MAG5035

Yea, this was why I didn't like seeing the more amplified solutions for this particular system. I'm a build the snowpack kinda guy when it's DJF, I hate starting over lol. Euro op dumps a lot of rain on spots with the big time snowpack, and in general really. Progresses much slower with the front, dragging this affair into the first half of Christmas Day before the cold air gets back in. GFS on the other side of the envelope getting cold rapidly back into pretty much the whole region on Christmas Eve before midnight. Doesn't have as much rain as the Euro and has been the one leading the most with that anafrontal type deal. Still punches LSV into pretty warm temps for several hours. All in all it looks like a 12-18hr period encompassing most of Xmas Eve where temps get up into the 40s-50s in most of the region. I just want to get the front through as fast as possible.

I took mostly hourly snow observations through the duration of this event so I experimented making a couple charts. Top was the snowfall rate per hour and the bottom was the running total with the hourly rate also part of the graph.

On the X-mas eve system/arctic front passage, not to be pessimistic but Models shifting toward the slower, much more amplified solutions is definitely a case of be careful what you wish for. For our region this may work out in western..perhaps some of interior central PA but I personally don't see much upside to this in the Sus Valley. GFS is the better scenario, focusing on the second wave running up the frontal boundary. Yea there's some snow to be had but it also delivers a ton of QPF (a lot of it rain) beforehand in eastern PA. Euro's even worse with more of a straight up lake's cutter and less emphasized secondary low that probably wouldn't change precip over in time for much. That sends a bigger warm push and 1"+ of rain into places that just got a boat load of snow before maybe a few hour period of snow at the end. All in what you want I guess. You might see that period of snow at some point X-mas eve to X-mas morning, but you might lose most of the pack to see it. I'd rather see the front progressed through faster and maybe set the next event up. Pretty far out in range yet for now, but it does seem like models are heading toward making this more of a QPF laden event. In the meantime there is a couple other weaker systems (Sun/Mon, and Tuesday-ish) to resolve, as one of those systems could muster up enough to put a swath of something across a part of the region.

I'm trying it out a bit. Main thing I'm having trouble with is it loading the radar image really slow.

Plot twist, it's snowing again tonight here.

Same here over on this side of the Laurels, got a fresh coating so far. Pretty nice aggregate flakes too.

You guys seeing much out of this patch of snow in the western half of the state this evening?

And the crazy part was State College just missed the band that pretty much could've doubled the amounts that were reported in and around the State College area, which were already big amounts. The 6z and early 12z guidance yesterday right when the storm was beginning had it there. Nothing had that deform band going as far W and NW as it did in the central/north central counties, and at the same time it appeared the coastal low took the somewhat less tucked in track. One thing to give the models credit for though was the amounts. I personally thought the 35-40+ amounts that popped up were probably a bit much given the steady system progression, but apparently not lol. Everything was showing that 2-3' swath for a few days, very reminiscent of Jan 2016 in that regard. Miller B's don't get much love in this region, and especially in the neighboring subforum (Pit/Western PA) for various reasons. That was pretty much what we had here though, a rather weak primary low transferring to a coastal low. Miller B's can produce a big snow swath through PA in the right setup and we had it for this one. A true miller A coastal low tracking from off the SC/NC coast and coming up probably would not have gotten the good stuff back so far into the western half of PA.

At any rate on to the weather going forward. I'm not seeing too much system wise between now and Christmas, other than maybe some kind of weak system at the beginning of this coming week. Temps are meh and setup kind of favors western and Laurels if there's any notable precip. Models have been pretty solid on an arctic cold shot crashing through on or about X-mas morning. Difference between models are on handling the frontal system. GFS has generally had an anafrontal look to it, with a rain to snow scenario with the frontal boundary. The Euro has a pretty dry frontal passage ushering in the very cold air. 12z Canadian had something insane that's not likely to happen, or at least I'd hope not. I don't think either the GFS or Euro scenario will completely erase much, if any of the snowpack even in most of the Sus Valley. As such, chances of a white Christmas (inch or greater on ground X-mas morning) seem pretty good. Zonal flow regime predominant for the next week, which will keep temps pretty seasonable. Also helping will be the presence of our new snowpack, which aside from the wildly varying top end amounts managed to give all of us in here and our western PA friends 10"+ plus sleet to anchor the pack in the LSV where it would be more vulnerable to a WAA intrusion. But a couple days of 40 or so this time of the year isn't going to melt things a ton, especially where the sleet fell. The only day/period that may be notably warmer is around the 23rd with that approaching frontal system. That may have more luck advecting warm air on a SW flow on the other side of the Laurel's but may not do much in central/eastern. Pattern wise going to the start of the New Year, it seems pretty workable. We neutralize the +EPO, which by the way was pretty positive for this storm that just happened. Build a bit of +PNA in the X-mas period with the cold shot. NAO/AO neutral to slightly negative. MJO staying in the circle on most guidance. I don't really see any kind of an overwhelming influence from any particular teleconnection. So if models latch on to any particular system, especially week between Xmas and New Years.. I'd like our chances of keeping the wintry going.

