November 2016 Observations and Model Discussion for the Pacific Northwest

[snow_wizard]

The ECMWF is definitely cold. The Weatherbell graphics show low 20s for Seattle on the coldest day. Teens in the outlying areas. More snow than last nights run also.

[SilverFallsAndrew]

Decent amount of lowland snow on 12Z ECMWF through day 10...

 

 

 

Because of the resolution that 3" at Salem is likely overdone as the hills which are 500-800' just south and west of Salem probably skew things.

[snow_wizard]

Decent amount of lowland snow on 12Z ECMWF through day 10...

We were just seconds apart on posting this.

[Heavy Snow]

Decent amount of lowland snow on 12Z ECMWF through day 10...

 

 

SCORE!

[snow_wizard]

Because of the resolution that 3" at Salem is likely overdone as the hills which are 500-800' just south and west of Salem probably skew things.

The point is it's better.

[snow_wizard]

The December 1956 "warning shot" is interesting. Almost a foot of snow at my location in what was otherwise a fairly warm month.

That was a sweet little event. Things got really good later in the winter also.

[SilverFallsAndrew]

The point is it's better.

 

I agree. Just pointing out that SLE isn't necessarily a favored location for snow accumulations with this pattern,. 

[SilverFallsAndrew]

That was a sweet little event. Things got really good later in the winter also.

 

What dates in December 49' were you referring to for the warning shot. Looking at the data for my location from that year it is hard to tell. It was a cold month overall, there were several cold snaps looks like around the 10th and then around the 19th and 20th, with highs around freezing and lows in the teens with the 19/20th. 

[Front Ranger]

Latest euro is first run to show a significant Arctic outbreak into the lower 48.

[SilverFallsAndrew]

It will be interesting to see what the EURO ensembles say. 

[luvssnow_spokane]

What the hell!? : "You have reached your quota of positive votes for the day" Crap!   

[Phil]

Modeling is much improved with the secondary wavebreak today, hence the improved solutions/increased meridional streamflow downstream. The struggles are occurring in the d5/d8 period, so that's the timeframe to watch IMO.

[Heavy Snow]

The updated run of the 12z EURO shows a modified Arctic Blast and Snow Storm for the lowest elevations west of the Cascades in the PNW. It looks like at this point it will be cold enough to snow even at the beaches per the 12z EURO.

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016112812/216/850tw.conus.png

[Timmy]

The updated run of the 12z EURO shows a modified Arctic Blast and Snow Storm for the lowest elevations west of the Cascades in the PNW. It looks like at this point it will be cold enough to snow even at the beaches per the 12z EURO.

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016112812/216/850tw.conus.png

Only 9 days away!

[Farmboy]

Looks like at least something halfway decent is a lock now.  Amazing how this place melts down after one bad run...

[BLI snowman]

We still have the JMA

 

[SilverFallsAndrew]

Looks like at least something halfway decent is a lock now.  Amazing how this place melts down after one bad run...

 

I wouldn't say lock. Strong possibility. 

[SilverFallsAndrew]

We still have the JMA

 

jma_T850_wus_9.png

 

Praise the Lord!

[SilverFallsAndrew]

http://www.tropicaltidbits.com/analysis/models/gfs-ens/2016112812/gfs-ens_z500a_namer_31.png

[Front Ranger]

It will be interesting to see what the EURO ensembles say. 

 

Indeed. This is the time (5-8 days out) when they're usually a very reliable indicator.

[Farmboy]

Though the timing of this thing keeps getting pushed back, it's interesting to note that the timing of the last couple pattern changes kept getting pushed back as well before the actual solutions manifested in the models...

[snow_wizard]

What dates in December 49' were you referring to for the warning shot. Looking at the data for my location from that year it is hard to tell. It was a cold month overall, there were several cold snaps looks like around the 10th and then around the 19th and 20th, with highs around freezing and lows in the teens with the 19/20th.

Probably the 19th - 20th. It got pretty mild after that and then the good stuff hit at the very end of the moth.

[chopper 918]

http://www.tropicaltidbits.com/analysis/models/gfs-ens/2016112812/gfs-ens_z500a_namer_31.png

 

Ehh...getting there.

[snow_wizard]

Though the timing of this thing keeps getting pushed back, it's interesting to note that the timing of the last couple pattern changes kept getting pushed back as well before the actual solutions manifested in the models...

