November 2018 Weather in the Pacific Northwest

[Jesse]

Intriguing. What do ensembles say?

So you’re a wind guy. That’s cool. We actually don’t have a lot of die hards here in that area. Rob, but he has been a no-show so far this year.

[ShawniganLake]

Intriguing. What do ensembles say?

The 0z ensembles don’t come out for another hour at least

[ShawniganLake]

FWIW. These speeds are knots as well

 

[Requiem]

FWIW. These speeds are knots as well

 

92321C19-2C2D-44B2-8C49-3EDB1F56280E.png4B88E412-1FE3-47B1-9405-EAED99A29AC6.png

 

Decently strong for PDX, very strong for the valley.

[Requiem]

So you’re a wind guy. That’s cool. We actually don’t have a lot of die hards here in that area. Rob, but he has been a no-show so far this year.

 

Oh, yes, I think this may be the same Rob I know a bit from the FOX12WeatherBlog. S.E Portland, loves those pressure gradients.

 

Anyways, I'm a die-hard wind and snow guy, and I love how dramatic our windstorms can be!

[SilverFallsAndrew]

FWIW. These speeds are knots as well

 

92321C19-2C2D-44B2-8C49-3EDB1F56280E.png4B88E412-1FE3-47B1-9405-EAED99A29AC6.png

 

No thank you.

[Requiem]

No thank you.

 

This concerns me, as it's not the first time EURO has shown a storm just like this one.

[SilverFallsAndrew]

Huge improvements on the ensembles. 

 

I've had my disputes over the years with Rob, but we're cool now. I actually hadn't seen him post anything for a few weeks back in October and was a bit worried, but I talked to him. He's doing okay, I think he'll be back on here when things get interesting. 

[Requiem]

Huge improvements on the ensembles. 

 

I've had my disputes over the years with Rob, but we're cool now. I actually hadn't seen him post anything for a few weeks back in October and was a bit worried, but I talked to him. He's doing okay, I think he'll be back on here when things get interesting. 

 

In what way are they improved?

[SilverFallsAndrew]

In what way are they improved?

 

Cooler, more cold members. Bookmark this link.

 

http://old.wetterzentrale.de/pics/MT8_Portland_Oregon_USA_ens.png

[Brennan]

January 2011 was the bust of all busts up here. We were dead set on the idea that we were going to relive December 1996 in Whatcom County. I just remember watching the snow fall during the overrunning event for several hours... knowing it was going to be gone by the next morning, but imagining it continuing for 3-4 days straight... Thanks for bringing up bad memories guys... The one thing that could squash all bad memories and busts around here for me would be a 18-24" snowstorm IN MY BACK YARD... Thanks. 

[Jbolin]

January 2011 was the bust of all busts up here. We were dead set on the idea that we were going to relive December 1996 in Whatcom County. I just remember watching the snow fall during the overrunning event for several hours... knowing it was going to be gone by the next morning, but imagining it continuing for 3-4 days straight... Thanks for bringing up bad memories guys... The one thing that could squash all bad memories and busts around here for me would be a 18-24" snowstorm IN MY BACK YARD... Thanks. 

Dec 1996 (after x-mas) 

[BLI snowman]

I think somebody posted some footage from the 1995 storm in Portland a while back and it looked REALLY bad to me. It was certainly overhyped up here though.

It was significant, probably a bit worse than 2000, 2006, and 2014 here. November 1981 and October 1967 were a bit stronger though.

[Perturbed Member]

NWS Portland has almost too many snowstorm busts to count.

 

PDX NWS bust in 2005 was one of the more memorable ones for me. I remember them going with that WSW even though all model support had been lost and NWS continued to stick to their guns. Embarrassing. Some schools I think considered closing just on the WSW alone. We got upper 30s and rain just as Mark Nelsen had forecasted.

[Perturbed Member]

Have there ever been any forecasts which overperformed completely? I can only think of a few: March 15th, 2015, December 11th, 2014, January 11th, 2017, December 14th, 2006 (in Seattle), January 1st-10th, 2004.

 

In PDX, Dec 2009 can be added to that list. There was also Nov 2003, that was a pretty interesting one. Read about it here:

https://www.weather.gov/media/wrh/online_publications/talite/talite0412.pdf

[Gradient Keeper]

GFS Super Ensemble and Canadian Ensemble 500mb Analog Composite

 

Day 6-10

Looking pretty good. A lot of cold/snow years showing up. Correlation scores need work, but there has been good run-to-run consistency suggesting we may see a cold pattern or at the least a backdoor cold shot. Colder runs ahead.

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_sup610.gif

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hght_comp_can610.gif

[SilverFallsAndrew]

GFS Super Ensemble and Canadian Ensemble 500mb Analog Composite

 

Day 6-10

Looking pretty good. A lot of cold/snow years showing up. Correlation scores need work, but there has been good run-to-run consistency suggesting we may see a cold pattern or at the least a backdoor cold shot. Colder runs ahead.

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_sup610.gif

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hght_comp_can610.gif

 

Droppin'! What interesting analogs you have there!

[Esquimalt]

Not liking the trends on either the 6Z or the FV3 06Z gfs. Good mountain snow pattern but nothing for us low level dwellers sadly

[MossMan]

Not liking the trends on either the 6Z or the FV3 06Z gfs. Good mountain snow pattern but nothing for us low level dwellers sadly

But Rob just came back! Hopefully the 12z’s will be improved.

[Esquimalt]

And good to have you back Rob. You were one of the reasons I got inspired to join this forum

[Phil]

Motherload of well-located Arctic air on the clown range 06z GFS...850mb temperatures drop to -44C over Northwest Canada.

