PNW December 2022 - Part II

[bainbridgekid]

31 minutes ago, Mid Valley Duck said:

Even though it still sucks compared to the other op runs. It did make some nice improvements on day 3.5-4.5. Weaker PV out in the NPAC, lets the ridge retro more and the trough carves out better

Just a small clarification about what has been excellent analysis by you. The PV is the Polar Vortex which specifically forms in the Arctic during the Winter. While it sometimes breaks up and moves down through Canada into the US, it is never out over the middle of the Pacific Ocean like that. That is just a trough of low heights and thicknesses.

[SnowWillarrive]

3 minutes ago, TT-SEA said:

I have seen it go from 50 degrees and raining and windy to snowing and sticking immediately here in a span of a couple hours when a c-zone moves in from the north.     The ground temperature thing is basically irrelevant.  

Ground frozen solid here and it icy here. Was just in North Bend this morning. Big snow piles everywhere. 

 

[Terreboner]

So to summarize:

Euro went apeshit with epic cold.

Every other model said hell no.

Euro regressed a little towards every other model.

Every other model except for GFS started improving.

All models including Euro now are a middle ground between epic and warm.

Now GFS is coming back towards the Euro and others.

Did I miss anything?

[MossMan]

7 minutes ago, WeatherGeek2022 said:

still a hunch that this thing folds on us.

Don’t make me pull out the late January 2019 screenshots! 

[TT-SEA]

Just now, SnowWillarrive said:

Ground frozen solid here and it icy here. Was just in North Bend this morning. Big snow piles everywhere. 

 

We still have 1-2 inches of snow covering the yard and its so hard now that I can walk across the top without breaking the surface. 

[Gummy]

5 minutes ago, TT-SEA said:

I have seen it go from 50 degrees and raining and windy to snowing and sticking immediately here in a span of a couple hours when a c-zone moves in from the north.     The ground temperature thing is basically irrelevant.  

December 22nd, 2020, from 59 and rainy to snow on the roadways in North Seattle.

[Front Ranger]

4 minutes ago, hawkstwelve said:

Didn't quite go all the way but 18z GFS was a definitive step towards the Euro/GEM/UKMET/ICON solution.

00z run should finish it off.

It gets closer eventually, but man, just 3 days out it's still way different and closer to the 12z.

[MR.SNOWMIZER]

This is how i feel about the gfs.

You just slip out the back, Jack
Make a new plan, Stan
You don't need to be coy, Roy
Just get yourself free
Hop on the bus, Gus
You don't need to discuss much
Just drop off the key, Lee
And get yourself free

[SouthHillFrosty]

A little bit better 

[LowerGarfield]

NWS Spokane is not buying it for next weekper AFD from 15 mins ago.

[Skagit Weather]

8 minutes ago, TT-SEA said:

If the temperature/dewpoint go below freezing then it doesn't even have to be heavy snow.    And if the temperature/dewpoint are above freezing then the ground won't be frozen.

I would argue it makes a slight difference, but not even close to the importance a certain unnamed meteorologist claims. If the dew point is below freezing, but the temperature isn't, it can have a hard time sticking. Earlier this month I saw hours of snow with a 30-32F dew point and temps in the mid 30s and nothing stuck. And even for temperatures right around freezing, if the ground is saturated by recent rain you may need a bit of extra intensity for accumulations to form. But once the temperature drops to 31F or 30F and below, the snow is going to stick no matter how "warm the ground is."

[snow_wizard]

The GFS is a horrible model in its current incarnation.  All other models crush us with cold air next week and the GFS is just very slowly getting there going a bit colder on each run.  At least it is catching on.

[TacomaWx]

Just now, snow_wizard said:

The GFS is a horrible model in its current incarnation.  All other models crush us with cold air next week and the GFS is just very slowly getting there going a bit colder on each run.  At least it is catching on.

Glad you finally made it and get to see all the crazy good changes today. 

[snow_wizard]

7 minutes ago, LowerGarfield said:

NWS Spokane is not buying it for next weekper AFD from 15 mins ago.

Pretty crazy to not be buying it for there.

[snow_wizard]

1 minute ago, TacomaWx said:

Glad you finally made it and get to see all the crazy good changes today. 

The ECMWF is off the chain!

[SnowWillarrive]

7 minutes ago, LowerGarfield said:

NWS Spokane is not buying it for next weekper AFD from 15 mins ago.

Of course they have to put faith into what Uncle Sam created with the GFS. 

[MikeInEverett]

How does the UW GFS look?

[snow_wizard]

I think one of the things that has made the models change is they finally "realized" the very dense cold air over the continent is going to put up a big fight against allowing the remnants of the offshore blocking to migrate eastward so quickly.

[snow_wizard]

3 minutes ago, SnowWillarrive said:

Of course they have to put faith into what Uncle Sam created with the GFS. 

To be doubting it in Spokane is a real head scratcher.

[GHweatherChris]

You guys shouldn't get excited, someone already made sure everyone knew that this is what next Friday looks like on the models...

[snow_wizard]

The ECMWF presents the chance it could remain cold until Christmas morning if things get pushed out just a bit more.

