MAG5035

18z GFS pretty close to making a decent event with the potential Valentine’s Day-ish storm. Actually for the forum majority (LSV) it’s pretty good H-burg south. An improvement from 12z which had a lighter area of snow run the Mid-Atlantic but not getting into southern PA. Looks like it’s generated from the northern stream energy attempted to interact with the southern. Canadian today also had this (pretty light) while the Euro was a nothing burger. Definitely don’t think this threat is dead. The pattern alignment is there in that timeframe that if we can get good interaction/phase in time, this can be the type of event we’ve been looking for. This could also turn into another 1/29 (in terms of placement of best snow) if this comes back toward the storm scenario but not in time for us. Or… it could be nothing, but I think we’re already aware of that possibility. Either way this is still D5-6, which has felt like the limit this winter for the models starting to consistently start dialing in on something. Not that they ever are consistent at that range and beyond but models have seemed to have more trouble than usual in the mid range this winter. Likely due to the progressive pattern and many moving parts.

Some updated thoughts on the pattern. The quoted above was the large post I made back on Jan 28th for reference and review. First off that was at the time, in the 5-7 day range of what was for most in here our messy waste of QPF last week…but it did remind me that the event at that range had started on most modeling as a mostly rain event and a more pronounced warm-up. And while it did end up mostly rain for roughly SE half of PA, it did end up being more focused on the second wave and cold did get into western/northern PA to make for a half decent ice and snow event by the end. And western PA cleaned up some Friday with the remaining deform snow. Anyways, main focus on this post is the pattern going forward. There’s really no big changes to my overall thoughts, especially the portions of my quoted post I bolded. We really are going as the Pac goes in terms of the teleconnections with a +NAO/AO. This week, we have troughing over Alaska which cuts the Siberian connection and also turns the source region a bit more Pacific-ish even though there is still solid Pac ridging. Additionally. we have a pretty established +AO. Both of these things will act to evacuate true arctic air out of the CONUS. Still, our region will have seasonable chilly weather with a couple bouts of days with somewhat above average temps. Other issue with these points is the storm track. Clearly a northern branch dominated week with several clipper waves running it. However, the pattern alignment has the mean storm track taking the clipper lows fairly well north of PA. The result of this becomes the aforementioned bouts of above average surface temps with the milder temperature pattern and W/SW flow ahead of the clipper systems. This also usually presents downsloping issues east of the mountains in said W/SW flow with precip. Definitely a week we could have benefited from even just a little bit of help from the NAO/AO realm. Next chance of a bigger system appears to be roughly near Valentines Day, but there’s several issues to overcome there. Lot’s of different moving pieces is one issue, especially in the northern branch. That has been a theme for the last month or so since we’ve established the colder regime back in early January. Timing a phase with a less robust southern stream and associated issues with ejecting energy out of the SW US/Mexico is another. Still a chance to be be watched though as we do set up a western ridge/eastern trough for this timeframe, but currently it looks too progressive and not enough dig and interaction of features… with progression likely enhanced more given +NAO/AO. These are common Nina issues which by the way, we are still in presently (NDJ ONI average was -1.0ºC). Despite that, some of the US precip patterns have been very non Nina-like, especially in the Pac NW. A drier California is a pretty common thing but the Pac NW usually has above average precip in a Nina. They’ve been shut out the past month just like California has. I suspect that has had to do with the anomalous and very persistent northern Pac/western US ridging.. which has helped us stay in the game for systems (with not a lot of luck locally) and have provided us with the colder Eastern US version of the La Niña state temp-wise. The MJO has indeed tended more towards Phase 2/3 in the last week, and is forecast to remain in that realm at least in the interim.. esp on NCEP guidance. Those phases are “colder” phases, and the trend has staved off my worry of a renewed pulse running 4-5-6 during the business end of February. Something like that would have likely helped move along the type of wholesale pattern change in the Pacific that would have taken us out of commission in the East. The Pacific teleconnections still look workable, with the EPO/WPO trending back negative. Those two tellys are starting out neutral (WPO) to positive (EPO) this week as part of what had been a forecasted brief reversal from both being persistently negative. And you can see how we quickly lose the really cold air out of the pattern in the CONUS with that brief reversal. The cons are no help from the NAO/AO (pegged at a solid positive), and some trending toward a negative PNA toward week two (esp on Euro and CMC ensembles). So that’ll be interesting to see what that does if it comes to fruition. I suspect a negative PNA would instigate more storminess and precip across the CONUS but could put us on the wrong side of it if it’s too strong given +NAO/AO. This all boils down to me having the opinion that the second half of the month could be a good bit more active than what the first half is presently shaping up to be (sans the Feb 4th event).. but with that could come more swings in temp anomalies and less persistent cold. That’s nothing really groundbreaking for how the second half of February typically goes, but the chance should be there to cash in on something.

