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November 2017 PNW Discussion Thread


stuffradio

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I think we'll truthfully be lucky to see half of what we saw last winter. But it's just the nature of how things work on here,  stupidly high expectations early give way to unyielding pessimism by the time January comes around and someone has gotten "screwed". Very little even-handedness when it comes to weenie winterdom. 

 

Depends on where you're talking about and what exactly people "see". For the region overall, I'll be surprised if you don't see a colder upper level Arctic air mass this winter.

 

For the Puget Sound, it wouldn't surprise me at all for them to top last year's snow totals. For the Willamette Valley, that will be a more difficult task.

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I feel like a lot of people have written December completely off the board but I think the second half of the month is still in the cards for some western cold. There have been some hints in the long range models that the ridge will retrograde around that timeframe over the last couple of days so any and everything is still on the table IMO.

 

It wouldn't be the first time Phil was 2 weeks late (no offense Phil!) with a pattern change  B)

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Cold Season 2023/24:

Total snowfall: 26"

Highest daily snowfall: 5"

Deepest snow depth: 12"

Coldest daily high: -20ºF

Coldest daily low: -42ºF

Number of subzero days: 5

Personal Weather Station on Wunderground: 

https://www.wunderground.com/personal-weather-station/dashboard?ID=KMTBOZEM152#history

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Depends on where you're talking about and what exactly people "see". For the region overall, I'll be surprised if you don't see a colder upper level Arctic air mass this winter.

 

For the Puget Sound, it wouldn't surprise me at all for them to top last year's snow totals. For the Willamette Valley, that will be a more difficult task.

I agree with this.

I think northern areas/ SW BC end up snowier than normal but not as snowy as last year.

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I feel like a lot of people have written December completely off the board but I think the second half of the month is still in the cards for some western cold. There have been some hints in the long range models that the ridge will retrograde around that timeframe over the last couple of days so any and everything is still on the table IMO.

 

It wouldn't be the first time Phil was 2 weeks late (no offense Phil!) with a pattern change B)

Considering it’s still November. Writting off the whole of December seems silly
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In a big way.

 

I just think people have their expectations set way to high this year.

Depends what the expectations are. If you're expecting cold/snowy weather *every single month* from November through March, yeah, that's not going to happen.

 

However, a midwinter Arctic blast, and a prolonged period of lowland snowfall lasting ~ 3 weeks, looks like a fairly reasonable expectation given the climatology of the current boundary conditions. We have enough +QBO left @50mb to prolong the favorable shear stresses into January, when seasonal wavetrain climatology becomes more favorable under said conditions.

 

After the Arctic blast in January, I think February/March will transition into the more classic -PNA/+EPO circulation, typical of modern day -QBO/Niña systems. So, a more 2007/08-ish pattern with cool/onshore flow, mountain snows, and lots of warmth east of the Rockies.

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Depends on where you're talking about and what exactly people "see". For the region overall, I'll be surprised if you don't see a colder upper level Arctic air mass this winter.

 

For the Puget Sound, it wouldn't surprise me at all for them to top last year's snow totals. For the Willamette Valley, that will be a more difficult task.

 

Basically what I called for in my winter forecast. I think we will see a colder upper level airmass than last winter. In fact I think there is a good chance we see a regional arctic outbreak. We have not seen one in about 4 years now. 

 

Most of the Willamette Valley SLE-PDX saw about 10-15" of snow last winter, Eugene to Albany had less, maybe 4-8". So the south valley could definitely top last winter with one good storm. 

Snowfall                                  Precip

2022-23: 95.0"                      2022-23: 17.39"

2021-22: 52.6"                    2021-22: 91.46" 

2020-21: 12.0"                    2020-21: 71.59"

2019-20: 23.5"                   2019-20: 58.54"

2018-19: 63.5"                   2018-19: 66.33"

2017-18: 30.3"                   2017-18: 59.83"

2016-17: 49.2"                   2016-17: 97.58"

2015-16: 11.75"                 2015-16: 68.67"

2014-15: 3.5"
2013-14: 11.75"                  2013-14: 62.30
2012-13: 16.75"                 2012-13: 78.45  

2011-12: 98.5"                   2011-12: 92.67"

It's always sunny at Winters Hill! 
Fighting the good fight against weather evil.

