Carvers Gap

The 12z EPS looks like a washed out version of the deterministic which I posted a few posts back. Good trends.

The green is convection, right...or is it the brown?

Here is the 12z Euro d10-15 pattern. The noticeable difference is Alaska. That Bering Straits low floods Canada with Pacific air. While it does have precedent, I think that feature is likely wrong. Get that our of there, and it is the GFS 12z run. IMPORTANT: What we are seeing(and this is under way even today) is a retrograding of the eastern North American ridge into the eastern Pacific. How long does it stay there? IDK. It could keep retrograding. But it is wild to watch the ridge get knocked down, and then "resurface" further west. How that ridge retrogrades is going to be key. A retrograding pattern has often been good to us regarding winter weather.

This is a pretty good trend from an albeit not-the-best model of reliability....This d11-16 5d map from the 12z GFS. That is a big time winter pattern if it verifies.

Who knows if the 12z GFS is right or not. I certainly don't. But for the sake of discussion...if that cold front comes in at the angle and slow speed that it does on that run, that is prime for over-running sometime after the 11th. We have seen that repeatedly during the past few years with Nina winters.

The January 3rd slider which is rain...The 12z Euro has frozen precip at higher elevations in the Apps and in SW VA(northern sections). Temps remain in the upper 30s and low 40s most of that day. If that moves in at night...we could see some snow above 3000' IMHO...maybe lower. That is a sneaky system.

The 12z GFS(so proceed at your own risk) has a monster Alaskan block by around 300. So far(famous last words), the pattern at 500 is moving forward with time.

I still think we are right on track for right around Jan 12. I would not be surprised to see it speed up or be delayed by a day or two. I also think we will have some minor chances prior. Models have not been great w/ details or seeing cold fronts this year. They flip around a lot. We go through the same thing every year with the same complaints. Sometimes models are simply too quick with the pattern change. They also really struggle with the NAO. Let us not forget they lost the pattern change in early December only to add it right back after 2-3 days when the pattern emerged from the 5-7 window where things get lost. I am not saying that happens this time, but it is worth considering. And no Icy, the pattern is not 16 days out...but I think you know that. There are no guarantees, but roughly timed, the EPO starts to build on the 8th-9th. The 12z AIFGFS(admittedly not an overly reliable model) has the beginning of the pattern change inside of 240 hours. In fact, I can make a pretty good argument the pattern change is underway now w/ the big -NAO which "should" retrograde into the EPO block. In my mind, we lost a 1-2 cold fronts in the pattern w/ the cold sliding to our north. Phase 6? Maybe and sure looks like it. The 12z GFS also has the ridge building into the eastern PAC around Jan 8th as well. I was showing maps last night, because quite frankly...I was trying to stay awake which I halfway noted....turn and burn to Knoxville. As noted the GFS (which has been truly awful this winter) had some phase 6 stuff yesterday. I haven't looked today. MJO plots at CPC have been largely unreliable this winter as the MJO has just flatlined. The driver going forward is likely HL blocking, but there will be a likely transition in order to get to that point. The biggest thing is to watch the 500 pattern and see if the EPO ridge keeps moving forward in time. If it does, models should trend colder. It looks to me like we are going to have to roll one ridge through the eastern pattern from Jan5-8th. I will check back in a bit. We rolled in last night at 3:00AM. Just catching up.

Haha. You are lucky I was posting maps at midnight to begin with. I normally don't do the (model) night shift. You're welcome. They are free, so you get what you pay for around midnight......

Nothing burger from the 0z Euro. I have read some conversations that the MJO rolls into phase 6 right as the EPO forms. We may be seeing some of that. The Euro at 500 is still better than 12z though IMO. See u at 12z tomorrow.

Nice looks and decent agreement in general with cold placement and vastness of the airmass.

Sitting in Knoxville… The 0z AIGFS is definitely quick with the EPO ridge as it installs it around the 8th, and the trough begins to kick eastward at that time. Very cold model and the 0z GFS has basically joined it. John covers all of that nicely above.

I am also noticing at tendency on the 0z GFS to include split flow with the -EPO.

The 0z GFS loses the feedback over Baja and looks a lot like the 18z AIGFS. Let’s see how the rest of 0z goes, but they are trending colder as John has already noted with the AIGFS.

Haha. Very!!!