December 2014 Observations for the Pacific Northwest

[SilverFallsAndrew]

In the words of "Snow" "score!"

[Jesse]

12z is way better.

Tsk tsk tsk... no arctic blast before New Years though.

[Jesse]

That Kona low seems a bit weaker so far on the 12z.

 

The Parallel GFS has the low way west of what the normal GFS shows.. What is the deal with that model? It is supposed to be better?

I believe the parallel is the upgrade if I'm not mistaken.

[FroYoBro]

Tsk tsk tsk... no arctic blast before New Years though.

The 12z doesn't show one. 

[SilverFallsAndrew]

Tsk tsk tsk... no arctic blast before New Years though.

 

No, but its a step in the right direction...

[SilverFallsAndrew]

I've noticed the colder solutions are the ones that are wetter for NW Oregon this weekend and early next week. Just something I've noticed.

[ShawniganLake]

The Canadian this morning is a big improvement over the 0z for the 8-10 day period. Pumps the ridge up into Alaska.

[Bryant]

Amazing write up from Mike Ventrice....

 

"My 6-10 and 11-15 day period discussions from this morning:

 

Models have rounded into better agreement this morning, all of which may be contributed to a local cyclonic wave breaking event setting up over the eastern U.S. during the latter half of the 6-10 day period forecast. Models often struggle with these wave breaking events and they have been clearly struggling over the past week as the forecast continues to trend warmer over the East. The latest models are moving away from the idea of a strong coastal "Nor'easter" to impact the coastal east and towards the idea of a major winter storm to impact the Midwest as a highly-anomalous upper-level cold trough digs across the central U.S. The change of pattern is clearly being driven by upstream processes over the Pacific Ocean. We have been locked into an El Nino driven pattern for the good portion of this month. That pattern will be ending during the 6-10 day period forecast, in response to a very deep upper-level cold trough sliding off the coast of Asia, forcing a high-latitude wave anticyclonic breaking event over the North Pacific. This event will result in warm upper-level ridge development over Alaska mid-to-late period, tanking the East Pacific Oscillation (EPO) into negative territory. A direct downstream response will be felt over the U.S., in which some colder air from the north will be able to freely flow down the Rockies and fuel the explosive deepening of a mid-latitude cyclone aiming to take shape over the Midwest and Ohio Valley. The details remain to be panned out, but the synoptic set up is favoring for strong dynamical forcing that results in a winter storm across the major markets in PJM mid-to-late period. A flux of moist tropical air from the east will fuel the system. This plume of mild, moist Atlantic air will result in unseasonably mild temperatures across the Northeastern U.S. around Christmas, setting up a possible heavy rain event for DCA, PHL, NYC in through BOS.

 

Now while the 6-10 day period forecast has trended warmer in response to this upcoming cyclonic wave breaking event, this particular event (in addition to the upstream forcing) is setting the stage for a major pattern change during the 11-15 day period forecast. With the massive cyclone to spin across the Great Lakes and up through eastern Canada late in the period, it will aid in advecting a highly anomalous cold air mass down the western two thirds of the nation, resulting in well below average temperatures to flood the western two thirds of the nation. We typically see major pattern transitions across the lower 48 following the development a significant mid-latitude cyclone, and this is the anticipated pattern evolution heading into the final week of the month.

 

11-15 day:

 

A period of cold weather and high heating demand is anticipated during the 11-15 day period forecast. High latitude blocking will be the theme during late December in through January, with a prominent upper-level warm ridge forecast to spin up over Alaska and build northward in through the North Pole and eastern Siberia. This pattern sets will generate cross polar flow from Siberia in through the U.S. during the time frame, sponsoring a period of well below average temperatures from the Pacific Northwest Basin in through the eastern two thirds of the nation. We have seen a significant shift in the ECMWF EPS towards the GFS model package solution, in which the model is now more aggressive with building a western U.S. ridge and deepening and eastern U.S. trough as heights build across the North Pole. A split of the tropospheric "Polar Vortex" looks prominent, which a lobe will likely spin down across the Hudson Bay and facilitate cold northwesterly flow on its western flank. Coast to coast cold weather will be the rule during the 11-15 day period forecast, impacting all major markets in the U.S. with exception of those in the Southwest.

 

Now while the state of convection in the tropics, specifically the Madden Julian Oscillation (MJO) is headed for the "Warm USA" phases, it will have no impact on the U.S. pattern as high-latitude blocking will set up over the North-Northeast Pacific, driving a series of arctic air masses down across the U.S. The pattern looks extremely similar to what was observed last winter or back in November, and we should expect a similar outcome... Cold temperatures and increased heating demand. Now while there will likely be some details that remain to be panned out in response to synoptic waves (winter storms) spinning around the U.S., we hold higher than average confidence in the upcoming pattern change that will end in winter-type conditions across the lower 48."

