December 2019 Weather Discussion for the PNW

[Deweydog]

Better than this winter. LOL!

Definitely. Especially considering some experts said this would be our coldest month.

[TacomaWaWx]

Definitely. Especially considering some experts said this would be our coldest month.

*Gasps*

[TigerWoodsLibido]

I just did a speed test. Getting 12mb at the moment. Thanks CenturyLink.

Sadly, ¢onca$t is the only consistent option if you want 60mbps or more. I watch so many ballgames it’s vital.

[SilverFallsAndrew]

Don't look now, but the CFS goes BALLz to the WallZ for the two weeks after Christmas. 

 

[TigerWoodsLibido]

[Deweydog]

Don't look now, but the CFS goes BALLz to the WallZ for the two weeks after Christmas.

 

Late January 2008 redux???

[Dave]

Is that good?

You have to mix with a bit of vodka and it's palatable then.

[MossMan]

Very much raining now.

[Phil]

Saw that on Ventrice's Twitter.

 

And that helps the Northwest how? By building up a death ridge right over us for endless days of inversions?

A SSW helps in two ways.

 

1) Long story short, it weakens the high latitude zonal winds and promotes pressure rises over the polar domain, almost like an “unshackling” of the Arctic cold pool from the PV/TPV, allowing for easier Arctic air intrusions across the middle latitudes, including the PNW (see last winter).

 

2) For a number of reasons, a SSW also cools/raises the tropical tropopause. The reduction in static stability aids in MJO genesis and propagation, which could possibly overwhelm this year’s regime of subsidence over the Maritime Continent if a SSW were to occur. SSWings often “shake up” the background state of tropical forcing especially in weak ENSO years. Of course, this can be a bad thing if the tropics are already favorable (see Jan 2013) but if the tropics are hostile (like right now, and last winter) it can only help.

[SilverFallsAndrew]

Phil, what do you think of those CFS maps? 

 

I think the GFS is a bit boring, but somewhat close to being decent. The cut off lows are messing with things though. 

[Front Ranger]

Definitely. Especially considering some experts said this would be our coldest month.

 

Don't count my chickens before they hatch and turn into frozen turkeys.

[SilverFallsAndrew]

There is a chance today ends up the warmest day of the month.

[Phil]

Phil, what do you think of those CFS maps?

 

I think the GFS is a bit boring, but somewhat close to being decent. The cut off lows are messing with things though.

That’s actually possible, though it’s tricky and dependent on the condition of the NAM/TPV too. I’m still seeing a very blocky, meridional pattern from late December through January, with significant cold air pouring into the US. But it might start in the central/eastern US then end up in the western US by late Jan/Feb under retrograding as wavestations retrograde. But again..it’s complicated, and the models are likely to continue flip flopping like crazy in the clown range.

[ShawniganLake]

Feels like December. Temp is down to

40F this afternoon with a storm total of 1.5” of rain. Even a dusting of snow on the higher hills west of Shawnigan this afternoon (2000-2500ft)

[Brian_in_Leavenworth]

A SSW helps in two ways.

 

1) Long story short, it weakens the high latitude zonal winds and promotes pressure rises over the polar domain, almost like an “unshackling” of the Arctic cold pool from the PV/TPV, allowing for easier Arctic air intrusions across the middle latitudes, including the PNW (see last winter).

 

2) For a number of reasons, a SSW also cools/raises the tropical tropopause. The reduction in static stability aids in MJO genesis and propagation, which could possibly overwhelm this year’s regime of subsidence over the Maritime Continent if a SSW were to occur. SSWings often “shake up” the background state of tropical forcing especially in weak ENSO years. Of course, this can be a bad thing if the tropics are already favorable (see Jan 2013) but if the tropics are hostile (like right now, and last winter) it can only help.

Thanks. Didnt catch that it is showing a SSW. Models had been showing a possible event last month but it looked like it was over Alaska/Siberia, and this map looked different then the ones then. At first glance I just saw high pressure over us and cold everywhere else.

[TacomaWaWx]

That’s actually possible, though it’s tricky and dependent on the condition of the NAM/TPV too. I’m still seeing a very blocky, meridional pattern from late December through January, with significant cold air pouring into the US. But it might start in the central/eastern US then end up in the western US by late Jan/Feb under retrograding as wavestations retrograde. But again..it’s complicated, and the models are likely to continue flip flopping like crazy in the clown range.

If it plays out like that, then it would be pretty similar to how 18-19 played out. Got cold in the East then it got cold here in early feb.

[Deweydog]

Don't count my chickens before they hatch and turn into frozen turkeys.

I do think the second half of the month will be kolder than the first...

 

(cool ups after warm downs)

[Omegaraptor]

Got up to 54. Balmy for December.

[Requiem]

I at least hope we'll get some good Gorge outflow going in the coming few weeks, especially as models are trending drier.

