Pittsburgh/Western PA WINTER ‘25/‘26

[Rd9108]

Gun to my head this just misses south with the highest amounts. Its only tuesday and a slow northern creep has happened so I guess we shall see what happens. If we were in the bullseye we would be sweating knowing this would wind up in Youngstown or Cleveland. Atleast we are tracking a bigger storm again. Now we wait for the 12z models. 

[RitualOfTheTrout]

6 minutes ago, Rd9108 said:

Gun to my head this just misses south with the highest amounts. Its only tuesday and a slow northern creep has happened so I guess we shall see what happens. If we were in the bullseye we would be sweating knowing this would wind up in Youngstown or Cleveland. Atleast we are tracking a bigger storm again. Now we wait for the 12z models. 

I agree, I think we are approaching the ceiling for how far north it can come, being in the bullseye would take significant changes. The changes in the handling of the phasing with the southern stream shortwave last night were what we wanted to see though, and as long as that continues, and we see some relaxation in the confluence at least we won't be totally shut out.

[colonel717]

21 minutes ago, Rd9108 said:

Gun to my head this just misses south with the highest amounts. Its only tuesday and a slow northern creep has happened so I guess we shall see what happens. If we were in the bullseye we would be sweating knowing this would wind up in Youngstown or Cleveland. Atleast we are tracking a bigger storm again. Now we wait for the 12z models. 

Yea, sensing the same. I think this is 6-12 due to high ratios for us while those to our south and east are 1-2 ft+. But we do still have time. There was a lot of north movement esp by GFS and feel that may halt today. But then I think closer to weekend we may see another push north. 

[Mailman]

The ICON, for you know what and giggles.

 

[colonel717]

5 minutes ago, Mailman said:

The ICON, for you know what and giggles.

 

 

Just minor changes...

 

[colonel717]

GFS not on board, as well as AI version way south.

[Rd9108]

2 minutes ago, colonel717 said:

GFS not on board, as well as AI version way south.

Lol gfs is terrible but concerning off course. Come on Canadian!

[colonel717]

3 minutes ago, Rd9108 said:

Lol gfs is terrible but concerning off course. Come on Canadian!

looks worse early on. Midrange model mayhem...

[Rd9108]

2 minutes ago, colonel717 said:

looks worse early on. Midrange model mayhem...

To be expected. Still time its only tuesday. 

[colonel717]

15 minutes ago, Rd9108 said:

To be expected. Still time its only tuesday. 

Its south but still a decent hit due to ratios.  Actually turns out better as run finished 13-14 inches 

We have until late tomorrow when storm comes ashore.

[Mailman]

Just a foot area-wide on the Canadian.

[jwilson]

I was reticent to share my thoughts on the upcoming system, because up until recently there had been a couple different "schools of thought," and even within those there are differential dynamics at play, like where the boundary sets, how cold is it, etc.  It was also setting up outside of normal confidence windows (7-to-10 days).  It all had to do with the ejection of the energy in the southwest.  Some models would kick the energy out under the confluence and suppress it or shear it apart.  Some models would hold and consolidate the energy to create something more akin to a SWFE (southwest flow event).

We're seeing a lot more acceptance across multiple models now, however, so an event of some kind appears likely.  I think the most relevant part to us is the level of phasing that occurs as that energy is stretched out from the southwestern CONUS.  We see a relatively flat flow, overall, and the trough is never allowed to turn negative, which means we don't yet see a scenario where this turns and rides up the coast or is captured.  The latter part is most relevant to the storm's overall potential and cap.  Without a negatively-oriented trough, we aren't as likely to see "historic" numbers up along the Atlantic side.  If you want an example of what I mean, look at the 06Z GFS at 300 hours (February 1st) and you'll see the type of negative turn coastal I describe.  Simply described as "bombogenesis."

