Phil

OMG, I'm saving a gif this run.

Haha, at 216hrs the anticyclone is coupled from the surface to 5mb. This would be extraordinary. So weird in how it happens though I'm not sold on it.

This run is so deep with the anticyclonic wavebreak that, through diffusuve heat and mass flux alone, it amplifies right into the lower stratosphere through what is typically a destructive conduit to opposing momentum transfer. Just blasts right up there. Haven't seen this since 2008/09.

I'm not sure I like that stronger vortex skirting northern Alaska, as it might promote more zonal transfer at the expense of meridional transfer.

No major changes to my prediction from December 16th, except maybe bumping up timing a few days. I think the extended range modeling is underestimating the -AO during mid-January, and possibly beyond as well though I could see a bifurcated NAM scenario w/ blocking from the EPO domain into the western Arctic with a vortex to the SW of Greenland.

The GFS/GEFS and CMC/ensembles are much more aggressive with the PV weakening than the ECMWF/EPS. In fact, the ECMWF operational almost dissolves the wave2 response completely. Which one is correct? GEFS over the next 16 days: http://www.atmos.albany.edu/student/hattard/realtime/u_65N_10hpa_gefs.png

Relax man, we'll be fine. We didn't see a single snowflake here until mid-January last winter. Actually, December has never been a winter month here really. Since 2010, even March has owned December in terms of snowfall and cold. If the first 10 days January don't perform, watch the final week of January and the first week of February. Then there's the classic Niña year early "March madness" period which is about as climo here as August humidity.

Finally someone set up a weather station at 4600ft in Snowshoe WV, right up there by the village. In yesterday's modest lowland wind event, they were sustained at 55mph, gusting to 65mph. I can't wait until a real wind event arrives..I bet they hit 100mph or greater up there. Even now they're sustained at 32mph, gusting to 43mph.

I'm more worried about the block setting up too far west vs too far east. Too much WPO at expense of EPO destructively interferes with the SE ridge and can dump energy offshore.

Congrats!

Much better progression on the 18z GFS. That NPAC block amplifies to the pole, locking the dominant trough in western and central North America.

Interesting..this run reflects more wave driving into the stratosphere but is slightly flatter in NPAC. Will have to see how it all balances out.

I think the 18z GFS is going to be even blockier and colder than the 12z, at least over the US as a whole. Already a more amplified Eurasian ridge by 96hrs, PV weaker as well. The 80s are back, y'all.

The PV/NAM was perturbed significantly on numerous occasions that winter, it just wasn't destroyed. There's a difference between a perturbed PV/NAM and a SSW/PV breakdown. In a Niña convective background, generally a SSW/PV breakdown (aloft) isn't required unless it's a true unrelenting monster. An example of this would be 1988/89, where the SSW event that began in mid/late January dropped the dominos and I'm sure you know what followed that event..

There wasn't a SSW/PV breakdown event in 2013/14. Arguably, the PV was stronger than ideal that winter, which assisted in keeping that Hudson Bay vortex planted firmly through the majority of Nov-Mar.

An inch or two of slop isn't my idea of a "carrot". At least you're back-peddling now.

It was a joke. Did I say anything in regards to its validity? Use your head, man.

You should consider a career change from lawyering to comedy.

If this were a Niño winter, you'd be rooting for a SSW/thermal/wind reversal in the stratosphere to bring about an Arctic blast, since the background convective state in a Niño is unfavorable to begin with (so blowing up that background state of the Niño system would only help). In a Niña, you don't want that, but a highly perturbed PV/NAM is still ideal.

Thank you. Ideally, if I lived in the PNW, I'd want the PV highly perturbed, would root against a full SSW/PV destruction. A weak PV/NAM allows wave amplification to self-sustain more easily and amplify further. However, a massive SSW/thermal wind reversal would rapidly cool the equatorial tropopause and ignite the MJO/equatorward tropical convection, which risks destroying the weak niña background convective/walker cell state. We saw this happen in January 2013, and it lead to (or technically was a reflection of) a cascade of events that semipermanently altered the H/W ratio(s), low frequency NPAC/PDO state, etc.

I know it's kinda new-agey, but keep an open mind to the idea. I think there's something to it. I actually was implying that the degree and nature of the blocking is very much influenced by process in the upper levels, particularly wave dynamics that arise via interaction with the PV above 150mb.

Clown range GFS looks just a tad chilly over the US: http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/8CA56DDD-5644-4C62-AA2A-505EC7653A06_zps5guqbrce.jpg

At least we've had snow this winter. I didn't see a single flake until the middle of January last year. Hope to never repeat that again in my lifetime.

In the end, the strength of the PV/NAM will determine the degree of self-sustaining wavebreaking in the NPAC (as a backdoor conduit for heat/mass transfer), hence, the corresponding Arctic potential in the PNW hangs in the balance. If all goes right, and that's still a big if, we could be looking at an Arctic blast in January (directed into the western US) for the first time in many years. If the PV wins, however, the next Arctic dump will probably slide east again, following a broadening and flattening of the NPAC block. Don't want that to happen.