December 2020 Weather Observations for the PNW

[FroYoBro]

Really pouring right now. Feels cold out there. 

[TigerWoodsLibido]

46F with the occasional shower.

[GHweatherChris]

More snowflakes mixing in under this intense echo!!

[SilverFallsAndrew]

Mostly snow now, temp down to 35. 

[MossMan]

That Jim member is still up to his tricks! 

[Jesse]

8 minutes ago, GHweatherChris said:

More snowflakes mixing in under this intense echo!!

12/11/20/20!!!!

[Brian_in_Leavenworth]

"(11 Dec 2020) Data flow issues from NCEP this afternoon may result in delayed or missing data for their models."

[Deweydog]

9 minutes ago, MossMan said:

That Jim member is still up to his tricks! 

Jim’s member needs a blue pill.

[Meatyorologist]

Just now, Brian_in_Leavenworth said:

"(11 Dec 2020) Data flow issues from NCEP this afternoon may result in delayed or missing data for their models."

It was delayed by 15 minutes. Obviously this run is going to blow all previous expectations out of the water...

[SilverFallsAndrew]

Snow on the coast range passes. 

 

[SilverFallsAndrew]

Alaska gets KOLD.

 

[Timmy]

Drove up the hill, this was at 1800’ near Scappoose at 1pm. I forgot my daughter’s coat.

[Meatyorologist]

GFS is trying to follow suit with the 12z at the end of the run. Could get interesting.

[Cloud]

It is expected to hit freezing tonight for the 1st time this month and 1st one in almost 3 week as we clear out. Saturday looks rather chilly before the next system moves in. 

[Meatyorologist]

Pattern evolution ends up being a tad too messy and progressive, but the ingredients are there. Still some marginal convective snow for the foothills Eugene northward and in the CZ with chilly onshore flow.

[Gradient Keeper]

3:25 PM Near west Gresham

1 PM Temp: 41.4

Current Temp: 38.4

Light rain with a slight easterly breeze

 

 

[FroYoBro]

6 minutes ago, DJ Droppin said:

3:25 PM Near west Gresham

1 PM Temp: 41.4

Current Temp: 38.4

Light rain with a slight easterly breeze

 

 

Close to some chunks mixing in!

 

Been at 42 degrees all day here on the westside. 

[Jesse]

39 with light to moderate rain continuing here. Chilliest afternoon of the season so far.

 Up over 1/3" for the day. High 42 low 38.

[AbbyJr]

 

[paulb/eugene]

The ECMWF ensemble model horizontal resolution drops to 65km into the second week which should explain the unrealistic snowfall forecast for lots of places around here.  Bellingham’s “pixel” may have an elevation of 1000’ or whatever if average elevation of 40 mile square is used .   Certainly the barriers to outflow of Arctic air into the region (cascades and Rockies) are underrepresented.

 

 

 

[Gradient Keeper]

A glimmer of something? Long Range 18z GEFS trying to go places. C'MON!!!!

[Jesse]

Down to 37 now with precip intensifying. Wasn’t expecting to get this close to snow mixing in today. Nice reminder that it is indeed winter now.

If this keeps up may need to jump in the car for a splat test.

[Gradient Keeper]

5 minutes ago, Jesse said:

Down to 37 now with precip intensifying. Wasn’t expecting to get this close to snow mixing in today. Nice reminder that it is indeed winter now.

If this keeps up may need to jump in the car for a splat test.

Right? Models yesterday/last night completely missed this. We're supposed to trust models with what they show in a week though? Hell nope!

00z GFS in 3 hours 10 minutes

[TigerWoodsLibido]

46F with some light rain.

[umadbro]

38, about to dip to 37. Moderate rain. .49" so far today. Gonna be icy quick as soon as the skies clear up.

[El_Nina]

Nice moderate rain still and 38. Up to 0.76" today. 

[Deweydog]

8 minutes ago, DJ Droppin said:

Right? Models yesterday/last night completely missed this. We're supposed to trust models with what they show in a week though? Hell nope!

