January 2017 Observations and Model Discussion for the Pacific Northwest

[HighlandExperience]

[bainbridgekid]

Euro coming in chillier too. Not as cold as the 12z GFS, but a decent push of cold air South. I'll be interested to see the precip maps.

 

The Northern solutions seem to result in much more lift and precipitation along the boundary than the Southern ones. Feels like a situation where either the boundary sets up North and BC/Whatcom gets hammered and it rains South of there or the boundary pushes further South but snow amounts are much lighter.

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2017012812/ecmwf_T850_nwus_5.png

[Bryant]

GFS Ensembles still keeps the low way off shore

[van city]

Where's is Tim and his snowfall maps that's the only thing that I will appreciate front him on this forum?

[VancouverIslandSouth]

Euro coming in chillier too. Not as cold as the 12z GFS, but a decent push of cold air South. I'll be interested to see the precip maps.

 

The Northern solutions seem to result in much more lift and precipitation along the boundary than the Southern ones. Feels like a situation where either the boundary sets up North and BC/Whatcom gets hammered and it rains South of there or the boundary pushes further South but snow amounts are much lighter.

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2017012812/ecmwf_T850_nwus_5.png

 

It's not much different than the last 3 runs of the ECMWF and would still bring some snow to the northern regions. Unlike the GFS, which is substantially different from the last 3 runs and wouldn't bring a flake of snow.

[Brennan]

Would be nice if he northern and southern stream would throw some mike tyson's at each other. This little cat fight bullshit is annoying.

[Phil]

Is this a humidity-related post?

Hammer.

[Phil]

This last minute change to a colder outcome may have much to do with the current MJO wave. Never underestimate how much of a player that is when it's up and running.

Models will always struggle during a PV degradation because they often underestimate and/or misinterpret how it affects the tropical convection and subsequent waveguide.

 

The model swings will only increase in amplitude over the coming week, in my opinion.

[Guest Dome Buster]

Dramatic change between the 0z and 12z GFS to say the least. Downright extreme when you consider how close the event is.

 

Link?

[Deweydog]

Link?

Patty?

[Brennan]

Patty?

Mayonaise?

[Deweydog]

Mayonaise?

On sausage?

 

Gross.

[Brennan]

On sausage?

 

Gross.

For once the joke is on you.

 

P.s. Where do I find old radar loops?

[Heavy Snow]

Lol, really?

Yeah it trended colder from last night's run.

[Heavy Snow]

Still plenty of snowcover in The Dallas and Selah Creek which is just north of Yakima.

 

http://images.wsdot.wa.gov/airports/Dalles.jpg

http://images.wsdot.wa.gov/sc/082VC02240.jpg

[VancouverIslandSouth]

The navgem seems to be living in its own little world, much warmer and further north than either of the other two. Still would be a more dynamic and enjoyable outcome than the 12z GFS; getting precipitation has been far more of a problem than getting cold this year.

 

http://www.tropicaltidbits.com/analysis/models/navgem/2017012812/navgem_mslp_pcpn_nwus_19.png

[Phil]

Remember that major SSW that was forecasted?

 

Failure. One of the reasons the upcoming period is losing potential, IMO, as momentum deposition is quite unfavorable for structural compromise.

 

First week of February does feature the wave driving, but thereafter it looks ugly w/ equatorward eliassen palm vectors and a secession of heat fluxes via poleward PNJ propagation.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/3CE86EA1-8BC0-4999-97C0-9AB90D9071C0_zps9of2lzxe.png

[Phil]

That big NE Siberian Ridge = nasty s**t in the d11-15 range and beyond, for the western states. This is because it retracts that EAMT forcing, re-strengthens the NPAC jet/EPO, throws up four corners high given February Rossby guides under multiwave tropical forcing, hence puts vortex over NAO/Hudson Bay and NE US, similar to 2014/15 in some respects.

 

GEFS and GEPS d11-15:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/53440441-95B0-4BA6-AB24-9D89FACE5E12_zpsg7fl4kfc.png

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/505B9045-58C1-4EF3-B932-065DD44E9B7A_zpsucibljgr.png

[Perturbed Member]

The navgem seems to be living in its own little world, much warmer and further north than either of the other two. Still would be a more dynamic and enjoyable outcome than the 12z GFS; getting precipitation has been far more of a problem than getting cold this year.

 

http://www.tropicaltidbits.com/analysis/models/navgem/2017012812/navgem_mslp_pcpn_nwus_19.png

 

NAVGEM refuses to bring that cold south, it must therefore be discarded. Can't possibly be right.

[Phil]

The NE Siberian Ridge also hurts wave driving into PV/NAM and is directly responsible for next +EPO burst as well. If there's one thing we all know, it's that an Alaskan vortex will almost always lead to warm temperature anomalies over the western 2/3rds of the US in mid/late winter, sometimes the entire country.

