Carvers Gap

Congratulations, everyone. The HOT donuts sign is on for this thread. Haha! Now, I am gonna go watch some football.

If we see that really cold shot between Dec 14-16, I would say we have a 50/50 shot(or better) at a strong anafront. As for Sunday night, I have no idea...it is interesting to see the GFS hang onto that. Overall, we need that ridge to backup just a bit. I see where several folks on other forums have been talking about -PNA. I don't know if that is a true -PNA. That looks like a +PNA on modeling, and it is centered a bit too far to the east.

Models haven't missed by much with the exception of the 4-5 day SER/feedback hiccup. They really haven't amplified the pattern with just a few exceptions. Mid-month may well change that. I think the wavelengths are just flatter, and that may help us later on as this will be tough to dislodge as climo gets increasingly colder. This has been a pretty cold start IMBY. I do think there is a window for a piece of the TPV to drop into NA to lower latitudes than the GL. Also, you noted that the Pac NW has been pretty active. That Pac flow also might be modifying the colder temps at the base of the trough, and that was shown on modeling. Interestingly, the Sierra Nevadas in California and the Colorado Rockies have been stuck under that ridge, and are way, way BN on snowfall. Lastly, the pattern doesn't really amplify in phase 7 of the MJO, but it can w/ phase 8. I think modeling erroneously tried to loop the MJO, and that made a mess. Now, it is forecast to stall by some models in phase 8. It may just keep on making the circuit, but...it did make a turn(per the EMON) today which could signal a stall. We will know more in a few days. Overall though, this has been a very cold start IMBY.

Congratulations, man!!! I just now saw this. Second half of winter is a toss-up for me. I tend to think the pattern we see right now will repeat and/or be very hard to break down. If this was an amplified pattern, I think it breaks down quickly. But these flatter wavelengths are gonna make it tough to budge. Cosgrove likes a backloaded winter and has sound analysis to back it up. I am gonna roll with 95-96 light. That would mean a cold start followed by a warmup which is followed by the worst of winter per Cosgrove. Now, that runs against my seasonal ideas, but it sure looks like that is on tap. My original ideas are winter in December followed by a gradual warm-up for Jan-Feb. I may still get that if December goes in the tank, ie Jan-Feb would almost have to be warmer against the norms. But Jan and Feb could be colder than my original ideas. The big thing for me is that the coldest air on the planet is here and in Asia. Our source regions have been lacking in recent years, but not this year. With the QBO at -25.35 for November(and an unexpected drop after what appeared to be the plateau before it rises), it sure looks like winter still has some life in it for Jan-Feb...I would guess the NAO is about to fire up. These strat warming episodes could very well make for some cold mischief during January.

It is back to 6" for portions of Sullivan Co on the 12z today. The AIFS has 1-3". I still think it is over done, but the GFS can sometimes score a weird coup from time to time. For now it is an extreme outlier. I wouldn't be surprised for NW facing slopes to see 1-2" out of that system tomorrow night.

And a great question I might add. A great question is always better than a great answer....The more I think about it, the more I think it is because they have more snow cover right now. The trough is just a tick too far to the East right now as well.

Here is the average(lows and highs) for December through the 4th. I will go back up and post the map(with the reference years above...give me a sec to edit that one)... 1985, 2000, 2010, and 2024(almost the same start) are very similar or colder to 2025. But that is about it.

Since 1980, the only month I can find w/ a faster(low max temp) start is 1985. Here is the Dec 1-4 data for 2025. These are the max temp departures. As Boone noted, overnight departures are not as strong. I have to think that is due to a lot of fog and cloud cover. I'll update w/ more recent numbers when this updates again. ***updated w/ reference maps of max AND low temp compositees***

With the potential or much colder temps this month, and a tendency not to soar way AN....we could be looking at a top 10 cold month for TRI. I'll have to go check and see...but that is off the top of my head. 7 day ensembles for mid month are -10 to 15F BN

I am just now catching up on overnight and afternoon modeling, so please forgive me if I am on stepping in old footprints. These are the real feel temps for the mid-month cold front. The GFS I "think" had this on d16 of its run a few days ago. It is now well within d10. The 12z EPS is the colder of all the ensembles, and that gets my attention w/ its usual warm bias. Some deterministic models don't get us above 20 degrees. This reminds me of the 09-10 setup. It got cold right as school let out - as in the very day school was dismissed for Christmas. Cars were stranded in a pretty good commuter snow storm. This could be an 83-84 deal where it gets cold and doesn't snow. I fully see that. However, I see the Euro cranking a big storm high around this time frame. Often, we will see cold temps and big snows coupled. These temps are pretty much on bare ground. The GFS gets TRI below zero(in some places) with actual temps. The thing that concerns me a bit is that the GFS has the warmest MJO!!! If it is just now catching on(and it has a habit of seeing cold shots before other models at range during December), then look out. Still time for things to change, but a big shot of cold air is growing likely but not certain. Once we get to day 6-7, I think the cold is baked in the cake...so a few more runs to go. TRI has managed -6.8F and TYS -7F(for the first six days of the month) without strong amplification. What I am seeing w/ deterministic runs is a tendency to amplify the pattern sooner than later.

The other thing I am noticing is an uptick of the mean snow total over TRI. That might be "IMBY" a bit too much, but that is usually a good thing for everyone when it goes up. The 12z AIFS-Ensemble has 2-5" of snow from TYS to SW VA. The 12z GEFS has 1-6" of snow from TYS to TRI.

I just think climatology really doesn't support super cold air until mid-December. There are lots of "whys," but I also think the MJO wasn't in the phase where the cold centers in southeastern NA. But it is MUCH colder than models had it when the SER was once modeled here w/ highs in the 70s. IMHO, modeling has tended to have a shallower trough and that has verified. The bitterly cold air I have seen modeled has been w/ the cold air masses of Dec 8th and 14th. And to the number that matters, TRI is -6.8F for the month so far. That is pretty big departure. Every day has been BN w/ a trace of snow on two of the six days. I can say this...I have been freezing my tail off while running in the mornings. I pretty much ice skated one morning on freezing fog. Pretty good start in my book.

Apparently, I just need to miss the 12z suite for all **** to break loose. Shiver me timbers, GFS w/ a piece of the TPV! Storms on the Euro.

Agree. As noted by a poster in another forum(maybe ENSO on the main page), this is a pattern which is often hard to break down, i.e. cold over the Hudson Bay, a small ridge over the Southwest, and kind of a flat, stable trough in the East. That Alaska feed into the SE is a classic old-school pattern. I know we've talked about it before. It seems like modeling has shown this in the past only for it not to verify. This time it is in place. That is a cold, cold feed at times.

I kind of see this more as a system where NE TN folks(SW VA) see the snow hang on just a hair longer w/ NW flow to follow. It isn't a big NW flow event, but it is present on all short range models, especially for the Plateau.