November 2016 Observations and Model Discussion for the Pacific Northwest

[Weather101]

Yeah, I became much more optimistic in this summer when the QBO failed to cycle negative. The Niña/+QBO combo rarely fails to deliver in the PNW.

 

The Niña/-QBO combo, on the other hand, fails more often than not, except during deep solar minimums.

Science

[Weather101]

Well while we wait for the models

 

Question time: Why does Santa Claus have a big sack ?

[Dave]

Get those studs on now!

Do that, and we can all expect windshield splat test only type of snow all winter unless you live in the higher hills.

 

Standard procedure is to wait until there is some snow on the ground, then rush to get them changed at Les Schwab at the same time as everyone else.  Count on a 4 hour wait.  This is necessary unless you choose to go without studs or would just like to cancel winter.  

[FroYoBro]

Well while we wait for the models

 

Question time: Why does Santa Claus have a big sack ?

I'm not sure I want the answer to that question. 

[seattleweatherguy]

Do that, and we can all expect windshield splat test only type of snow all winter unless you live in the higher hills.

Standard procedure is to wait until there is some snow on the ground, then rush to get them changed at Les Schwab at the same time as everyone else. Count on a 4 hour wait. This is necessary unless you choose to go without studs or would just like to cancel winter.

I'm at 423 feet

[FroYoBro]

Anyone staying up for the 0z GFS run? 

[Weather101]

Anyone staying up for the 0z GFS run?

Yup, Are you?

[FroYoBro]

Yup, Are you?

 

We'll see! 

[Trainwreck]

I'm at 423 feet

Are you sure you're not 420'?

[Weather101]

[Jesse]

My joke got deleted It wasn't even that bad...

 

There's other places for the extreme OT stuff. This isn't an AOL chat room.

[Cold front]

Why was Frosty the Snowman smiling?

The snow blower was coming down the street. Ba dum pum.

[Weather101]

There's other places for the extreme OT stuff. This isn't an AOL chat room.

Oh no

[Weather101]

Why was Frosty the Snowman smiling?

The snow blower was coming down the street. Ba dum pum.

LOL

[Gradient Keeper]

00z GFS

Begins in.... 3 minutes

 

Let's continue the trend of the offshore ridge being suppressed, not pushing as far inland, and a strong ridge. We definitely want a good southeast US ridge. If I really wanted to be greedy around day 7 I'd really like seeing the offshore ridge merging with the Aleutian/western Alaska block. We just need the block to hold.

 

Feel free to play along (You may need to refresh pages)

Northwest view - http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nwus&pkg=mslp_pcpn_frzn&runtime=2016112912&fh=0&xpos=0&ypos=197

North America view - http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=namer&pkg=z500_mslp&runtime=2016112912&fh=0&xpos=0&ypos=197

North Pacific view - http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=npac&pkg=z500_mslp&runtime=2016112912&fh=0&xpos=0&ypos=197

Alaska view - http://www.tropicaltidbits.com/analysis/models/?model=gfs&region=ak&pkg=T850&runtime=2016112912&fh=0&xpos=0&ypos=197

[Deweydog]

Block is much stronger on the 0z.

 

You heard it here first!

[Trainwreck]

There could be a merge. You heard that here first.

[crf450ish]

.SYNOPSIS...
Another storm system will bring a chance of light snow to the
area Wednesday with snow showers persisting in the Idaho
Panhandle through Thursday. Unsettled and breezy conditions return
for the weekend. By the beginning of next week temperatures have
the potential to be the coldest we have seen so far this winter.

&&

.DISCUSSION...

...Another winter weather system is expected for later tonight
through Thursday...

