Central PA Winter 2022/2023

[Bubbler86]

18 minutes ago, Itstrainingtime said:

MU admitted that he missed the mark badly on January - after nailing the snowless December, he thought that January would be winter's coldest and snowiest. 

I guess if MU somehow manages to get a tenth of an inch tomorrow...January will be in the running for the snowiest! 

He was just the one I read that said Cutter, cutter, cutter. 

[paweather]

@Blizzard of 93Can you give us any hope!? 

[MAG5035]

12 minutes ago, GrandmasterB said:

The NAM is concerning even for State College. I think that's probably curtains for down here. Really the theme of the season, just can't get anything to work.

The NAM has had a solution like this since yesterday, pretty insistent on 850s warming faster in southern half of PA and not providing much snowfall even in the AOO-UNV part of C-PA where the other model guidance has been suggesting some of the best potential totals. The HRRR holds that layer longer getting the period of snow into at least some of the Sus Valley. This is in reference to the main heavier area of precip associated with the deep southerly fetch and best forcing.

The real killer in the LSV’s snow potential and possibly to some degree in this particular area, and I’ve mentioned this a couple times the last few days… is the positioning of the WAA snowband that breaks out. Because the timing of that feature is such that it would definitely snow anywhere in here. Unfortunately that has trended to favor the northern half of PA, leaving the main slug and a shorter time window for front end snow before the column gets warmed. I still think the NAM is a bit fast with that, and I favor more toward the HRRR’s take holding in the CAD and the low levels a bit longer. I also don’t recall the NAM doing all that well in this situation either when it came to the Dec 22 front end snows that managed to get into some of the Sus Valley. 

At any rate as it looks this afternoon, I think if CTP upgrades to any warnings it’ll be for the northern half of that watch area, where the early WAA snow is focused on most short range guidance. A 2-5 advisory is probably going to be good for the rest of the watch area. They’ll probably maintain advisory for the rest of their CWA for various impacts NW-SE ranging from 1-3 down to T-1 and trace of ice potential. Still going to have to monitor radar trends as this gets closer, because if there is a more widespread area of WAA snows that breaks out ahead that doesn’t focus on just northern PA, then there could be a better chance for some of the southern tier to see more snow. 

[canderson]

1 hour ago, Mount Joy Snowman said:

Yes sorry I meant HRRR.  If you squint hard enough it's maybe a pinch better than 12z but Lancaster still basically nill.  On the bright side I might get to witness some decent rates in Harrisburg over lunch break. 

Wanna make snow angels in Riverfront Park together? We'll prob have a 40 minute window before it's mud. 

[medmax]

Omg even State College is gonna torch. Guys the LSV curse followed me north!

[Bubbler86]

Euro 12Z.  Still better than most though more steps down from its uber run 36 hours ago.  Albany and Binghamton both eventually go to rain or taint. 

 

[MAG5035]

Here’s the business end of CTP’s short term disco this afternoon:

Quote

SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
High pressure parked over northern New England should supply
sufficiently cold air for precip to begin as snow over the
entire forecast area. However, a warm nose aloft will eventually
work in, changing the snow to mixed precip by late in the day.

After detailed discussion internally, external collaboration
with WPC and surrounding WFOs, and particularly the wisdom for
"Leveraging the uncertainty of ensemble guidance" - passed down
from our recently retired SOO (Science and Operations Officer),
we`ll continue to ride the Winter Storm Watch for at least one
more model cycle as the probability for 6 inches or more is less
than 40% (where it`s maximized) in most places surrounding
Interstate 80. 4-5 inches looks pretty solid in the current
Watch area, with similar or slightly lesser amounts being more
definitive outside of the Watch.

In either case, a few-several hour period of moderate to heavy
snowfall rates will likely lead to high impact for travel, but
we still need to draw the line somewhere when it comes to
actual amounts. Given our criteria of 6"/12 hour for a warning
and the aforementioned probs for that amount - Advisory Criteria
Amounts look more probable, but we don`t want to downplay the
"Impact", especially from the Central/NCent Mtns east across the
Middle and W Branch of the Susq Valley.

Strong synoptic support and anomalous moisture/IWV transport
from the GOMEX into retreating cold dome will produce an
initial, quick "2-3 hour dump" of snow with a high likelihood
of 1+ inch/hr rates across the interior zones. The main
uncertainty lies with how long the heavy snow/rates will last as
there will be an inevitable transition to wintry mix due to
tremendous WAA driving burgeoning warm nose aloft followed by
300-700mb layer dry slot arriving from the OH Valley by the
evening.

Several deterministic pieces of guidance and GEFS indicate that
the max Tw aloft will stay just below zero through 18z for much
of the CWA east and north of a line from KELZ to KUNV and KSEG,
with the PTYPE snow between 11-13 and 18-19Z.

