Part I - January 2020 Weather Discussion for the PNW

[Blizzard777]

https://www.reddit.com/r/Seattle/comments/emlmha/so_were_still_two_days_away_from_the_snow_right/?utm_medium=android_app&utm_source=share

 

Posted 50 mins ago. The cat is really out of the bag now.

Plenty of avocados still...I’m good

[Cloud]

GEM, on the contrary to the GFS, is actually stronger and further north. Valley gets rain sadly but PDX gets a big snowstorm with east winds. Weird how different models are for that thing...

Mid to long range forecast is like Pachinko or Plinko is you're familiar with the Price Is Right. At Day 1, the model knows where to put the ball, these are the current conditions, as it drops the ball going into Day 2 to Day 7, there are many paths for it to take so this creates a lot of uncertainty. Each model behaves different as it bounces it ways through the many paths. This is why we have ensembles and ensemble means, they're better to look at than 1 Operational run.

 

Edit: Also when ensemble means becomes very consistent in the long range, it should be very hard to discredit. This is what Tim tries to portrays many times with the EPS when it's super consistent. 

[VancouverIslandSouth]

Gfs ensembles are improving up here for snowfall on both Sunday and mid week. Did you see the track map Hawkstwelve posted earlier? Most of those tracks are perfect for us

 

Would take only a very minor tweak to the SW in the operational to get a major snowfall Sunday. As for the mid-late week stuff, we should be set for at least one good shot of snow so long as things don't trend further offshore.

[TacomaWaWx]

34 with a DP of 32 in Tacoma. Bit of Fog here but can see the moon still.

[AJ1013]

Light rain and 47F here.

[Esquimalt]

Would take only a very minor tweak to the SW in the operational to get a major snowfall Sunday. As for the mid-late week stuff, we should be set for at least one good shot of snow so long as things don't trend further offshore.

Yeah I'd be more enthused but the issue is that we only have the GFS on our side.  All the others are way less favourable. 

[TacomaWaWx]

Highs at or below freezing for 12 days in Seattle.

 

even the Warmer run showing 12 sub freezing days in a row is pretty impressive.

[VancouverIslandSouth]

Sunday afternoon battleground setup:

 

[TT-SEA]

Not when they toss up 3 days of snow.

 

Just taking the snow out the picture... when I run the precip loop for the next 16 days on the 00Z GFS the thing I notice immediately is how dry it is in my area overall after Sunday.   In terms of dry weather... it does not get much better in the middle of winter than the 00Z GFS. 

 

And look at the snowfall total for Wednesday - Saturday per that run for that ULL event:

 

 

 

The totals are likely overstated as the GFS is very prone to do... and even the overstated amounts still result in almost no snow in my area.     That set up in generally dry for King County... at any time of the year.

 

I got more snow yesterday evening in about an hour than the GFS shows for the entire 3-day event.

 

On the other hand... some places will score big with that set up!

[Esquimalt]

Sunday afternoon battleground setup:

 

Still just showing us getting around 3 inches.  Very underwhelming for such a nice track. 

[Winterdog]

Highs at or below freezing for 12 days in Seattle.

 

Not that it will actually happen but the current record for KSEA is 10 consecutive days below freezing set in 1969 I believe.  It would be nice to break that. 

[Winterdog]

The thing that is nice about this run is that we will all have some snow cover going into it and with the eastward drying fetch in the LR that snow is going to stick around.

[VancouverIslandSouth]

For the poster who wanted to see Artic air pouring out around YVR Island and looping back into the Puget Sound: 

 

[TT-SEA]

The thing that is nice about this run is that we will all have some snow cover going into it and with the eastward drying fetch in the LR that snow is going to stick around.

 

No doubt... it will be a layer of cement.  

[Cloud]

Just taking the snow out the picture... when I run the precip loop for the next 16 days on the 00Z GFS the thing I notice immediately is how dry it is in my area overall after Sunday.   In terms of dry weather... it does not get much better in the middle of winter than the 00Z GFS. 

 

And look at the snowfall total for Wednesday - Saturday per that run for that ULL event:

 

 

 

The totals are likely overstated as the GFS is very prone to do... and even the overstated amounts still result in almost no snow in my area.     That set up in generally dry for King County... at any time of the year.

 

I got more snow yesterday evening in about an hour than the GFS shows for the entire 3-day event.

 

On the other hand... some places will score big with that set up!

 

Yeah as we're getting closer it would seem the east wind will play a huge factor in how much snow people will get. This should concern snow lovers around the Puget Sound. 

If anything, go buy some chapsticks. 

[VancouverIslandSouth]

Still just showing us getting around 3 inches.  Very underwhelming for such a nice track. 

 

I wouldn't be too concerned about the exact totals just yet. The low is still a notch too far to the north, about 50~100km further south and totals would be substantially higher, much further north and it will largely be a non-event.