Yup, there’s also part 1-9 of coverage of this on Youtube, since you guys have been reminiscing about old school TWC. Jeff Morrow traveled west from H-burg to Breezewood to cover the snow. This was a huge storm, especially between here and Pittsburgh but this area had about 2 feet. State College had 18” despite turning to mix/rain mid-storm.

This area back here usually does mix and ice events like I’d imagine Worcester, MA does New England nor’easters. Even with how quiet the next week looks you’ll probably see some more snow up on the plateau with the NW flow.

My totals were approx 0.1” of ice, a T of sleet and a T of snow… oh and 2.02” of regular rain. State of the snowpack, that snow hole can stay on my neighbor’s side of the tree line haha.

One thing I forgot to mention last night was Penn State Main Campus actually cancelled classes today for this event. You could imagine all the “back in my day” comments that came from that decision.

Woke up a bit ago to freezing rain and sleet here and temp down to 31ºF. Never thought I’d be so glad to hear the pingers. Driveway, deck, and cars are pretty froze up. There doesn’t appear to be a big amount of ice in the trees. Rain gauge is at 2.02”, this was one heck of a rain event. Looks like the local rivers are going to just barely miss flood stage. I think the only thing that kept this from being a full fledge flooding event was a lot of the snow pack staying in tact.

Yea that’s quite a difference, just using the official stations you can see that stations like LNS and THV have a pretty decent southerly breeze and that even extends up to Reading too. If I’m being honest I think York, Lancaster, possibly Adams, and those few LWX counties Hagerstown east are probably the rest of the way cooked for this event and I wouldn’t be surprised if they get dropped from the advisory. Ice accruals reaching a tenth and more I think likely stays Harrisburg north and west and probably more so out of the city. The issue in the LSV is if the precip shuts off before the cold air can get down there, which is looking more likely. HRRR shuts off precip there there by about 17-18z and the cold’s too late. NAM hangs a few hours longer and does get some measurable mixed down into the southern counties. The new 0z HREF still supports the advisory as well but it may end up being too cold overnight vs the current ground truth with the warmer temps that snuck up into the southern tier.

Down to 34ºF, moderate rain. The rainfall portion has definitely exceeded my expectations today around here in terms of totals. Gauge is at 1.42” for the event now.

Looking at the Mesowest obs, the 32ºF line is starting to ooze under the I-80 corridor from the north. About an hour or two ago the nearest <32ºF ob I saw from that direction was Coffin Rock haha. The temp here is now near 35ºF and the NNE breeze has ramped up some gusting up to 15mph, so the low level cold air advection is in action. Been watching the HRRR and I think temps could be to a point to start supporting ZR here a couple hours before it’s been advertising it here (by about 10pm or so vs after midnight). Guess we’ll see.

Temp has been slowly starting to fall, down to right at 36ºF currently. Since midnight it has only ranged from 34.3 - 37.4ºF today. Winds are light NNE. About the only good thing from this whole mess is I’m finally getting to see how my rain gauge is working. That’s at 0.89” for the event so far.

I could certainly at least see a few flood advisories pop up this evening for the smaller tributary and poor drainage type stuff. From what I saw around here before dark there was a pretty good response with run-off and most of the small streams and drainage channels are snow/ice clogged. It’s either doing that or just absorbing into the snowpack.. but definitely not into the frozen ground. Unless there’s any ice jam type issue I think the bigger streams/rivers will be okay, although all those rivers you mention are forecast to get at or near caution stage. Main stem Susquehanna looks to be only a modest rise.

This is pretty much the condition of every non-paved driveway around here today despite mid 30s temps, and we haven’t even got to the actual winter storm part of the system yet haha.