Model soundings indicate the changeover is likely by late
morning over the Laurel Highlands and reach the mountains north
of KIPT by around 22Z. An examination of model time sections
indicates the strongest lift will occur well beneath the DGZ, so
expect snow/liquid ratios not far from 10:1. Ensemble mean qpf
currently suggests a widespread 3-6 inch snowfall is likely
across much of the forecast area, with significantly less across
the Lower Susq Valley, where a change to rain is likely after a
relatively short period of snow. 1+ inch/hour snowfall rates
are possible for a time Thursday, given the plume of GOMEX
moisture and strong forcing associated with coupled jet
structure.

 

[GrandmasterB]

GFS will not give it up. Continues to show more snow than any other model. I’m assuming it goes down in flames.

[Bubbler86]

1 minute ago, GrandmasterB said:

GFS will not give it up. Continues to show more snow than any other model. I’m assuming it goes down in flames.

GFS and Euro leading the snow train.  KUCH is MUCH lower vs 10-1 one the GFS in the LSV but still the top like you said. 

[paweather]

Going with the GFS Euro train! 

[Blizzard of 93]

25 minutes ago, Bubbler86 said:

GFS and Euro leading the snow train.  KUCH is MUCH lower vs 10-1 one the GFS in the LSV but still the top like you said. 

The 18z GFS 10-1 & Kuchera look VERY close in the LSV….

[MAG5035]

2 minutes ago, Bubbler86 said:

GFS and Euro leading the snow train.  KUCH is MUCH lower vs 10-1 one the GFS in the LSV but still the top like you said. 

It’s been that way on the Euro as well, esp in SW PA and  the Laurels.

Kuchera calculates ratio off of the warmest temp in the column and the method can sometimes be an issue in fringe areas. Highly marginal 850 temps are likely to blame and it is coming around the key few hours of heavy precip in the late morning that are immediately preceding the mixing. JST gets 3.0 in 3 hrs off of a 10:1 rate from 15-17z, with an intense burst of nearly 2” of one hour. Highly doubt with those kinds of rates that JST only gets 0.8” total snowfall.. unless of course they are sleeting (a possibility). CTP has mentioned in their disco the last couple days that they’ve liked an 8-10:1ish ratio… mainly due in this case to the max forcing occurring below the DGZ. 

 

[Blizzard of 93]

15 minutes ago, paweather said:

Going with the GFS Euro train! 

I agree….this storm is fairly straightforward, do the GFS might be able to handle this one.

It has been very consistent with this event.

[Bubbler86]

4 minutes ago, Blizzard of 93 said:

The 18z GFS 10-1 & Kuchera look VERY close in the LSV….

Not on these maps.  1-2" difference. 

 

[Blizzard of 93]

2 minutes ago, Blizzard of 93 said:

The 18z GFS 10-1 & Kuchera look VERY close in the LSV….

I still like 2 to 4 of snow for Harrisburg tomorrow. 
The radar is juiced & the precip should come in like a wall, so as long as rates are moderate to heavy, we should snow.

We only need a few hours of good snow to get a few inches!

[Blizzard of 93]

Just now, Bubbler86 said:

Not on these maps:

 

Less than 1 inch difference is Not MUCH…

[Bubbler86]

4 minutes ago, MAG5035 said:

It’s been that way on the Euro as well, esp in SW PA and  the Laurels.

 

Kuchera calculates ratio off of the warmest temp in the column and the method can sometimes be an issue in fringe areas. Highly marginal 850 temps are likely to blame and it is coming around the key few hours of heavy precip in the late morning that are immediately preceding the mixing. JST gets 3.0 in 3 hrs off of a 10:1 rate from 15-17z, with an intense burst of nearly 2” of one hour. Highly doubt with those kinds of rates that JST only gets 0.8” total snowfall.. unless of course they are sleeting (a possibility). CTP has mentioned in their disco the last couple days that they’ve liked an 8-10:1ish ratio… mainly due in this case to the max forcing occurring below the DGZ. 

 

Yea, it is useful for compares but is not always better than simply 10-1.    A lot of posters (mostly in the MA) post the one that shows the most snow regardless of conditions. 

[Bubbler86]

1 minute ago, Blizzard of 93 said:

Less than 1 inch difference is Not MUCH…

In my area it is 3.0 to 4.6 just using the map numbers.   But with a snow of 4" a 1" difference is 25%.  Substantial. 

[Blizzard of 93]

3 minutes ago, Bubbler86 said:

In my area it is 3.0 to 4.6 just using the map numbers.   But with a snow of 4" a 1" difference is 25%.  Substantial. 

You said LSV…so I was referring to Harrisburg & Lancaster….not much difference. 
Lol, I am good with either GFS map at this point!

