Pittsburgh/Western PA WINTER ‘25/‘26

[blackngoldrules]

Winter Storm Watch

URGENT - WINTER WEATHER MESSAGE
National Weather Service Pittsburgh PA
204 AM EST Thu Jan 22 2026

OHZ039>041-048>050-057>059-068-069-PAZ013-014-020>022-029-031-073-
075-WVZ001>004-012-021-509>511-513-221515-
/O.NEW.KPBZ.WS.A.0001.260125T0000Z-260126T1800Z/
Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson OH-
Muskingum-Guernsey-Belmont-Noble-Monroe-Lawrence-Butler-Beaver-
Allegheny-Armstrong-Washington-Greene-Westmoreland-Fayette-Hancock-
Brooke-Ohio-Marshall-Wetzel-Marion-Monongalia-
Ridges of Eastern Monongalia and Northwestern Preston-Preston-
Western Tucker-
Including the cities of Malvern, Greensburg, New Philadelphia,
Monessen, Wheeling, Cambridge, Weirton, Zanesville, Parsons,
Ambridge, Canonsburg, Coshocton, Dover, Uniontown, Cadiz, Fairmont,
Follansbee, Salem, New Martinsville, Kittanning, Martins Ferry, Saint
George, New Castle, Washington, East
Liverpool, St. Clairsville, Butler, Bruceton Mills, Monaca,
Caldwell, Kingwood, New Kensington, Beaver Falls, Wellsburg,
Woodsfield, Aliquippa, Morgantown, Moundsville, Latrobe, Columbiana,
Steubenville, Ellwood City, Murrysville, Waynesburg, Lower Burrell,
Pittsburgh Metro Area, Hendricks, Coopers Rock, Ford City, and
Carrollton
204 AM EST Thu Jan 22 2026

...WINTER STORM WATCH IN EFFECT FROM SATURDAY EVENING THROUGH MONDAY
AFTERNOON...

* WHAT...Moderate to major impacts to the region are possible later
this weekend with periods of moderate to heavy snow.

* WHERE...Portions of east central Ohio, southwest and western
Pennsylvania, and northern and the northern panhandle of West
Virginia.

* WHEN...From Saturday evening through Monday afternoon.

* IMPACTS...Travel could be very difficult to impossible later this
weekend and Monday morning.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation.

[blackngoldrules]

06z GFS. Yikes. Not sure what Euro is showing when ratios are added as I don't have the paid version. Almost 10 inches 10:1 ratio.

Sent from my SM-S931U using Tapatalk

[southpark]

38 minutes ago, blackngoldrules said:

06z GFS. Yikes. Not sure what Euro is showing when ratios are added as I don't have the paid version. Almost 10 inches 10:1 ratio.

Sent from my SM-S931U using Tapatalk
 

What a turnaround on the GFS. Wish the storm was starting right now with that run!

[colonel717]

We are at 12-13 inches with all this to the west for the NAM

 

[southpark]

3 minutes ago, colonel717 said:

We are at 12-13 inches with all this to the west for the NAM

 

Let's hope that sleet line doesn't get any closer and goes south in future runs.

[SteelCity87]

06z Euro

[colonel717]

26 minutes ago, southpark said:

Let's hope that sleet line doesn't get any closer and goes south in future runs.

Yea but we would have 15+ by the time it may even mix for a little so at that point no big deal. It's not letting me WTOD at the beginning if it even happens at any point. 

[jwilson]

NBM mean on today's 7 UTC run up to 11" even.  Spread tightened a little more to 7" to 13" on average.  1 in 3 odds of >12" total.  >8" up slightly to 68% chance.

Most guidance held, so I guess we're waiting to see if a last minute de-amplification occurs.

(As a side note, I see a lot of Kuchera maps, but just be careful about those as they tend to get overdone on totals.)

[colonel717]

14 minutes ago, jwilson said:

NBM mean on today's 7 UTC run up to 11" even.  Spread tightened a little more to 7" to 13" on average.  1 in 3 odds of >12" total.  >8" up slightly to 68% chance.

Most guidance held, so I guess we're waiting to see if a last minute de-amplification occurs.

(As a side note, I see a lot of Kuchera maps, but just be careful about those as they tend to get overdone on totals.)

