MAG5035

It took a minute to jog my memory since I was thinking of another late April cold snap and snow but yes I remember this storm. In fact, the C-PA thread at the time is still back on about page 10 of the Upstate NY/PA forum ( I linked it below). Obs/pics were discussed roughly in the Page 18-20 range and I didn’t get too far into it but I’m sure there was plenty of lead up discussion. Really shows that the C-PA thread has been going for a long time (with several of the same personalities as well) haha. Anyways, I think that storm was a stronger one but I do believe this one might have better preceding cold. Certainly at 850mb.. this event looks to be starting tomorrow with temps at that level easily below 0 in central/eastern PA. We actually don’t need the dynamic top down cooling to initiate changeover as it will already be cold enough. It’s a matter of overcoming warmer boundary layer temps which is where the elevation factor/solar/timing plays in. Back with that 2012 storm, it went from zero accumulation in the valley to 6-10” at the top of the Allegheny Front here. I honestly don’t expect that kind of variability with this as I’m expecting something notable on the ground at my spot (at least a couple inches). This probably doesn’t have a problem mixing with snow in a lot of places into the Sus Valley but if there’s a clean transition period in some region of C-PA with heavy rates then I think all bets are off and decent accums happen in lower elevations as well. I still think you need to be above 1000ft and west of the river for seeing any accums.

I think it’s possible it could mix with snow some in the metro areas, or certainly at least the Harrisburg area… not sure about all the way in York/Lancaster though I certainly wouldn’t say the chance is 0%. I do expect it’ll be mainly rain SE of I-81 except for some of the ridges which may have some snow and maybe some minor accumulations. The low track’s pretty good if not a tad inside but it’s a matter of getting cold enough air to the low levels in eastern PA and this is a more dynamically driven setup with getting it cold enough. So I don’t think it’s quite there to get much into the Sus Valley. Between here and the Susquehanna River in the ridge and valley region will likely present the greatest variability in potential snow accums from an elevational standpoint with the deeper valleys. This is probably a >1000’ elevation type deal to see accums and like a >1500-1600’ to see advisory+. A total collapse of the column and heavy rates could mitigate the elevational variability but that seems mostly likely to happen deep in the central and esp northern part of the state.

Had some flurries this morning. This makes it 2/2 for snowing on Sunday this month and the last 3 Sundays in a row.. I’ve been fairly busy and not able to post much but have been keeping an eye on tomorrows system. It did catch my attention that models across the board have been pretty robust on accums the last few days in the central counties and it looks like CTP is finally starting to oblige to that reality with ramping up their grids. It’s probably not enough either. Laurel’s and north central counties are likely looking at some kind of a headline event. This is obviously a highly diurnal and elevational situation, seems like arrival of significant precip is slated for the late afternoon and going into a good bit of the evening. It looks like a pretty decent slug of moisture so that coupled with the developing coastal low will probably promote a quick changeover to snow in the central counties and remain so if rates remain steady and moderate to heavy. If it’s heavy it will eventually accumulate on most things despite all the ad nauseam springtime disclaimers, especially getting towards the evening (after 5 or so). Not sure what to expect here, though the top of Wopsy 4 miles up the road from me at 2400’ (and similar elevations in the Laurels could get a lot of what the new 3k NAM is throwing down. Down here? It very well could end up an advisory type event with a quick decisive changeover and heavy rates. Certainly expect to see some kind of accumulation at this point being at 1300’. I will say the overwhelming factor in favor of me seeing 8-10” is the fact I rolled the dice and I pulled the mower out of the storage garage and put the snowblower away yesterday.

Definitely, and he barrels up on this wreck seemingly unaware at a point when people are out of cars and stuff is on fire. Do a lot of truckers just not utilize things like CB radios as much anymore? And I even hear a CB radio in the background toward the end of that video.

Temp was briefly under 20ºF with the passage of a brief snow squall. 25.5ºF is as high as it’s gotten this afternoon. Peak wind of 41mph today. Just a brutal day as March 28ths go.

Insane cold temps aloft today, certainly a big driver in terms of lapse rates and instability with these snow squalls today and their long reach away from the lakes/mountains. Then you add in the late March solar/diurnal component. Core of cold at 700mb is moving over PA this afternoon with near -30ºC temps. Given heights, that’s only at approximately the 9200ft level. You have to go above the Arctic Circle to see similar cold at that level anywhere else in the N Hemisphere.