 

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I feel like a lot of people have written December completely off the board but I think the second half of the month is still in the cards for some western cold. There have been some hints in the long range models that the ridge will retrograde around that timeframe over the last couple of days so any and everything is still on the table IMO.

 

It wouldn't be the first time Phil was 2 weeks late (no offense Phil!) with a pattern change B)

It's usually one week. ;)

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Thanks Brett! This really Made Christmas cheery  :angry: https://twitter.com/BrettAWX/status/935176886367522817

 

Sets things up nicely for retrogression around December 15th-20th period...

Cold Season 2023/24:

Total snowfall: 26"

Highest daily snowfall: 5"

Deepest snow depth: 12"

Coldest daily high: -20ºF

Coldest daily low: -42ºF

Number of subzero days: 5

Personal Weather Station on Wunderground: 

https://www.wunderground.com/personal-weather-station/dashboard?ID=KMTBOZEM152#history

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I feel like a lot of people have written December completely off the board but I think the second half of the month is still in the cards for some western cold. There have been some hints in the long range models that the ridge will retrograde around that timeframe over the last couple of days so any and everything is still on the table IMO.

 

It wouldn't be the first time Phil was 2 weeks late (no offense Phil!) with a pattern change  B)

 

I think both Phil and I have been consistent in leaving the second half of December, especially later in the month, on the table. But the strongest signal for awhile has been for cold in January.

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Sets things up nicely for retrogression around December 15th-20th period...

Almost no way it happens before Christmas, IMO. The initial trigger for the retrogression (EAMT --> mass flux) doesn't become favorable until sometime around the winter solstice.

 

The retrogression won't be easy for the modeling to handle, so it will probably start showing up in the clown range sometime around Christmas, or it might not get recognized until it's something like 8-9 days out (if the progression is complicated enough).

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Depends what the expectations are. If you're expecting cold/snowy weather *every single month* from November through March, yeah, that's not going to happen.

 

However, a midwinter Arctic blast, and a prolonged period of lowland snowfall lasting ~ 3 weeks, looks like a fairly reasonable expectation given the climatology of the current boundary conditions. We have enough +QBO left @50mb to prolong the favorable shear stresses into January, when seasonal wavetrain climatology becomes more favorable under said conditions.

 

After the Arctic blast in January, I think February/March will transition into the more classic -PNA/+EPO circulation, typical of modern day -QBO/Niña systems. So, a more 2007/08-ish pattern with cool/onshore flow, mountain snows, and lots of warmth east of the Rockies.

 

That's a very unusual scenario, FWIW. Considering Dec 2008 lasted about two weeks and that was exceptionally long.

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Almost no way it happens before Christmas, IMO. The initial trigger for the retrogression (EAMT --> mass flux) doesn't become favorable until sometime around the winter solstice.

 

The retrogression won't be easy for the modeling to handle, so it will probably start showing up in the clown range sometime around Christmas, or it might not get recognized until it's something like 8-9 days out (if the progression is complicated enough).

Well that really really sucks!!!!!  :angry:

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Almost no way it happens before Christmas, IMO. The initial trigger for the retrogression (EAMT --> mass flux) doesn't become favorable until sometime around the winter solstice.

 

The retrogression won't be easy for the modeling to handle, so it will probably start showing up in the clown range sometime around Christmas.

 

What's to say the trigger doesn't occur earlier though? I'm still not convinced that we'll be waiting that long to see a solid retrogression signal.

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Cold Season 2023/24:

Total snowfall: 26"

Highest daily snowfall: 5"

Deepest snow depth: 12"

Coldest daily high: -20ºF

Coldest daily low: -42ºF

Number of subzero days: 5

Personal Weather Station on Wunderground: 

https://www.wunderground.com/personal-weather-station/dashboard?ID=KMTBOZEM152#history

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That's a very unusual scenario, FWIW. Considering Dec 2008 lasted about two weeks and that was exceptionally long.

Yeah, with the PV breaking down around New Years, I don't see anything interrupting the Arctic express until the MJO propagates west of the dateline in late January.

 

Kind of a weird setup.

