PNW December 2022 - Part II

[GHweatherChris]

Surface temp maps, the most accurate maps ever.......

[Gradient Keeper]

2 minutes ago, Perturbed Member said:

Looks like its actually snowing decently in the coast range.

I'd say so. That also was not modeled or expected.

[Slushy Inch]

1 minute ago, TT-SEA said:

A little warmer when you go out through 4 p.m.

Slightly cooler than the 18Z run but warmer than the 12Z run.

Not on the mean. Mean drops back to 30.

[TT-SEA]

2 minutes ago, ShawniganLake said:

Does weatherbell have maps for HRDPS?

Yes... this is just the Tuesday system.

[snow_wizard]

Control snow map.  Both are better than the 18z!

[TT-SEA]

Just now, 12345WeatherNerd said:

Not on the mean. Mean drops back to 30.

My bad... thought I was on the EPS mean.

The mean does look similar though.

[lowlandsnow]

The EURO control is better that the 18z

[GHweatherChris]

This  coolish snap is disappointing, just a lack of excitement. 

[Gradient Keeper]

00z ECMWF 10 Day Rainfall, Snowfall totals

[lowlandsnow]

The control has a high of 17 on Thursday for Seattle

[snow_wizard]

3 minutes ago, Deweydog said:

Depends on your definition. Compared to 1990, this event will be night and day.  That was a sprawling upper level-supported monster which verified thicknesses about 26dm lower than anything progged at this point down here. It was very much a top down air mass. This one will bottom up, maybe on an unprecedented level if you manage to convince yourself of the current surface progs.

I call this one a continuation play.  The cold air got brought close by an exceptional setup, and will be shoved down here by a much less exceptional setup.  In the end this will be a wickedly cold east wind though.

[SilverFallsAndrew]

I’d like to see North Bend on the southern Oregon coast have a high of 23 before we try any 1990 comparisons. 

[snow_wizard]

2 minutes ago, GHweatherChris said:

This  coolish snap is disappointing, just a lack of excitement. 

Not for the interior.

[Slushy Inch]

2 minutes ago, lowlandsnow said:

The control has a high of 17 on Thursday for Seattle

Mean is not much more.

[TT-SEA]

Looks like the snow is about done out here at least... ended up with just over 3 inches.    ECMWF did well on timing and movement of the precip and showed the main event would be from 4-10 p.m.   The 12Z run was a little too high on precip amounts in general for King County.    

[GHweatherChris]

1 minute ago, snow_wizard said:

Not for the interior.

I don't live there, duh.

[Slushy Inch]

5 minutes ago, TT-SEA said:

My bad... thought I was on the EPS mean.

The mean does look similar though.

That's 6 hour max temp!

[snow_wizard]

Those EPS snow maps moving the right way is a great development tonight. 

The moisture plume is slightly more suppressed when it's off the coast as well.  Arctic high pressure to the north exerting more force on it.

[Gradient Keeper]

1 minute ago, SilverFallsAndrew said:

I’d like to see North Bend on the southern Oregon coast have a high of 23 before we try any 1990 comparisons. 

 I should have clarified. I am speaking specifically how fast the arctic air is modeled to blast into eastern Washington with 850s -19c to -23c butting up against the east slopes of the Washington Cascades. It comes in so quickly. When was the last arctic blast to do so?

6z GFS in 2 hours 17 minutes

[Perturbed Member]

7 minutes ago, Gradient Keeper said:

I'd say so. That also was not modeled or expected.

Yeah the radar isn't showing much or shows nothing at all in these spots. Must be fairly low level moisture maybe. 

[TT-SEA]

Just now, snow_wizard said:

Those EPS snow maps moving the right way is a great development tonight. 

Do we use ensembles for an event starting in about 24 hours?    

[snow_wizard]

2 minutes ago, 12345WeatherNerd said:

Mean is not much more.

This is going to be very real.

[CliffMassYelledAtMe]

Last night was Whiskey Sour. Thinking tonight will be Dark and Stormy. Headed to the store tomorrow. Any themed drinks I should get ingredients for? 

