Carvers Gap

I don't trust the MJO plots right now. I quit using them about three weeks ago(roughly). I do think there are about to be some good things happen in the phase 8 region though, and that might be a legit signal - I hope. February in phase 8-1-2 would be crazy good. So far(fingers crossed) Feb looks like it is going to be a winter month this year....the Nina should begin to retreat to weaker levels by then. A weak Nina in February w/ a negative QBO is usually a great combo. I think what is driving the bus right now is the EPO (NAO component possible), and until it relents...going to assume blocking trumps the rest.

Even though that last storm is highly doubtful on the 18z GFS and because there is really a pause for a bit until the next models roll....that storm is a great example of a vortex coming into central or SoCal and causing a winter storm here, ie the Los Angeles rain rule. The GFS does seem intent on building a glacier in the Apps for sure. Prob isn't right, but lets see if the Euro AIFS has a hint of a storm around the 24-25th. Ensembles have keyed on that timeframe of late. Gonna be a fun clown map for the full run nonetheless.

And somehow, the GFS goes from that crazy northwest low to a SE winter storm...just like that. What a wild model. It is DGEX level right now after 150 on most runs.

It is everywhere right now, man. Hope you don't have it, but if you do...hope you feel better fast. Some great anti-virals out there right now - probably the only silver lining if you can call it that.

I think the thing to watch for is energy diving into the back of the trough around the 17th. The 500 Geopotential maps look ripe for mischief on the GEFS. I tossed the GFS as soon as it started to transfer energy from Calgary to Seattle - same deal where it tries to connect to energy 400 miles to the west and not realistic.

The West has had two atmospheric river events so far this winter...probably technically one, but really two good storm cycle in Mammoth. We normally(I don't think) get the Pineapple Express until Nino winters. I wouldn't mind a strong STJ w/ so much cold lurking. The thing which interests me the most is HL blocking trapping part of the TPV, and forcing it southward. We are playing w/ house money right now since climatology supports our coldest weather at this time of year. It is probably one of the few times of year where I find the coldest wx model, and ride with it (with some confidence that other modeling is too warm). The main error was the GFS trying to extend a piece of the trough almost 1,000 miles to the West which just wasn't realistic. It has had some really weird runs since Thanksgiving. Another one is under way where it has a beautiful block over the top, but zonal flow underneath for a time - not realistic IMHO. I did notice that @Met1985said the GFS was the only model which got the mountain snow overnight correct. Other models were to dry. I suspect that is true for the 17th. I little 1-3" slider wouldn't surprise me if it occurs at night.

The irony is the 18z GFS, now that it has sobered up a bit, is still producing some decent clown maps. It could have a little bit of DGEX in it, and probably does. However, I do wonder if it is handling the qpf a bit better? Still has 6-10" over TRI w/ both systems, and the GEFS has been pretty steadfast in that. It still would be a coup, but at least now it would be a realistic coup. The 1,000mi Pacific fetch is not present on this run. The 17th vort looks pretty vigorous. I suspect your original thoughts may end up being correct. The NBM is pretty aggressive for a model which most of the time is not.

Can you spot the error? 18z is on the left. 0z from last night is on the right. It isn't just the little system in the PAC. It is the unrealistic fetch and completely wonky northern stream depiction. The 0z run last night was just a really, really, really bad run from a model standpoint IMHO. Now, that 18z is running...we see a realistic system which "might" increase precip w/ future runs.

Th 18z AI GFS(yeah, I know) is wild. I really wish it had winter numbers for ice and snow. As is, you are left to guess. I do think ice is a huge risk w/ this pattern. The 18z GFS has two, light snow events...the 17th event has a bit more moisture. Read the advice from MRX regarding northern stream systems. Let's see if the 17th system doesn't start to add back some moisture during the next few runs. It is just now coming out of the 5-7 window where sometimes systems get "lost" and still might be a couple of runs from exiting that window.

