December 2020 Weather Observations for the PNW

[Gradient Keeper]

4 minutes ago, Brian_in_Leavenworth said:

Last night's GEFS starting with day 17.  Imagine a SSW event with this 500mb pattern

 

 

With just a little amplification that turns into a cold, possibly historic pattern. Here we go! C'MON!!!!

[VancouverIslandSouth]

Just now, SouthHillFrosty said:

Hey guys did you see [insert model that nobody has ever heard of]? It shows 3 feet of snow for everybody!!

In what timeframe?  I haven't checked the long range CFS lately.

[FroYoBro]

Dropped into the upper 40’s here this evening. Brrrr. 

[GHweatherChris]

Radar has a sword penetrating Forks currently!

[VancouverIslandSouth]

5 minutes ago, DJ Droppin said:

RGEM 4mb weaker, 700mb Frontogenesis is weaker than the NAM.

The 0z ICON is similar to the RGEM, perhaps slightly further north:

[BLI snowman]

 

3 minutes ago, FroYoBro said:

Dropped into the upper 40’s here this evening. Brrrr. 

Crazy to think we could be seeing highs that are several degrees colder than this later on next week.

[wxmet]

2 minutes ago, hawkstwelve said:

It keeps it all as rain but there are some strong rates shown in there.

10 mm is almost .4 inches. If that was snow with a 10:1 ratio it would be 4in/hr rates. 

[VancouverIslandSouth]

1 minute ago, hawkstwelve said:

It keeps it all as rain but there are some strong rates shown in there.

None of the Canadian models seem very good with precipitation type for some reason, if the 850mb temps are below freezing at that point it will be snow in yellow-red areas near the low. I think they drop below freezing right after that.

[AbbyJr]

14 minutes ago, Brian_in_Leavenworth said:

Last night's GEFS starting with day 17.  Imagine a SSW event with this 500mb pattern

 

 

And both the Euro, GFS, and GEFS predict a major SSW by early January. Winter is coming. 

[bainbridgekid]

00z is already noticably North at hour 6.

[weatherwonder]

11 minutes ago, DJ Droppin said:

With just a little amplification that turns into a cold, possibly historic pattern. Here we go! C'MON!!!!

The pattern change is coming first week of January 

I think is going to be a winter to remember for cold and snow lovers alike

[Requiem]

Excited for the vigorous frontal passage tomorrow-- some heavy rain and gusty winds perhaps.

[Gradient Keeper]

This is no good. HR 18

[bainbridgekid]

2mb stronger and a notch NW of the 18z.

[SouthHillFrosty]

WHERE IS THE PANIC BUTTON

[Front Ranger]

Little stronger, little further north.

Going to be a dynamic storm, that much is guaranteed.

[Gradient Keeper]

HR 24

[VancouverIslandSouth]

3 minutes ago, DJ Droppin said:

This is no good. HR 18

Looks 2mb stronger and slightly further north, the dreaded last minute shift north. Not nearly as bad as the NAM up here, but we're right on the knive's edge. Still a bit of backwash snow further south though.

[bainbridgekid]

Clear trend North the last 5 runs.

[Requiem]

1 minute ago, Front Ranger said:

Little stronger, little further north.

Going to be a dynamic storm, that much is guaranteed.

Yeah, at the very least it'll be pretty fun to watch the sharp wind shift associated with the front.

[wxmet]

GFS caves to the ECMWF

[GHweatherChris]

Stronger means Norther.

[Gradient Keeper]

Just now, bainbridgekid said:

Clear trend North the last 5 runs.

Yuck. 4 distinct trends the past 4 days. South, North, South, and back to the north.

[Gradient Keeper]

Pivotal not running, so have to rely on Tidbits

00z GFS Day 1

[wxmet]

GFS is warmer at KSEA which is probably why it’s showing heavy rain instead of snow with a temps in the upper 30s. Brutal. I definitely need to move.

[High Desert Mat?]

Really wanna hear from Phil on the SSW incoming!!  The start of it to the end of it. I just keep seeing 384hr maps. 

[Gradient Keeper]

Day 2

[seattleweatherguy]

10 minutes ago, bainbridgekid said:

2mb stronger and a notch NW of the 18z.

All rain or snow still possible 

[The Swamp]

4 minutes ago, High Desert Mat? said:

Really wanna hear from Phil on the SSW incoming!!  The start of it to the end of it. I just keep seeing 384hr maps. 

Right?  it never seems to get any closer.

[Gradient Keeper]

I just saw this on Pivotal

[ (20 Dec 2020) An outage at one of our hosting providers is resulting in missing images this evening. This should be resolved soon. ]

[MR.SNOWMIZER]

9 minutes ago, wxmet said:

GFS is warmer at KSEA which is probably why it’s showing heavy rain instead of snow with a temps in the upper 30s. Brutal. I definitely need to 

Typical Western Washington.

[SouthHillFrosty]

Super super low quality photo, but definite cut back on the models tonight

[Gradient Keeper]

Day 3

[Gradient Keeper]

The coming SSW is so abnormally anomalous the computation of data has crashed the models tonight.

[VancouverIslandSouth]

The 0z HRDPS looks similar to the 0z GFS for strength/positioning of the low:

[seattleweatherguy]

Just now, VancouverIslandSouth said:

The 0z HRDPS looks similar to the 0z GFS for strength/positioning of the low:

Looks too north for snow for me but perfect for you?

[Brian_in_Leavenworth]

20 minutes ago, High Desert Mat? said:

Really wanna hear from Phil on the SSW incoming!!  The start of it to the end of it. I just keep seeing 384hr maps. 

Someone else asked him that.  He replied:

Lol, well it’s moving up in timing. It’s just more of the event has entered the picture.

The blocky, highly meridional pattern you mention is directly associated with the tropical forcing/poleward EP flux vectors behind the SSW, so I don’t think you can really separate them.

I view the SSW is sort of an inflection point, or fork in the road, where its occurrence (or lack thereof) can/will have significant impacts for months afterwards following the same trigger. For instance, had the SSW in January 2019 failed, February 2019 outcome likely would have been very different..probably would’ve been an ordinary, canonical niño February. Deposition of momentum/Dt would have been radically different.  

[seattleweatherguy]

I have to say Whatcom country/Victoria/Vancouver is long over due to be nailed. 

[VancouverIslandSouth]

1 minute ago, seattleweatherguy said:

Looks too north for snow for me but perfect for you?

The totals look very similar to the GFS with at least a couple inches down there as well:

[Gradient Keeper]

Day 4