[Phil]

If the NE Siberian ridge can re-locate towards the Taymyr Peninsula/Kara sea domain, wave driving improves dramatically both from Eurasia and NPAC as EAMT won't be igniting that NPAC jet/EPO and the tropical convection will lose exhaust route to PAC/WHEM.

 

This will happen in late February or early March. Might be too little too late at that stage, but we'll see if the system can pull off a midwinter style retrogression..it is quite possible..

[Jesse]

The NE Siberian Ridge also hurts wave driving into PV/NAM and is directly responsible for next +EPO burst as well. If there's one thing we all know, it's that an Alaskan vortex will almost always lead to warm temperature anomalies over the western 2/3rds of the US in mid/late winter, sometimes the entire country.

The models have been all over the place four days out. I'm not too worried about the long range right now.

 

Something tells me February will be cool overall in the west. Almost opposite of -ENSO climo to suddenly switch to warmer in the late winter.

[Phil]

The models have been all over the place four days out. I'm not too worried about the long range right now.

Something tells me February will be cool overall in the west. Almost opposite of -ENSO climo to suddenly switch to warmer in the late winter.

True, but with a weak background state, intraseasonal forcings often override with higher amplitude. See years like 2012/13, 2005/06, 2000/01, 1999/00, 1984/85, 1980/81, 1966/67, 1960/61, and many additional years that featured the aforementioned weak background state.

 

The -ENSO "climo" operates on lower/seasonal frequencies through tropical convective conduits to the mid-latitude wave-train. If these conduits are compromised, it can have global consequences both through mechanical and thermodynamic feedbacks. Remember that this system state, in any ENSO of low frequency background, is a globally driven process, and the small sliver of equatorial Pacific SSTAs is merely a constructive *reflection* of that system state. These SSTAs don't arise spontaneously, they're a response to large scale fluid-inertial, mechanical, and thermodynamic processes that are driven by systematic dis-equilibrium, on a number of timescales.

[Phil]

For example, did you know that there's a multi-millennia ENSO oscillation? Exactly the same as the yearly ENSO oscillation in structure and circulation, but operating on 1000-5000+ year timescales..and it's actually larger in amplitude than the yearly ENSO cycle. By comparison, the yearly ENSO cycles we've come to know and love are just tiny blips superimposed in this long term ENSO cycle, similar to the weekly blips we observe on our yearly ENSO cycle.

 

Similar to the yearly ENSO oscillation, this super long term ENSO oscillation is expressed through altered global circulations, convection, and significant global temperature variations. It appears to be driven by orbital cycles like obliquity and precession, which alter the equator to pole thermal gradient and mechanical/wave structure(s), very similar to the short term equator/pole thermo-mechanical structures that precede our yearly ENSO events, though these shorter term imbalance structures appear to arise from both external (solar/geomag) and internal (QBO/general fluid inertia) processes that alter geo-domainal energy distribution and conversion.

[Jesse]

Interesting info about the large scale multi millennial ENSO cycle. Makes sense.

 

Are we in a positive or negative phase right now, big picture?

[Jesse]

The low level airmass in and around the Gorge is cooling nicely for inversion season being over.

 

Troutdale is 40 with east winds as of 1pm today. They were 44 with east winds as of this time yesterday.

[Phil]

Interesting info about the large scale multi millennial ENSO cycle. Makes sense.

Are we in a positive or negative phase right now, big picture?

Most of the early/mid Holocene from 13,000 to 9,000 +/- 1000 years before present, and 7000 to 3500 +/- 500 years before present, was dominated by the +ENSO long term mode. The long term -ENSO mode dominated from 9000-7000 +/- 1000 years ago, and starting around 3500 +/- 500 years ago, the long term ENSO state began to decline again, and high frequency amplitude began to increase. There was a prolific +ENSO stretch about 1000yrs ago, however long term we're now headed down, and that increase 1000urs ago appears to be a mark of the increasing instability since then.

 

This is a great paper:

 

http://adsabs.harvard.edu/abs/1999GMS...112..373C

 

The long term +ENSO mode tends to be more stable and feature a reduction in high frequency (yearly/decadal/centennial) variability, while the long term -ENSO mode tends to be more unstable and feature increased high frequency variability. The more stable, +ENSO mode tends to precede the termination of ice ages and rapid warnings into stable interglacial states, while the unstable -ENSO mode tends to precede the termination of interglacials and marks the initiation of glacial states.

[Phil]

The bottom line appears to be (getting back to the original point) that high frequency processes, from the time scale perspective we care about, appear to dominate over the lower frequency background processes. In our seasonal case, the intraseasonal variations in tropical convection and circulation can override the background tendency of said processes, or amplify them when they're synchronized.

