December 2016 Observations and Model Discussion for the Pacific Northwest

[Heavy Snow]

The updated run of the 12z KING EURO showing a widespread 3"-4" of Snow for PDX Metro by Thursday 4pm.

[Kayla]

Weaker and further south...I'm sensing a trend.

[TT-SEA]

Still snowing in Seattle on Friday morning per the 12Z ECMWF.

[Heavy Snow]

The updated run of the 12z KING EURO showing a widespread 3"-4" of Snow for PDX Metro by Thursday 4pm.

 

Update: KING EURO showing solid widespread 4"-6" by Thursday 10pm.

[FroYoBro]

Hmmm. The Euro is pretty interesting for Portland. Probably less of a quick warming shot with that weaker low structure like that. Could stay snow for a while. 

[Perturbed Member]

Of course I made this prediction before the 12z Euro...I'll have final thoughts tomorrow (Think Jerry's final thought type of wisdom). But most models showed a lot of the metro getting sticking snow yesterday and look how that turned out. Don't live or die by the snow maps. 

 

Agree the snow maps can't always be trusted but this setup is much more reliable for PDX than the very difficult to predict setup from yesterday. Much higher confidence on this one.

[Kayla]

Looking more and more like mostly just a snow event for PDX.

[Heavy Snow]

Weaker and further south...I'm sensing a trend.

Hmmm. The Euro is pretty interesting for Portland. Probably less of a quick warming shot with that weaker low structure like that. Could stay snow for a while. 

 

Yup, good trends this morning from yesterday. I'm more confident now in PDX getting a nice snow storm.

[Front Ranger]

This is one of those times I wish I could see what the Euro shows between 48 and 72 hours. But awesome to hear it's still showing snow in the lowlands at 72 hours.

[FroYoBro]

In other news, it is actually lightly raining here. 

[FroYoBro]

Looking more and more like mostly just a snow event for PDX.

 

Doubt it. A changeover is still going to happen, but it could be put off a little bit. 

[TT-SEA]

This is one of those times I wish I could see what the Euro shows between 48 and 72 hours. But awesome to hear it's still showing snow in the lowlands at 72 hours.

 

Weatherbell.  

[Randyc321]

Update: KING EURO showing solid widespread 4"-6" by Thursday 10pm.

Can you post a Western Wa map?

 

Thanks

[TT-SEA]

12Z ECMWF shows snow from Seattle northward through 10 a.m. on Friday.

 

And THEN shows more show for Seattle up to Bellingham on Saturday morning!   

[Kayla]

This is one of those times I wish I could see what the Euro shows between 48 and 72 hours. But awesome to hear it's still showing snow in the lowlands at 72 hours.

 

850s stay around -5c to -6c in Western WA lowlands and PDX are gets up to around 0c to +1c (before dropping again) through that timeframe. 

[Heavy Snow]

Wow, this is interesting. KING EURO is showing the East winds persisting at PDX through Friday at 4pm. It shows the light South winds getting all the way to the edge of Multnomah County but not breaking through until Friday 10pm, yikes!

[Deweydog]

Looking more and more like mostly just a snow event for PDX.

This is still a transition event, regardless of the low's strength and track.

[Front Ranger]

Looks like still snow in places at day 4? EDIT: Yep.

[Heavy Snow]

Can you post a Western Wa map?

 

Thanks

 

I would post it but we are not really allowed too since it's a subscription site. Maybe somebody else can help you out here. You can sign up for a 7 day free trial.

[SilverFallsAndrew]

December 1994 redux?

[Kayla]

Doubt it. A changeover is still going to happen, but it could be put off a little bit. 

 

Of course. But rather than an ice event it's looking more like all snow then a pretty quick transition to just plain rain.

[MR.SNOWMIZER]

This is still a transition event, regardless of the low's strength and track.

transition to what?

[Kayla]

In other news, it is actually lightly raining here. 

 

Yeah, lightly snowing off and on here this morning.

[Deweydog]

transition to what?

A Trump administration.

