December 2016 Observations and Model Discussion for the Pacific Northwest

[SilverFallsAndrew]

Only 20 at 9am. Low sun angles!

 

Well if it doesn't cloud up as early tonight we could see some lower lows...

[FroYoBro]

Looking very busty

 

You being obsessed with this busting is going to be a bust. 

[BLI snowman]

My snow day tomorrow is looking less likely. Can't wait to drive home in blowing snow and stalled traffic! 

 

Snow is always more enjoyable with others!

[Front Ranger]

Yeah, big windstorm for Portland and wet snow north of Seattle.  Models have been pretty consistent in showing that energy hitting the coast midweek next week, so there's still some potential for a surprise with it.

 

The 12z GFS was totally different for that time frame. No storm at all, blocking situation upstream quite a bit different.

[MR.SNOWMIZER]

Well, a gargantuan, steroidal +NAO vortex will always be detrimental to meridional streamflow over the US. I mean, look at this thing. It's seemingly dominating the entire hemispheric wavetrain. Good lord..

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/CC4DDAC4-BC21-4299-8B41-F74DECBF05D5_zpsywyhwntb.png

Yeah I seen that shitt in the paper today. WTF is going on man!!

[ShawniganLake]

I was here over the weekend, Monday, and early this morning.

 

The idea that Dewey and I are closet sadists has been rehashed here repeatedly..it's a hilarious tradition of sorts but completely untrue in reality.

I seem to remember a couple of people asking your opinion on the pattern progression this morning, so it made sense you were posting this morning.

[BLI snowman]

The 12z GFS was totally different for that time frame. No storm at all, blocking situation upstream quite a bit different.

 

It has the same undercutting Tuesday energy as other models/runs have. Just weaker and further south. Then it looks like another storm later in the week.

 

 

 

[ShawniganLake]

12z GFS actually shows the Seattle area getting more snow than the 00z run showed, so there's that. Through hr 54, it looks like anywhere from 2-7 inches with more along the Puget Sound shoreline, less around the EPSL and further North. Snow mainly starts late Thursday night/early Friday morning.

 

12z GEM is considerably better than the 00z run, but delays the onset of snow until Friday during the day. Snow starts slowly Friday morning and gets cranking by Friday afternoon. By Saturday night, it shows 4-7 inches with more in the EPSL, less near the shorelines. No evidence of downsloping on this run, which is a bit odd. Whatcom looks to continue snow through Sunday - by Sunday night they have 10+ inches.

 

12z WRF is the most apparent with the downsloping for EPSL, showing practically nothing throughout the whole event for us. God I hope it's as wrong as it was on Monday.

 

12z Euro up next. Not too bad of runs so far today.

Where are you getting those snow totals with the GEM.

[liquidsnow]

12z GFS actually shows the Seattle area getting more snow than the 00z run showed, so there's that. Through hr 54, it looks like anywhere from 2-7 inches with more along the Puget Sound shoreline, less around the EPSL and further North. Snow mainly starts late Thursday night/early Friday morning.

 

12z GEM is considerably better than the 00z run, but delays the onset of snow until Friday during the day. Snow starts slowly Friday morning and gets cranking by Friday afternoon. By Saturday night, it shows 4-7 inches with more in the EPSL, less near the shorelines. No evidence of downsloping on this run, which is a bit odd. Whatcom looks to continue snow through Sunday - by Sunday night they have 10+ inches.

 

12z WRF is the most apparent with the downsloping for EPSL, showing practically nothing throughout the whole event for us. God I hope it's as wrong as it was on Monday.

 

12z Euro up next. Not too bad of runs so far today.

 

 

Always trust the WRF with overrunning events. One hopes that the low weakens considerably to nullify the downsloping winds.

[ShawniganLake]

Weatherbell regional maps of the Seattle area. Your area looks to do incredibly well over the next few days on this run.

In general I think the GEM precip maps are terrible, but I don't have access to the hi res or weather bell stuff. Hopefully everyone gets something.

[Phil]

I seem to remember a couple of people asking your opinion on the pattern progression this morning, so it made sense you were posting this morning.

I normally sit back and read when an event is nearing or ongoing since I have less to add (PNW microclimates aren't something I'm knowledgeable about). Since I was name dropped this morning I responded with a few thoughts, but mostly I'm here to watch the pictures and observations roll in.

 

Then the models swung a bit, and I became the piñata for whatever reason..almost as if I caused it to happen.

[Deweydog]

I normally sit back and read when an event is nearing or ongoing since I have less to add (PNW microclimates aren't something I'm knowledgeable about). Since I was name dropped this morning I responded with a few thoughts.

 

Then when the models swing, I'm suddenly the piñata.