[Timmy Supercell]

Been having a decent amount of rainfall down here. Temps in the 40's and been soaking wet all today. Not a speck of snow left except for some of the grocery store piles in parking lots from the beginning of December.

[TacomaWaWx]

There’s been a couple heavy downpours today, but nothing too crazy. Up to 0.23” for today.

[Guest CulverJosh]

Fox12 has a pretty lame-azz 7 day.

[Deweydog]

Stairway to Heaven is on the radio right now. As I listen to the words I’m suddenly struck by the possibility it was written about the 1968 Sudden Stratospheric Warming...

[MossMan]

Stairway to Heaven is on the radio right now. As I listen to the words I’m suddenly struck by the possibility it was written about the 1968 Sudden Stratospheric Warming...

We are going to get hammered!!!

[ShawniganLake]

Fox12 has a pretty lame-azz 7 day.

I wonder why that is?

[Deweydog]

I wonder why that is?

Because women talk too f*cking much!

[Rubus Leucodermis]

That F420. Is that a new Ford Model?

 

Maybe the 420 part is a clue as to how grounded in reality it is?

[Guest CulverJosh]

Because women talk too f*cking much!

Get a grip man...really. So do soyboys.

[Guest CulverJosh]

Those that know, don’t talk much. I usually say very little at work.

[ShawniganLake]

Because women talk too f*cking much!

Interesting. I would have blamed the lame-azz weather.

[Dave]

I threw my thermometer into the freezer to simulate cold temps. It looks it's about 5 degrees at the moment. Definitely vodka cold.

[El_Nina]

Still at 0.99" for today. Was hoping to get an inch but it's just that kind of year.

[OysterPrintout]

I say very little at my job I have a quiet aura of an extremely wise man while I unclog those toilets just thought I should mention that to everyone here so they know.

[Dave]

Since the models are duds at the moment, I have a question for the Sounders up there.

 

Eugene experiences an ice storm about every 3 or 4 years and about once a decade we get a severe one with .75" or more thickness. Portland gets more than that thanks to the gorge.

 

I don't recall hearing about many severe ice storms up there.

 

Is freezing rain a rare event, or have I just missed hearing about them?

[SilverFallsAndrew]

Since the models are duds at the moment, I have a question for the Sounders up there.

 

Eugene experiences an ice storm about every 3 or 4 years and about once a decade we get a severe one with .75" or more thickness. Portland gets more than that thanks to the gorge.

 

I don't recall hearing about many severe ice storms up there.

 

Is freezing rain a rare event, or have I just missed hearing about them?

 

I think they had a pretty bad one in January 2012. 

[Rubus Leucodermis]

Since the models are duds at the moment, I have a question for the Sounders up there.

 

Eugene experiences an ice storm about every 3 or 4 years and about once a decade we get a severe one with .75" or more thickness. Portland gets more than that thanks to the gorge.

 

I don't recall hearing about many severe ice storms up there.

 

Is freezing rain a rare event, or have I just missed hearing about them?

 

It's a much rarer thing in Seattle than in the Willamette Valley, though it can happen (see Dec 1996 and Jan 2012).

[Omegaraptor]

+9 departure at PDX today. 54/45.

[MossMan]

Since the models are duds at the moment, I have a question for the Sounders up there.

 

Eugene experiences an ice storm about every 3 or 4 years and about once a decade we get a severe one with .75" or more thickness. Portland gets more than that thanks to the gorge.

 

I don't recall hearing about many severe ice storms up there.

 

Is freezing rain a rare event, or have I just missed hearing about them?

Dec. 1996 & Jan. 2012 come to mind. That was south of me though, both events stayed as snow up in my area. The area between North Bend and near the summit got nuked a few years ago, can’t remember exactly when though. Was in awe of how many downed trees there was when driving through there. Only freezing rain event that I remember up in my area was sometime in the early 2000’s. Wasn’t enough to cause damage though.

[SilverFallsAndrew]

 ZR events I can remember in the valley.

 

January 93 (localized to south valley)
December 95

February 96

December 96

January 98

January 04'

January 05'

December 08'

 

I've pretty much lived up here since I moved back to Oregon in 2010. We don't get a lot of ZR because we are usually in the warm layer. I know Eugene had a big ZR event in December 2016, that event was snow from about Albany-north. I know Salem had a decent ZR event in January 2017 with an overrunning event on the 7-8th, it fell on top of about 3-4" of snow. 

 

The two biggest ZR events I experienced in the valley were January 04' and December 2008. The December 08' one was from late in the day on the 20th through the 21st. What was unique about that one was it fell on top of about 4-5" of snow and then turned back to snow on the 22nd when we got another 6-7" of snow. The trees did not do well with that one. 

[Dave]

It's a much rarer thing in Seattle than in the Willamette Valley, though it can happen (see Dec 1996 and Jan 2012).

96 was ridiculously bad. I was living in Portland at the time. We had three trees in the backyard topple over. Someone rang our doorbell and they said "sorry to bother you, but are you aware that one of your trees is blocking the road?".