRR. But remember.. HRRR goes out to 18 hours except for the 0,6,12,18z runs and we're still not really at the time when this deform from the deepening coastal gets flung back into PA at the end of the regular HRRR runs. And I'm more looking at other short term guidance for anything out past that anyways. The major features (850/700 lows) are well placed to go along with a very robust 850mb jet pointed into eastern PA so there's likely going to be a stripe of more significant totals.. just not sure on how widespread.

I'm talking about several runs including all of Friday with the op being south and ensemble mean barely getting the 6" line above the mason-dixon line. That 30-40" solution in VA/DC was a couple days before that. Nowhere did I say I discounted it... I just said I didn't think it was superior to other guidance the few days leading up and it wasn't.

Not wrong though, I don't think it was overly superior to other model guidance trying to reel this thing in the last few days. There was that particular run he referenced where the bullseye was in northern VA but it also spent a whole model cycle being south with the 0z Friday run missing a chunk of the Sus Valley and the very area of eastern PA and northern NJ targeted with what will likely be the biggest totals (2'+) was only getting a trace at best.

Looks to be up over 2" now, moderate snow. On the southern end of some enhancing on the radar. Best snow has seemed to be residing in the north-central between UNV-IPT and NW of that line a bit so far this evening. Also another band of imbedded heavier snow working up from Frederick up toward York/Lancaster.

About 1.5" total so far. Steadier snow has finally got here in the last hour.

Nice burst of snow after what has been a pretty quiet afternoon (only light snow of the "for show" variety). Big flakes. Should be getting into some steadier stuff in the next hour or two.

Houtzdale too, although I guess that's only 5 miles down the road.

Hard to ignore the trend on guidance centering the biggest amounts on far eastern PA/northern half of NJ into NYC with the coastal low getting captured a bit higher up the coast. Now when i say "biggest amounts" I"m mainly talking about the excessive stuff (20+). I still like the general 8-14" in our region, but we're going to have to watch the southern tier and NW part of C-PA for some bust potential either direction as well as a zone TBD that could see higher amounts than the said 8-14". As mentioned, the most intense deform from the coastal winding up targets far eastern PA/Nj/NYC, but the overall fetch and likely extension of this deform is still going to reach back into C-PA and questions are where and how intense? You look at models like the 3k NAM and RGEM and they actually arc the best snow with this more through northern/central, while Euro/GFS runs southern third of the state. I'm not sure the near term guidance (HRRR) is robust enough with the precip shield/banding later on tonight into tomorrow but there's a lot to be determined yet and HRRR (outside of the 0,6,12,18z) doesn't even reach out to where the coastal really winds up yet. Also have to monitor the slot far southern tier LSV and maybe some mix while precip's light but worst case scenario I still expect at least 5-8". Again though, the overall picture is this continues to look like a long duration general 8-14" snowfall over the area. Ratios. Taking a rough gauge of the latest Euro snowmap, for instance... The big amounts stretching back deep into C-PA are driven more by high ratios while the big amounts in the Lehigh Valley into NJ are driven by QPF (likely the better bet to realize widespread big amounts). This is also notable on the RGEM too. Not to say there won't be notably higher ratios late in the storm, but I think it will be narrowed down where the bands set up at that stage of the storm inside of the overall precip shield. If your running a steady light to moderate rate outside of heavier bands, probably going to continue to have 10-12:1 type ratios. Biggest takeaway, patience is definitely required for this event.

Saw flurries start as early as about 5am this morning snow but really didn't get going til about 9am this morning. Currently light snow and 1.3" on the ground. I'm not really seeing many surprises in the early going. Guidance has had this starting slow for days and that's what its doing. Near term stuff has had the initial surge of snowfall followed by a bit of light period while the precip shield rebuilds from Ohio and pushes into PA later this afternoon, which judging by radar trends seems on target.

When I made this storm thread I said western PA folks were welcome to post obs and discussion over here. With that said let's keep the posts useful and on topic.

Another areawide Euro thrashing at 0z. I-81 corridor from Harrisburg to Scranton roughly being the bullseye, although most of eastern PA is 20"+ on Kuchera and Euro hasn't yet relinquished the snow completely all the way through hr 69.

Lol, good luck over there too. Looks like Pittsburgh's going to be getting started within the next couple hours.

Incoming

I don't know why we're all so feisty in here tonight. Here's the thing with some of these crazy amounts coming out of models like the RGEM. If someone in eastern PA sees 40-55" from this storm I'll buy everyone in here a beer lol. To me, nailing down this deform band late in the storm means trying to locate an area that sees perhaps up to two feet or so but likely more of a general 18-24" bullseye area. Other than that, this is within a zone where basically every regular in here including 2001kx and wmsptwx should easily see a warning event and I think this is mostly a 10-14+" swath for everyone under I-80 (and probably above it too eastern third to half of PA). We'll have to watch for the slot and perhaps a slight bit of mixing toward the MD border, but I don't think this kills totals all that much by the end if it happens. We should have snows flung back into PA for a good while even if we don't get the intense deform band in our area.

26°F and calm. About to be a good bit more snow in the yard.

Hah maybe they forgot to change the units from cm to inches. Funny thing is that still would convert to 18-24" there, lol.

15.4" on 1.2" precip"

Yup, that's been the last 24 hrs in a nutshell watching guidance evolve with this lol.

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.