Even worse, a transparent pinata.

[Heavy Snow]

I normally sit back and read when an event is nearing or ongoing since I have less to add (PNW microclimates aren't something I'm knowledgeable about). Since I was name dropped this morning I responded with a few thoughts, but mostly I'm here to watch the pictures and observations roll in.

 

Then the models swung a bit, and I became the piñata for whatever reason..almost as if I caused it to happen.

Your thoughts are always appreciated here. The reason that happened is because you're important and your voice carries a lot of weight.

[liquidsnow]

.SHORT TERM...There is a front offshore and it becomes

increasingly west-east oriented through Thursday and then moves

north through Western Washington late Thursday afternoon and evening.

 

Clear Skies today will give way to high clouds tonight. The clouds

will increase Thursday with snow starting up in the south, probably

midday, and spreading north through the rest of Western Washington

around late afternoon. Easterly pressure gradients will rise, with

windy weather in the typical gap wind areas on Thursday--which is

west of the passes for the most part and around Enumclaw.

 

Snow Thursday night will turn to rain by daybreak Friday in much of

the lowlands. Cool air tends to bank up against the east slopes of

the Olympics-so it might take an extra six hours there, and the

precip is usually heaviest there in this overrunning easterly flow

type of system. The Seattle metro area should get some drying from

the easterlies and 1-3 inches is a good forecast for now. There is a

winter storm watch up for most of Western Washington--my guess is

that most areas will end up with a winter weather advisory and Hood

Canal will get a winter storm warning for heavy snow.

 

Currently there is still Fraser outflow--but it is not all that

strong, the Bellingham to Williams Lake gradient is -10mb and steady-

-til that collapses chilly air will keep a mix of wintry precip

around Bellingham. For Thursday night, that will be snow. For Friday

morning there could be a little sleet or freezing rain mixed in, and

then after that it is hard to say--but I think the forecast for

Western Whatcom county could be five degrees too warm for the highs

and the lows Friday through Monday, so that is something to work on

today.

 

So, back to Friday--rain will fall at times for the most lowlands

except perhaps that wintry mix for Whatcom county and the places

that are slower to scour in the morning like Hood Canal and maybe

along the Strait. The afternoon and Friday night are rainy, and then

the 12z GFS has a weather system and 1002mb low moving on to the

coast--that fills and mushes out into the Columbia Basin Saturday.

The 1000-850mb thickness ranges from 1320dm at Hoquiam to 1296dm at

Bellingham--so the north may still flirt with wet snow but nearly

all the lowlands should have rain Friday night. The precip moves

into the Cascades and dries up Saturday morning--the foothills of

the Cascades should have a snow level that is below 500 feet in the

north to maybe 1500 feet in the south but we may see wet snow on the

hills for a few hours around daybreak Saturday--the path of that low

keeps the low level flow coolish and interesting and even though the

850mb temp is fairly warm at -3c around Seattle on that 12z GFS.

 

Looks good for Bellingham.

[Jesse]

Even worse, a transparent pinata.

I have been absolutely relentless with my attacks on Phil. A vicious dog comes to mind.

[Phil]

Even worse, a transparent pinata.

Well I guess that explains it then.

[DareDuck]

Bend hit 0, always nice to see. 27 for the low at PDX this morning. Coldest temp of 2016!

Actually hit -2 at the 715 and 735 readings.

[Deweydog]

I have been absolutely relentless with my attacks on Phil. A vicious dog comes to mind.

I just don't see this supposed devious yet apparently transparent plot. He's not the burning bush but what he's been saying for months generally has shown at least some merit. I actually like the fact he's sticking to the more generalized stuff. When he deviates from it, things typically fall apart a bit.

[MossMan]

Basically the AFD from NWS Seattle is calling for a non event for the I-5 corridor...most likely downgraded to a WWA instead of a WSW and all rain by Friday daybreak. No big deal, nothing to see here, move along. I hope Seattle gets smashed with a foot of snow.

[WinterWx]

NWS already back-tracking on snow for Seattle tomorrow. Saying 1-3 inches due to drying from the easterlies then a rapid transition to warm rain by early Friday.  This is starting to feel like bust potential again.  However, maybe it's a good thing that NWS is back-tracking given their failures of late.

[Kayla]

NWS here in Portland is still saying widespread 2-4" of snowfall with the usually favored areas getting 3-6" then turning to freezing rain with up to 0.25" of accumulation. Changeover doesn't look to occur until around midnight tomorrow.

 

Seems like an accurate forecast at this point to me. We'll see what the Euro says in a few minutes.

[Phil]

I have been absolutely relentless with my attacks on Phil. A vicious dog comes to mind.

