Carvers Gap

After 240, the NAO has simply taken over the pattern on the 12z Euro. Really good run after a meh-run by the 12z GFS.

Not sure how I am out to 258 at 500 on WxBell w/ the surface graphics lagging...but that looks like winter storm.

I "think" the ridge in the east kind of retrogrades westward....pops, gets beat down, pops up westward until about Jan 8-10 when it hits the best location. I am hoping with that AR out of the way, the trough which forms in the GOA is far enough west to allow the PNA or EPO to form.

After a pretty ho-hum first 240 hours...the 12z Euro slides a slp along the low road.

And you know the blocking is having an effect on modeling when it is trying to snow in Louisiana, Mobile, AL, and in the Panhandle of Florida late in the 6z Euro AIFS deterministic run - this also found on ensemble members of the 6z GEFS and 6z Euro AIFS ensemble. Cold shots like that have not been an uncommon occurrence during recent Nina winters, and is a bit of a thorn for those of us who have been well below snow climatology for several years in eastern sections of the forum. Haha! The 6z Euro AIFS even has snow to the South Carolina coast. So, that should give you all an idea of where modeling went overnight and at 6z.

If we just need things to worry about(other than latitude and elevation), the cold source in Canada is less w/ overnight runs. That means we have to score w/ Canadian and not Arctic air. Thankfully, we are talking January and not mid Feb. The STJ was a bit more active overnight, but a dry pattern would be still on the table I think. The 6z GFS put 4-6" of snow over most of E TN w/ the exception of SE sections. The mountains got nearly 3 feet on that run.

Ensembles are also starting to show a bit o a snow signal. @Knoxtronmentioned that yesterday, and that has increased overnight. As early as....Something to watch is the 6z GEFS is picking up a mid-south slider around New Year's. I can't find that at on other modeling, but several 6z GEFS members have it. I wouldn't put too much stock in that one, but it was worth a mention. January 2 still has some BIG differences across deterministic runs. If a model doesn't send it on Jan 2, I am seeing a trend to send it Jan4-5. Pay me now or pay me later type of stuff. Ensembles still have this timeframe as cold as does the GFS/AIGFS suite. Honestly, there are too many winter events to screenshot across deterministic, AI, and ensemble runs this morning. Let's see if that continues as a trend. Definite trends by deterministic models late in their runs to build a western ridge.....Let's see if we can get some of this inside of 5 days.

These are the d10-15 maps, 5 day maps. The transition to this occurs much earlier. If those western Atlantic heights back into the Davis Straits and hook into the EPO.

Really good trends in overnight modeling. Modeling has multiple winter storms. The 0z Euro pretty much goes eastern trough after the Jan 2 cold front w/ one ridge rolling through.

The 0z AIGFS has these maps. Sorry, it doesn't have clown maps or precip types. Use your imagination. Looks like it has a clipper and a WAA event.

Check out this front as it comes through Sunday night...Some places could well have single digit wind chills by Tuesday morning.

I may post slightly less over the weekend(Saturday and Sunday). I am gonna sit back and enjoy watching model run chaos. So, if you see fewer posts...don't assume the modeling has been poor. But I will leave you with this. Some things I see and then I don't post about(hard to believe, right?!). I think at some point, there is a good chance that we see this. LC has been banging the drum for late January into early February. Low and behold, the control shows this today. Have a great weekend, everyone!

Interestingly, one of the most useful models I can find right now is the Euro Weeklies control. It is basically a 4 week extension of the 0z Euro deterministic run after day 15. It has been doing really well if one accounts for its biases - the ensemble weeklies not so much. I haven't been discussing the weeklies as much lately due to their errors and inconsistencies. But again most models past 120 hours are struggling mightily. They are all over the map. One thing the weeklies are signaling is that we are possibly about to enter a very dry time frame. Now, that might sound bad and it could be. However, many of the areas which get snow...that signal will show up as dry. I noticed the CPC analogs are almost all from the 2020s. That probably isn't unwise on their part, but it probably means they are going to be wrong. This winter doesn't remind me of 2020s winters at all. This one has a bit of old school in her bones. And no, I don't want an ice storm either. I don't mind a mixed bag, but I like my lights on. After Helene knocked us out for several days...I am not a fan of running a generator 24/7. During the winter, "no power" is about ten times worse. Pipes freeze. There is no heat. There is no travel.

