Western PA/Pittsburgh Winter 2021/22 Discussion

[Rd9108]

Well looking at the 500mb maps and other forums seems as that kicker that was amping this thing up is weaker with each run. That should help keep this thing from cutting further west.

[Rd9108]

Maybe the Fv3 has a clue

[MikeB_01]

The biggest uncertainty is the TROWAL (trough of warm air aloft) and
just how much of a SLR reduction we`ll receive. Latest 00z NAM Nest
suggests a warm nose of 1-2C at 850mb in the trowal, while other
models suggest a little colder. If this were to occur, snow ratios
would be greatly reduced if sleet becomes mixed, or even a brief
period of freezing rain. However, at this time, it does appear this
is the warm outlier. Given the other models are colder and the
combination of evaporational and dynamic cooling associated with the
steady/heavy precip band, the current snowfall forecast assumes
little to no melting. If the warm solution were to verify, we can
easily knock off a few inches of snowfall.. but will still receive
accumulating snow as the warmest warm air shifts away quickly.

 

 

This is from the forecast discussion this morning. Definitely considering the NAM, but clearly marking it as the warm outlier.

[MikeB_01]

4 minutes ago, Rd9108 said:

Maybe the Fv3 has a clue

Beautiful deform band on that run. 

[Ahoff]

These trends and updates from the NWS is making me more comfortable.

[Ahoff]

19 minutes ago, MikeB_01 said:

So you're saying there's a chance...

I’ve never seen totals that high from them, lol.

[MikeB_01]

I’ve never seen totals that high from them, lol.

Me neither. Especially that wide spread.

Now that is definitely the high end. That is the max. But I’ll take a chance.


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[Ahoff]

2 minutes ago, MikeB_01 said:

Me neither. Especially that wide spread.

Now that is definitely the high end. That is the max. But I’ll take a chance.


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Oh definitely high end, but the fact that they expanded it is telling, hopefully.

[TimB]

12z RGEM was a sleetfest. That 12” total doesn’t seem to be mostly snow.

[KPITSnow]

12 minutes ago, TimB84 said:

12z RGEM was a sleetfest. That 12” total doesn’t seem to be mostly snow.

That’s not good given it was one of our best producers for a while now 

 

im just getting the feeling that we are going to get less than six inches and dry slot/slop and 50 miles west and north will see a foot. 
 

hopefully we can get a move SE. 

 

edit: and before anyone says I’m too negative it is exactly what most models have been trending towards 

[meatwad]

[MikeB_01]

21 minutes ago, TimB84 said:

12z RGEM was a sleetfest. That 12” total doesn’t seem to be mostly snow.

 

19 minutes ago, KPITSnow said:

That’s not good given it was one of our best producers for a while now 

 

im just getting the feeling that we are going to get less than six inches and dry slot/slop and 50 miles west and north will see a foot. 
 

hopefully we can get a move SE. 

 

edit: and before anyone says I’m too negative it is exactly what most models have been trending towards 

Honestly, i didn't think the RGEM was bad. I saw the sleet show up, but the column cooled fast enough that Im not worried. Awesome rates on that run.

[TimB]

52 minutes ago, MikeB_01 said:

Another observation, NWS probably isn't putting much stock into the path/idea the NAM has been taking. NWS Cle hasn't even issued anything but a hazardous weather outlook for most counties. They obviously don't think the heaviest snow will set up over their area.

It’s a positive sign that they haven’t put the possibility other p-types into the forecast, and that others like TWC haven’t added the “some mixed winter precipitation possible” wording. Using the 1/19/19 storm as an example, TWC carried mostly rain long before the NWS ever did.

[Ahoff]

1 minute ago, TimB84 said:

It’s a positive sign that they haven’t put the possibility other p-types into the forecast, and that others like TWC haven’t added the “some mixed winter precipitation possible” wording. Using the 1/19/19 storm as an example, TWC carried mostly rain long before the NWS ever did.

That’s what’s surprising me too.

[MikeB_01]

1 minute ago, Ahoff said:

That’s what’s surprising me too.

 

4 minutes ago, TimB84 said:

It’s a positive sign that they haven’t put the possibility other p-types into the forecast, and that others like TWC haven’t added the “some mixed winter precipitation possible” wording. Using the 1/19/19 storm as an example, TWC carried mostly rain long before the NWS ever did.

I just think this is where met intuition / experience comes in ahead of modeling. The discussions are full of comments about the rate of evaporative cooling. Even if we sleet, it should be brief and then we should be thumping again.

[KPITSnow]

Just now, MikeB_01 said:

 

I just think this is where met intuition / experience comes in ahead of modeling. The discussions are full of comments about the rate of evaporative cooling. Even if we sleet, it should be brief and then we should be thumping again.

I agree with this. I do think the bigger issue is dry slotting. 
 

GFS is solid but still has the dry slotting issue.

[Rd9108]

[MikeB_01]

GFS?


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[Burghblizz]

11 minutes ago, MikeB_01 said:

 

I just think this is where met intuition / experience comes in ahead of modeling. The discussions are full of comments about the rate of evaporative cooling. Even if we sleet, it should be brief and then we should be thumping again.

I think this is why we all do well - but it’s like 5” to 12” well, as opposed to a nice tight range. 

Where it’s ripping it will be ripping. Where it’s not, it might be a light mix for while, which will further hold totals down. So any prolonged period with that gets you behind the game.

So a deeper storm hurts - because of the warm air aloft. But it also can HELP with dynamic cooling.

[Rd9108]

Just now, MikeB_01 said:

GFS?


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apparently

[Rd9108]

My thoughts of course I want the high totals but give me a prolonged period of a 2inch per hour band and I'll be happy.

[meatwad]

[Burghblizz]

1 minute ago, meatwad said:

I wouldn’t worry about the exact orientation of pink and blue. I think that’s a 2” hour.  

[Rd9108]

GFS gas ALOT of precip

[MikeB_01]

GFS gas ALOT of precip

Woah.


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[Ahoff]

16 minutes ago, meatwad said:

is it even realistic to see that much mixed precip and ice?  Seems like an uncommonly high amount over a large area.

[MikeB_01]

is it even realistic to see that much mixed precip and ice?  Seems like an uncommonly high amount over a large area.

It’s pretty expansive. Though it totally depends on the warm layer aloft. We know the surface-925 will be plenty cold. Even if the 850 level is 33 for a little, I think it is very brief. We have a deepening ULL with heavy rates and it will cause that column to cool quickly.


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[Ahoff]

6 minutes ago, MikeB_01 said:

It’s pretty expansive. Though it totally depends on the warm layer aloft. We know the surface-925 will be plenty cold. Even if the 850 level is 33 for a little, I think it is very brief. We have a deepening ULL with heavy rates and it will cause that column to cool quickly.


.

I hope so.  This could be pretty great.

[meatwad]

Looks good

[Gordo74]

Just now, meatwad said:

Looks good

loving this one.