I was looking back at PennDOT announcements for the district that happened in. They had their section of I-80 on a Tier 1 restriction which restricts tractors without trailers, light or unloaded trailers, motorhomes, personal vehicles with trailers, cargo delivery trucks meeting the definition of a commercial vehicle, school buses unless chains are used etc. I didn't realize they had a 5 tier restriction guideline. At any rate at some point (think it was after the accident), they put it up to a tier 3 from the Bellefonte interchange (I-99) east through the rest of Centre and Clinton.. which restricts all commercial vehicles except loaded single trailers with chains or approved alternate traction device. https://www.penndot.gov/TravelInPA/Winter/Pages/Vehicle-Restrictions.aspx Either way given the ample advance warning of this storm and lane/speed restrictions in place, I'm kinda surprised such a massive crash could occur. Doesn't anyone use a CB anymore? Rapidly changing conditions with a squall is one thing.. but a large snowstorm is a pretty constant condition with reduced visibility and traction.

PSP Update on that I-80 wreck in Clinton County yesterday, 55 commercial vehicles and 11 passenger vehicles. https://wjactv.com/news/local/police-interstate-crash-with-dozens-of-vehicles-kills-2

This thing kicked it into an even higher gear when it got into NWS BGM territory. Multiple counties with 40"+ reports, including right around NWS Binghamton themselves. Incredible.

My mom forwarded me pics from a couple of her friends up in her hometown of Renovo, Clinton County where that band sat for awhile last night. K&L Auto just outside of town Tamarack

Where that band set up and sat last night over those north-central counties got in excess of 2 feet, so a 3+ foot total somewhere isn't out of the realm of possibility. The models having the 20-30+ swath for days ended up being right in the end, just that it ended up being more W than what any model had and then it did arc over to Williamsport.. although the worst of that band was actually north of IPT for awhile and they still got what they did. I don't know what happened here. Looking at you guys' totals this morning, my 10.7" is on par with @Itstrainingtime and the Lancaster folks with some of the ones around Harrisburg actually doing slightly better even with the sleet. This was a big bust for me personally, as I was expecting mid teens here and when yesterday mornings models came in at the beginning of the storm I thought 20" was realistic. I think that intense band setting up just to the west of here for awhile got me into a subsidence zone. I never got the 2-4/hr rates. I'm still happy, it's a double digit snowfall in December either way. Roads are still a mess this morning and my back street hasn't been plowed yet. Couldn't imagine folks that ended up with more than twice of what I got.

The February 2003 storm (PD2) had 18.2" measured on campus. And there was a sneaky forgotten about nor'easter Jan 6, 2002 that dumped about 13-15" in UNV. I think the Feb 5-6, 2010 storm was also about 13-15" in the UNV area as the really high totals were just south. So sounds like you guys did about as good or better than the Feb 2003 event, that's pretty good company to be in.

10.7" was my final here.

Been back to a decent snow after a bit of a lull for awhile. Finally arriving at the 10" mark.

Definitely. Only question there would be if you get that 2-4 within the next hour lol

That’s awesome. 20 is probably doable for you. That main snow band is just sitting over rural Clinton and Lycoming. Renovo would probably be quite the place right now.

I Jebwalked on down to Sheetz just a bit ago. Prob gonna take a good part of the morning to get roads straightened up after the snow stops.

Wow that's impressive, are you in State College? That's a pretty big difference from State College to down here in Altoona if so. I'm between 9.5"-10". Just didn't get those rates in that timeframe with the deform banding settling just west and NW of here.

1.3" of sleet?? Congrats in advance on the white X-mas lol.

Slightly higher than 850mb level, about 800-850 mostly. Here's a cross section of the NAM at 0z at it's 0hr initialization. Did the cross section from roughly Huntingdon county to Allentown with Harrisburg in the middle. That line for producing this cross section is drawn slightly south of Tamaqua. Doing one from here across to NJ with Tamaqua in the middle didn't have that patch of slightly above freezing air but that broad layer of near 0ºC. Likely was just a enough of a warm tongue to do the trick to get sleet.

@jim123 Yep the pivot is starting to become evident on radar. This def bodes well for at least State College. Need a bit of building near Somerset County to feel better about keeping the decent rates here in Altoona, but looks like it's trying to do that.

8.6" with heavy snow falling now. Bigger and fluffier flakes with this current burst of heavier.