The timing is actually progressing nicely.

[Heavy Snow]

We still have the JMA

 

jma_T850_wus_9.png

SCORE!

[luvssnow_spokane]

Only 9 days away!

nope actually starts next Monday/Tuesday.  Just FYI.

[bainbridgekid]

What about face value?

When your face is this pretty, you have to value it pretty high. 

[Jesse]

Praise the Lord!

MAGA.

[Gradient Keeper]

12z runs were not awful, but certainly not ideal for Cold/Snow lovers. Not yet.

 

12z GFS for Willamette Valley/northwest Oregon very low snow levels even with onshore flow, but little to no chance below 500-1000'. It wouldn't take much change of the 500mb pattern though for a backdoor blast as the ridge is pushed east from 150-140 W. Columbia Basin cold pool very evident and persistent. I also notice the potential for systems moving in from the southwest that might draw in colder air from the Gorge. 12z GFS Ensembles for PDX improved a lot in the mid range with 850mb mean down to -7c and many members -6c to -9c(Suggests SOME further room for improvement is possible) 6-10 Day Composite Analog wasn't horrid and suggested the pattern has a slight chance for improvement.

 

12z GEM was improved. Ridge position near 150 W and a BC slider system dropping south. It was tantalizingly close to a blast. More promising is after day 8 we see a classic pattern evolve with our offshore ridge retrograding and merging with Aleutian ridge becoming a block near 155-160 W. Definite re-load written all over this and likely modified blast at the least possible.

 

12z ECMWF through day 8 was similar to the GFS in some respects. It was very close to a backdoor blast. Afterwards it looks ugly.

 

My consensus from this mornings runs is that we were quite close to seeing significant arctic air into eastern Washington/Columbia Basin with a classic backdoor blast via Gorge. The GEM was the closest to giving us a regional blast. The 500mb pattern overall is so changed from previous runs. It's not even close to what we had been seeing. The fact we are seeing so much variability of 12z runs today tells me they are no closer to handling the upper level pattern than yesterday. That can both be a great thing or we could see things turn even more unfavorably.

 

They do not yet have a clue as to how this plays out, or if the North Pacific is more blocky with arctic air possible for WA/OR, or does the energy moving through the Aleutians win out, or do we just end up with a ridge thrown up over the west coast. Right now it seems all solutions are possible and I couldn't say that 12-24 hours ago. I still think we have to wait until Wednesday 12z or 00z before we see a stronger model consensus on ridge axis position, strength of block, level of amplitude, and how much energy pushes through the Aleutians, off Siberia. There are far more unknowns right now than I've seen the past 3 days. Cautiously optimistic. Onto 00z!!!!

[Bryant]

Went to bed @ 11pm last night with heavy rain falling @ 38 degrees. Woke up at 6am this morning to an inch of snow on the ground.

Pics for the less fortunate?

[Bryant]

Looks like a decent warning shot next week... (mon-wed) Short and sweet. After that not great.

One complex pattern at a time...

[Bryant]

When your face is this pretty, you have to value it pretty high.

He does have a pretty face, I'll give him that

[MossMan]

FWIW, the 12z WRF shows some snow in the South Sound and what looks like a PSCZ during the day Monday.

 

 

http://www.atmos.washington.edu/wrfrt/data/2016112812/images_d2/ww_snow24.180.0000.gif

And usually the pscz ends up further north to start with than what is typically modeled so hopefully!!

[Heavy Snow]

Some Euro ensemble maps:

 

 

SCORE!

[BLI snowman]

12z Euro ensembles look better to me, versus 00z.

[Deweydog]

PDX back safely in the 50's today. Thanks, clean coal.

[Jesse]

PDX back safely in the 50's today. Thanks, clean coal.

Makes sense considering the warm airmass we're in. Oh wait no it doesn't.

[Deweydog]

Makes sense considering the warm airmass we're in. Oh wait no it doesn't.

50 is the new 40.

[FroYoBro]

Makes sense considering the warm airmass we're in. Oh wait no it doesn't.

We are getting sun breaks and it isn't like the airmass is really that cold.

[Jesse]

We are getting sun breaks and it isn't like the airmass is really that cold.

WSW winds are likely the bigger culprit.