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What's to say the trigger doesn't occur earlier though? I'm still not convinced that we'll be waiting that long to see a solid retrogression signal.

Because the slow propagating tropical forcings won't produce a favorable circulation to tap that East-Asian terrain and displace mass downstream until it propagates to ~ 160E.

 

Until then, boundary conditions favor +WPO/+PNA, which will actually increase WAFz into the NAM/PV domain, producing the wave-1 response/weakening the vortex aloft, which is a good thing since this will cool the equatorial Pacific tropopause and open the conduit for the progression of the MJO into a more favorable domain for the EAMT forcing and subsequent retrogression of the NPAC circulation.

 

So IMO the dominoes have already been placed, but they can't topple faster than the laws of physics allows, if you know what I mean? It takes some time for the entire process to play out.

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Does anyone ever remember a huge ridge of high pressure sitting over us for 4-5 weeks during winter? 2 weeks, sure, pretty common. I just don't remember one ever lasting an entire month. I could be wrong of course.

Oh, I'm not saying the entire period will be ridgy. There should be periods of SW flow/GOA trough in there as well.

 

I just don't see the GOA ridge/western trough/SE-ridge pattern returning for another month. But when it does, I think it could really amplify/establish for awhile.

 

The SE-ridge in particular could be a strong/semipermanent feature through the entire J/F/M period.

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Oh, I'm not saying the entire period will be ridgy. There should be periods of SW flow/GOA trough in there as well.

 

I just don't see the GOA ridge/western trough/SE-ridge pattern returning for another month. But when it does, I think it could really amplify/establish for awhile.

 

The SE-ridge in particular could be a strong/semipermanent feature through the entire J/F/M period.

That makes sense.

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Because the slow propagating tropical forcings won't produce a favorable circulation to tap that East-Asian terrain and displace mass downstream until it propagates to ~ 160E.

 

Until then, boundary conditions favor +WPO/+PNA, which will actually increase WAFz into the NAM/PV domain, producing the wave-1 response/weakening the vortex aloft, which is a good thing since this will cool the equatorial Pacific tropopause and open the conduit for the progression of the MJO into a more favorable domain for the EAMT forcing and subsequent retrogression of the NPAC circulation.

 

Hmmm, interesting. I still feel like you might be betting too much on a molasses heavy mass flux but stranger things have happened! 

Cold Season 2023/24:

Total snowfall: 26"

Highest daily snowfall: 5"

Deepest snow depth: 12"

Coldest daily high: -20ºF

Coldest daily low: -42ºF

Number of subzero days: 5

Personal Weather Station on Wunderground: 

https://www.wunderground.com/personal-weather-station/dashboard?ID=KMTBOZEM152#history

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Hmmm, interesting. I still feel like you might be betting too much on a molasses heavy mass flux but stranger things have happened!

Haha. In that case, what are you betting on?

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Depends on where you're talking about and what exactly people "see". For the region overall, I'll be surprised if you don't see a colder upper level Arctic air mass this winter.

 

For the Puget Sound, it wouldn't surprise me at all for them to top last year's snow totals. For the Willamette Valley, that will be a more difficult task.

 

I think a more condensed winter is an easy call. Probably means a better shot at a farther reaching, maybe more regionally hard-hitting event, but quicker, and with a lot more unfavorable patterns.

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Haha. In that case, what are you betting on?

 

Blind luck! Mainly past history, my leading analogs and some of the long range ensemble models.

 

Have you seen the ECMWF weeklies for today yet?

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Cold Season 2023/24:

Total snowfall: 26"

Highest daily snowfall: 5"

Deepest snow depth: 12"

Coldest daily high: -20ºF

Coldest daily low: -42ºF

Number of subzero days: 5

Personal Weather Station on Wunderground: 

https://www.wunderground.com/personal-weather-station/dashboard?ID=KMTBOZEM152#history

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Or a Pac Jet extension....

 

Or that.

Cold Season 2023/24:

Total snowfall: 26"

Highest daily snowfall: 5"

Deepest snow depth: 12"

Coldest daily high: -20ºF

Coldest daily low: -42ºF

Number of subzero days: 5

Personal Weather Station on Wunderground: 

https://www.wunderground.com/personal-weather-station/dashboard?ID=KMTBOZEM152#history

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Man, look at the glow on the Agung webcam right now. Light from the rising magma reflecting off the ash cloud.