[Kayla]

This is still a transition event, regardless of the low's strength and track.

 

Of course it is. But more of a transition snow event rather than a transition ice event.

[BLI snowman]

Of course I made this prediction before the 12z Euro...I'll have final thoughts tomorrow (Think Jerry's final thought type of wisdom). But most models showed a lot of the metro getting sticking snow yesterday and look how that turned out. Don't live or die by the snow maps. 

 

Eh, overrunning snow setups are a very different animal from what we saw yesterday. Especially for cold outflow areas.

[MR.SNOWMIZER]

Something big is coming.

[luvssnow_spokane]

Something big is coming.

that's what she said...

[Deweydog]

Of course it is. But more of a transition snow event rather than a transition ice event.

There will be a switch to ice. Gorge gradients will likely persist well beyond the time the warm tongue pushes in. Gross.

[TT-SEA]

Wow... could get about 2 feet of snow in my area from Thursday through Saturday per the 12Z ECMWF.

 

Never transitions here but there is tons of precip.  

[luvssnow_spokane]

Looking really good on the euro. Plenty of potential with this setup.

 

HOUR 120

 

 

 

 

 

 

[SilverFallsAndrew]

Just not impressed right now with the source airmass...At least yet. Just doesn't smell like more than a 1-3" event. I think a 1-3" type event in this early Dec timeframe would be very meaningful though. 

[BLI snowman]

Of course. But rather than an ice event it's looking more like all snow then a pretty quick transition to just plain rain.

 

Yeah, I don't see too much ice happening. Airmass to our east isn't quite cold enough for a widespread ice storm anyways IMO but with the cold air column looking denser we shouldn't see a prolonged transition out of snow. The west winds and milder air will probably mix down in a rather uniform fashion.

[BLI snowman]

There will be a switch to ice. Gorge gradients will likely persist well beyond the time the warm tongue pushes in. Gross.

 

Not so sure, I think by Friday morning the stratiform stuff will be over and the west winds will punch in rather uniformly. Most of Thursday looks like it could stay snow, especially near or north of the gorge. 

[Front Ranger]

Just not impressed right now with the source airmass...At least yet. Just doesn't smell like more than a 1-3" event. I think a 1-3" type event in this early Dec timeframe would be very meaningful though. 

 

DP is 14 at BLI...

[SilverFallsAndrew]

DP is 14 at BLI...

 

I am more talking about PDX.

 

I think W. WA should do well...Though if I lived Seattle-north I would be starting to get concerned about the southern trend...

[Front Ranger]

Euro has another low approaching the OR coast at day 6.

[Kayla]

There will be a switch to ice. Gorge gradients will likely persist well beyond the time the warm tongue pushes in. Gross.

 

So gross. Either way, definitely a high impact system and I tend to go with the model that has the slowest moderation.

[Front Ranger]

I am more talking about PDX.

 

I think W. WA should do well...Though if I lived Seattle-north I would be starting to get concerned about the southern trend...

 

Eh, same source air mass at work for everyone here. It should be cold enough for just about everyone SLE north at least come Wed night.

[bainbridgekid]

Sure is nice not to have to hang all our hats on one potential event.

From the Seattle AFD:

 

.LONG TERM...An active weather pattern is likely with a tricky
balance between the northern and southern streams--there will likely
be blocking around Alaska. This should make for a low snow level and
give the lowlands periodic flirtations with snow. Fraser outflow
could continue at times through the weekend but probably will not be
especially strong. Looking at the 12z GFS...there is a chance that a
weather system around Sunday night will be problematic for Western
Washington as the modified arctic front could push back south into
Western Washington at that time. The 00z ecmwf looks like there
could be light to moderate outflow through the weekend into the
Bellingham area, but keeps southerly gradients and milder weather
for most of Western Washington with no shift south. Then around 12z
Tuesday of next week the euro takes a southern stream low pressure
center and frontal system into Oregon--and Fraser outflow resumes as
the arctic front strengthens.

 

And that's all after Thursday's storm.