MAG5035

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.

45 mph is the current measured peak gust back this way (around 730p). Temp is back to 38ºF

Nothing crazy to report here, I ended up going through a broken part of the line and didn’t even get a downpour. Only a gust to 32mph with the passage. Getting some higher gusts now post front (up to 34 mph max gust so far). Temp falling rapidly down to 52ºF… a 10 degree drop in the last 30 min.

Have to acknowledge the winter threat coming up on Wednesday, I know I haven’t been posting as much lately. The key thing I see for this is simply where the best QPF and rates set up. It’s as simple as that really, given good agreement on progged low track to the south of PA and sufficient cold for a snow column. We go through this Every. Single. March/late season. If the rates are there, the snow is going to pile up on more than the mulch.. and that includes roadways and everything else in between except maybe @canderson’s property lol. With that said, having chilly but somewhat marginal surface temps and the higher March solar insolation… an event with light rates (and/or the fringe areas within the precip shield) is probably going to have some trouble accumulating on a lot of surfaces outside of higher elevations. Most guidance and ensembles are showing decent rates/amounts over a good part of our subforum. The NAM seems to be the least on board for a widespread heavier event in C-PA actually having the axis of heaviest QPF running the northern half Mid-Atlantic forum’s turf and also our southern tier. 12z was pretty nice, however the new 18z has the same axis but tightened up the good QPF. It seems like the biggest amounts in play for this event is probably going to reside in the 3-6” range. Again, rates are important.. especially with this being progged to be generally a daytime event.

Not to snow on everyone’s Spring/Sixers parade haha, but I do have a changeover and some snow to report this early morning (dusting). 511 cams just up the hill from me in Cambria look to have gotten an inch or so.

February was the first full month for my weather station so here were the basics for the month. The 30.2ºF mean looked pretty close to average compared to the local climo (KAOO) despite a handful of days that did spike up into the 50s and a couple 60+ days.

Well the reason for less freezing rain in this general area and at least the eastern Laurels was because most of the precip fell as sleet. Surface temps weren’t super cold, but that 925-900mb layer definitely was.. and it held fast for the most of the heavier precip in a pretty big chunk of the central. The main warm advection push aloft during the bulk of the event came higher in the column from about 850-700mb level. There’s no input from terrain or CAD that high up to delay or mitigate a strong WAA push, so that can often overachieve… hence why it mixed all the way into NY and north central PA didn’t see much actual snow at all. 830am this morning I measured 1.5” of sleet this morning and what I could guesstimate was about a tenth or so of ice… which has all melted off the trees this morning. Most of the sleet accum will definitely remain on the non-paved surfaces, but roads are in good shape now. It was real mess to clean up, I had to use the snowblower to remove it. But considering I’m in one of the 4 counties under a wind advisory this afternoon, I’m glad freezing rain issues weren’t huge. Extra bonus.. that 1.5” of sleet is technically the biggest snowfall I’ve had this month lol.

Pouring sleet right now, probably about an 80/20 blend IP vs ZR. Approx 1.2” of sleet accumulation. 31ºF/30ºF

Close to an inch of sleet on the ground. Think we’re starting to transition towards the ZR phase but precip is still about a 50/50 blend of sleet and freezing rain. The sleet on the ground is starting to firm up with more ZR in the mix but so far accrual is still in the glaze category and not really measurable yet. 30.7ºF/28.1ºF temp and dewpoint. Winds are up a bit, gusting past 15mph at times and mostly southerly.

RIght at a half inch of sleet now. Still mostly sleet and it’s pretty heavy at the moment with some large pellets. The street was actually plowed about an hour ago and the sleet’s been building back up on it. Temp up a bit to 28ºF after bottoming out around 27ºF around 11pm.

You’ll have to see what the p-types are when that heavier stuff on your doorstep coming at you from the southern tier gets there.

An hour into sleet bomb 2022. Hey it can keep doing this over having a half inch of freezing rain.

Precip arrived just before 10. As expected, full blown pingers so far… with a tad of ZR in there enough to have a glaze on most non-treated surfaces. Already getting on the roads despite the road crews being on the scene. 27.5ºF.

Currently 28ºF/21ºF. It’s looking like this event will be rolling by about 10pm here.. gonna be a mess.

I wouldn’t write off issues completely. Yea surface temps got a tad freezing today, they were supposed to. They should fall below freezing when precip arrives. Here’s what the 23z HRRR just initialized 925mb (3000 ft) temps at. They’re about 1 degree or so warmer at precip arrival around 4-5z. But yea -6 to -5ºC is about 21-23ºF. Pretty decent depth and strength of the low level cold, so that depth suggests to me sleet’s definitely in the equation the first couple hours all the way to the mason-dixon despite what p-type maps show. Here’s THV’s sounding generated from the HRRR at 05z (approximate precip arrival). The warm nose is elevated but easily notable, but the column is below freezing from 900mb (approx 4k feet) on down to the surface. Otherwise I think CTP’s forecast/headlines are fine, though I probably would’ve considered a few more central/south like Centre, Huntingdon, Fulton, Franklin, for maybe a bit more freezing rain and less sleet. If 925-850 air advects in warmer/faster that could mean the I-80 counties also get 0.25”+ ice in exchange for a bit less sleet/snow. That’s definitely a distinct possibility as well. I do think as noted by a few in here that QPF might be a thing in the LSV as noted on the newer NAM runs. If that’s the case, that’s probably a bigger limiting factor in higher ice totals than temps IMO. This isn’t Feb 3-4, the CAD is already locked in for most of the night with the precip attacking it.