00z GFS in 3 hours 10 minutes

In defense of the models, they didn’t miss this.  It’s actually playing out pretty much exactly as the GFS/WRF indicated.  Deformation precip with a weak surface low to the south and a moderately chilly air mass.

[Timmy Supercell]

Been snowing here for the last hour and a half. Moderate at times. If there is enough moisture could be my first full inch of the season.

Roads don't yet have much but looks like 1/2" on vehicles.

[Jesse]

3 minutes ago, Timmy_Supercell said:

Been snowing here for the last hour and a half. Moderate at times. If there is enough moisture could be my first full inch of the season.

Roads don't yet have much but looks like 1/2" on vehicles.

Bummer. I'm sorry to hear this dude.

[Gradient Keeper]

18z GEFS Day 10-16 GIF. I know it's the Drunk Uncle, or rather an average of 30 various Drunk Uncles doing Drunk Uncle things, but this is about the best the ensembles have looked yet. Maybe? C'MON!!!!

 

 

[Gradient Keeper]

6 minutes ago, Deweydog said:

In defense of the models, they didn’t miss this.  It’s actually playing out pretty much exactly as the GFS/WRF indicated.  Deformation precip with a weak surface low to the south and a moderately chilly air mass.

I'm speaking specifically of temperatures. Colder than forecast.

[Rubus Leucodermis]

43 minutes ago, paulb/eugene said:

The ECMWF ensemble model horizontal resolution drops to 65km into the second week which should explain the unrealistic snowfall forecast for lots of places around here.  Bellingham’s “pixel” may have an elevation of 1000’ or whatever if average elevation of 40 mile square is used .   Certainly the barriers to outflow of Arctic air into the region (cascades and Rockies) are underrepresented.

Basically as many of us suspected. And there are a lot of mountains within 40 miles of Bellingham.

[SilverFallsAndrew]

10 minutes ago, Deweydog said:

In defense of the models, they didn’t miss this.  It’s actually playing out pretty much exactly as the GFS/WRF indicated.  Deformation precip with a weak surface low to the south and a moderately chilly air mass.

Yeah today was the day I thought I might see my first flakes. 34 with light non-sticking snow right now, about what I was expecting if the moisture panned out. Yesterday was the one that caught my off guard. Snow levels were so low because we started off around 30, didn't warm much, and gradients were flat allowing the column to go isothermal with that heavy band of precip. 

[Deweydog]

42 minutes ago, DJ Droppin said:

I'm speaking specifically of temperatures. Colder than forecast.

What forecast?

925mb temps were consistently progged to drop to around 0c this evening.  That generally suggests some areas around the metro would likely dip into the mid 30’s with the precip.

This was actually a really good setup, just didn’t have much of any wet bulb help to tap into.

[TigerWoodsLibido]

Some spots around Springfield hit 50F. Business as usual, gonna be close to average. Hopefully can get December below average again. We are at +0.8F so far. Good to at least get some rain as we are still in moderate drought here.

[BLI snowman]

Nice to see lows going to the south for a change.

[TigerWoodsLibido]

Looks like a S wind of about 5-9 mph. Nothing of interest but still good to get a profile of the region.

[Timmy Supercell]

39 minutes ago, Jesse said:

Bummer. I'm sorry to hear this dude.

lol I don't hate snow.

[Timmy Supercell]

Solid 1" inch outside!

Still several hours left of the day so I'll wait to give another update.

[Brian_in_Leavenworth]

1 hour ago, paulb/eugene said:

The ECMWF ensemble model horizontal resolution drops to 65km into the second week which should explain the unrealistic snowfall forecast for lots of places around here.  Bellingham’s “pixel” may have an elevation of 1000’ or whatever if average elevation of 40 mile square is used .   Certainly the barriers to outflow of Arctic air into the region (cascades and Rockies) are underrepresented.

 

 

 

No doubt affects both he temperature and precipitation forecasts,    That might explain why, for example, the monthlies show a huge ridge for January and February in the sweet spot, troughing in BC and the PNW, yet still shows above normal temps.  

But there aren't terrain issues at the 500mb level, so that one is probably more accurate.