[Deweydog]

1 minute ago, snow_wizard said:

I call this one a continuation play.  The cold air got brought close by an exceptional setup, and will be shoved down here by a much less exceptional setup.  In the end this will be a wickedly cold east wind though.

That’s a pretty decent term for it. It’s definitely very unique, which is cool and all but also leaves one pretty skeptical overall. From the sharp inversion precursor ridge to the rocket ship retrogression and massive unstable block to the undercut ridge replacing it as the subtle meridional driver, it’s pretty goofy.

[snow_wizard]

Just now, TT-SEA said:

Do we use ensembles for an event starting in about 24 hours?    

Good question.

[jcmcgaffey]

This convergence hasn’t amounted to much here north of seattle. Dusting to maybe 1/2”. Its not sticking to streets yet but is still snowing continuously even under no precip on the radar. Does look like another batch is coming through in a bit. 

[TT-SEA]

1 minute ago, 12345WeatherNerd said:

That's 6 hour max temp!

Yes... thought that was what you were talking about.   I see now you meant temps at 4 p.m.   Although the ECMWF does show the precip is about over by 2 or 3 p.m. for the Seattle area.    Temps definitely crash after that system moves through.

[snow_wizard]

1 minute ago, Deweydog said:

That’s a pretty decent term for it. It’s definitely very unique, which is cool and all but also leaves one pretty skeptical overall. From the sharp inversion precursor ridge to the rocket ship retrogression and massive unstable block to the undercut ridge replacing it as the subtle meridional driver, it’s pretty goofy.

Never seen one unfold like this.  

[LowerGarfield]

24 degrees and very light dusting so far. Going to bed soon or at least I hope.

[snow_wizard]

1 minute ago, TT-SEA said:

Yes... thought that was what you were talking about.   I see now you meant temps at 4 p.m.   Although the ECMWF does show the precip is about over by 2 or 3 p.m. for the Seattle area.    Temps definitely crash after that system moves through.

It still likes that backwash snow after the crash also.  That often treats the EPSL very well.  The crash behind the low is pretty darn impressive actually.

[Meatyorologist]

Already starting to see our first glimpses of Tuesday's system on the coastal radar.

[Slushy Inch]

2 minutes ago, TT-SEA said:

Yes... thought that was what you were talking about.   I see now you meant temps at 4 p.m.   Although the ECMWF does show the precip is about over by 2 or 3 p.m. for the Seattle area.    Temps definitely crash after that system moves through.

Ah true

[Snownerd3000]

3 minutes ago, CliffMassYelledAtMe said:

Last night was Whiskey Sour. Thinking tonight will be Dark and Stormy. Headed to the store tomorrow. Any themed drinks I should get ingredients for? 

Dude I'm sipping on one right now. You should check out Jeffrey Morganthaler iteration. Sooooo good

[Gradient Keeper]

Ohhh... Arctic front into Hermiston now! This was not forecast.

[TT-SEA]

2 minutes ago, snow_wizard said:

It still likes that backwash snow after the crash also.  That often treats the EPSL very well.  The crash behind the low is pretty darn impressive actually.

Per the ECMWF the main front clears the Seattle area by early to mid afternoon before the temps crash.    But then does show a c-zone feature later Tuesday night which might well be another arctic front type situation.  

[Requiem]

How does EPS look for PDX? 

[TT-SEA]

2 minutes ago, Gradient Keeper said:

Ohhh... Arctic front into Hermiston now! This was not forecast.

ECMWF showed temps crashing there from the 40s to the upper 20s between about 10 p.m. and midnight. 

[JW8]

OP does look to be on the "warm" end

[Gradient Keeper]

1 minute ago, TT-SEA said:

ECMWF showed temps crashing there from the 40s to the upper 20s between about 10 p.m. and midnight. 

Right, tonight's run did, but I don't think any previous did. Tonight's runs are playing "catch up" with surface temps and position of frontal boundaries it seems.

[Slushy Inch]

2 minutes ago, JW8 said:

OP does look to be on the "warm" end

By quite a bit.