November 2017 PNW Discussion Thread

[stuffradio]

I don't take much stock in really long range models, and this is ridiculously extreme, but just for fun, here is last nights 18Z CFS run for December.

 

DOXOWfJXkAAnzei.jpg

I have un-canceled winter now! I'm putting my snow tires back on, and the plow blade on my Toyota Corolla!

[TigerWoodsLibido]

If the Arctic air is deep enough I find it hard to believe it won't come this far south. We will get at least one blast to come all the way down here.

[TT-SEA]

12Z ECMWF reduces the wind strength on Monday afternoon compared to the 00Z run.

 

[HighlandExperience]

If the Arctic air is deep enough I find it hard to believe it won't come this far south. We will get at least one blast to come all the way down here.

It will stop right at the Columbia

[MossMan]

[MossMan]

I have un-canceled winter now! I'm putting my snow tires back on, and the plow blade on my Toyota Corolla!

Pictures or it didn’t happen!

[snow_wizard]

I don't take much stock in really long range models, and this is ridiculously extreme, but just for fun, here is last nights 18Z CFS run for December.

 

DOXOWfJXkAAnzei.jpg

 

Holy crap!  That would be 1884 territory.

[snow_wizard]

The ECMWF is very interesting at day 10.  It cuts off a low and shoves it under an anomalous Western GOA ridge.  Dangerously close to becoming a Kona low and the northern branch threatens to take over the show for the NW.  The Pacific is still shut down at day 10.

[TT-SEA]

12Z ECMWF did away with any kind of ridging or inversion-type pattern in the long range... just keeps the current pattern of daily storms going in true November fashion.   Surface maps shows at least some rain in almost every 6-hour period for the next 10 days.

[snow_wizard]

If the Arctic air is deep enough I find it hard to believe it won't come this far south. We will get at least one blast to come all the way down here.

 

You will.

[snow_wizard]

If nothing else this is fun to look at.  The ECMWF ensemble control model shows an epic cold wave later in the month.

[snow_wizard]

12Z ECMWF did away with any kind of ridging or inversion-type pattern in the long range... just keeps the current pattern of daily storms going in true November fashion.   Surface maps shows at least some rain in almost every 6-hour period for the next 10 days.

 

It gives us fairly normal observed weather, but with the NE Pacific in anything but a normal configuration.  Big changes on very short notice are pretty likely.

[MossMan]

If nothing else this is fun to look at. The ECMWF ensemble control model shows an epic cold wave later in the month.

That map is on my birthday...That would be the perfect gift!

[Phil]

Huge difference in the IO convection this year compared to last year at this time, despite the eastern periphery of the Niña cell/135E exhaust pipe remaining largely unchanged in its longitude.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/F6D3D3C5-8339-4594-ABA9-3E26087996A4_zps1borypt0.jpg

 

Wavenumber one regime dominating this year, wavenumber two regime dominated last year. This is a big deal as it relates to cyclonic wavebreaking over Eurasia, which is responsible for the weakened NPAC jet/-PNA circulation right now.

[Geos]

What a flip from last November, so far.

 

 

 

That is an impressive turnaround. 

[snow_wizard]

That map is on my birthday...That would be the perfect gift!

 

The 850mb temp anomalies it shows are around 14C below normal.

[Phil]

So, when you get down to it, the explanation for the ongoing pattern of enhanced NPAC ridging is an enhanced cyclonic wavetrain over the Eurasia, arising from/through different behaviors in the EHEM tropical forcings this year.

 

The downwelling -QBO is likely to blame for the difference in the tropical circulations, since its influence on the thermal winds/tropopause height/tropopause temperature significantly changes the low frequency static stability integral in the crucial domains of bihemispheric thermodynamic communication, as it relates to ENSO/annular modes.

[snow_wizard]

Huge difference in the IO convection this year compared to last year at this time, despite the eastern periphery of the Niña cell/135E exhaust pipe remaining largely unchanged in its longitude.

 

 

Wavenumber one regime dominating this year, wavenumber two regime dominated last year. This is a big deal as it relates to cyclonic wavebreaking over Eurasia, which is responsible for the weakened NPAC jet/-PNA circulation right now.

 

Could this offset the possible effects of a developing -QBO?  It kind of seems like it could.

[TT-SEA]

It gives us fairly normal observed weather, but with the NE Pacific in anything but a normal configuration. Big changes on very short notice are pretty likely.

True.

 

And normal is good right now as well.

[Phil]

So, the question is, what happens when the shear-stress cycle completes its run (as the downwelling QBO easterlies reach the crucial 50mb domain) and we lose the harmonious thermomechanical network that's assisted in maintaining these poleward NPAC anticyclones?

 

As of now, it's anyone's guess, but at the very least, something in the pattern is likely to change in a big way towards the holidays/new year.

[Geos]

Low of 39 last night... up to 48 already.    Still waiting!   

 

Zero chance over the next 10 days it appears.

 

Crazy you haven't seen upper 20s at least by now. 36 here very early this morning. 

[Geos]

If nothing else this is fun to look at.  The ECMWF ensemble control model shows an epic cold wave later in the month.