[snow_wizard]

1 minute ago, GHweatherChris said:

You guys shouldn't get excited, someone already made sure everyone knew that this is what next Friday looks like on the models...

Nearly a week of cold with a good snow event is pretty exciting.  Warmups do occur after a good round of winter on many occasions.

[HuskyMaestro]

Crazy how this season is my first actual winter model riding season with an account (as well as others) and it just so happens to be some of the wildest rollercoaster model riding for everyone. 

No beginner's luck in weather I'd assume. 

[GHweatherChris]

Just now, snow_wizard said:

Nearly a week of cold with a good snow event is pretty exciting.  Warmups do occur after a good round of winter on many occasions.

#itwasajoke

[TT-SEA]

14 minutes ago, Skagit Weather said:

I would argue it makes a slight difference, but not even close to the importance a certain unnamed meteorologist claims. If the dew point is below freezing, but the temperature isn't, it can have a hard time sticking. Earlier this month I saw hours of snow with a 30-32F dew point and temps in the mid 30s and nothing stuck. And even for temperatures right around freezing, if the ground is saturated by recent rain you may need a bit of extra intensity for accumulations to form. But once the temperature drops to 31F or 30F and below, the snow is going to stick no matter how "warm the ground is."

I think the surface of the ground responds very quickly to changes in temperature/dewpoint.     If its snowing and not sticking then the weather conditions are to blame... not the ground.   And vice versa.

[weatherwonder]

4 minutes ago, GHweatherChris said:

You guys shouldn't get excited, someone already made sure everyone knew that this is what next Friday looks like on the models...

Rudolph’s red nose !

[Brian_in_Leavenworth]

3 hours ago, Brian_in_Leavenworth said:

This run showed a lot less snow for the NE than before.

 

[umadbro]

1 minute ago, TT-SEA said:

I think the surface of the ground responds very quickly to changes in temperature/dewpoint.     If its snowing and not sticking then the weather conditions are to blame... not the ground.   And vice versa.

April 2022 says hello. Snow started sticking immediately. Also helped that flakes were the size of paper plates.

[PuyallupChris]

1 hour ago, Ice_is_Everywhere said:

Any chance that CZ feature Sunday and Monday hits areas further south than modeled?

I seem to remember hearing there was a surprise CZ in the Burien/Seatac area in that giant storm around '89. That was the first big snowstorm I remember, and my memory as a 6 year old is that it was like 12 inches of snow.  Of course, we always distort our childhood memories, don't we. 

It can happen.  I seem to remember a handful of what seemed like mini convergence zones in the Federal Way area in the early 2000s, but I don't know of any research into that.

 

In general, though, it seems very rare that CZs will drift past downtown. 

[TT-SEA]

8 minutes ago, MillCreekMike said:

How does the UW GFS look?

10-day snowfall total.    So silly.  

[SnowWillarrive]

5 minutes ago, snow_wizard said:

The ECMWF presents the chance it could remain cold until Christmas morning if things get pushed out just a bit more.

Really hope folks just south of the traditional c zone can score late Sunday night. Would be an amazing appetizer. 

[LowerGarfield]

10 minutes ago, snow_wizard said:

Pretty crazy to not be buying it for there.

If know....very unusual for them. They are in agreement on the earlier system esp for my area which makes sense but it seems a bit shocking they are not in on Tuesday-Thursday. They also saw the latest Euro.

[TT-SEA]

3 minutes ago, umadbro said:

April 2022 says hello. Snow started sticking immediately. Also helped that flakes were the size of paper plates.

Hello April 2022! 

I didn't like you very much.    I sure hope your friend April 2023 is more seasonally appropriate.  

[snow_wizard]

18z GEFS takes 850s on the second dip down to -5 vs -3 on the 12z.  Getting better.

Meanwhile the second dip on the EPS mean drops to -11.

[LowerGarfield]

Can someone copypaste Spokane's AFD? I'm on my phone at work so I can't do it but I want to know what you think.

[snow_wizard]

6 minutes ago, GHweatherChris said:

#itwasajoke

I realized that just after I posted that.

[Brian_in_Leavenworth]

13 minutes ago, snow_wizard said:

Pretty crazy to not be buying it for there.

They are buying snow, except the Thursday system where there's a warmup.  They weren't sure what areas would remain snow for that one.

[Front Ranger]

3 minutes ago, Brian_in_Leavenworth said:

 

He's a pro met and a 174 hour snow map from the GFS is breaking his heart? 

[snow_wizard]

3 minutes ago, LowerGarfield said:

If know....very unusual for them. They are in agreement on the earlier system esp for my area which makes sense but it seems a bit shocking they are not in on Tuesday-Thursday. They also saw the latest Euro.

Are you talking about snow or cold they aren't in for?  The snow could be more complicated I suppose.

[Front Ranger]

4 minutes ago, PuyallupChris said:

In general, though, it seems very rare that CZs will drift past downtown. 

Yes, but ones associated with Arctic fronts are different because the front itself is sinking south, causing convergence with warmer air as it does.

Not usually as powerful as the CZs that develop north of Seattle, though.