That was out of part of CTP’s morning discussion. I agree to a point, you have to be careful with modeled freezing rain as actual observed ice accrual is very sensitive to drop size, rain intensity, surface temps, etc etc. 0.75” of conditional freezing rain QPF on x model doesn’t often translate to 0.75” thick ice on the trees. With all that said, my big thing about this particular event the last couple days is I feel there has been sufficient support to reach 0.25” ice in a good portion of this swath of the CWA mentioned above on that AFD snippet. I honestly expected watches to be issued yesterday on all the counties at least down to I-80 given that support plus this being a multi-faceted potential high impact event between the combo of near warning to warning level ice plus sleet and snow..And they’re still worried about this rain to heavy sleet thing too. As far as surface and road temps, I agree with that in the Sus Valley but most of the interior 2/3rd of the CWA between US 6 and US 22 has a snowpack and frozen ground from the long stretch of cold weather. Some of the secondary roads around here froze up early this morning despite temps above 32 since about mid day yesterday. Plus if sleet does in fact mix in sooner, that’s just going to cool surfaces faster anyways. And further down in the Sus Valley I was surprised first thing this morning that it initially wasn’t included when advisories finally did get issued. I guess I don’t understand why it took so long. A T of ice warrants an advisory, and that has looked likely even in the further reaches of the LSV for awhile. Just my thoughts, I’m not hating on the NWS by any means. Moral of the story is this type of event is very difficult and frustrating to forecast.

Haha I normally keep heat around 68ºF or so in the main parts of the house and I can fire up the wood pellet fireplace to warm it up more without bumping up the regular heat.

39ºF here this afternoon so far and cloudy with 26ºF dewpoint. Surprisingly it got all the way down into the upper teens this morning (17.5ºF). Not very much snowpack melt, which is currently a 3-6” hard pack in the yard. Since I got this new weather station rolling just after midnight on the 15th of Jan I don’t have full January monthly data but the mean temperature the last 2.5 weeks from then til now is 19.7ºF, and there were a couple 24 hour periods (midnight to midnight) that averaged in the single digits. It’s been pretty cold here lately.

Yea it always is with this type of an event. I kinda disagree with CTP minimizing the ZR threat in favor or a more rain to sleet/snow. I think once that near 1040 high gets positioned just to our north, surface cold is going to try to bleed deeper into central PA before the 925mb-800mb layer cools enough to at least allow for more sleet… which will allow for a longer period of freezing rain. We’re usually lamenting not having a stronger high with these messy systems and we actually have a decent one eventually during this event. We all start this main wave on Thur as rain but I think you guys up there see more frozen (sleet than eventually snow) and a shorter ZR period for a transition, while this area down here could be more 50/50 ZR and sleet turning to T-2” type snow at the end. Then the big thing for the Sus Valley is going to be determining how much ice and sleet can accumulate towards the tail end as the snow threat has been pretty minimal there and the snowier models (GFS and Euro) have really tightened the gradient on the SE side of the swath the last couple runs. Here’s what the 12z HREF had for freezing rain, it’s a model that CTP seems to utilize a good bit in short/near term.. which is another reason I’m kind of surprised the ZR is being downplayed. It has a pretty widespread area of .25-.50” (warning criteria ice) The model only goes out to 48hr and the event isn’t over yet at 12z Friday, so here’s it’s positioning of the p-types at the end of the run.

I’ve seen a couple snarky comments on the last couple postings that CTP has put out regarding the upcoming event. A couple comments pertaining to why not put up ice watches, etc etc. I think the CTP criticism that takes the cake that I’ve seen today is our local met going after them about the meaning of Groundhog Day.. @Atomixwxshould get a kick out of that lol. At any rate, CTP has only issued watches in the northern tier counties to this point because that’s likely that only part of the region where warning criteria snow/ice (mainly snow) is a near certainty as it pertains to the whole guidance suite. The rest of the region is a crapshoot at the moment. With the heavy snowfall swath mainly NW, the big issue is how much of every other p-type falls before any potential change to snow NW to SE towards the end. A warmer or colder scenario could both preclude warning criteria icing in the central/upper Sus Valley counties. They also still have time to observe a couple more runs of models as this primary wave of this two pronged system is slated for Thursday. I expect watches to be expanded some overnight as things are starting to zero a little bit on an icing swath that has a good chance of meeting criteria. These type of p-type issues are going to be best resolved with short/near term high res guidance that is just starting to get all the way in range of this. The other thing to consider is the longevity of the primary wave. The 0z 12k NAM for example does get a changover to snow all the way into the Sus Valley but runs out of precip, while the 3k NAM which only goes out to 60 looked like it had a longer lasting event. Just a lot of variables to this. We go through these wave or waves running a pressing frontal boundary type events at least once a winter. They always suck trying to nail them down. I’d almost rather watch another blizzard go up I-95…. Almost.

