December 2016 Observations and Model Discussion for the Pacific Northwest

[MossMan]

Currently 20F here right now! Brrr! Been a long time since I have seen the models struggle this badly...could make for something epically insanely great...or 48 degree rain. Almost better to just shut the models down and go with the street lamp approach and wait!

[MossMan]

Almost time for the Euro...yahoooo!!

[Heavy Snow]

Models don't really know what's going to happen tomorrow, this weekend, or next week.

 

How are computers going to take over the world if they can't even get a d amn 3 day forecast right?

Good point. I'm just hoping to see some snow tomorrow.

[Weather101]

22F and clear

[luvssnow_spokane]

I am just stunned how much cooler it looks to stay in Oregon on Thursday compared to the puget sound.

 

 

 

 

[BLI snowman]

What's your call for east wind areas? I am on the fence whether it will be a blessing or a curse.

I'd lean towards an inch or two less. Any more than 2" down near the river would be gravy IMO.

[snow_wizard]

The GEM looks frigid at the end of next week too.

 

That's a very good sign.  That model is more reluctant to go really cold for us in most cases.

[Winterdog]

only 9 days away!!!  Thats not clown range

Around here day after tomorrow is clown range.

[liquidsnow]

 Epic fail!!!  

WARM AIR ALWAYS WINS!!!

 

http://i.imgur.com/KqrDpCG.gif

[Timmy]

New afd for pdx should help put our minds at ease

[Weather101]

WARM AIR ALWAYS WINS!!!

 

http://i.imgur.com/KqrDpCG.gif

Loooooooolll

[mountainman]

I am just stunned how much cooler it looks to stay in Oregon on Thursday compared to the puget sound.

 

hrrr_t2m_washington_19.png

ummmm looks about the same to me dude

[seattleweatherguy]

How's the euro looking

[Jesse]

I'd lean towards an inch or two less. Any more than 2" down near the river would be gravy IMO.

I'm not really close to the river. Guess I'll just wait and see. I'd be thrilled with 2" that's what she said.

[Kayla]

Great write-up by the Portland NWS describing why they are sticking with their 2-4" snowfall amounts in the PDX metro area.

 

"Speaking of frontogenesis, will make a semi-quick comment about the
forecast about the PDX Metro area. Models...including the 00z NAM,
GFS, and 12z ECMWF...all show excellent frontogenetical forcing
producing strong lift through the dendritic growth zone of -12 to -18
deg C in the atmosphere. Cold air outflow pouring out from the Gorge,
combined with increasing S-SW flow trying to work its way into the
PDX metro will only increase this during the late morning and early
afternoon hours. This would result in decent QPF and snow
accumulation rates around midday. Therefore, we believe some of the
models that have lower-end QPF may be mistaken. The enhanced lift and
increasing precipitation will likely serve to cool the column to keep
temps near or slightly below freezing until the strongest area of
frontogenetical forcing passes off to the N-NE around 00z Fri (4pm
Thu local time). Also, strong easterly flow will probably add some
upslope component and modest cold air damming in western portions of
Washington and Yamhill Counties, so areas such as Forest Grove,
McMinnville, Newberg and Dallas may see more snow than one would
otherwise suspect. Tweaked the wording of the WSW to reflect this.

Bottom line is that 18z and early 00z runs have only served to
increase confidence that this will be a significant event for at
least the northern half of our CWA." Weagle

[Winterdog]

Hi neighbor! What part of Arlington are you located at? 

I'm addressed out of Arlington but live a few miles south and east of the town.  My elevation is around 400 feet so I'm not in the valley.

[snow_wizard]

FWIW December 1884 had a very similar progression to what we have had and what is being shown on the GFS.  Warning shot with a little snow...bigger shot with a lot of snow...biggest shot with more snow.  We actually have a chance at the coldest December on record after the warmest November.  I'm just stating what the models show is possible.

[Deweydog]

New afd for pdx should help put our minds at ease

Sticking to their guns. I'd like to think they're smarter than us.

[mountainman]

Wow coldest December?  I don't know.  It hasn't even been that cold yet around here even

[snow_wizard]

WARM AIR ALWAYS WINS!!!

 

 

The guy with the chair could actually be the cold front.

[MossMan]

I'm addressed out of Arlington but live a few miles south and east of the town. My elevation is around 400 feet so I'm not in the valley.

Gotcha, I'm also addressed out of Arlington but I'm west of smokey point at about 300ft.

[Winterdog]

How's the euro looking

I'm not even going to look at that sucker or read anymore of these posts for fear my delicate psyche will be shattered with another wiggle of the southern stream.

[snow_wizard]

Wow coldest December?  I don't know.  It hasn't even been that cold yet around here even

 

As I said...assuming what the models have hinted at is correct.  1884 and 1983 began with modest cold just like this and those two were epically cold.  I probably wouldn't have mentioned it if it weren't for that crazy Alaska block.

[MossMan]

I'm not even going to look at that sucker or read anymore of these posts for fear my delicate psyche will be shattered with another wiggle of the southern stream.

It's exhausting!