[Ruin]

with the shift 50 miles or so with the snow more north glad I didnt get excited. All I want is a few back to back snow storms nothing to big is that to much to ask to have snow on the ground for a month?

[Bubbler86]

4 minutes ago, Blizzard of 93 said:

You said LSV…so I was referring to Harrisburg & Lancaster….not much difference. 
Lol, I am good with either GFS map at this point!

You are right there.  It is near 1" in the LSV.

[paweather]

Just now, Ruin said:

with the shift 50 miles or so with the snow more north glad I didnt get excited. All I want is a few back to back snow storms nothing to big is that to much to ask to have snow on the ground for a month?

Your asking for a lot 

[mahantango#1]

ABC-27 Did not waiver on their amounts from last night. Which is unusual. Usually their the ones downplaying Snowfall amounts.

[Itstrainingtime]

26 minutes ago, Blizzard of 93 said:

I agree….this storm is fairly straightforward, do the GFS might be able to handle this one.

It has been very consistent with this event.

You might very well be right! As of now, none of us can say with any certainty how much or how little it will snow in our general area. We all have opinions and there's reasons behind all of them.

I do find it somewhat humorous that you've been bashing the GFS most of this season, but now that's "forecasting" the most snow...you support it.  

[MAG5035]

6 minutes ago, Blizzard of 93 said:

I agree….this storm is fairly straightforward, do the GFS might be able to handle this one.

It has been very consistent with this event.

I dunno if I’d call it straight-forward haha, at least the part that ultimately matters (snow on the ground).  GFS is getting good snow to the LSV and even SW PA because it focuses the preceding warm advection snowfall there instead of a thinner stripe across northern PA as the higher res short range models and the Euro have been showing. I tend to think there will be better coverage with a system like this to deliver something closer to a Euro type solution but I’m not currently buying the full GFS type scenario that has some of the best totals actually in southern PA and some of the Sus Valley. I mentioned in my post in the last page that will have to see how radar trends go tonight and how well the meso guidance is modeling it. The WAA stuff is the key part of seeing any notable accums (advisory type amounts) in southern PA. 

[paweather]

Yuck!

[Itstrainingtime]

1 minute ago, paweather said:

Yuck!

I honestly think that will end up being pretty close. Time will tell. 

[paweather]

3 minutes ago, Itstrainingtime said:

I honestly think that will end up being pretty close. Time will tell. 

Yeah it’s likely 

[MAG5035]

30 minutes ago, Bubbler86 said:

Not on these maps.  1-2" difference. 

 

That’s some really disjointed action going on however Pivotal generates their maps, especially comparing Huntingdon County to Franklin haha. Here’s the Weatherbell ones. I only took it out to 30 to focus on the main part of the event. The total snow out to 72hrs is picking up the eventual backlash/upslope snows in western PA Thursday behind the system.

GFS 10:1

GFS Kuchera, it actually makes a bigger bullseye. 

As much as I’d love this solution the GFS is probably a bit too cold and SE. But on that topic, one thing to watch tonight is the snow swath as this comes up. Near the Ohio River (about 20-30miles either side) has been making a sharp dividing line on guidance, especially from Louisville to the confluence with the Mississippi. The NAM is uniformly above the river being the furthest NW, while the GFS snows on most of western and northern KY with the initial warm advection precip that eventually turns into what it does here on the front end. So if there’s a massive bust later this evening in the NWS Paducah realm in western KY, for example… where GFS has their equivalent of warning type snowfall for nearly the other half of their CWA that has no winter headlines…that might be an indicator of the GFS being on to something. 

[Bubbler86]

3 minutes ago, MAG5035 said:

That’s some really disjointed action going on however Pivotal generates their maps, especially comparing Huntingdon County to Franklin haha. Here’s the Weatherbell ones. I only took it out to 30 to focus on the main part of the event. The total snow out to 72hrs is picking up the eventual backlash/upslope snows in western PA Thursday behind the system.

GFS 10:1

 

GFS Kuchera, it actually makes a bigger bullseye. 

 

As much as I’d love this solution the GFS is probably a bit too cold and SE. But on that topic, one thing to watch tonight is the snow swath as this comes up. Near the Ohio River (about 20-30miles either side) has been making a sharp dividing line on guidance, especially from Louisville to the confluence with the Mississippi. The NAM is uniformly above the river being the furthest NW, while the GFS snows on most of western and northern KY with the initial warm advection precip that eventually turns into what it does here on the front end. So if there’s a massive bust later this evening in the NWS Paducah realm in western KY, for example… where GFS has their equivalent of warning type snowfall for nearly the other half of their CWA that has no winter headlines…that might be an indicator of the GFS being on to something. 

Yea, different suites algorithms really vary especially in questionable situations like this.   Sometimes make discussions seem off base unfortunately.