PNW December 2022 - Part II

[SnowWillarrive]

13 minutes ago, snow_wizard said:

From what I can tell temps are running to 3 to 5 colder in areas where the north winds have taken over compared to ECMWF expectations.  Big big deal.

Im worried precip will be gone by the time temps drop. Taking forever 

[Rubus Leucodermis]

1 minute ago, Mid Valley Duck said:

Euro is best case scenario for the Willamette Valley. But I think its scouring out the valley and metro too quickly.

Depends on the direction the wind is coming from. South wind can scour PDX out in a hurry. More westerly can mean a slow and messy transition.

[joelgombiner]

Based on pressure obs and wind circulation it looks like the low is somewhere around Ft. Lewis. 

 

[Hawksfan2008]

2 minutes ago, TT-SEA said:

What a fun morning... about as dynamic as it gets with that low passing right over Seattle.     We went from the house shaking in the wind and rain pounding against the windows and the power out to gentle, calm snow falling in about an hour.

I couldn’t believe how quickly the roads were covered with as much standing water as there was. They’re gonna be a disaster with the cold air coming in. 

[LowerGarfield]

For those in Skagit County, there was a pretty solid windstorm on this date in 2018. I remember our Panera closed due to wind and I walked from Burlington to Skagit Station. Every store I passed had a handwritten sign saying"no power", a boss man or boss lady on the phone on the other side of the glass with the power company, and employees milling around looking bored.

As for today, I'm now at 22F with cloud cover and it is very bright with the snow glare on the ground.

[Deweydog]

2 minutes ago, Perturbed Member said:

That airmass was much warmer than this one right?

How well did the metro area do as a whole?

Being on the far western end of the metro I think I should be safe from that downsloping but the outflow of cold air will also be shallower. Sometimes these far west areas especially around Forest Grove and Banks do pretty well from damming up a bunch of cold air against the coast range but not sure that will be deep enough to matter here. 

You’ll be in a pretty decent position I would think. And yeah, that low level air mass was far less intense with advection temps in the low-mid 30’s which wet bulbed into the upper 20’s during the afternoon in the sweet spots.

[Cloud]

Precips wrapping up here? At the edge of it now as the low sinks south. Hoping to get another hour out it. 

[TT-SEA]

6 minutes ago, VancouverIslandSouth said:

That's the sort of thing that happens a lot near the Fraser outflow. Unusual to see down there though. 

And now snowing at Tiger Summit too...

 

[Mid Valley Duck]

2 minutes ago, Deweydog said:

So bizarre the NWS going with lows 10-15 tomorrow night in the advection. It’s like they don’t realize how incredibly rare that would be.

They are team NAM

[Ice_is_Everywhere]

2 minutes ago, lowlandsnow said:

What does radarscope show for the central sound anymore snow coming?

 

Maybe a little. There’s a band up by Shoreline that might move south.

[RentonHill]

next 10 days will be some serious blessings

[Cascadia_Wx]

2 minutes ago, Mid Valley Duck said:

Euro is best case scenario for the Willamette Valley. But I think its scouring out the valley and metro too quickly.

Yeah, I’m skeptical about how fast the Euro wants to warm things up Friday into Saturday after bringing in an airmass that, at face value on this run, advects PDX into the upper teens Thursday night. I don’t think it’s going to give up the fight that easily and this is a classic case of models underestimating the tenacity of the low level cold coming out of the gorge.

[TacomaWx]

Just now, Cloud said:

Precips wrapping up here? At the edge of it now as the low sinks south. Hoping to get another hour out it. 

I’m still liking our chances for some snow after the front passes. Still precip north of the transition line.

[Cloud]

14 minutes ago, SouthHillFrosty said:

Rain/snow mix here and 33. I doubt we might be able to get any accumulation with the amount of water everywhere 

Depends on your precip rates. It stuck immediately here with the switch. 

[Doinko]

East wind is still holding on at PDX, 36 there

[Cascadia_Wx]

4 minutes ago, Deweydog said:

So bizarre the NWS going with lows 10-15 tomorrow night in the advection. It’s like they don’t realize how incredibly rare that would be.

I’d be impressed if they got below 20.

[Deweydog]

1 minute ago, Mid Valley Duck said:

They are team NAM

I’d make a joke about the Mariners still not having made the playoffs for 20+ years but I can’t anymore.

[Sam]

16 minutes ago, Christensen87 said:

I keep looking out the window, still raining in Kent at 38 now from 41 ten minutes ago. It's coming!

aaaaaaaaaaaaany minute now

[SilverFallsAndrew]

3 minutes ago, Mid Valley Duck said:

They are team NAM

I’d honestly be stunned if PDX dropped below 20. If they do I will be officially impressed. 

[BLI snowman]

9 minutes ago, Doinko said:

I'm in the west metro, but do you think the wind could reduce our snow chances initially? The WRF-GFS is showing 55mph+ gusts accelerating down the west hills, but much lighter wind just a few miles S/W.

