PNW December 2022, winter might be coming; but mostly canceled.

[Omegaraptor]

10 minutes ago, DeepFriedEgg said:

Let's get out of this awful pattern and reset. No point in delaying the inevitable ARs, split flow and west coast ridging. 

This is better than probably 80% of our winter weather lol

[bainbridgekid]

5 minutes ago, TT-SEA said:

18Z GFS has spoken... and of course its very snowy tonight.    Somehow we are going to get 3-4 inches even out here despite the ECMWF showing the precip never makes it this far.   

I can think of quite a few times models overestimated the drying effect of East winds here. 12/21/08 was a classic example. Might have to do with them underestimating the effect of the Cascades and overplaying CAA too. They block a lot of that dry air from reaching Puget Sound with moisture moving in from the SW.
 

With borderline temps it won’t snow that much in Seattle but I bet the models that keep all the moisture West of Puget Sound are wrong.

[Perturbed Member]

14 minutes ago, Doinko said:

ICON keeps us as rain on Sunday

The ICON is one of the models that I actually think has a warm bias. I find it does a fairly poor job of accounting for offshore flow around here. The worst problem with it though is that it seems to greatly exaggerate shadowing relative to other models. Sometimes it seems to think the Coast Range is about the same elevation as the Himalayas.

[Perturbed Member]

 

[SouthHillFrosty]

3 minutes ago, bainbridgekid said:

I can think of quite a few times models overestimated the drying effect of East winds here. 12/21/08 was a classic example. Might have to do with them underestimating the effect of the Cascades and overplaying CAA too. They block a lot of that dry air from reaching Puget Sound with moisture moving in from the SW.
 

With borderline temps it won’t snow that much in Seattle but I bet the models that keep all the moisture West of Puget Sound are wrong.

I believe even last year, models over estimated east winds….. I could be thinking of a different year tho

[TT-SEA]

Some patches of blue sky out here...

[SnowWillarrive]

6 minutes ago, Perturbed Member said:

The ICON is one of the models that I actually think has a warm bias. I find it does a fairly poor job of accounting for offshore flow around here. The worst problem with it though is that it seems to greatly exaggerate shadowing relative to other models. Sometimes it seems to think the Coast Range is about the same elevation as the Himalayas.

Can’t pay attention to the ICON. Totally missed on the recent event. 

[TT-SEA]

8 minutes ago, bainbridgekid said:

I can think of quite a few times models overestimated the drying effect of East winds here. 12/21/08 was a classic example. Might have to do with them underestimating the effect of the Cascades and overplaying CAA too. They block a lot of that dry air from reaching Puget Sound with moisture moving in from the SW.
 

With borderline temps it won’t snow that much in Seattle but I bet the models that keep all the moisture West of Puget Sound are wrong.

The ECMWF is usually really good with precip.    

But the 12Z run was the first run to keep everything from Seattle westward... prior runs had more precip in King County.

[DeepFriedEgg]

5 minutes ago, Perturbed Member said:

The ICON is one of the models that I actually think has a warm bias. I find it does a fairly poor job of accounting for offshore flow around here. The worst problem with it though is that it seems to greatly exaggerate shadowing relative to other models. Sometimes it seems to think the Coast Range is about the same elevation as the Himalayas.

I mean if we really look back it was definitely the most accurate with temps at PDX. I mean PDX has yet to hit freezing during this ENTIRE "event". I mean that is just pathetic. The fake cold we had before this was much more impressive...

 

Coast range ALWAYS eats up more moisture than is modeled, especially in Washington County.

[gusky]

12 minutes ago, TT-SEA said:

No idea what will happen.   The ECMWF shows the precip only makes it as far east as 405 and shows 925mb temps around +2C overnight.    The GFS shows precip all over King County with a 925mb temp of -1C.   

This event is already in progress and the GFS and ECMWF are still miles apart.   

Story of the past week

[runninthruda206]

4 minutes ago, TT-SEA said:

Some patches of blue sky out here...

Wow that’s beautiful 

[Requiem]

18 minutes ago, DeepFriedEgg said:

We only get so many shots at getting arctic air west of the cascades. Let's stop wasting time with this near miss.

Remarkably frustrating pattern for here, sure, but I feel like at some point with all this blocking there's gonna be a favorable outcome for us...

[jakerepp]

40 minutes ago, WeatherGeek2022 said:

I guess it's time to start making sacrifices

I already moved to AZ for you all. I can't do anything more.

