jwilson

Here's a color map to go along with my prediction. So the locations probably aren't perfect. Forgive my color scheme and photoshop skills (this was a quick job). It's more of a general idea. I'm mainly posting this to see how well I do versus the models and whether they are properly estimating the warmth, or if personal experience is the better rubric. In terms of sleet: though I don't include measurements for it, there could be inches of sleet in those areas highlighted, obviously more as you go north in and around the city metro. Ice calls for the possibility of freezing rain. I don't imagine there will be significant accumulations of it, but a quarter inch+ in some localized cold spots isn't out of the question. I do hope I bust low on these numbers, particularly south of the city, but I'd prefer to go conservative when there's a mixing possibility.

Update for next week's system: I'm watching the 12Z GFS and notice a lot of energy hanging around at H5. Obviously, the initial wave is a cutter and does us no good, but after that we see a bit of packed dynamite hanging around in the south and down into Mexico. This is at hour 126, so it isn't fantasy range. The present evolution of this isn't useful for us, but what we could eventually get to is a classic Miller A if the NS drops in and phases. We'd have the 50/50 low and a high pressure to our north. Too early and west with the phase and that's bad (like the CMC shows), but if the low develops in the Gulf and pushes east, then phases, we have a pretty significant storm that would probably be decent for us. It goes without saying but it all depends on the location and timing. Despite the rain storm ahead of time, there is a possible out to another good event next Thursday/Friday. I guess we'll see how it goes.

I forgot to mention there is a slight freezing rain hazard possible for places that change over to rain. If the surface doesn't warm as much as the 850s, which is possible if the primary low stays as far south as some models indicate, southern Allegheny into Washington and Greene counties could see a prolonged freezing rain event. Maybe .25-.50 which is a lot of freezing rain. The 3K NAM does push surface temps up to 33-34 or so while the 850s stay below freezing, so that's more of a sleet/snow or even plain rain signal, but the opposite is still possible.

Yeah, despite the 0Z NAM shift from last night, I don't see enough change to make me feel all warm and tingly. I think this system is setting up for disappointment from city points south. I'll say 2-5" (of snow) in the city and points south, with about 1-2" around the Mason Dixon line (mostly after temp crash). There will likely be an area that gets 2-4" of sleet or more on top of that snow, perhaps somewhere into Northern Allegheny just above the city into Westmoreland and Armstrong counties. The jackpot zone will probably setup into Lawrence, Butler, and Clarion counties running northeast, and of course more as you get into central/northern PA. Hopefully February brings more success. Of course, we get another cutter this week followed by a clipper parade.

The ICON didn't really change at all, but in fairness it's a lesser model. I don't know if it has any biases. If the GFS and/or Euro look the same and don't follow the NAM, then it's a concern.

NAM verbatim looks like ~1 hour of sleet in extreme southern Allegheny, obviously longer points south, but otherwise is all snow. It's still very close to too much WAA despite the primary shift from northern WV to southern. Talk about threading the needle.

Hmm... NAM could be a sampling issue, though I've noticed this "clipper" wave is coming in colder (maybe more south) than some of the models expected. I won't get too excited until we see if the GFS, among others, follow suit, or if the NAM simply flips right back north at 6Z. It led the way in 2016, so I won't totally discount it, either.

We're well below normal so far (if we finish that way, it would make 3 of the last 4 winters). I agree that expectations for this winter were high. Things looked to align, but at this point, we're going to need a backloaded winter. The blocking that I think we require continues to be two weeks away in the long-term. Maybe by February it will actually coalesce. I'm hoping we don't revert to a bad pacific pattern or lose our moisture conveyor if the blocking comes together, but that's always possible.

I honestly don't know much about your area. Had to google the town. Are you near Uniontown? What's your local microclimate like? It looks like you'd be in the ridges and susceptible to upsloping (orographic lift) thus more snow potential. If you get stuck in the warm sector like the rest of us south of Pittsburgh and west of the Apps, then you'll probably get no more than the city. Still waiting until 0Z, but right now even the meso models aren't promising. 3K NAM takes the line into Butler and almost north of Armstrong.

I'll make a guess after the "clipper" rolls through and the 0Z model runs, but I would think 3-6" for places between Washington and Pittsburgh is a fair call right now. I'd still err on the side of lower figures, probably with either more rain or a couple inches of sleet cutting back snow amounts.

Always a bridesmaid ...

AFAIK, Al Roker isn't even a meteorologist. He has a B.A. in Communications. The people behind the scenes are probably using the GFS mostly, or some kind of blend. Right now, though, most of the models aren't on our side if you're looking for heavy snowfall.

The Euro control and EPS both were north of the OP this morning. That's a bit of a red flag at this juncture. I'd bet even the Euro and Ukie maps - which look decent enough - look much worse if you filter out sleet. The NAM basically gives the metro area a foot of sleet. Wouldn't surprise me much if a lot of that turns to rain in real-time. My confidence is waning. I haven't jumped off the bridge just yet, but I have my toes to the edge.