Well for some of the western and northern zones, that next nugget comes tomorrow in the form of a sneaky clipper haha. I don’t think much of that will make it into the Sus Valley though.

Some solar (shortwave) radiation will still radiate through clouds, even in overcast. Speaking of solar, despite having temps in the low 20s (down into the high teens at times in snow showers) all afternoon, my driveway has mostly melted off despite having the full accumulation on it early this morning. It gets direct sun plus its a newer blacktop surface so it will still absorb solar despite all that this time of the year. 4.5” is probably going to be my rough total, although I’m going to measure around some. This stuff really blew around.

I think that band has more to do with the larger scale forcing aloft, as it has propagated eastward and it’s currently residing from about a Mount Union-Lewistown-WIlliamsport line. It’s actually not ideal orographically on the east side of the Laurel’s. Being an anafrontal type setup vs a more traditional coastal storm there’s no low level easterly fetch that will help enhance from that aspect. If you look closely at CCX radar (and LWX as well) you can see the low level flow is actually northwesterly and even see some of the lake enhanced stuff propagating NW-SE underneath the synoptic precip shield that has the deep southerly fetch aloft. Part of why the good rates will shut off quickly and not linger once that max forcing moves out of the area early this afternoon.

Lighter rates now but the wind has really ramped up in the last 15min with the temp falling further (from 24 to 22ºF). Recent high gust to 29mph. It’s gonna be hard to measure additional snowfall.

Just measured 4.3”. So that’s roughly 1.5” in the last 45 min or so… a straight fluff bomb. Rates back to moderate.

Getting into what’s probably going to be the money band with this. Heavy snow and now 23ºF.

Moderate to heavy snow currently and a decent breeze. Have had some 25 mph gusts. Temp already down to 24ºF. Closing in on 3” here so far and it’s a nice powdery snow that’s already doing some drifting.

Haha I’ll make it simple. I think pretty much everyone in here is good for a mainly 4-8” type event. Actually my biggest concern at the moment resides in my own general area, having watched the 3k NAM and also the HRRR at times showing a soft spot in accums in this particular area (between about here down to Cumberland,MD) between the now established precip shield in western PA and the slug associated with the low itself that arrives from the south. That could cost me a warning snow if that came to fruition so I’ll definitely be watching how things evolve overnight with that. Other than that, I really think everything looks good for everyone to see their biggest snowfall of the season and likely a warning type snowfall. I think the ceiling on this in C-PA is probably 10” max.

You’d be surprised how fast the 93 superstorm moved. It actually occurred during a +NAO state. The low center went from the northern Gulf off the FL Panhandle to exiting New England in about 24hrs or so. Obviously the insane phasing situation and setup made that a way bigger storm.. This one’s still dynamic though and it has the far reaching significant cold to tap into as well.

Frontal passage noted just before 11pm here. Temp/dew is down to 40/34. 511 cams in and around the Pittsburgh metro are rockin pretty good with snow on the ground (main roads still mainly wet).

There wasn’t a point I’ve seen anywhere near 2 feet being portrayed anywhere in PA with this system. The NAM and couple global runs (think mainly the EC and Canadian) have tried to present a 10+ swath at times but that was like a 10-15” type range. I did look back and saw the 18z NAM that was posted last night. That still seemed like a pretty big exception to what has mostly looked like more of a 6-10” type event on the high end. That’s the thing with this, up through the first part of yesterday this was still looking like a western half of PA bullseye. We’ve made a pretty big shift east to get the LSV fully involved. What that also means is this has became more progressive to get us there, so that’s going to take the top end off accumulation potential. It still looks like it could easily be the biggest snowfall of the season in parts of the LSV regardless, so I guess it’s all in one’s perspective of what’s a good storm.

I wouldn’t say it’s overdone, this is easily a 6-10” (or greater) type event for wherever the swath sets up. It’s a timing thing, NAM seems to both press the front pretty well and hold back the wave long enough.