[Perturbed Member]

I'm not too worried about the P type not being snow on Sunday. I'm a lot more skeptical of things when we are dealing with onshore flow and marginal temps but I feel a lot more comfortable when the gorge gets involved here, even though we don't have a frigid airmass east. I think it will be cold enough.

Both the Euro and the GFS clearly think it will be all snow here and the soundings on both models also confirm that. 6 of the past 7 GFS runs look pretty much the same and show decent accumulation here. As of this morning even the 12z GEM jumped on board.

The most curious bit is still that both models show the precip getting enhanced as the band hits NW OR/SW WA and we are seeing this fairly consistently across runs. Now I'm not comparing this to 1/10/17 but I remember that event had some dramatic convergence as the approaching moisture ran into a surging east wind and the precip really blew up right over the metro area and we got thundersnow. This setup is of course different but I wouldn't mind some kind of homeless man's version of that. 

[Meatyorologist]

1 hour ago, gusky said:

Yes

Even this "awful" pattern looks decent for inversions and "fake cold" (probably my least favorite term on here), and is sort of primed for retrogression.

[Meatyorologist]

14 minutes ago, Perturbed Member said:

The ICON is one of the models that I actually think has a warm bias. I find it does a fairly poor job of accounting for offshore flow around here. The worst problem with it though is that it seems to greatly exaggerate shadowing relative to other models. Sometimes it seems to think the Coast Range is about the same elevation as the Himalayas.

+10000 likes. I've noticed the EXACT same biases.... Also simply does not understand the concept of evaporative cooling.

[jakerepp]

24 minutes ago, MR.SNOWMIZER said:

Right up road from home. 32 degrees winter hanging on today better than expected. 

I would jump in the car and just drive around aimlessly for hours in those conditions.

[Meatyorologist]

10 minutes ago, TT-SEA said:

Some patches of blue sky out here...

Beautiful

[TT-SEA]

@GHweatherChris  Precip incoming now!  

[GHweatherChris]

2 minutes ago, TT-SEA said:

@GHweatherChris  Precip incoming now!  

I am really hoping the NWS and model forecast busts, there is high potential of that here, the easterlies are going strong, has a classic overrunning feel to the potential.

[joelgombiner]

Sea-Tac has cooled from the high of 39 back down to 38, and the dew point is rock solid at 28. ESE wind up to 13 mph keeping the air cool and dry. 

[Perturbed Member]

5 minutes ago, DeepFriedEgg said:

I mean if we really look back it was definitely the most accurate with temps at PDX. I mean PDX has yet to hit freezing during this ENTIRE "event". I mean that is just pathetic. The fake cold we had before this was much more impressive...

 

Coast range ALWAYS eats up more moisture than is modeled, especially in Washington County.

According to the ICON I should have never seen anything but rain the past week. I've seen snow falling 3 different times and had a light accumulation, a quarter inch on non-road surfaces a few days ago.

Most models rightfully show lots of shadowing in showery precip but the ICON will sometimes even show significant amounts for startiform precip. Relative to other models, it is simply overdone. 

You can watch the ICON over a period of time and look at its projected QPF and then compare to actual values at those locations. The ICON will frequently be too low.

tldr; Just use the Euro, it obliterates the ICON.

[Meatyorologist]

Kind of getting underlooked right now, but with inversions and cloudcover, Sun/Mon will struggle to reach freezing in the Puget Sound region. Lows could be frigid too.

[Requiem]

4 minutes ago, Meatyorologist said:

+10000 likes. I've noticed the EXACT same biases.... Also simply does not understand the concept of evaporative cooling.

I just find it a very inaccurate model-- I've heard it's far more accurate for its native Europe than our local microclimates. It heavily amplifies wind in strange spots, overdoes precipitation, doesn't resolve low pressure systems properly, doesn't get evaporative cooling or even marginal snow situations, etc.

[BLI snowman]

44 minutes ago, Cascadia_Wx said:

Is it just me or does it seem like the station at The Dalles has been running warm lately?

41 and cloudy here after a low of 33.

Always a warm spot there at the airport, being right at river level. Looking at the Mesowest map right now they're probably a couple of degrees on the outlierish side I would say on average...

 

[thickhog]

13 minutes ago, DeepFriedEgg said:

I mean if we really look back it was definitely the most accurate with temps at PDX. I mean PDX has yet to hit freezing during this ENTIRE "event". I mean that is just pathetic. The fake cold we had before this was much more impressive...

 

Coast range ALWAYS eats up more moisture than is modeled, especially in Washington County.