 

Unfortunately, there’s nothing to dislodge it, since the same pattern that builds the cold (Aleutian ridge) also flattens waves/dampens fluxes. We’ll need an external forcing of some kind to drive it south.

 

[MossMan]

Motherload of well-located Arctic air on the clown range 06z GFS...850mb temperatures drop to -44C over Northwest Canada.

 

Unfortunately, there’s nothing to dislodge it, since the same pattern that builds the cold (Aleutian ridge) also flattens waves/dampens fluxes. We’ll need an external forcing of some kind to drive it south.

 

Hopefully that external forcing will show up in future model runs! Bring it!

47, mostly cloudy, and breezy at the moment.

[Phil]

Omg, I want some of this.

 

https://twitter.com/nwschicago/status/1066853234562740224?s=21

[Phil]

Hopefully that external forcing will show up in future model runs! Bring it!

47, mostly cloudy, and breezy at the moment.

I’m trying to think of what could do the trick, lol. Another Scandinavian ridge/Siberian High descent would be nice.

 

The MJO returning to the EHEM helps prime the wavetrain out of Eurasia, but if the Alaskan block retrogrades to the Aleutians too quickly, you’re left with a +EPO slowly rotting away while convection marches back to the warm pool.

 

It’s a tightrope walk. All about timing.

[Tyler Mode]

Have there ever been any forecasts which overperformed completely? I can only think of a few: March 15th, 2015, December 11th, 2014, January 11th, 2017, December 14th, 2006 (in Seattle), January 1st-10th, 2004.

January 10th, 2017.  Suppose to be a few inches of snow.  I measured about 6" at my house, my parents got close to a foot!

[Esquimalt]

I’m trying to think of what could do the trick, lol. Another Scandinavian ridge/Siberian High descent would be nice.

 

The MJO returning to the EHEM helps prime the wavetrain out of Eurasia, but if the Alaskan block retrogrades to the Aleutians too quickly, you’re left with a +EPO slowly rotting away while convection marches back to the warm pool.

 

Walking the tightrope..

What are your thoughts on the overall pattern for December out here?

[Tyler Mode]

I think somebody posted some footage from the 1995 storm in Portland a while back and it looked REALLY bad to me.  It was certainly overhyped up here though.

That's because the storm moved south of you guys up there.  About a mile away a whole apartment complex lost it's roof and some people were without power for 2 weeks.  I remember getting out of school early as the sun was shining and it was very warm...by the time we got to my house, the wind had really picked up and limbs were already coming down. 

[Jbolin]

Hey Tim, it's raining again

[Phil]

What are your thoughts on the overall pattern for December out here?

If we’re playing it on the conservative side, then a slightly cooler than average month with plenty of storminess and precipitation seems likely, trending warm after the solstice. In this case, lowland snowfall is most likely between 12/10 - 12/20.

 

If we maximize potential and time the wave-1/wave-2 transition perfectly, then we get a weakened PV or SSW during mid/late December and a two-phased cycle of retrograding waves, culminating in an Arctic blast towards Christmas with cold hanging around longer (into early January).

 

The latter is less likely, but possible. If a giant Scandinavian Ridge & descending Siberian High/Asian Arctic dump starts showing up on the models after the first week of December, *before* any move to Aleutian Ridge/+EPO, that would be a good sign.

 

If models trend faster with the evolution to Aleutian Ridge/+EPO, that would actually be a bad sign. I know it’s counterintuitive, but you don’t want the Aleutian Ridge *until* the wavetrain is primed and ready. Once it is ready and the cycle of slowing phase speeds is established, *then* you want the Aleutian Ridge to establish and go bonkers. Otherwise all it does is kill the potential since it dampens fluxes for the wave-1 (which is a prerequisite to unravel the vortex via the wave-2 follow-up).

[Phil]

So, long story short, timing is everything here.

 

If the NPAC transitions too fast, your result is a few weeks of coolish stormy weather with a vortex in Alaska. If it transitions too slowly, you risk a glancing blow with the majority of the cold sliding east.

 

We need the Goldilocks solution. Timed just right.

[MossMan]

Currently in the rain shadow...and I’m good with that! Current view from my office window overlooking I-5 and to the west.

[Phil]

Through 96hrs on the 12z GFS, the shift from 06z reflects what I was saying above. The NPAC transition is improved (slower/deeper with the NW-Pacific waves holding a better position, and for longer). Could be a very different run this go around.

 

Every little bit matters...timing differences of 24hrs upstream can make the whole difference.

[ShawniganLake]

Currently in the rain shadow...and I’m good with that! Current view from my office window overlooking I-5 and to the west.

I was just going to say the rain shadow looks strong today. Pouring rain here, but barely anything down in Victoria

[Jesse]

So, long story short, timing is everything here.

 

If the NPAC transitions too fast, your result is a few weeks of coolish stormy weather with a vortex in Alaska. If it transitions too slowly, you risk a glancing blow with the majority of the cold sliding east.

 

We need the Goldilocks solution. Timed just right.

Sounds like the story for every cold episode in history around here.

[Farmboy]

Motherload of well-located Arctic air on the clown range 06z GFS...850mb temperatures drop to -44C over Northwest Canada.

 

Unfortunately, there’s nothing to dislodge it, since the same pattern that builds the cold (Aleutian ridge) also flattens waves/dampens fluxes. We’ll need an external forcing of some kind to drive it south.

 

. I think the key word of this post is 'unfortunately'. Unfortunately, this is how most PNW winters roll these days. Lol...

[Jesse]

Rain has made it further inland than I was anticipating for today. Have already had sprinkles and light rain here this morning. Hopefully bodes well for some higher totals later.

[Phil]

[Phil]

Now that I’m back home, you guys are gonna get tired of me very quickly.

[Kayla]

GEM is quite chilly.

[Phil]