Carvers Gap

It would make a lot of sense if the pattern was about to break for warm...for that blizzard to show in exactly that spot. The GFS has held to that since yesterday. I would encourage everyone to not get their hopes up. I actually don't like tracking Christmas systems since so many get their hopes up. But I really want to see the GFS hit this from day 16. Also, do remember that systems are often lost between d5-7. Let's get that out of the way now. LOL.

That is a blizzard. Wow. It will assuredly change, but the 18z has a full fledged blizzard after 300.

The 18z GFS has two "mood flake" systems, and one boomer. Plenty to track for December.

Really, the pattern right now is cold, reload, and more cold. That might end later in December.

The 18z GFS has the anafront again. Gonna be wild if it hits from d16. Seems like it hit that Christmas Eve anafront(from a few years back) at the same range.

Currently snow is falling in west Kingsport. A little band has been set up. Just barely missed today.

I think the bigger warmup comes between Dec 22 and mid Jan…that could be wrong, but that is what it appears to me. Lots of precip in the MC at that time.

I do think there will be a ridge which rolls through between the cold shot on the 14th and the next one on the 18th. That has been strongly modeled, Bastardi has noted the WPO has been erroneously modeled by the Euro/EPS suite for weeks. He thinks there is a problem with its algorithm. He noted the WPO appears to be driving the pattern. When it weakens, other drivers take over.

I just don’t see the evidence of it being in 6. There is no ridge in the east at the moment. Only the EPS is modeling a big warm up. It could happen. There were some overnight runs which support that. But the EPS has struggled mightily. All of these warmups have yet to verify. I think after the 20th seems right.

I don’t buy the 12z EPS right now. It has no support from its deterministic model and has been wrong for several weeks in trying to slide a permanent ridge into the east. I think a ridge is coming but more likely around the 20th. I can’t tell if it just rolls through or is a pattern change. I could be wrong, but I think we are good through the 18th with possibly one more trough after that before we get a break.

Interestingly, the Euro Weeklies control and ensemble are exactly opposite again. Last time, the control won that battle. The control is 30 day strong trough. As for the MJO, there is some activity in 7-8-1-2. This morning it began the anticipated loop/stall in 8. I have little doubt the convection forecast for 1-2 will eventually propagate into 6. It looks to me like that will happen sometime in the third or fourth week of December. It could be earlier. Currently the MJO plot is in 8 and the atmosphere reflects that with an eastern trough in place and eastern troughs forecast through roughly Dec 20. Again, it is early December. This is not snow climo for valley locations.

Basically on 12z modeling, I am seeing a continuation of the current pattern w/ a chance of strong amplification around or just after mid-month. Which side of that amplification we end up? That is certainly up for debate, but I "think" the MJO probably places us in the trough. There is a rapid progression of short waves along the northern branch. For now, most of them are just a bit too far north. That could easily change. Each one will have to be watched. There are a lot of them. Definitely northern stream driven w/ some minor interaction w/ the Gulf.

And this one day map is mildly creepy.

The 12z GEFS moved the core of d10-15 cold from the Yukon to Quebec when compared to 0z.

Not without precedent, but these are some BIG swings d10-15. Good trends at 12z. Newer runs are on the left. 12z GFS vs 6z GFS 5d 500 anomaly map. 12z Euro vs 0z Euro. The Euro moved from an eastern trough to a western trough. Now, this is just deterministic stuff. So far, ensembles look pretty steady.

The 12z Euro is much colder than its 0z version. Was 0z the hiccup or is 12z the hiccup? I would tend to think that 12z follows continuity. So, we stick w/ it, but with one eye over our shoulder.

Cold rain here, but....the GFS did nail the deformation band over NE TN. Unfortunately, the thermals not so much!

It appears the 12z GFS will have the anafront on Christmas Eve. Only 60 more runs to go. What could go wrong?!

I think a lot of this is just fighting climatology. Again, and I sound like a broken record...it is really rare to track snow prior to mid-December at lower elevations. The higher elevations above 2500'...that is a different story. For most of us, we just recently exited meteorological fall. Our best climatology is mid-Jan to early-Feb. So, we are about 5-6 weeks away from best climatology IMBY. That said, the RGEM, NAM, and GFS all show light snow this weekend. In some cases there are two chances. Nothing big, but mood stuff. Higher elevations could score 1-3" of snow.

RadarScope is changing over to mix over the northern TRI. It mostly rain, but I can see mix on the windshield. This is early for that.

This if for roughly the same time frame. The 6z GFS, 0z EPS, and 0z CMC. Let's see if the Euro deterministic is leading a change. For now, the ensembles are not there. The 6z Euro looked like it would have been cold. Time will tell. I certainly am no fortune teller!

For ONLY kicks and giggles, let's see if the 6z GFS can hit the half court shot on Christmas Eve.

The 0z EPS has a much different solution than any other global ensemble including the AIFS. The GEFS, GEPS, and AIF still have the cold shot next weekend. The 6z GFS has a the Christmas Eve cold shot(which really could go either way). I think the widely diverse solutions are due to the various MJO solutions. The EURO at range has struggled so far during late fall and winter. It certainly is good enough to score a coup, but it erroneously called for the beginning of December to be warm(after the weeklies had it cold). I would suspect there is a severe cold shot headed into the Lower 48. Things get scrambled when that happens.

The 6z GFS has returned to a much colder look. The 0z Euro is definitely warmer after mid-month. Its ensemble is not as much. Both the 0z GEPS and 0z GEFS are not warm. I think the warm-up looks to be set just after mid month. But there is this on the LR GFS, and take with a huge grain of salt...a major league anafront. This would be a nightmare or travel. You don't have to guess what the weather looks like under that. Lots of uncertainty after the 20th, so we'll see.

Basically, the December 1995 pattern would repeat later that winter, but with better climatology in place for cold air to make it to this latitude and hold. IMBY(not the folks at elevation), we are fighting climatology every step of the way right now. It eases up after Dec 10th or so, and becomes more favorable with each day. When I first started tracking, I rarely tracked during the first 20 days of December. But if this pattern were to repeat during the second half of winter, I think the cold presses more. Now, the STJ is inactive...so northern stream systems are gonna have to do the trick. I still think we have a shot to score before this breaks just short of Christmas. One caveat, this may not break down before Christmas. Some MJO plots are stalled through the end of the month and into early January on the left side of the MJO. Also, modeling tends to break down patterns a bit too early. That said, a New Year's thaw seems realistic. If it is twenty below w/ five feet of snow...you can look back on this comment and thank me for it!