Hmm I’m not sure, the WeatherBell total QPF maps also had the 2.12”. Something’s lumped together probably. Some of that 1.11” heavy freezing rain is likely part of the the 1.23” of plain rain. Adding the 1.23 of plain rain and 0.63” ice is 1.86” and adding approx 3” of snow which was about 10:1 even on Kuchera comes out near that 2.12”. Either way it’s a lot of p-types to sort out of a lot of QPF.

Basic 18z Euro breakdown. It’s about as good if not better in C-PA for snowfall vs the GFS now. Good part of the LSV sees ice. Only bigger difference is in the transition. GFS is a prolific sleet maker while the Euro is more of a ZR to snow transition with much less sleet. Personally I think with this setup there will be a zone of measurable sleet somewhere but that may come at the expense of snow…especially in the central counties where both models do manage advisory snow at the tail end. Euro vs GFS sleet: Euro total QPF: Euro total Freezing rain accum Euro total snowfall:

I want to see the map with all the start times for all the different p-type transitions.

Here’s the morning take from CTP. Haven’t seen any real breakthroughs with overnight or 6z guidance. Still in the same camps with the GFS op most generous with frozen. Euro/Euro EPS/Canadian seem fairly close having the snow swath further northwest. GEFS sort of in the middle (6z did step back some snow means in the central vs 0z) but still showing a more robust transition. They all show transition for most/all with varying amounts of ice/wintry mix. I still tend to think the GFS has the right idea progressing the front and cold air, which the Euro had that idea a couple days ago. That may not ultimately be enough to get good snows into the Central/Sus Valley, but it would ramp up the mix/icing potential. GFS and also the NAM (which doesn’t cover the whole event yet) have pretty mean looking swaths of sleet accumulations while the Euro has very thin sleet zone but a good bit of freezing rain. Tons of stuff to consider here in addition to where these swaths might end up. Also to keep an eye on, short range stuff like the NAM are starting to pick up on ZR to kick the event off Wed night in central/eastern PA. Given how cold it has been, I’d bet on that scenario especially in areas with snowpack. Some spots could actually have a ZR/Rain/more ZR/mix/snow type of itinerary with this event.

Definitely variable temps this morning around here. KAOO at 16ºF but most obs in and around town are in the single digits and it’s 7.5ºF here currently

Yea this event looks like a pretty big mess incoming. We will warm up especially Wed/Thur ahead and during the first portion of this system. Def not going to be a tremendous warm-up but some of the southern tier probably gets to 50 or so at some point (sufficient to get the AC fired up down there lol). Big thing I’ve noticed is despite the modeling differing and switching around with how it presses mixed and snowfall into the state, they’ve been building/pushing a stronger high more directly to our north. Initially it looked like the main body of high pressure was going to send the cold southward into the central US and not immediately push east as much. But now we have pretty much everything building 1040+ mb high pressure eastward just above Lake Huron roughly centered in the Ontario/Quebec border region. There’s way too much cold available in this pattern with a stronger high positioned like that, so I’m not buying an all rain event from this, or thunderstorms or whatever. There’s also no low that really cuts west of us on models/ensembles now, so this has tended a bit more progressive. The big question I’m considering right now isn’t whether this cold presses and changes things over to a mix for at least a good portion of folks in here. It’s if we can get the depth of cold necessary in time to turn to any accumulating snow of substance. I do think any really significant snow chances generally favor NW and maybe some of NC PA at the moment, but I also think everyone sees some amount of ice/sleet as well.. potentially significant amounts for some. The setup screams favorability for a long swath of significant ice/sleet along the frontal boundary.

I’m just shy of 20” so far this winter here, which is fine and I’m glad that I’ve been able to hang onto a pack for a few weeks. But that’s also just shy of 50% of what I expect for an average season here so there’s some work to be done. On the other hand, it’s also about 3” ahead of the whole 2019-2020 winter at this point. Give me the winter with tracking opportunities. More often than not things normally even out to some degree eventually. I’d rather be nailing down where an event is going within a good overall pattern over tracking down the actual favorable pattern or window of opportunity just to have a chance at snow. Even in good patterns a specific location isn’t going to make out on every event.