[SilverFallsAndrew]

A pretty decent gfs run and no one is talking about it.

[Gradient Keeper]

Amazing write up from Mike Ventrice....

 

"My 6-10 and 11-15 day period discussions from this morning:

 

Models have rounded into better agreement this morning, all of which may be contributed to a local cyclonic wave breaking event setting up over the eastern U.S. during the latter half of the 6-10 day period forecast. Models often struggle with these wave breaking events and they have been clearly struggling over the past week as the forecast continues to trend warmer over the East. The latest models are moving away from the idea of a strong coastal "Nor'easter" to impact the coastal east and towards the idea of a major winter storm to impact the Midwest as a highly-anomalous upper-level cold trough digs across the central U.S. The change of pattern is clearly being driven by upstream processes over the Pacific Ocean. We have been locked into an El Nino driven pattern for the good portion of this month. That pattern will be ending during the 6-10 day period forecast, in response to a very deep upper-level cold trough sliding off the coast of Asia, forcing a high-latitude wave anticyclonic breaking event over the North Pacific. This event will result in warm upper-level ridge development over Alaska mid-to-late period, tanking the East Pacific Oscillation (EPO) into negative territory. A direct downstream response will be felt over the U.S., in which some colder air from the north will be able to freely flow down the Rockies and fuel the explosive deepening of a mid-latitude cyclone aiming to take shape over the Midwest and Ohio Valley. The details remain to be panned out, but the synoptic set up is favoring for strong dynamical forcing that results in a winter storm across the major markets in PJM mid-to-late period. A flux of moist tropical air from the east will fuel the system. This plume of mild, moist Atlantic air will result in unseasonably mild temperatures across the Northeastern U.S. around Christmas, setting up a possible heavy rain event for DCA, PHL, NYC in through BOS.

 

Now while the 6-10 day period forecast has trended warmer in response to this upcoming cyclonic wave breaking event, this particular event (in addition to the upstream forcing) is setting the stage for a major pattern change during the 11-15 day period forecast. With the massive cyclone to spin across the Great Lakes and up through eastern Canada late in the period, it will aid in advecting a highly anomalous cold air mass down the western two thirds of the nation, resulting in well below average temperatures to flood the western two thirds of the nation. We typically see major pattern transitions across the lower 48 following the development a significant mid-latitude cyclone, and this is the anticipated pattern evolution heading into the final week of the month.

 

11-15 day:

 

A period of cold weather and high heating demand is anticipated during the 11-15 day period forecast. High latitude blocking will be the theme during late December in through January, with a prominent upper-level warm ridge forecast to spin up over Alaska and build northward in through the North Pole and eastern Siberia. This pattern sets will generate cross polar flow from Siberia in through the U.S. during the time frame, sponsoring a period of well below average temperatures from the Pacific Northwest Basin in through the eastern two thirds of the nation. We have seen a significant shift in the ECMWF EPS towards the GFS model package solution, in which the model is now more aggressive with building a western U.S. ridge and deepening and eastern U.S. trough as heights build across the North Pole. A split of the tropospheric "Polar Vortex" looks prominent, which a lobe will likely spin down across the Hudson Bay and facilitate cold northwesterly flow on its western flank. Coast to coast cold weather will be the rule during the 11-15 day period forecast, impacting all major markets in the U.S. with exception of those in the Southwest.

 

Now while the state of convection in the tropics, specifically the Madden Julian Oscillation (MJO) is headed for the "Warm USA" phases, it will have no impact on the U.S. pattern as high-latitude blocking will set up over the North-Northeast Pacific, driving a series of arctic air masses down across the U.S. The pattern looks extremely similar to what was observed last winter or back in November, and we should expect a similar outcome... Cold temperatures and increased heating demand. Now while there will likely be some details that remain to be panned out in response to synoptic waves (winter storms) spinning around the U.S., we hold higher than average confidence in the upcoming pattern change that will end in winter-type conditions across the lower 48."

Sounds promising

[Gradient Keeper]

A pretty decent gfs run and no one is talking about it.

Agreed. It is interesting that the 12z GFS(Parallel) was quite good today keeps the rex block in tact well west of us. 500mb anomalies look really good too. Good potential for reloads given Alaskan Block/Kona low position at Day 10-beyond.

[SilverFallsAndrew]

Sounds promising

What do you think droppin dog

[SilverFallsAndrew]

Agreed.

It is interesting that the 12z GFS(Parallel) was quite good today keeps the rex block in tact well west of us.

500mb anomalies look really good too. Good potential for reloads given Alaskan Block/Kona low position at Day 10-beyond.

