Carvers Gap

Cancel winter at your own peril on Dec 9th. It's a Mid Atlantic forum tradition which I don't partake in. Also, remember when I "canceled" the cold to start December? How well did that work out? I do think we see some warmth after the 20th. Is it a pattern change? It could be, but a 2-3 week pattern relaxation seems about right. The 12z Euro actually looks decent. Cold to the end of the run. The MJO is all over the place. I think there is convection in a lot of areas which is producing conflicting signals. John noted that yesterday. The plots at CPC are to the left of center, but chose your own adventure. The MJO has managed to loop back barely to 7 in the COD. I would guess it comes back around to 8. It normally goes counter clockwise. Why? Because the weather moves from west to east. Unless that changes, it doesn't really make long term transits in reverse. And my broken record advice...climatology does not support much snow at this time of year in the valleys. Enjoy being in the game in early December - that is a bonus for all bu the 1960s and a handle of winters since then. FTR, I have sat through many early December Christmas parade in short sleeves!

Fortunate indeed! I remember walking through the neighborhood and just listening to the wind how as very fine snow was falling. Fun evening.

I have shrubs that finally recovered this season!!! They got absolutely scorched.

In TRI, that would be 0.5" of ice preceding 10-12" of snow. Give me the snow...I don't want any ice. Slow-ish moving wave. If it was closer, I would post maps.

Real temps behind that fall to -10F in some places and -20F for WCs. Fun run. Unlikely we see that every run, but fun!

Lets try that again, and this time NOT in centimeters. In my haste I clicked centimeters. Up to 30" of 10:1 snow. Most assuredly, if that wasn't Digital snow, that would be much more due to higher rates due to colder air. 40" Kuchera in W VA.

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.