We could still get a good haul from a long-duration overrunning event.  That's what you're seeing in the southern US on the 06Z GFS, for example.  Approaching two feet of snow in places like Chattanooga and Knoxville.  Those numbers are unusual but not totally unprecedented.  Chattanooga got 18" from the 1993 system, for example.  Knoxville got 17.5" back in 1960.  It is rare, to be sure, but it can happen, and the depth of the cold makes it a possibility.  But the rarity should give you an indication of how likely model depictions are at this range.

The biggest problem for us might be wave spacing combined with the confluence.  You have a decent sized TPV lobe pushing down, but you also have another one or two discrete pieces of energy riding behind it.  We're looking at a high of around 10 degrees on Saturday.  That's colder than typically ideal when you're talking about big snows.  There's also no real blocking in place.  Some of the long-range looks appear to show a -NAO establishing itself.  I think the main reason for this system, at all, is the sudden collapse of the AO (going deeply negative) and a transient PNA slide to neutral.  If the MJO can continue propagating west, that might help keep our chances alive going forward.  The AO is likely to rebound some but could stay well negative to displace the cold for us.

As I'm typing this, we see how the 12Z GFS handles things quite different from 06Z.  The 12Z keeps the energy separated and doesn't allow for any phasing to occur until the primary low is well out into the Atlantic.  A lot of the energy from the 06Z that was stretched and created a SWFE was instead held back and closed off over Baja, Mexico on the 12Z.  The 12Z Canadian is more like the 06Z GFS.  The Canadian is a good middle ground, and while it is out of what we may consider an "ideal" position for us, ideal often means flirting with raindrops.

Part of me thinks the even more interesting period to watch is after next weekend, but that much remains TBD.

I'll probably dig into the maps a bit more later, hopefully after a few more model runs to see if any kind of consensus builds.  There are a still a wide range of possibilities.

[colonel717]

UKie is 15+

[RitualOfTheTrout]

Don't like seeing the GFS revert to keeping the shortwave cutoff and not phasing.  It just means that option is still in the realm of possibilities. If the GFS were the only one giving us snow, I wouldn't feel too good about our chances either. No matter what the Euro shows we still have time for these important pieces to change towards or away from our favor. 

I'd love to get 6-8 inches of pure powder with temps in 10s followed by a massive arctic blast, and so far, I think that is within a reasonable realm of possibilities. 

[colonel717]

3 minutes ago, RitualOfTheTrout said:

Don't like seeing the GFS revert to keeping the shortwave cutoff and not phasing.  It just means that option is still in the realm of possibilities. If the GFS were the only one giving us snow, I wouldn't feel too good about our chances either. No matter what the Euro shows we still have time for these important pieces to change towards or away from our favor. 

I'd love to get 6-8 inches of pure powder with temps in 10s followed by a massive arctic blast, and so far, I think that is within a reasonable realm of possibilities. 

I agree if something like the ICON is the end result, more than satisfied. 

[colonel717]

KMA looks similar to Ukie

[Rd9108]

From another Met

The good news is the GEFS mean phases the shortwave over the Midwest - very possible we just had a bad GFS run that will correct in 6 hours

[RitualOfTheTrout]

4 minutes ago, Rd9108 said:

From another Met

The good news is the GEFS mean phases the shortwave over the Midwest - very possible we just had a bad GFS run that will correct in 6 hours

That's my guess, although we have seen a small step back on the phasing with 12z models besides the ICON but nothing like the GFS and we still get some decent snow. It could just be noise level stuff this far out too with the GFS just being an extreme outlier wrt handling that interaction. 

[colonel717]

EURO looks like 7-12 depending on ratios

[Mailman]

That'll work.  Only 4-5 days to go.

[Rd9108]

Could be worse lol

[RitualOfTheTrout]

6 minutes ago, Rd9108 said:

Could be worse lol

Geez, it must really be getting close to 15:1 - 20:1 ratios here. Not sure I'd buy that per se, but at least we aren't sitting partly cloudy.

Euro did step back like the others; we will have to watch that going forward. We want as much of a complete phase as possible. I think it's really going to take until 12z Thursday to have a lot of confidence how that plays out.

[Rd9108]

5 minutes ago, RitualOfTheTrout said:

Geez, it must really be getting close to 15:1 - 20:1 ratios here. Not sure I'd buy that per se, but at least we aren't sitting partly cloudy.