Most kuchara are about 13-15 to 1 which is quite possible for a good part of the storm. 

[Burghblizz]

I’d say the 6Zs more than held serve!

[Gordo74]

8 hours ago, colonel717 said:

Skinner has been a good surprise. 

He may even end up being the advantage in, dare I say, a playoff round with all of his experience. Really fun to be tracking both a snowstorm and pens playoff chances again. It’s like the early 10’s all over again.

[RitualOfTheTrout]

Great overnight runs that look to be continuing into 6z. I passed out and missed all the fun, the prior two nights staying up late and getting up for work took their toll lol. Looks like I missed a good Pens game too. 

[colonel717]

[Gordo74]

4 minutes ago, colonel717 said:

I feel like this is purposeful rage bait with stopping it at 7am Sunday when it’s an all day event Sunday,

[Ahoff]

Yea, that snow map is tricky from NWS.

[TimB]

Those maps can only ever go out 72 hours. 

[jwilson]

21 minutes ago, colonel717 said:

Most kuchara are about 13-15 to 1 which is quite possible for a good part of the storm. 

The issue with Kuchera isn't necessarily the math but rather model output, so the maps themselves are often flawed.  Ground truth is typically less, but that doesn't mean they are always wrong, of course.

Snow calculation is complex, as is my explanation here (apologies).  The actual equation for Kuchera is this:

Quote

 

1) Find the maximum temperature in the lowest 500 hPa in degrees K (MaxT).

2) If MaxT is greater than 271.16K, then the liquid equivalent ratio (RAT) is 12.0 + 2.0*(271.16-MaxT).

3) If MaxT is less than 271.16K, then the liquid equivalent ratio (RAT) is 12.0 + (271.16-MaxT)

 

But nearly none of the output products in models take into account the other variables of snow growth.  Lift, dendrite growth, and humidity, for example.  Snowfall rates are never constant over X time.

As a basic tenet, highest snowfall ratios (say 25:1) occur when most of the lift is situated at temps in the atmosphere between -12 and -18 Celcius.  Otherwise known as the "snow production zone."

There's a method (Cobb) that uses a layered approach to estimate snowfall ratios at a given time.  It can be paired with Bufkit data to estimate total snowfall, because the Bufkit software has the highest vertical resolution to pair with soundings.

Using this with the 6Z GFS run, for example, gives us 13.2" of snow on 1.04" of precip at AGC.  Ratios vary from 5:1 up to 30:1 in hour snapshots.  That's a higher-end result when compared with the averaged NBM data (0.79" precip average).  Same method is 9.6" of snow on the 0Z GFS run.  We can run this on the NAM, too, but it's not yet within range. 

My main point is that, looking at the 6Z Euro for instance, if people start expecting 17" they are quite likely to end up disappointed, so I had wanted to put out a general caveat emptor for those reading the maps that maybe aren't aware of the limitations.

[RitualOfTheTrout]

3 minutes ago, jwilson said:

The issue with Kuchera isn't necessarily the math but rather model output, so the maps themselves are often flawed.  Ground truth is typically less, but that doesn't mean they are always wrong, of course.

Snow calculation is complex, as is my explanation here (apologies).  The actual equation for Kuchera is this:

But nearly none of the output products in models take into account the other variables of snow growth.  Lift, dendrite growth, and humidity, for example.  Snowfall rates are never constant over X time.

As a basic tenet, highest snowfall ratios (say 25:1) occur when most of the lift is situated at temps in the atmosphere between -12 and -18 Celcius.  Otherwise known as the "snow production zone."

There's a method (Cobb) that uses a layered approach to estimate snowfall ratios at a given time.  It can be paired with Bufkit data to estimate total snowfall, because the Bufkit software has the highest vertical resolution to pair with soundings.

Using this with the 6Z GFS run, for example, gives us 13.2" of snow on 1.04" of precip at AGC.  Ratios vary from 5:1 up to 30:1 in hour snapshots.  That's a higher-end result when compared with the averaged NBM data (0.79" precip average).  Same method is 9.6" of snow on the 0Z GFS run.  We can run this on the NAM, too, but it's not yet within range. 

My main point is that, looking at the 6Z Euro for instance, if people start expecting 17" they are quite likely to end up disappointed, so I had wanted to put out a general caveat emptor for those reading the maps that maybe aren't aware of the limitations.

