MAG5035

Pretty much all guidance except the NAM (until 0z tonight) have been showing good front snows with varying degrees of mixing later in the event (Euro pretty much an all snow event back in our area). The new 0z NAM now joining the party with the bigger front end thump. So def not a fluke or anything, but a little early to be including accums like that in the grid forecasts considering how rapidly this current one went sideways the last few days.

Might as well put up a pic of the “ice board”. A little over a half inch of ice encased sleet. Ice accrual on trees isn’t too notable yet.

Pinging away here as well. Pretty much all sleet falling moderately.

0z NAM def coming in colder vs 18 and 12z with the mixing portion of the Thursday storm. Very intense front end thump of snow as well.

No sleet at all?

Screaming southerly winds showing on velocity near the 850mb level, >60knots showing up. Basically the reason why this has WAA aloft and associated mixed precip driving further and further north has been so robust. With the lowest 0.5º tilt you can make out the general wind direction near the radar site as well, which is out of the ESE. That easterly component at the surface is going to keep temps from going much of anywhere.

Hopefully we can stay more sleet for a good bit of this event. Looking at the dual pol products on the radar with the higher tilts it looks like the mixing layer is still pretty high up.. roughly about the 4,000ft level (up closer to the 850mb level). So that gives a good bit of time for droplets to refreeze thru the colder 925mb level to the surface.

Ugh. At least on the bright side being caught up in the traffic behind the wreck is always better than being caught in the actual wreck itself.

Looks like a pretty heavy area of precip about ready to get to your neck of the woods within the next 30 min.

On a lighter note, CTP point and click FTW apparently with the 6-12" 48+ hrs out just thru Thursday daytime. Boy if only... lol.

29ºF and moderate mixed precip. Call it maybe a 60/40 sleet to freezing rain blend with a little bit of glazed-in sleet accumulation on untreated stuff already. Tonight's gonna suck.

Yea it's def attainable in the warning area. The main consequences of the models trending NW the last several runs are aloft, with much more robust warming at the 850mb and 925mb level, especially looking at today's runs. Surface CAD is still about the same which will maintain freezing rain, and I know it's above freezing in some spots right now but dew points are mostly in the 20s and this is coming overnight as well. I'm hoping more sleet is able to nose down and knock freezing rain down some here. This is my point and click for tonight, then 12ºF for a low tomorrow night, ugh.

The positives I see for Thursday are a better positioned high pressure to the north and the fact that this is coming pretty quickly on the heels of tonight's system...which about the only thing that's gonna be good for other than ice tonight is finally moving the gradient some as we do have some half decent cold that will come in behind. That aforementioned high actually builds overhead before shifting north of us as this next system approached. So I think we can at least get widespread front end snow if this stronger high holds in. That's part of what sunk us with the current one, which I've mentioned a couple times. Problems I see are that the overall mean trough axis is still going to be similarly positioned to where it is now (a bit too far west for my liking) and that's going to present the opportunity for this to track like the current system, potentially sending the surface low up the west side of the apps to an eventual transfer to the coast. Southern tier is pretty vulnerable to mixing in this setup IMO. Looking at mid-level features, even the Euro is a bit left of my liking with the 850mb low (roughly taking that overhead). The GFS and || GFS had a more focused 850mb low that went west and drew a stronger southerly flow and more mix. The stronger surface high to the north is extremely important for front end snow and maybe getting this low pressure under us, although I"m somewhat pessimistic of that happening without at least some surface low reflection carrying up west of the Apps up to at least the Ohio River. Probably don't want this to slow down at all either. The faster on the heels of the current system, the better chance it has at staying under us.

Can't help but marvel at the craziness of this weather event down in Texas. San Antonio socked in with heavy snow and FOURTEEN DEGREES. Brownsville, TX sitting colder than MDT right now at 32ºF and reporting light snow. The Brownsville NWS was saying in their discussion their ASOS sites aren't even equipped with freezing rain sensors bc well, guess that stuff never happens down there lol.

New 0z HREF showing support for upgrading that swath of watches to what would likely be an ice storm warning. This is the accrual algorithm. 24 hr snowfall:

Yea it's not going to get that far over, it's too cold there lol. However, pretty much all guidance has moved to running this surface low up the west side of the Apps basically up to SW PA before it shows any signs of jumping to the coast. That's not going to cut it, we need this to stay under PA. Really the only difference this makes for central PA is it just makes thing's icier (more freezing rain) since there is enough of a CAD setup to hang in surface temps near or below freezing over all the area for a good portion of the event before maybe spiking above freezing into the LSV below the turnpike right at the end. This is going to affect the northern tier's snow accumulation's some as the mixing is likely going to drive pretty far into northern PA now with a track like that. Still should be a half decent snowfall up there though. A stripe somewhere in the central counties is probably going to see a decent sleet accumulation (1-2") where somewhat deeper cold likes to stay anchored. The silver lining? The majority of the main wave of precip associated with the surface low Monday night is out of the area in about 10hrs or so. Then we can focus in on the next incoming mess Thursday.

Speaking of AFD updates haha.