Euro did step back like the others; we will have to watch that going forward. We want as much of a complete phase as possible. I think it's really going to take until 12z Thursday to have a lot of confidence how that plays out.

Yeah not expecting to know anything. A lot of details to iron out.

Looks like temps are gonna be around 10 degrees during the storm. Thats how you get big numbers but I still dont buy 12 inches of snow from .6 inch of liquid 

[Rd9108]

One final point. Here's the trend of the EPS

[colonel717]

NWS Pgh discussion

Starting to hear alot of chatter about snow this weekend? Lets break down the forecast and discuss some potential outcomes, and have a moment to talk about forecast uncertainty:

We like to think about the forecast as a train heading into the rail yard. You start on one track. As you go through time, that one track turns into two, then perhaps four, and eventually, you could end up with tens on potential tracks the train could take as it arrives. Lets think of these tracks as potential scenarios for the weather. You start off the forecast process right now on one track (there is really only one scenario for what's happening right now). Out a couple days, there may be a couple scenarios for what weather might happen. If you go out as far as 5-7 days, the forecast has a good deal of uncertainty with many potential scenarios.

Ironically, much of the uncertainty in the weekend storm (most likely to happen between Saturday night and Monday) will come down to "tracks" (not the railroad ones). For simplicity, well break the storm potential down into three scenarios...

Scenario #1:

The storm track stays well to the south and the area ends up with very little to no snow. This would produce <1" of snow accumulations, if any. This scenario is around 20% likely at this point given current weather prediction guidance. While mostly dry, scenario would be the coldest (temperatures 20-30F below average).

Scenario #2:

The storm track forms to the south and then curves north as it heads towards the mid-Atlantic region. In this scenario, the region would see snow, but not the worst of the storm. This storm track would produce notable accumulations (likely >1" but <6"). This scenario is around 50% likely at this point given current weather prediction guidance.

Scenario #3:

The storm track forms to the south then curves up the spine of the Appalachians before reforming off the coast. In this scenario, the region would see the heaviest snow from the storm. This track would produce heavy accumulations (likely >6" to as much as 12"). But this scenario is 30% at this time given current weather prediction guidance.

Given the current forecast, here's what we know right now: eastern Ohio and northwest PA have the lowest probability of warning criteria snow (>6"), while the ridges of PA/WV have the highest probability of warning criteria snow). Remember, staying in tune with the forecast will be important, because as we draw closer, we will know more information and gather forecast confidence as we narrow down the amount of potential "tracks" and iron out more specific details of snow amounts and impacts.

[colonel717]

Here are several EPS members that with ratios would likely give us 1-2ft So there is some ability for this storm to improve.

[Rd9108]

[colonel717]

Would be nice to pull in 3 inches tomorrow as an appetizer.

[RitualOfTheTrout]

2 hours ago, Rd9108 said:

Yeah not expecting to know anything. A lot of details to iron out.

Looks like temps are gonna be around 10 degrees during the storm. Thats how you get big numbers but I still dont buy 12 inches of snow from .6 inch of liquid 

Cold is one factor, but you also need good lift / omega in the DGZ when you are looking at the sounding to get an idea on ratios. You can assume we "should" do better than 10:1, like 12:1-14:1 but it's an average through the storm really. Don't get me wrong, looking at those snow maps is fun, I just think sometimes we see this big number on the Kuchera output and it's a setup for disappointment when NWS starts putting out official numbers etc. If it's ever going to be close though, being far from any potential warm layers is probably it's best bet.

One other note, as we watch that energy crash onto the west coast, if it comes in at a higher latitude and or doesn't drift SE towards baha that gives it a better starting point. Just a thought, but if that could happen, and we get a faster ejection and phase, that could make a big difference for us. I'd really like to see all Allegheny in at least the .5 qpf range to really start thinking we might make 6+.

EPS mean made a nice jump NW and the latest NBM looks a bit further NW as well with precip distribution. 

[colonel717]