PREACH

[GHweatherChris]

1 minute ago, GHweatherChris said:

I am really hoping the NWS and model forecast busts, there is high potential of that here, the easterlies are going strong, has a classic overrunning feel to the potential.

We are actually in Aberdeen right now, trying to get the ladies to hurry up their shopping so I can get home and monitor things real time.

[DeepFriedEgg]

2 minutes ago, joelgombiner said:

Sea-Tac has cooled from the high of 39 back down to 38, and the dew point is rock solid at 28. ESE wind up to 13 mph keeping the air cool and dry. 

Not sure if there is enough precip for enough evap cooling.....

[Meatyorologist]

1 minute ago, joelgombiner said:

Sea-Tac has cooled from the high of 39 back down to 38, and the dew point is rock solid at 28. ESE wind up to 13 mph keeping the air cool and dry. 

When the slug of moisture reaches the area tonight, models are consistent with an associated DP hike as temps cool to the wet bulb. Should make for a wet snow if precip is heavy enough

[JW8]

21 minutes ago, SouthHillFrosty said:

Zoomed in of Tim’s map. 

The GFS is the friend that just tells us what we want to hear. 

[Doinko]

24 minutes ago, Perturbed Member said:

The ICON is one of the models that I actually think has a warm bias. I find it does a fairly poor job of accounting for offshore flow around here. The worst problem with it though is that it seems to greatly exaggerate shadowing relative to other models. Sometimes it seems to think the Coast Range is about the same elevation as the Himalayas.

Thanks for this, I didn't know about the ICON's bias to keep things too warm. That makes me feel better about Sunday's event!

[Requiem]

I do genuinely think the east wind will make a significant difference as far as our snow prospects go. Sorta reminds me of a better version of another very marginal situation back in January 2021.

[TT-SEA]

1 minute ago, Meatyorologist said:

When the slug of moisture reaches the area tonight, models are consistent with an associated DP hike as temps cool to the wet bulb. Should make for a wet snow if precip is heavy enough

ECMWF shows a low of 34 tonight in Seattle.

[Doinko]

1 minute ago, Requiem said:

I do genuinely think the east wind will make a significant difference as far as our snow prospects go. Sorta reminds me of a better version of another very marginal situation back in January 2021.

We had some decent moderate snow for a while with that, just started to accumulate slightly on grass and then the precip stopped. I wouldn't mind a repeat though

[Cascadia_Wx]

4 minutes ago, BLI snowman said:

Always a warm spot there at the airport, being right at river level. Looking at the Mesowest map right now they're probably a couple of degrees on the outlierish side I would say on average...

 

Sure, I just remember it spitting out some pretty funky warm readings last winter and spring too. I guess it’s acting like a typical airport station.

[BLI snowman]

23 minutes ago, Perturbed Member said:

The ICON is one of the models that I actually think has a warm bias. I find it does a fairly poor job of accounting for offshore flow around here. The worst problem with it though is that it seems to greatly exaggerate shadowing relative to other models. Sometimes it seems to think the Coast Range is about the same elevation as the Himalayas.

Yeah, just as an example the ICON didn't do saw hawt (or did too hawt, I guess) with the precip type for the Pierce and King County lowlands yesterday morning. Showed what looked to be a 500-1000' snow level with the precip there even at 12 hours out.

 

[Doinko]

31 minutes ago, Perturbed Member said:

 

Southward shift keeping PDX as the bullseye! Great to see

[SilverFallsAndrew]

1 hour ago, BLI snowman said:

Correct me if I'm wrong, but that was Salem's last really good (5"+) snowstorm right? I know they also did well with the snow showers on 12/26/21, but the 2016 event was more uniform in its coverage and not as elevation dependent.

You are correct there has been nothing with that kind of widespread coverage near those amounts since. They had a really solid event on 1/7/17 too, but that was more like 3" downtown. They got totally donut holed in February 2018 and the February 2019 stuff was pretty elevation dependent too. Parts of West and South Salem did really well, but the flatlands were more in the 1-2" range with a couple of different events. Lower parts of Salem probably had about 2-3" last December on the 26th last year, with the bigger totals being above 500' down south. 

[Front Ranger]

57 minutes ago, Doinko said:

ICON keeps us as rain on Sunday

I haven't been paying attention. How has the IKON been doing with this pattern?

EDIT: Caught up with other replies, sounds like it has sucked.

[seattleweatherguy]

11 minutes ago, Meatyorologist said:

When the slug of moisture reaches the area tonight, models are consistent with an associated DP hike as temps cool to the wet bulb. Should make for a wet snow if precip is heavy enough

Around what time will the moisture arrive?