You PM'ed me to complain about a lighthearted comment I made about your own characterization of me. I deleted it, per your urgent request, then you go back and continue on with the backhanded trolling and claims of ulterior motive(s) on my part..hilarious.

 

At this point, I'd say your a** is fair game.

[SilverFallsAndrew]

Not trying to be a debbie downer, but based on my 25 years of watching weather in this climate, I don't have a lot of confidence in widespread accumulation over 2" anywhere outside of favored locations like Forest Grove, Banks, etc...

[bainbridgekid]

NWS already back-tracking on snow for Seattle tomorrow. Saying 1-3 inches due to drying from the easterlies then a rapid transition to warm rain by early Friday.  This is starting to feel like bust potential again.  However, maybe it's a good thing that NWS is back-tracking given their failures of late.

Not really much of a back track.

 

They've been conservative all along and a widespread 1-3" is still a solid event for Seattle.

[Sometimesdylan]

Anywhere from 5-10 inches of snow has fallen so far here in Juneau. It's dumping! Should continue throughout the day.

[TT-SEA]

GFS MOS has 36 at SEA tomorrow and then 43 on Friday.

 

That is not real good... pretty significant warm up on Friday.     Hope its really wrong but I am doubting that now.

[luvssnow_spokane]

12z Euro is running... Epic bust, or more hope?

[Heavy Snow]

The updated run of the 12z GFS is showing good snow accumulations from PDX Metro North through Friday 4pm. Here are two snowfall maps using the 10:1 ratio and the more accurate Kuchera ratio. The Kuchera ratio is more accurate because it takes more variables into play. It's usually more conservative but the times it shows the same or even more than the 10:1 means confidence is high in getting solid snow throughout the event. 

 

http://maps1.pivotalweather.com/maps/models/gfs/2016120712/060/sn10_acc.us_nw.png

 

http://maps1.pivotalweather.com/maps/models/gfs/2016120712/060/snku_acc.us_nw.png

[Phil]

Not trying to be a debbie downer, but based on my 25 years of watching weather in this climate, I don't have a lot of confidence in widespread accumulation over 2" anywhere outside of favored locations like Forest Grove, Banks, etc...

Expect an angry PM from Jesse any minute now, asking you to delete this post.

[Deweydog]

Not trying to be a debbie downer, but based on my 25 years of watching weather in this climate, I don't have a lot of confidence in widespread accumulation over 2" anywhere outside of favored locations like Forest Grove, Banks, etc...

December 1994!!!

[Sometimesdylan]

JNU NWS Office this AM

 

"Models in agreement for an even colder air mass to move in for

the weekend and then again mid week. Began the trend to lower
temps for this time. For now staying toward the higher side of
the model temp spectrum. The cold air and increasing winds will
result in freezing spray for some of the inner channels and cold
wind chills, especially at higher elevations."

[liquidsnow]

Not trying to be a debbie downer, but based on my 25 years of watching weather in this climate, I don't have a lot of confidence in widespread accumulation over 2" anywhere outside of favored locations like Forest Grove, Banks, etc...

 

I hear you as there's so many ways this could bust.

 

1) Downsloping keep the lowlands dry

2) Precip isn't intense to start and the surge of warm air leads to a transition before heavier precip arrives

3) Southerly winds.

4) Everyone in Puget Sound eats tainted Burritos.

[Sometimesdylan]

FWIW this is the first overrunning event we've had in a couple years that has not just switched to rain and melted off the next day.

 

Seems like since 2011/2012 most of the overrunning events would be a day of cold snow followed by a half day of heavy wet snow switching to rain.

[Heavy Snow]

12z Euro is running... Epic bust, or more hope?

 

We just want it to show what it showed last night.

[SilverFallsAndrew]

My formula for gorge outflow is it has to be at least 28 at The Dalles and 24 at Pendleton when precip arrives. That is just for I-205 east...

[Timmy]

Hr 24 euro looks like it went towards the gfs

[WinterWx]

Model riding can be gut wrenching this time of year

[bainbridgekid]

Euro hour 24.

 

Not significantly different from the GFS with the handling of the low so far. Clear double barrel signature.

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2016120712/ecmwf_z500_mslp_wus_2.png

[Jesse]

I just don't see this supposed devious yet apparently transparent plot. He's not the burning bush but what he's been saying for months generally has shown at least some merit. I actually like the fact he's sticking to the more generalized stuff. When he deviates from it, things typically fall apart a bit.

I agree with this. I thought it was interesting that others perceived what I have in the past. That is all.

[Front Ranger]

Hr 24 euro looks like it went towards the gfs

 

Has less warm air invading southern OR than GFS does...