 

#WhiteThanksgiving.

[Deweydog]

Very 1950-esque drizzle out there.

[Phil]

So, the question is, what happens when the shear-stress cycle completes its run (as the downwelling QBO easterlies reach the crucial 50mb domain) and we lose the harmonious thermomechanical network that's assisted in maintaining these poleward NPAC anticyclones?

 

As of now, it's anyone's guess, but at the very least, something in the pattern is likely to change in a big way towards the holidays/new year.

I could see the system state transitioning in three different ways.

 

1) Into the classic Niña/-QBO cell state, like 2007/08, which was steady -PNA/+EPO with the PV/NAM recoiling before dumping into Eurasia. Strong pump from the WPAC/IPWP into the NPAC/NAM domain.

 

2) A more chaotic cell state, like the 1980s, with limited phase locking allowing for episodic-yet-prolific amplifications of the upstream surf zone producing large-scale Arctic outbreaks. Some modest forcing relocation away from the off-equator WPAC/IPWP.

 

3) A 1960s type cell network, which was very -PNA in the equatorward manner (like 2007/08) but featured convection that was centered away from the off-equator WPAC/IPWP exhaust pipe, relatively speaking, allowing for that big wavenumber one, cyclonic breaker train in the NW NATL (-NAO), which overcame the +EPO tendency and kept Arctic air in the vicinity of the western US.

 

The problem with #3 as an analog is we're still relatively "beefy" with the IPWP/WPAC warm pool, which is to be expected following a multi-decadal regime of z-cell expansion/global warming, not to mention solar maximum hangover. Lots of thermal inertia involved when it comes to the warm pool, so while I'm not ruling out a 1960s cell state, I'm not expecting to see it this early in the game (eventually it will happen, but retracting the warm pool is a multi-decadal process).

 

If it does somehow happen this winter, though, then we might be in some trouble going forward, in regards to climate, given how much thermodynamic forcing/inertia would be required to reverse 35 years of poleward warm pool charging within a single year (hence the aforementioned unlikelihood). That would not be just a one-and-done deal without some bizarre external forcing to save the day.

[TT-SEA]

Nice day now... a few sprinkles this morning but now filtered sun and a little east breeze.

 

[MossMan]

Nice day now... a few sprinkles this morning but now filtered sun and a little east breeze.

 

Raining, dark, and 44 degrees here.

[TT-SEA]

Raining, dark, and 44 degrees here.

 

East wind is my friend here. 

[Phil]

Could this offset the possible effects of a developing -QBO? It kind of seems like it could.

I'd argue it's partially a result of the transitioning QBO, and will change further over the next several months.

[snow_wizard]

I'd argue it's partially a result of the transitioning QBO, and will change further over the next several months.

 

Past history is a big fan of locking in these blocked GOA patterns if they sustain in both October and November.  We'll have to see if that gets over-ridden or not.

[seattleweatherguy]

If nothing else this is fun to look at. The ECMWF ensemble control model shows an epic cold wave later in the month.

Something like this or better every month would make this a good winter. Can't wait.

[Geos]

East wind is my friend here. 

 

Gloomy here as well.

 

At least you're seeing some better weather.

 

[Geos]

Is that the Kona low north of Hawaii some of you speak of?

 

[TT-SEA]

Gloomy here as well.

 

At least you're seeing some better weather.

 

http://www.ssd.noaa.gov/goes/west/wfo/sew/vis.jpg

 

 

Filtered sun and no low clouds... and a drying east breeze.   I will take it.  

[TT-SEA]

Crazy you haven't seen upper 20s at least by now. 36 here very early this morning. 

 

33 is the lowest temp here so far... and that was while it was dumping snow last Sunday.   Then it went up to 34 when the snow ended and stayed there all night in the fog and low clouds.   It only got down to 39 here last night as the clouds formed as it got dark yesterday evening.

 

Also had 34 on Halloween morning... while it was 31 down in the valley.   We had better mixing up here.

 

SEA has also not seen a freeze... and they usually have a freeze before me.

[MossMan]

Moderate rain and even darker now!

[snow_wizard]

Is that the Kona low north of Hawaii some of you speak of?

 

 

Yup.  That is a very critical juncture right there.  Something like that could evolve into an excellent pattern very easily.

[snow_wizard]

Gloomy here as well.

 

At least you're seeing some better weather.

 

 

It just got pretty gross here as well.

[TigerWoodsLibido]

Yup. That is a very critical juncture right there. Something like that could evolve into an excellent pattern very easily.

So any chance any of that polar air can get displaced over us in time for the arrival of it? Seems there isn't a major pool of arctic air to draw from.

[TT-SEA]

It just got pretty gross here as well.

 

Here too now... glad we got a couple hours of nice weather.

[crf450ish]

I don't take much stock in really long range models, and this is ridiculously extreme, but just for fun, here is last nights 18Z CFS run for December.

 

DOXOWfJXkAAnzei.jpg

The Missouri River in Great Falls would freeze hard enough to drive on. The confluence of the Columbia & Spokane river would also freeze hard enough to walk on...maybe ride snowmobile on.