Carvers Gap

The 18z AIGFS is straight up frigid. Let's continue to keep an eye on Jan 12th. If we can get that down to roughly 7 days, that may be a legit time to track something decent. That run had a decent snowstorm for middle and west. My main concern is this...if modeling, which has tended to under model cold fronts(exception Jan 2), then that cold could be stronger than shown.

I think it is also worth noting that NE TN and SW VA may well see some snow in the air tomorrow if the 18z RGEM is correct.

I am not convinced of the correlation between phase 6 and cold. What I think is occurring is QBO induced HL blocking(in some cases) is simply prevent the MJO signal from having influence over NA. I think the MJO has a much bigger impact when HL blocking is absent. As Cosgrove noted, the best thing we can do is simply look at the vortices lined-up which are approaching the US. You can kind of see the stormier patterns and deduce timing of such. Use analogs to fish out a good 500 pattern in addition to wx models. That is more accurate than relying on simply teleconnections which I am always guilty of...

So, when I look at that. I see an East African/IO wave working from 1-2 to 4-5 and then to 6(and then fizzling out). I also see some convection at the dateline which is phase 8. Looks like the phase 6 dies out. In my mind, that would correspond to the warm waves prior to the 12th per lagged composites? Looks pretty weakfish to me in general with 2-3 strong days in 6. I think HL blocking eventually trumps it unless it holds onto that stronger look for more than 2-3 days.

Pretty good looks in my book. I used to only do long range stuff based on precip anomalies and temp anomalies. I don't think I am much better today with all of the extra stuff. Here are some Euro LR ext maps centered on d15-46. I have attached both the mean and control runs. You can see below normal temps with above normal precip(yeah, that surprised me). I actually went through and looked at the precip by 7 day increments to see if it was just one big rainer. Nope, it looks like normal precip with the exception of the first maybe ten days. BN temps, AN precip, and a solid 500 map.

Thanks for that info. I was having a hard time reconciling what look like really cold maps with that phase. I know there are times when the MJO has less influence.

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......