 

Similar to how the 1963 and 1843 eruptions began, with lava flows and moderately sized ash plumes preceding a series of explosive eruptions ~ one month later.

 

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Hmmm..new inflation being noted on Agung's S/SW flanks. Even with the eruption ongoing, magma pressure is increasing under the mountain/in the lower magma chamber.

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Volcanic lightning also evident on the webcam.

 

Edit: There's also some healthy convection nearby, so it might also be that. After all, this is the Indo-Pacific region (aka: the global champion of deep convection).

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Polar vortex weakening over the next two weeks, according to the GEFS, as viewed through U-wind anomalies @ 10mb/60N.

 

Image from Dr. Hannah Attard's website.

 

http://www.atmos.albany.edu/student/hattard/realtime/u_65N_10hpa_gefs.png

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Flashback to Nov 2006 when that actually did happen on the 26th. Around here it went from 42F with rain showers at 4am to 29F with heavy snow by the evening. Probably was pretty similar over there.

One of the most amazing events in my lifetime, here is what I wrote in the "This day in history" thread yesterday...

 

On this day...11/26/06 in the morning the snow started to stick, by 1pm the power was off as the heavy wet snow started taking down trees and limbs. By that night it was still snowing with a foot on the ground...it continued until the evening of the 27th when the arctic front pushed through and temps plummeted to the upper teens. 18” of snow, tree destruction like I have never seen, and no power for nearly a week since the damage was so extensive. That was one hell of an event especially since the forecast called for a sloppy inch with possibly another inch with arctic passage... 

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Elevation 580’ Location a few miles east of I-5 on the Snohomish Co side of the Snohomish/Skagit border. I love snow/cold AND sun/warmth! 

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Blind luck! Mainly past history, my leading analogs and some of the long range ensemble models.

 

Have you seen the ECMWF weeklies for today yet?

The weeklies haven't come out yet. Will post them when they're available.

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I was going to mention January 1985. December 85' had a lot of ridging too I think, especially the latter half of the month. 

Snowfall                                  Precip

2022-23: 95.0"                      2022-23: 17.39"

2021-22: 52.6"                    2021-22: 91.46" 

2020-21: 12.0"                    2020-21: 71.59"

2019-20: 23.5"                   2019-20: 58.54"

2018-19: 63.5"                   2018-19: 66.33"

2017-18: 30.3"                   2017-18: 59.83"

2016-17: 49.2"                   2016-17: 97.58"

2015-16: 11.75"                 2015-16: 68.67"

2014-15: 3.5"
2013-14: 11.75"                  2013-14: 62.30
2012-13: 16.75"                 2012-13: 78.45  

2011-12: 98.5"                   2011-12: 92.67"

It's always sunny at Winters Hill! 
Fighting the good fight against weather evil.

 

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Last winter was pretty spectacular in that there was essentially no torching in December and January. That is pretty rare. 

Snowfall                                  Precip

2022-23: 95.0"                      2022-23: 17.39"

2021-22: 52.6"                    2021-22: 91.46" 

2020-21: 12.0"                    2020-21: 71.59"

2019-20: 23.5"                   2019-20: 58.54"

2018-19: 63.5"                   2018-19: 66.33"

2017-18: 30.3"                   2017-18: 59.83"

2016-17: 49.2"                   2016-17: 97.58"

2015-16: 11.75"                 2015-16: 68.67"

2014-15: 3.5"
2013-14: 11.75"                  2013-14: 62.30
2012-13: 16.75"                 2012-13: 78.45  

2011-12: 98.5"                   2011-12: 92.67"

It's always sunny at Winters Hill! 
Fighting the good fight against weather evil.

 

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There are several other -ENSO years that had something similar around this time period, too. Including some of the main analogs I've talked about.

 

1995: Dry/chilly from 12/4 to 12/8.

1989: Dry/chilly from 12/9 to 12/18

1984: First week of the month.

1954: 11/28 to 12/3

 

1962 also had something similar a little later in the month.

 

2005 and 2011 really stick out for me, just based on how long the dry weather lasted and how recent they were. 

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