Yup lol just saw. It does make sense since there's still time to review more guidance tonight ahead of this. Saw Mount Holly go right to warnings for half their CWA and figured CTP was about to do the same. So watches on a swath of south-central PA for the heightened ice concern (possible areas of .25"+). Some of the central/north central watch counties plus the non watch counties to advisory for more mixing eating into snow totals and likely more of a sleet event over ZR for the mix type. Also, I understand the LSV folks kind of tuning this out for the Thursday one but this next one starting well, tomorrow is still going to get everyone in here with at least a fairly high impact advisory level winter storm.

Ice storm warnings up for bordering counties over in Mount Holly CWA all the way down to Lancaster. This going to be another event CTP goes straight to warnings for a bunch of counties?

Probably never. That is a gigantic expanse of the southern US under winter storm warnings. And those wind chill warnings that cover pretty much the entire north central US also are including a large portion of those winter storm warned counties. Def a historic and wide reaching arctic air outbreak.

Only real big difference is the more robust high pressure progged to our north and NE for Thursday (and overall in the rest of the CONUS. That was the kind of high pressure models had north of us for Mon/Tues a few days ago whenever it was looking mostly snowy in PA. Helps deflect the surface low to the coast in time and at worst anchors a CAD wedge if the low tries to work up the other side of the Apps. Going to be extremely important to maintain that, because Thursday's storm could easily do the same thing the next one up seems destined to do, especially in the LSV. Mon/Tues storm arrival: Thursday storm arrival:

CTP's latest update on Mon/Tues. I'd be ecstatic with that clean of a storm and 4-6"...but personally expecting a much messier outcome. I'm always a proponent of the cold hanging in better in C-PA than modeled, especially in the interior counties.. but CTP is really bullish inside the area boxed in by I-80 and the turnpike (N-S) and US 219 & US 11/15 (E-W). That area in particular is going to be the hardest to forecast, and clearly CTP is favoring a colder column and perhaps factoring climo in with the track. 12z Euro still the coldest aloft while having the most expansive freezing rain, which I still don't get how the p-types get ZR out of a large portion of the interior central showing solidly below zero at 925 and surface.. and even 850. Issue is, column also warms between 850mb all the way up to 700mb in this zone at least briefly with 700 temps right around 0ºC or slightly above in roughly the eastern half of PA on some guidance. So I think even if the mostly frozen precip did happen here that it could be more sleet than snow, which would easily knock those bullish totals down. Otherwise, my main points from last night's post are pretty much unchanged. I personally think CTP should consider watches for some south central counties (all current non-watch counties NW of Franklin/Perry counties as that would be the region with the best chance to achieve a stripe of .25"+ ice in the very possible event that we get more of a freezing rain/sleet deal vs the more snow/sleet event being portrayed there in CTP's forecast.

As for conditions here it's still 23ºF with a solid freezing drizzle and some occasional snow grains. Untreated stuff is starting to get a really nasty thin glaze on it.

Yea the 0z guidance generally did not help the cause for more frozen precip further southeast in PA tonight. Models trended tighter to the apps tonight with the NAM actually taking the low right through western PA and the Euro getting underneath but showing reflection up into WV on the west side of the apps. GFS is mostly SE of PA but def edged tighter. Having the surface low really close isn't going to cut it here and obviously we're cooked if the NAM was actually right. My argument for a more frozen outcome than being modeled is heavily dependent on the low pressure actually staying SE of PA with some room to spare. That would allow a fighting chance for the surface cold air to bleed into PA more and also a SE track would imply the thermal boundaries aloft are shifted SE as well to where it favors more frozen. Already mentioned about the high earlier with how the portion that stretches north of us across Ontario/Quebec seems weaker and also a bit further north than a couple days ago. This was one of the keys for holding the cold air east of the mountains and helping keep the low SE. Should note that Euro looks the strongest of the models with that particular feature. I would consider the runs at least thru 12z (and probably thru 0z) to see where we're at today and also to have a good look at where this initial wave of precip running up Sunday night is going to be placed before making any rash decisions. But in light of how things look tonight this is shifting towards these main things as it stands. 1- How much ice does the LSV (SE of I-81) see before a potential change to rain. 2 - What the dominant mix type (freezing rain vs sleet) is going to be in the portion of central PA NW of I-81 including places like IPT, UNV, AOO, JST, Carlisle, Bedford, etc. and if some snow can still occur (more possible the further NW one goes). And 3 - How much potential mixing cuts into the more predominant snow potential for the rest of the north-central and NW portion of C-PA (NW of IPT over to Clearfield, St Mary's, Bradford, etc). This still has time to shift back the other way to some degree and the position of the cold air boundary is going to be extremely important, especially with how well the models represent it. This low is basically going to ride this baroclinic zone and it's not going to be something that easily yanks the cold air east towards a rapidly deepening surface low in time.

Thursday was actually the one I was more worried about cutting/p-type issues vs the current upcoming Mon/Tues event . The current system is occurring in the middle of a seismic shift of the NAO and AO neutralizing and possibly going somewhat positive from being like -4 and -6 respectively. With the EPO/WPO tending positive, PNA trending positive, and no intense NAO blocking to counter...our luck is probably going to run out soon with our nice run with a lack of major cutters.