Haha, time for the role reversal. Trying to nail stuff in the Sus Valley has been extremely frustrating for me this winter. With this setup I’m only going to acknowledge the western half of PA has the best chance of seeing what could be significant snow (6+) for now. I do agree on the flash freeze potential and likely some kind of snow accumulation with a big time shot of cold being pulled into a very rapidly deepening coastal low. Models, especially the global ones have been too overzealous on the eastern edge of snow swaths so I’m taking some pause for this. The potential for a good snow event for everyone is there though.

Still getting some snow bursts but additional accumulations have stopped with max solar and temps around 33ºF. Have measured 3.4” and it’s definitely a wet snow. Most roads are now wet. This was basically on target for what I was expecting here. As I mentioned in my last post, problem for the Sus Valley was the best of the precip shield ending up tracking northwest. Rates would have overcome the marginal temps. But as it is, the result is the north-central being upgraded to warnings being a couple degrees colder and ended up with the best of the QPF.

I’d imagine it’s cashing in at least about as much as here. I’m nearly 2k feet lower than Blue Knob summit here off the Allegheny front and I’m over 3” now. Surely it’s at least a couple degrees colder up there. They may not be getting quite the rates though. The big thing with the storm evolution I’m seeing this morning is that the best precip/rates is running western PA to central and esp northern PA above the turnpike. Pretty much looking like best precip is going the HRRR route (more NW axis) as opposed to even what the 6z NAM had this morning and especially what most 0z guidance had overnight. That’s unfortunately to the detriment of the LSV, which needed the rates the most to overcome the marginal temps. At any rate, I’m not sure how much keeps til the weekend up there as we moderate prior to the next system. Good news though is the western half of the state is currently well positioned for potentially an even bigger snowfall with Fri Night/Sat’s system (especiallly in the higher ground) and a significant cold shot for the second half of the weekend. It’s unfortunate that what is looking like one the best synoptic snow weeks of the winter (with no stupid mix and ice) around these parts is coming after half decent conditions at Blue Knob were hit pretty hard by the mostly warm and wet weather the couple weeks.

Already at 2.3” and moderate/heavy rates here. 31ºF

Snow has begun here, light dusting. 31ºF/26ºF

Current temp/dewpoint is 30ºF/23º. My biggest unmixed period of snowfall this winter was the Jan 16th event with 5.2” prior to the mixing and 982mb low going over my head. So having a look at things this evening I honestly give this event a slight chance of beating that here (Thinking about 3” in the backyard is a decent bet). I tend to agree on the elevational nature of this event to a point and marginal sfc temps and whatnot, but I personally think it’s being overplayed with this setup. Like okay, I think most 4-6” or so amounts if they show up are likely going to be in the north-central and/or on the higher parts of the ridge and valley. However, this is a pretty decent slug of moisture coming at us being a southern stream system. If it comes in rocking rate wise right off the bat, elevation is probably going to matter less. Arrival time per the HRRR ranges from a couple hours pre-dawn SW to about 7-9am going LSV to northern tier… thus solar isn’t going to have too much of an influence during the first part of this event. Big question mark for me is right on the southern tier LSV, but even the more northerly HRRR manages a couple inches there. I will say that there is a chance that the southern tier LSV may mix or rain at the very beginning before cooling the column enough to snow when the heavier stuff sets in, so I wouldn’t get too scared right off the bat. I know it feels like I’ve been at odds with CTP’s thinking pretty much every winter event this season when it comes to discussing my thoughts in here, but I do think this warrants an advisory for most or all of CTP’s CWA. Like I said, I think this is elevational to a degree but not enough so to think that a majority of the Sus Valley can’t manage 2” to verify an advisory (or 3” in this neck of the woods). Hope they’re right, because the heavier stuff arrives during a big portion of the morning rush tomorrow. They must be going off of the NBM (national model blend) pretty hard, because this is about the only guidance I can find that jives with their accumulation map well.

I’m sure one would have to be at some point if the models hold with things. CTP doesn’t seem to be really acknowledging this as a strictly snow event anywhere, painting it as starting as snow/ice and going to a mix (rain/snow) during the day in their grids and referenced in their AFD. I mean i kinda agree that if we don’t have moderate or heavier rates that this could mix with rain in low spots given marginal surface/near surface temps but otherwise thermally this appears to me to be a strictly snow vs rain type event and pretty much all of our subforum has a sufficiently cold column for snow.