I don't trust a model past 120 hours right now though I talk plenty about them - that is the fun of tracking, right? As for snow climatology, I am actually AN. Many of you are exactly at normal as climatology hasn't supported snow yet. I know it easy to see places like Indiana, Illinois, and Ohio get snow. That would be like Atlanta comparing their snow climatology to here. Mid-West climatologyis definitely NOT our climatology or standard here at any time of the year - not even close. Until models get the NAO/AO/EPO/PNA situation worked out....gonna be a slog in regards to figuring things out. My rule of thumb right now is that if any model sees a cold front...it likely verifies. Again, go to ensembles members and count them. Try to find the median for a run (not the mean which could be skewed) and look to see if that number increases as time gets closer. Right now, the GEM and counting ensemble members is about the only way to go. As for Nina...again, middle and west Tenn have taken E TN to school during the past several Nina winters. Nina winters have tempered the snow drought in those areas which had been huge. NE TN is in a significant snow drought as are portions of SW VA. Members this way just don't say much about it. Weak Nino and Nina winters(this is one!) are when NE TN peeps score....so I think this winter might end up differently due to the QBO. Remember, the end of January and February is a month when wavelengths shorten. That adds more opportunities than the dead of winter. I think the biggest obstacle going forward is below normal precip and not temps. So, if you need something to worry about...that is the fly in the ointment and has been for several days on modeling. @Holston_River_Ramblermentioning the STJ as key is an underrated post. I think we have a warm-up sometime after the 6th, but I can't really perceive when as that window is probably a good snow window as well. For now, it looks like several cold fronts dropping down. Most of these fronts have been correcting southward and stronger as the day nears - let's see if that trend continues. But again, until we know the duration and intensity of the NAO and any subsequent ridge out West...very tough call but I lean seasonal right now w/ a mix of warm and cold days. In about two weeks, seasonal will get the job done. The "now you see it and now you don't" Aleutian ridge runs are not helping models after day 8!

Just uncanny that you all talked about the 1982 ice storm, and the 18z GFS rolls with that slider w/ ice on the south side. FWIW, the 12z GEM had almost the exact solution. Long way out there at 200 hours, but it is inside of d10.

Both the 12z GEM(finally finished its run) and the GFS have a weak slider around Jan 4-5. Could be something and could be nothing.

We did the southwest coast of Oregon....huge fan! I like YNP...the crowds have been bad lately. The Sierra Nevada and Oregon Coast have a lot more room to spread out, even if parking lots are crowded. We fished in places where we saw maybe 5-10 total on the trail all day and only one other angler. The southwest coast of Oregon is a blast. Bucket lists are the Alps of Italy and Crested Butte to see the Alpine Meadows during late June and early July. Boulder and Alamosa for running for sure. Fairbanks as well. I have too many bucket list items for my checkbook! LOL. Does anyone know why the GEM is running late today? It looks like it is hung-up at 100ish....

Some decent storm looks. As @Holston_River_Ramblernoted about this time frame....definitely some ingredients in place for one or more storms. That trough east of Hawaii is usually money. Image 1: D11-16 AIGFS Image 2: Day 10-15 Euro Image 3: The end of the Euro run and not an uncommon look across modeling at 12z.

Yeah, @John1122shared some posts about it a few years ago. I am hooked on watching atmospheric river events now. Their storm total is 67" so far. It is hugely important for California. The Los Angeles Water District gets a ton of water from the east slops of the Sierra Nevada. We traveled out there last summer - mainly because the outdoor opportunities are just about endless. The city of Mammoth is a decent size, but it is REMOTE. The hiking there is pretty incredible, and the scenery is about as close to what I would imagine the Alps would be. I am a huge Yellowstone NP fan, but this area might top that - plus no grizzlies!!! Their ski season was in serious danger. The ground was bare which is pretty unprecedented. So, getting this much snow will save their season. The webcams there are wild today w/ the wind. It looks like most of the lifts are closed. I know they have to pack and groom a lot of those slopes since bare ground was their prior to Christmas Eve. My hope is to one day travel out there during an atmospheric river event. Plane tix into Vegas are cheap if you are willing to drive the 6 hours from there. Reno is the better airport(only three hours), and you can see Lake Tahoe on the way. But man, those mountain drives are no joke in places. We really enjoyed Yosemite NP at Tioga Pass, a white knuckle drive but worth it. It is only about 1.5 hours from Mammoth. If you like fly fishing alpine streams - no place better I don't imagine.

And the 12z AIGFS does exactly the same thing as the 12z Euro.

The 12z Euro really wants to get rid of the Aleutian high. By roughly 162, it pretty much begins the process of wiping it out within hours. The run ends w/ the EPO hooking into the NAO. Now, I am not saying that is gonna happen, but if that does...that is the gold standard.

The 12z AIGFS is a fun pattern. Cold with chances.

12z is a bit more interesting in terms of winter wx. The GFS is again stronger with the Jan2 cold front. Both the the GEM and GFS hint at WAA right after.

Interesting quote from MammothSnowman after a very rough start to their season(uncharacteristically no snow in much of the Sierra Nevada)... Storm Summary as of Christmas afternoon, the snow study site showed 4.66 inches of water content at 6 AM, and at 2:30 PM, the gauge is at 6.07 inches with 14.7 inches of new snow today. Snowfall Storm Total amounts at the snow study site are an estimated 65 inches. Adding the 30% adjustment for the Top, the Powder Fields of Mammoth would now have received over 79.5 inches of fresh snow. The Christmas Miracle Storm has come through with tons of base snow, and the season is saved at the last bell. Amazing…

@John1122, Mammoth is getting absolutely hammered right about now. Those cam stills are impressive.