[Perturbed Member]

Low locations by 10PM Thursday...

 

 

The cluster of lows on the NW have mostly gone away, good to see. Looking like somewhere near the mouth of the Columbia is the most likely spot at this time. Seems like a good place for a regionwide event if the low could actually produce some juice. 

[TacomaWaWx]

For the poster who wanted to see Artic air pouring out around YVR Island and looping back into the Puget Sound: 

 

can't wait to watch this roll in.

[Blizzard777]

The thing that is nice about this run is that we will all have some snow cover going into it and with the eastward drying fetch in the LR that snow is going to stick around.

If we’re going to get cold a blanket for my plants would be appreciated 

[Requiem]

Mark posted an update, says that there's agreement that the "event" for PDX will be Wednesday-Thursday but he is watching Monday for snow as well (thinks it'll be confined to the West Hills and areas above 500 ft or so). He also points out of course, that the exact track of the low is very difficult to see this far out.

[Perturbed Member]

Just taking the snow out the picture... when I run the precip loop for the next 16 days on the 00Z GFS the thing I notice immediately is how dry it is in my area overall after Sunday.   In terms of dry weather... it does not get much better in the middle of winter than the 00Z GFS. 

 

And look at the snowfall total for Wednesday - Saturday per that run for that ULL event:

 

 

 

The totals are likely overstated as the GFS is very prone to do... and even the overstated amounts still result in almost no snow in my area.     That set up in generally dry for King County... at any time of the year.

 

I got more snow yesterday evening in about an hour than the GFS shows for the entire 3-day event.

 

On the other hand... some places will score big with that set up!

 

WA county special! Less dry air and some upslope against the coast range. Still doesn't add up to more than 2-3 inches of fake GFS snow.

[Frontal Snowsquall]

[seattleweatherguy]

Hopefully I will get some snow sun thru Thursday period or I blame east winds

[TT-SEA]

WRF is surprisingly dry by Monday morning... 

 

 

 

The greatest potential for snow here is from 4-7 p.m. on Sunday evening.   By 10 p.m. the dry air has spread all the way out here.

 

I wonder what else is happening from 4-7 p.m. on Sunday?   My satellite went out last night with less than an inch of snow.    <_>

[Thurston Howell III]

I lived west of Hiway 16 in Port Orchard at 400' and would get some crazy snow at times.  Right at the edge of those hood canal snows.  

[Thurston Howell III]

Have several friends out in the hills, Seabeck hood canal area and amazing how many times they get 6" or more snowfalls.  

[TT-SEA]

WRF shows that I get about 4-5 inches of snow during the game and then it ends and there is really not much more snow here after that point for the rest of the week.

 

[MossMan]

Actually doesn't look half bad for Sunday, at least for places with some elevation. Better than the 12z.

 

According to this map it’s a good thing I moved back in 2018!

[TT-SEA]

Actually doesn't look half bad for Sunday, at least for places with some elevation. Better than the 12z.

 

 

 

 

Don't use the 12km resolution for snowfall maps... unless you really like being disappointed.   Its terrible with terrain.

[MossMan]

WRF shows that I get about 4-5 inches of snow during the game and then it ends and there is really not much more snow here after that point for the rest of the week.

 

Well if you lose satellite we will keep you informed in the banter thread! I will be swearing lots!!

[snow_wizard]

The WRF looks utterly fantastic for the East Puget Sound Lowlands Sunday evening.  The surface low takes the perfect path for enhanced snowfall in the EPSL with plunging temperatures on the back side of the low.  With cold air already in place in Whatcom County a flash freeze possible with this.

[Frontal Snowsquall]

00z UKMET just updated. Days 4-6.

 

http://img.meteocentre.com/models/ukmet_amer_00/GZ_D5_PN_096_0000.gif

http://img.meteocentre.com/models/ukmet_amer_00/GZ_D5_PN_120_0000.gif

http://img.meteocentre.com/models/ukmet_amer_00/GZ_D5_PN_144_0000.gif

[Christensen87]

It's only out to Tuesday night..

I think he’s saying cause the east winds will eat away all the snow along the foothill communities.

[wxmet]

ECMWF 00z looking better for Seattle late Sunday night and early Monday morning. C-zone develops behind the low.

[TT-SEA]

And the new 00Z ECMWF agrees that it will be dumping snow here during the game...

 

[TT-SEA]

It's only out to Tuesday night..

 

 

It will not show much more snow here.   I already saw the GFS maps for Wed - Sat.

[Perturbed Member]

10 AM Monday

33-34F mix in PDX

 

[Perturbed Member]

Low is a bit further south

[Timmy]

10 AM Monday

33-34F mix in PDX

 

splitting hairs but that’s rain at pdx

[Deweydog]

And the new 00Z ECMWF agrees that it will be dumping snow here during the game...

 

Gonna have to rely on the running game...