Tonight through Thursday morning...Model solutions remain quite
consistent on breaking down the shortwave ridge tonight and
Wednesday and replacing it with an upper level trough. Light
precipitation is expected to begin late this evening as a weak
warm front develops per isentropic analysis. Although there isn`t
much precipitation west of the Cascades currently, the echoes are
beginning to intensify as they track slowly eastward. Most of the
precipitation associated with this front will be confined to the
far northern portions of Washington and extreme northern Idaho as
it tracks east of the Cascades. Precipitation will becoming much
more widespread as the trailing cold front moves into the region
later tonight and Wednesday. This has been trending slightly
slower with each successive model run. Now the front is expected
to arrive in the Cascades and Wenatchee area between 4-7am and
into the Spokane/CdA/Pullman area between 7am-10am. The front will
then move completely into the Idaho Panhandle between 10am and
early afternoon. Once it moves here its eastward push will be
impeded by a shortwave trough which will drop southeast via
southern BC. 500 mb temperatures will plummet with the arrival of
this feature and lapse rates through the dendritic layer will
steepen as well. This pattern persists through the entire night
and even into Thursday while the mean mid-level flow takes on a
north-northwest orientation. This is a favored setup for numerous
showers, mainly over the central Idaho Panhandle, Camas Prairie,
and Blue Mountains. So what sort of weather will this bring?


* Snow....We are quite confident that this event will begin as
snow for almost all locations as the cold front approaches. The
only exceptions would be over the southern Columbia Basin south
of Highway 2 or so. By afternoon, snow levels will rise to
around 2000 feet in the north to around 3000 feet in the south,
however based on the convective nature of the atmosphere, we`d
expect to see a mix of rain and snow showers, especially for the
eastern third of Washington and the Idaho Panhandle. Snow
levels will fall again to the valleys floors overnight and into
Thursday. This is when we could see appreciable snow
accumulations for the central Panhandle.


* Impacts...This is the hard part of the forecast. Although most of
what falls ahead of the cold front will be snow, road
temperatures may not be all that conducive to accumulations as
they quickly rise above freezing. Confidence is good that it
will accumulate over the northern valleys and over western
portions of the forecast area, but as the front nears north
Idaho those accumulations become a little less sure as road
temps are expected to rise above freezing. Accumulations then
become much more likely overnight. So locations south of the
Silver Valley such as Clarkia, Avery, and Bovill stand a good
chance of significant snows as the threat of showers continues
from late tomorrow afternoon through Thursday. We will issue a
winter weather advisory for 4 to 8 inches of snow, with anywhere
from 2 to 4 inches in the Silver Valley. Snow accumulations
will also be possible on the Camas Prairie, mainly overnight and
into early Thursday above 2000 feet, but accumulations here
should fall short of advisory criteria with about 1 to 3 inches
possible. Similar amounts are expected to occur over the Blue
Mountains. fx

Thursday through Sunday...The western edge of a trof containing
conditionally unstable air lingers overhead of Eastern Washington
and Northern Idaho Thursday but gets pushed quickly to the east by
an incoming low amplitude, yet very broad, ridge of high pressure
Thursday night. The flow becomes more north to northeast Thursday
night into early Friday. By late Friday a well maintained plume of
subtropical moisture fluxing through the ridge sags southeast and
over Eastern Washington and Northern Idaho. The flow is quite zonal
and as a result the pops remain highest over the mountain locations
within the close vicinity of the Cascade Crest, near the British
Columbia Border and mountains of North Idaho with a discrete
rain/snow shadow encompassing the lowland (non mountain) locations
between the Cascade Crest and the North Idaho Mountains Friday Night
and Saturday. Once the moisture plume passes to the south a trof
behind it drops down and through as well allowing for robust/gusty
west and northwest winds on Sunday along with colder temperatures
and dropping snow levels as the airmass behind the passing trof is a
cold conditionally unstable one. /Pelatti

...Colder temperatures Sunday night through at least early next week...

Sunday night through Tuesday: Models agree on the general upper
level pattern of a trough exiting the region. There is still a
chance of precip...mainly across the mountains through Monday.
Then a ridge will build across the west coast and shift inland
towards Wednesday. Meanwhile at the surface...high pressure will
move south out of Canada and into western Montana. This is a
classic set up for a cold air intrusion into our region.