Well, the good news is the Euro and Ukie both stayed south and worked a transfer to the coast (again). The Euro gives us almost zero breathing room. I would think, with the tight gradient that close, those of us south of the city probably get some mixing. If not rain, then sleet. The Ukie looked a lot like the 12Z Euro from yesterday and is much more comfortable. The bad news is the NA models are adamant about a stronger phase and cutting the low up into Pennsylvania. The GFS is consistent, at least, and only gave us something notable back on Sunday. Since then, it loves the interior New England special. The NAM is a bit closer to workable, but still brings up too much WAA. The ICON has moved south, though the evolution is a tad odd, with multiple lows on the boundary. Despite the move, it again begins phasing too soon and pushes a southerly flow north. I can't think of any examples off the top of my head, but I'd be curious if anyone has recollection of a storm where the propagation of the warm tongue stopped between Morgantown and Pittsburgh. Perhaps say as far north as Washington.

Unfortunately, I have to think cwc is correct. Anything remotely borderline and we'll probably lose the fight to rain. Now I haven't been living near the city long, but I'm very familiar with the warm tongue, and I don't see a fresh source of cold air to keep it at bay (unless there's something I'm missing). If the primary tracks on a line from Kentucky to WV, we're probably warm. If it goes through Tennessee and waits until Virginia to pivot or transfers to the coast, we may be okay.

0Z NAM - still at range, mind you, so somewhat limited utility - has the primary low crossing through Kentucky. That's too far north. Huge WAA surge in the end. There would be a snow to rain to light snow scenario. Not a great solution, pretty much blends the GFS and Euro. Unfortunately, we basically need all Euro.

That's a good point. I really don't know much about these off-hour runs. However, the 6Z continued the 0Z movement which ran into 12Z. For the 18Z to go back the other way makes me a tad nervous. Perhaps we won't like what we'll see at 0Z, or maybe it's nothing. Here are the last two runs compared: You can see the gradient has moved up into southern Allegheny. Of course, the snow isn't entirely finished in the bottom run, but it's probably done for our area.

18Z Euro a slight tick north, more in-line with the Ukie. I realize it was relatively minor movement, but we don't have much more room to go in that direction. I suppose the relative consistency of the GFS since Monday shouldn't be discounted. I guess we'll see how the 0Z runs go, but any more northward shifting and we're in barney.

I don't normally trust the NAM at range. It does show a potential outcome, however, where this is more of a frontal boundary system that moves through and ends without redevelopment. The GFS cranks that initial wave from Thursday as a 50/50. The NAM has less confluence. I will say I'm not sure if the NAM would actually be done when it cuts off, as it might still try and develop a secondary low offshore. Of course, it would probably be too late to give us more snow, but it could come down to timing. The Euro and its ensemble members are clearly favoring redevelopment, seems right around New Jersey, and that's part of the reason it has less of a rainy influence.

Yep, time to hug the Euro. Sadly it is on its own. Even more south of the UK. 16" in Allegheny. Best model to have on our side, but I have to wonder if it is downplaying the warm-air surge while the GFS is over doing it.

12Z roundup so far: High-res NAMs look like all snow for tomorrow's event. The GFS is less certain, poking in the warm tongue. City on south would probably mix verbatim. As for the weekend, the GFS remains consistent with a north and more phased system. FV3 and Icon much the same as the GFS. The Canadian is going to look the same once it gets out to range. The overnight run of the Euro was a continued improvement from 12Z yesterday, we'll have to see if it continues that trend or folds to the GFS. The Ukie last night was also much farther north than yesterday's runs. Overall, I think this is one of those systems that comes down to the wire. Meaning: even as the event starts, we aren't quite sure what we're going to get. We have working against us a lack of fresh cold air, as evidenced by the shortwave that may not even stay frozen, and zero blocking. We don't really have that banana high anymore, either, until late.

The NAMs at range look like all snow for that pseudo clipper Thursday. Won't be much, but hopefully it stays all frozen. There were improvements on the Euro at the upper levels, so not all is lost, but I'll be extremely concerned if the Ukie folds to the Euro/GFS camp. Outside of that, we still have to get into NAM range for the main system to completely give up hope. Things certainly not ideal right now.

Euro is brutal. Over 65 miles, you go from 2 inches to 24. Unfortunately, it's been somewhat consistent now. I'd feel a lot better if it was flopping between solutions. If we could ever get the blocking and this juiced southern stream to connect, we'd be fine, but we'll probably lose the moisture as soon as the blocking kicks in.

As far as I see it right now, we need one or two things to save this one from going north like the Euro and GFS intimates. Either the low remains less amplified and more strung-out, and perhaps delays amplification until it gets East of us (seems unlikely given the overwhelming model "consensus" this early), or we get a northern stream pulse, some kind of PV lobe to help suppress the low to our south. We don't have much in the way of blocking which is a serious problem, but we do have an advertised banana high, which may be too far north, and a potential 50/50 low to slow progression, which is the evolution of the Thursday/Friday shortwave. Oftentimes with these bigger storms, you'll see a table-setter event that basically portends where the snow will fall. As it looks like the pseudo clipper will push too far north to prevent a changeover, I worry the storm behind it will follow the same path. That second low would look better in Tennessee or even further south. If it tracks right over Kentucky, we're in trouble. I'd rather have one of the GFS or Euro on my side right now. I have much less confidence in the iCON and Ukie.

That's really not unusual in this time frame. Large jumps in precise locations are relatively normal 4-7 days out. If it still looks like that come Thursday or Friday, then we can be concerned. Aside from that, the long range is showing some REALLY cold air dropping into the CONUS (as low as -22F locally). That will probably moderate in the mid-range, but we could see some bitter temps.