I expect the wind would be a factor pretty much area-wide on Thursday. It's going to be a very intense gradient and almost a true mountain wave profile. And it's a give/take scenario since the initial warm frontal band supplying us with enough juice to punch through that would also be an indicator of warmer air moving in aloft more quickly. I think it's going to take a real needle threading to get more than a dusting, unfortunately.

Best case scenario snowfall wise is maybe something like 1/3/2016 with the snowy first wave, but the offshore gradients look a lot stronger with this so there's a lot more dry air advecting in that that initial band will have to overcome.

Edited December 20, 2022 by BLI snowman

[SouthHillFrosty]

31 and light rain. Temp continues to drop.

[RentonHill]

Down to 29.8. Maye almost an inch so far? Flakes have turned very small now but still coming down good. 

[Deweydog]

1 minute ago, Cascadia_Wx said:

I’d be impressed if they got below 20.

As far as an overnight low, anything below 25 would be impressive to me during a deep advection event and no wet bulb to chase. Definitely seems like they won’t warm much at all during the day on Thursday and might even continue to tick downward.

[Christensen87]

2 minutes ago, Sam said:

aaaaaaaaaaaaany minute now

 

[SilverFallsAndrew]

4 minutes ago, Doinko said:

East wind is still holding on at PDX, 36 there

46 in Oregon city. 

[WildrootParable]

I'm so sad that the precip stopped as soon as the cold showed up! Noooo! 

Oh well. At least we have about an inch flash-frozen on the ground. I'll take it. 

[Tyler Mode]

1 minute ago, SilverFallsAndrew said:

46 in Oregon city. 

42 in BG.

[BLI snowman]

10 minutes ago, Deweydog said:

So bizarre the NWS going with lows 10-15 tomorrow night in the advection. It’s like they don’t realize how incredibly rare that would be.

I.....don't believe that they do.

[Deweydog]

1 minute ago, BLI snowman said:

I expect the wind would be a factor pretty much area-wide on Thursday. It's going to be a very intense gradient and almost a true mountain wave profile. And it's a give/take scenario since the initial warm frontal band supplying us with enough juice to punch through that would also be an indicator of warmer air moving in aloft more quickly. I think it's going to take a real needle threading to get more than a dusting, unfortunately.

Best case scenario snowfall wise is maybe something like 1/3/2016 with the snowy first wave, but the offshore gradients look a lot stronger with this so there's a lot more that that initial band will have to overcome.

1/3/16 was great in that we snuckily benefited by the goofy shortwave which cooled the mid/upper levels but the outflow was purely gorge-oriented. Very bizarre way to score snow in the mid 20’s here.

[Mid Valley Duck]

5 minutes ago, SilverFallsAndrew said:

I’d honestly be stunned if PDX dropped below 20. If they do I will be officially impressed. 

The NAM drops PDX below 20 by 10pm tomorrow lol

[snowbustcity]

Back to a really good snowfall rate in NE Seattle. 

[The Winter Warlock]

Dive, dive, dive. Plenty of moisture still.

[Katzen]

Sammamish right now, very fine snow coming down. Was wet and rainy earlier.

[T-Town]

Wind is from the north now and temp has dropped from 43 to 40. 

[Tyler Mode]

PDX hasn't dropped below 20 since 2017...and that was 11 in January, almost 5 years.

[BLI snowman]

2 minutes ago, Deweydog said:

1/3/16 was great in that we snuckily benefited by the goofy shortwave which cooled the mid/upper levels but the outflow was purely gorge-oriented. Very bizarre way to score snow in the mid 20’s here.

And I think that one was pretty much all rain north of Olympia or so.

[Doinko]

1 minute ago, Mid Valley Duck said:

The NAM drops PDX below 20 by 10pm tomorrow lol

33 to 12 in 15 hours according to the NAM...

[GobBluth]

Just now, Tyler Mode said:

PDX hasn't dropped below 20 since 2017...and that was 11 in January, almost 5 years.

With snow cover and clear skies.

[Deweydog]

5 minutes ago, BLI snowman said:

I expect the wind would be a factor pretty much area-wide on Thursday. It's going to be a very intense gradient and almost a true mountain wave profile. And it's a give/take scenario since the initial warm frontal band supplying us with enough juice to punch through that would also be an indicator of warmer air moving in aloft more quickly. I think it's going to take a real needle threading to get more than a dusting, unfortunately.

Best case scenario snowfall wise is maybe something like 1/3/2016 with the snowy first wave, but the offshore gradients look a lot stronger with this so there's a lot more that that initial band will have to overcome.

Could be a damned if you do, damned if you don’t… Models have some history of overselling the depth of the gradient. 12/20/08 was sold pretty heavily as having a pretty significant downslope component but we ended up dead calm during most of the WAA. It’d be a big model miss at this point but a boy can dream! A scenario like that would lead to a more tentative mid level situation though…

[BLI snowman]

13 minutes ago, RentonHillTC said:

next 10 days will be some serious blessings

So much for the bone dry December.

Another October-style fakeout in the works.