Main changes to the forecast was to lower temperatures. Lowered
temperatures anywhere from 3 to 12 degrees...with the biggest
changes by next Tuesday and Tuesday Night. Temperatures will lower
about 10 degrees from Sunday to Monday and about another 4-8 by
Tuesday. Average high temperatures by early next week are usually
in the mid 30s to around 40...we instead will be seeing highs in
the mid 20s to mid 30s. East slope Cascades valleys and portions
of the western Columbia Basin will be the last to see the colder
air reach them. Average low temperatures are usually in the mid to
upper 20s...by next Tue morning we could see temps in the teens to
lower 20s with Wednesday morning temperatures potentially getting
down into the single digits to lower teens. /Nisbet

 

 

 

 

 

TEMPS IN THE SINGLE DIGITS?????? D**n it boy! 

[Gradient Keeper]

Day 2

 

http://maps1.pivotalweather.com/maps/models/gfs/2016113000/048/500h_anom.na.png

[IbrChris]

I've got a contest here if anyone is interested.

Looks pretty fun...Nice prize too.

[Gradient Keeper]

Day 3

 

http://maps1.pivotalweather.com/maps/models/gfs/2016113000/072/500h_anom.na.png

[Gradient Keeper]

Day 4

 

http://maps1.pivotalweather.com/maps/models/gfs/2016113000/096/500h_anom.na.png

[The Swamp]

Day 4 looks amazing.

[Deweydog]

Blocking is much stiffer, stinkier and subversive.

[bainbridgekid]

Block definitely looking blockier at hour 108.

[Gradient Keeper]

Day 5 MUCH BETTER. Energy on northwest side of block much weaker this run
 

http://maps1.pivotalweather.com/maps/models/gfs/2016113000/120/500h_anom.na.png

[The Swamp]

I'm starting to think we may be in for 500-1000 ft snow levels.

[TT-SEA]

00Z GFS is drier up here compared to the 12Z run.

[Front Ranger]

Well while we wait for the models

 

Question time: Why does Santa Claus have a big sack ?

 

1x a year.

[MossMan]

Day 5 MUCH BETTER. Energy on northwest side of block much weaker this run

 

http://maps1.pivotalweather.com/maps/models/gfs/2016113000/120/500h_anom.na.png

Officially getting excited now! Oh the water pump on my wife's SUV just went out...the last time I had a water pump go out in one of our vehicles... December 2008.

[bainbridgekid]

Low sliding down the coast Sunday night is a couple mb stronger on the 00z. It'll be interesting to see how it handles moisture.

 

EDIT: It slides further offshore though and ends up drier. Details details though.

[Front Ranger]

Blocking is much stiffer, stinkier and subversive.

 

Expect a Trump tweet about it shortly.

[Heavy Snow]

Officially getting excited now! Oh the water pump on my wife's SUV just went out...the last time I had a water pump go out in one of our vehicles... December 2008.

 

Great sign!

[MR.SNOWMIZER]

This run looks dangerous.

[MossMan]

00Z GFS is drier up here compared to the 12Z run.

Not concerned about precip at all...we can start looking at that on Saturday.

[seattleweatherguy]

This run looks dangerous.

Dangerous?

[crf450ish]

I'm starting to think we may be in for 500-1000 ft snow levels.

You think the swamp will freeze over?

[TT-SEA]

Might be an Oregon snow event when the air is cold enough for lowland snow on Sunday night and Monday.

 

http://www.tropicaltidbits.com/analysis/models/gfs/2016113000/gfs_mslp_pcpn_frzn_us_22.png

 

http://www.tropicaltidbits.com/analysis/models/gfs/2016113000/gfs_mslp_pcpn_frzn_us_24.png

[Front Ranger]

Not concerned about precip at all...we can start looking at that on Saturday.

 

Bingo.

[bainbridgekid]

Might be an Oregon snow event when the air is cold enough for lowland snow on Sunday night and Monday.

 

http://www.tropicaltidbits.com/analysis/models/gfs/2016113000/gfs_mslp_pcpn_frzn_us_22.png

 

 

Hard to imagine that being sea level snow in Oregon with the low still to their NW though.

 

I'd feel pretty good if we can get a low that strong sliding down the coast. Easy to get some convergence in situations like that like the 12z showed.