Go parallel gfs. Bet you are tracking the euro closely.

[Guest Winterdog]

Amazing write up from Mike Ventrice....

Hmmm. Sounds a lot like Phil's scenario. Does this mean there might be some validity to all those acronyms he throws around?

[Gradient Keeper]

The Canadian this morning is a big improvement over the 0z for the 8-10 day period. Pumps the ridge up into Alaska.

Yeah, huge improvements. On board with the GFS/ECMWF for NPAC/Alaskan Block. Nice to see......

[Bryant]

Hmmm. Sounds a lot like Phil's scenario. Does this mean there might be some validity to all those acronyms he throws around?

Phil's a smart dude

[Gradient Keeper]

What do you think droppin dog

I'm going all-in, because why not.... If I'm wrong, it's not surprising because we probably have a 4% of an Arctic blast during any Winter. If I'm right? That would be cool.

[Jesse]

No, but its a step in the right direction...

Towards not having one?

[Gradient Keeper]

Go parallel gfs. Bet you are tracking the euro closely.

Yeah..... but I have to leave in a minute, Christmas Shopping!

[Deweydog]

A pretty decent gfs run and no one is talking about it.

Whatcha need to know?

[stuffradio]

The 12Z Euro shows close to an inch of snow by day 10. Much better than 00z when it was showing much less than an inch of snow by day 10.

[westiztehbest]

GFS showing substantial snowfall potential a few days after Xmas.  Let's hope things stay consistent and move up in time as the next week goes by.  Glad we have something to watch finally.  The lack of snow here is noticeable.  Got a quarter inch here yesterday - which seems to be a pattern this year with +PDO/+ENSO - total weak sauce.

 

 

[HighlandExperience]

The 12Z Euro shows close to an inch of snow by day 10. Much better than 00z when it was showing much less than an inch of snow by day 10.

 

Hey  you have a weather bell subscription right?

 

Post the snowfall map =)

[MR.SNOWMIZER]

Could get cold I guess.

[Jesse]

Hmmm. Sounds a lot like Phil's scenario. Does this mean there might be some validity to all those acronyms he throws around?

 

If things don't go as advertised solar will be blamed.

[Deweydog]

If things don't go as advertised solar will be blamed.

No... it will be your fault.

[Jesse]

No... it will be your fault.

[Kayla]

ECMWF looks pretty arctic to me....

[BLI snowman]

Yeah, Euro actually looks good today.

[antipex]

If things don't go as advertised solar will be blamed.

 

This remains a very weak solar cycle, and activity seems to be trending downward again. It'll be interesting to see what sort of impacts this may have on our climate as we approach the next minimum...

 

[Kayla]

Yeah, Euro actually looks good today.

And so continues some great model trends. (I feel like we have been saying this for weeks now). It is nice to see the event at 192 hours now though.

[Jesse]

Yeah, Euro actually looks good today.

Indeed.

 

I also like the fact that the AR event has been toned down a little. Sunday is looking like the only really bad day for the mountains now. Could be snowing in the Washington cascades again by Monday or Tuesday.

[stuffradio]

Hey  you have a weather bell subscription right?

 

Post the snowfall map =)

I was instructed I'm not allowed to or I will have my account disabled. You can buy your own subscription is what I was told.

[Phil]

This remains a very weak solar cycle, and activity seems to be trending downward again. It'll be interesting to see what sort of impacts this may have on our climate as we approach the next minimum...

 

solar-cycle-sunspot-number.gif

On a 1-2 month resolution, the Sun has really had an effect on the tropical-mid latitude relationship, and is partially responsible for the El Niño..

 

Strong correlation coefficient between solar and PDO suggests the relationship is legit:

 

http://catchmypicture.com/qhmS0x.jpg

[Phil]

If things don't go as advertised solar will be blamed.

Yep. A lot of people find it hard to believe that solar could be relevant on such short timescales, but it is. You don't get correlation coefficients above 0.85 by chance..

[catnip]

 

[MossMan]

 

MT8_Vancouver_Kanada_ens.png

Looks a tad chaotic! Models still trying to figure out this complex situation.

[Deweydog]

Speaking of the PDO, November came in at a tidy 1.72.  Highest November number since the Reagan administration.  

[Jesse]

Yep. A lot of people find it hard to believe that solar could be relevant on such short timescales, but it is. You don't get correlation coefficients above 0.85 by chance..

Sooo...we're screwed?

[DareDuck]

Can't wait to head down to CA tomorrow. Skiing at Mammoth for the weekend then down to Socal to visit family. Perfect time to get out of here, this has to be the worst weather. 4 days with temps between 35-45, .09" of rain, and only a few hours of sun.