 

Much like what happens with the long term cycles, sometimes the intraseasonal variations will synchronize fully with the seasonal background/ENSO tendency, constructively interfering to produce a super ENSO event, where the background state is high in amplitude and dominates over any intraseasonal divergence. Sort of like the screaming feedback between a microphone and speaker.

 

Something similar often happens with the long term ENSO/climate cycles, when the orbitally-driven equator/pole thermo-mechanical dis-equilibrium reaches a particular threshold, the higher frequency variability will couple with this underlying long term mode, rapidly amplifying this state, abruptly throwing the system into and out of ice ages and interglacial periods. This can happen extraordinarily fast when the coupling is very coherent and anomalous, sometimes occuring within a decade or two, though obviously it requires thousands of years to build/melt ice sheets.

[Deweydog]

The low level airmass in and around the Gorge is cooling nicely for inversion season being over.

 

Troutdale is 40 with east winds as of 1pm today. They were 44 with east winds as of this time yesterday.

They would have been in the 30's three weeks ago.

 

It's dying. Acceptance will be liberating.

[Guest Dome Buster]

Having a mini-vacation in Sunriver right now.  Brother is coming down from Redmond in a few hours.  Surprising cloud cover here.  Maybe the warm front is stronger and further south than forecast?  Thoughts?

[Jesse]

They would have been in the 30's three weeks ago.

 

It's dying. Acceptance will be liberating.

 

Impossible to tell. 

 

Even if it is slowly fading it is still a factor. Acceptance will be liberating.

[Phil]

Additional papers if anyone is interested.

 

Long term ENSO variability:

 

http://www.sciencedirect.com/science/article/pii/S0012821X04007083

 

Long term Niño state during last glacial maximum precedes end of ice-age, mid-Holocene Niña state precedes cooling. Thankfully, the latter hasn't yet coupled and amplified, though it shows signs of doing so.

 

http://adsabs.harvard.edu/abs/1999GMS...112..373C

 

Tropical convection as a trigger for rapid climate change:

 

http://www.sciencedirect.com/science/article/pii/S0012821X05002190

 

Goes to show how unstable the system actually is, and that a mere change in global convection/circulation can alter the planetary energy budget and global climate substantially.

[Deweydog]

Impossible to tell.

 

Even if it is slowly fading it is still a factor. Acceptance will be liberating.

You're the only one here who thinks inversion season is completely over.

 

Or maybe you're just trying to be superfunnyguy.

[VancouverIslandSouth]

The 18z has trended a bit further north; it would bring at least a bit of transitional snow to the Puget Sound. Otherwise not a remarkable run, the low is a bit stronger and further north but slow and dries out rapidly as it approaches.

[snow_wizard]

The 18z has trended a bit further north; it would bring at least a bit of transitional snow to the Puget Sound. Otherwise not a remarkable run, the low is a bit stronger and further north but slow and dries out rapidly as it approaches.

 

I actually hope the low trends weaker and dies over the ocean on future runs.  Not out of the question.  That would allow a stronger intrusion of cold and might give us a snow chance a bit later on.

[Perturbed Member]

FWIW

 

NAM still looking decent for the cool air.

 

http://www.tropicaltidbits.com/analysis/models/namconus/2017012818/namconus_T850_nwus_53.png

[ShawniganLake]

The 18z has trended a bit further north; it would bring at least a bit of transitional snow to the Puget Sound. Otherwise not a remarkable run, the low is a bit stronger and further north but slow and dries out rapidly as it approaches.

Yea further north and stronger will likely be better for us.  The good GFS runs have been the ones where the modified arctic boundary has been able to tap into the moisture associated with the offshore low.  If that low dies offshore it seems likely that the air mass will moderate by the time we have another precip chance. 

[ShawniganLake]

Looks like Seattle cracked 50 again today.  This month is really losing its stance statistically. 

[snow_wizard]

Looks like Seattle cracked 50 again today.  This month is really losing its stance statistically. 

 

Pretty lame.  PDX will certainly put in a nice average this month, but SEA is still looking for a solidly cold January.

[Perturbed Member]

PDX NWS

 

A good part of this
forecast period will see a low pressure system to our southwest and a
slow moving system sliding by to our north in southern Canada. This
puts us under a confluent upper jet that will send moisture at times
over our area from the low to our southwest. The position of the low
and the cool system just to our north will contribute to developing
possibly significant offshore flow through the Gorge that intensifies
Wednesday on both the GFS and the ECMWF and continues into at least
Friday. This cold air damming setup is good for drawing cold air
again into the Gorge where precipitation has a good chance of turning
wintry again, possibly snow, and lowering snow levels again in the
valleys west of the Cascades. Details are still a bit sketchy but
trends are pointing toward Thursday as being the most interesting
day. On Friday the ECMWF lifts the low through and we should
moderate, but the GFS takes the low inland to our south and this
would keep us in the colder air longer. The Canadian model is in
between, but a bit more like the GFS than the ECMWF.