I just saw what the 18z Euro had and quite honestly it’s absurd what it’s p-type conditional has vs looking at it’s column temps. I made a post about that with the 12z run and I think 18z run is even colder. It’s even colder than the NAM aloft with all the NAM’s sleet. So the Euro is printing out all that freezing rain in southern PA while at the same time having BOTH 925mb AND 850mb temps below zero in the entire LSV except near the Mason-Dixon Line at HR 36 and 39, which are significant precip frames. One thing or the other might be wrong, but if there is that cold of a column I can guarantee freezing rain isn’t going to be the dominant p-type during that portion of the storm.

I think the 3k NAM’s ice map might be about the most reasonable ZR map I’ve seen all day. Since the NAM seems to be the one seeing the sleet the most, it makes sense that it paints the ridges in 0.25”+ while having less ice in the valleys, simply because that extra 1000-1500’ to fall and refreeze into anchored down CAD at the surface. I know it seems like I’m conducting the watch/warning train in here but I’m also not expecting a widespread excessive damaging ice event either given the depth of the CAD that should be present (more sleet). My point was just that a good portion of C-PA has more than a reasonable chance of seeing 0.25”+, hence maybe issuing a watch product when there was still 24-36hrs prior to event start. I think the only part of central PA that actually does see something more excessive on the order of >0.5”+ is the Laurel’s. It’s going to be a rough go up there.

Yea I don’t know it’s whatever I guess…like I mentioned this morning I don’t know why you don’t put a blanket watch out for at least a big chunk of the CWA and go warning/advisory as needed when you see where the sig ice swath is looking to set up in the near term. It better warns the public IMO. Most non-weenies aren’t going to read the HWO haha. It was even mentioned in the discussion this morning about issuing watches/warnings even if it’s just short of criteria due to the impact on roads. I mean the model support for warning criteria as well as WPC probs has been there for at least issuing a watch for the potential over a good bit more of the area than they have. At any rate we’re less than 24hrs from this starting and It’s likely to at least be a higher impact advisory event for most. 1-2”+ of sleet followed by 0.1-0.2” of ice isn’t gonna be much better on the roads than up to an inch of sleet and 0.2-0.4”+ of ice.

I do remember reading that previous post and I didn’t really read it as him suggesting winter was over in that post. I’ll have to find it again at some point. I mean it is a fair take now that we’ll be entering March in 5 days, especially in the LSV. But aside from trying to hash out what the MJO is going to do, I see the EPO/WPO forecast to take another dive second week of March and now the NAO/AO being forecast to at least neutralize in that timeframe as well. Yea there’s going to be more spring fling to be had the next couple weeks and AC’s cranking and @candersonis going to be doing more planting and garden prep haha… but you get those teleconnections lined up and start getting shortened wavelengths with the seasonal transition in the right spot and suddenly you might be talking about maybe not another wintry mess, but a clean snowstorm. March is going to March, aka be unpredictable. Enjoy it haha, that colds coming fast. It’s down to 35ºF here.

Is he talking about final for the month of February though? Sun/Mon is still in February and that potential event seems to be by the wayside. There’s some conflicting signals, but given what I see overall teleconnection wise the next couple weeks there’s no way in heck I’d just call winter off after Friday.

It’s scrutinizing time. Here’s the Euro at 42 hours. 1 hr ptype 2m temps 925mb (3000ft) temps 850mb What part of all that would make one think such a widespread area of freezing rain in southern PA? The -3 to -6ºC 925mb temps alone easily suggest to me sleetbomb and the 850 level isn’t even evacuated out Harrisburg and north at that point. The p-type map is really suspect to me if those low level temps in fact end up that cold.

The timing of this event being mostly Thur evening into Fri morning favors freezing rain accrual with say 30-31 temps, esp if it starts as and/or mixes with sleet. If this were primarily coming through during the day we are getting within that time of the year where solar would have an impact on such things.

I generally agree for main roads if freezing rain is the main mix p-type, but if it starts as a sleet bomb there will definitely be roadway issues… which I don’t think that map product even considers. That map is generated off of whatever CTP and other forecast CWA’s have input into their grid forecasts and those impacts are calculated off of certain criteria (ice, snow, blowing snow, flash freeze, ground blizzard, snow load), which can be separated out on the WPC site. You can see the difference between grids for CTP and PIT.

Oh yea, gotta have cold air if we’re going to get a wintry mess tomorrow eve haha. Pretty wide ranging temps across PA currently.