I made a similar point a few days ago, although you dove much more into the technical side.  This is why I would rather see total qpf for an event when determining if it's a "better" run vs Kuchera or even 10:1 if you are talking surface maps. 

That being said, looking at maps with all these high totals for our backyards is fun as long as you keep yourself grounded and as you say, don't end up disapointed. I never got some of the angst people had when someone posted a "clown map" Afterall, where else outside of a weather forum would something like that be understood or appreciated? 

[Burghblizz]

10 minutes ago, jwilson said:

The issue with Kuchera isn't necessarily the math but rather model output, so the maps themselves are often flawed.  Ground truth is typically less, but that doesn't mean they are always wrong, of course.

Snow calculation is complex, as is my explanation here (apologies).  The actual equation for Kuchera is this:

But nearly none of the output products in models take into account the other variables of snow growth.  Lift, dendrite growth, and humidity, for example.  Snowfall rates are never constant over X time.

As a basic tenet, highest snowfall ratios (say 25:1) occur when most of the lift is situated at temps in the atmosphere between -12 and -18 Celcius.  Otherwise known as the "snow production zone."

There's a method (Cobb) that uses a layered approach to estimate snowfall ratios at a given time.  It can be paired with Bufkit data to estimate total snowfall, because the Bufkit software has the highest vertical resolution to pair with soundings.

Using this with the 6Z GFS run, for example, gives us 13.2" of snow on 1.04" of precip at AGC.  Ratios vary from 5:1 up to 30:1 in hour snapshots.  That's a higher-end result when compared with the averaged NBM data (0.79" precip average).  Same method is 9.6" of snow on the 0Z GFS run.  We can run this on the NAM, too, but it's not yet within range. 

My main point is that, looking at the 6Z Euro for instance, if people start expecting 17" they are quite likely to end up disappointed, so I had wanted to put out a general caveat emptor for those reading the maps that maybe aren't aware of the limitations.

Good info and good balanced take. I’ll still look at the clown maps and dream, but great info for what is more likely (which isn’t bad at all)

[southpark]

30 minutes ago, colonel717 said:

I'll reserve judgement until they put out the next one since that should cover the scope of the storm.

[MikeB_01]

Good morning, all. NAM is running. Lets keep track on this 12z suite.

[Burghblizz]

31 minutes ago, Gordo74 said:

I feel like this is purposeful rage bait with stopping it at 7am Sunday when it’s an all day event Sunday,

lol - rage bait. Yeah, I had to do a double take at the timeframe. I really do think though it’s because they don’t want to put out a map that extends more than 72 hours out. 

[Rd9108]

I saw this on Facebook. Who are these guys and why do they think its a good idea to predict 16-22 inches for area A. No model even with ratios is predicting that. 

[colonel717]

37 minutes ago, jwilson said:

 

Always appreciate your detailed posts. I am obviously someone who is guilty of posting Kuchara at times , but I certainly don't ever expect those totals that any model puts out. Maybe RD9108 does.. Just kidding bud..  It helps me put together a range. As ROTT said, it is fun. That is what following this weather is all about for me. Enjoy any snow we get.  

[Rd9108]

SREF mean is almost 11-12 inches at 10 to 1. 

[Rd9108]

Deep Mind 

[TimB]

NAM is going to be meh, isn’t it?

[colonel717]

NAM is south of where it was this morning. Its so over...

[Burghblizz]

6 minutes ago, TimB said:

NAM is going to be meh, isn’t it?

It was looking stringy and unorganized at first, but it’s getting its act together by hour 72. The end result will be good.

Taken literally, it suppresses the precip at first, and then drives the SLP into our backyard which creates mix and dry slot issues.

I guess it’s an example of threading the needle to get a “fail” for bigger snows, but verbatim still probably 10” +

[MikeB_01]

2 minutes ago, TimB said:

NAM is going to be meh, isn’t it?

I think it look very similar to the 6z. Only difference i can see through hr 69 is the HP over new england is suprressing the precip shild slightly. 

 

At the 500 level, the southern energy seems to be a little more outfront of the kicker from the north. This should cause more amplification, but it doesn't appear to be when you look at the reflectivity maps