[luvssnow_spokane]

SEATTLE AFD:

 

... Clouds will increase from the southwest on Thursday. Models are a

tad slower in bringing precipitation northward, but all show
precipitation developing in the south interior and on the central
coast during the mid afternoon period, in the greater Seattle area
between 5 and 7 PM, and in the Bellingham area around midnight
Thursday night. Precipitation will begin as snow in the interior
and change to rain from south to north during the evening south of
Seattle and after midnight to toward morning from Seattle
northward. Snowfall will last about 6 hours and will amount to 4
to 6 inches in the Hood Canal area and 1 to 3 inches elsewhere.
The NAM is a bit heavier with the snowfall amounts (locally up to
4 inches), while the drier GFS keeps most areas from Puget Sound
and I-5 eastward drier with strong easterly pressure gradients
cutting back on snow amounts to 2 inches or less. The current
forecast of 1 to 3 inches in the lowlands (with the exception to
the heavier amounts around Hood Canal) appear to be on track. A
zone update was made to adjust the timing of the onset of
precipitation later into the day Thursday in the south and mainly
in the evening for areas from Seattle northward.

Model consistency and continuity is not really too good at this
time from Friday through Sunday. Cold air will remain just north
of the Canadian border and lower pressure will be right over
Western Washington. Any shift of the surface trough or tracks of
low pressure will mean the difference between snow levels around
500 feet or 1000-1500 feet. The current forecasts generally appear
to be on track at this time.

Other than the change to the timing of the precipitation onset,
current forecasts look good. Albrecht

[Kayla]

Sticking to their guns. I'd like to think they're smarter than us.

 

2-4" still seems like a very reasonable forecast to me at PDX. Still forecasting only 1.25" on your doorstep?

[Jesse]

Sticking to their guns. I'd like to think they're smarter than us.

It seems like whenever there is a situation like this they always end up with egg on their face. I would feel better if they were being bearish.

[catnip]

Currently 16.5 here.

[Heavy Snow]

WARM AIR ALWAYS WINS!!!

 

http://i.imgur.com/KqrDpCG.gif

HAHA!

[MossMan]

As I said...assuming what the models have hinted at is correct. 1884 and 1983 began with modest cold just like this and those two were epically cold. I probably wouldn't have mentioned it if it weren't for that crazy Alaska block.

I wonder how the weather weenies of 1884 were handling the lame warning shots...

[SilverFallsAndrew]

Wow. The 00z has so many goodies IDK what to do...

[Heavy Snow]

FWIW December 1884 had a very similar progression to what we have had and what is being shown on the GFS. Warning shot with a little snow...bigger shot with a lot of snow...biggest shot with more snow. We actually have a chance at the coldest December on record after the warmest November. I'm just stating what the models show is possible.

I think you might be onto something.....

[Brennan]

SEATTLE AFD:

 

... Clouds will increase from the southwest on Thursday. Models are a

tad slower in bringing precipitation northward, but all show

precipitation developing in the south interior and on the central

coast during the mid afternoon period, in the greater Seattle area

between 5 and 7 PM, and in the Bellingham area around midnight

Thursday night. Precipitation will begin as snow in the interior

and change to rain from south to north during the evening south of

Seattle and after midnight to toward morning from Seattle

northward. Snowfall will last about 6 hours and will amount to 4

to 6 inches in the Hood Canal area and 1 to 3 inches elsewhere.

The NAM is a bit heavier with the snowfall amounts (locally up to

4 inches), while the drier GFS keeps most areas from Puget Sound

and I-5 eastward drier with strong easterly pressure gradients

cutting back on snow amounts to 2 inches or less. The current

forecast of 1 to 3 inches in the lowlands (with the exception to

the heavier amounts around Hood Canal) appear to be on track. A

zone update was made to adjust the timing of the onset of

precipitation later into the day Thursday in the south and mainly

in the evening for areas from Seattle northward.

 

Model consistency and continuity is not really too good at this

time from Friday through Sunday. Cold air will remain just north

of the Canadian border and lower pressure will be right over

Western Washington. Any shift of the surface trough or tracks of

low pressure will mean the difference between snow levels around

500 feet or 1000-1500 feet. The current forecasts generally appear

to be on track at this time.

 

Other than the change to the timing of the precipitation onset,

current forecasts look good. Albrecht

Current forecast looks good until it doesn't... so like, when the Euro comes out.

[luvssnow_spokane]

 each model run feels like this...

 

 

 

 

[luvssnow_spokane]

Current forecast looks good until it doesn't... so like, when the Euro comes out.

honestly I do not see the euro changing much

[Deweydog]

It seems like whenever there is a situation like this they always end up with egg on their face. I would feel better if they were being bearish.

After the 12z's this morning I went into retreat. Then Mark did too, and I honestly follow him like The Grateful Dead. Hard to get off that thinking at this point. The NWS stuff sounds swell, they've really fell in love with that f-word lately, but it does sound like rationalizing a bit of an unrealistic call.

[luvssnow_spokane]

Euro running ... Low is a bit closer and an itsy-bitsy stronger..

[Front Ranger]

Portland NWS continues their longstanding tradition of weenie-ness.

[Deweydog]

2-4" still seems like a very reasonable forecast to me at PDX. Still forecasting only 1.25" on your doorstep?

Yup. 3:45!

[Timmy]

Euro precip looks good for .4-.6 in the pdx metro through 00z tomorrow