***MRX***.DISCUSSION... Issued at 1249 PM EST Sun Jan 11 2026 Currently a few snow showers are moving northwest to southeast across mainly northeast Tennessee and southwest Virginia. These showers are producing quick bursts of light to moderate snow for several minutes before quickly moving out, even with temperatures in the mid to upper 30`s. It`s strong enough to cause a dusting of snow accumulations, especially in the higher terrain of the northern Plateau, but once the snow shower moves out anything on the ground quickly begins to melt. Expect these scattered snow showers to continue through the afternoon hours as there is still plenty of returns back into eastern Kentucky that still need to work their way eastward. In addition the winds out of the northwest are gusting pretty good in the higher elevations with numerous places likely seeing 30-40mph gusts. Will continue with the wind advisory for the East Tennessee mountains, especially with winds getting enhanced by the snow showers we`ll likely see periods just above advisory level winds. Quiet weather and a quick warm up to start the work week with highs climbing back into the 50`s for much of the Valley by Tuesday. Front will move through Wednesday along with precipitation. Expect the precipitation to start as rain for most, and temperatures will drop overnight and we switch over to snow. Won`t get too in the weeds with model diagnostics and snow amounts because the one consistent thing with this upcoming Wednesday/Thursday system is that the long range deterministic models do not have a good handle on it at all... Which is to be expected in a northwest flow event that can drastically change based on temp/moisture availability/forcing/etc. It would be a fools errand to pick your favorite deterministic model that shows 6" of snow in the central valley, or (on the opposite end) the model that shows no snow in the valley and just a dusting in the Appalachians... and expect them to verify. In northwest flow snow events it`s a good idea to wait until the higher resolution short term models and hourly models start to ingest the upcoming event. This far out a look at the probabilistic guidance is probably of more use. The 90/95th percentile shows some very extreme amounts, but if you look at the mean/median and the 25-75th percentiles a more traditional northwest flow event is the common sentiment. For example (do not take these values as a forecast) for Knoxville some of the deterministic data shows 5+ inches of snow, but the median/mean and box and whiskers data points to a 0.5-2" event, which aligns more closely to what typically happens in a northwest snow event. Also worth keeping an eye on is the timing of the transition to snow and the best forcing. If you want accumulating snow in the valley you traditionally want your best forcing and heaviest precipitation to occur overnight as during the daytime the sun really limits how productive the clouds are at ice nucleation. So long story short with what might occur on Wednesday into Thursday. LOW confidence in snow amounts (don`t believe just a single model) HIGH confidence snow will occur somewhere with the Cumberland Plateau, southwest VA, and especially the East Tennesse mountains having the best chance to see accumulations. If you have travel plans that involve going over the Appalachians or the Cumberland Plateau plan on possible snow accumulations on the road. Good news is this event looks to be a clean transition from rain to snow, and hopefully keeping the gross icy stuff to a very short window and any ice impacts minimal. Best thing to do right now is pay attention to the forecast updates as the models will likely continue to oscillate wildly in snow potential, and confidence should begin to increase when we`re about 72 hours and higher resolution models and hourly models start to come into play. As we head into the weekend cold temperatures remain in place with yet another possible snow maker looking to move through somewhere over the eastern US. If you thought models were handling Wednesday/Thursday poorly then you don`t even want to glance at the weekend. A lot of what might happen Saturday/Sunday will depend on what happens Wednesday/Thursday, but if you have any upcoming weekend plans keep an eye on the forecast for possible travel impacts in the higher elevations.

I just read a post from JB which pointed out 12z ICON at 180. Now, I don't really use the ICON much, but that run illustrates the concern which we mentioned here(well before JB) of the TPV getting trapped and sent south. I don't think that particular ICON solution comes to pass, but it could happen a few days later if HL blocking locks cold in over NA with that big EPO in place. I don't think the scenario of the TPV getting sent south(at least a part of it) is a given, but I would give it a 60/40 chance. Anyway, that ICON run is worth a look if just for kicks and giggles.

Good looking run of the 12z ensembles today. As noted so there is no confusion...there is a ridge forecast to roll through from roughly the 22-25th. All three major ensembles are now showing the potential for yet more cold to arrive around the 25th or just after. That is good news. On modeling earlier in the week, the EPO kept retrograding into Asia and the wait for more cold could well have lasted through the first week of Feb(that is still on the table BTW). We are also seeing deterministic models flirt with VERY cold air masses. When we see the big highs which Jed mentions, that is usually an indicator of another cold air mass. The end of the Euro was frigid. We won't see that type of Euro every time, but ensembles do support the potential for yet more cold. The big thing to watch for is continued blocking over the top w/ ridging in the eastern Pacific. And we aren't having to wait 14 days for more cold...it is cold right now.

The risk of that cold air mass sits right outside of d10. The 12z GEM got to where the Euro did at 240...we just couldn't see the rest of the run. That would be something else. Still, I think we have some light snow chances prior to that...but if the GEM and Euro are correct, that would quiet the pattern after 240.

It is in fantasy land, but the end of that 12z Euro run is gonna get a lot of press if it can reproduce that tonight. The 12z GEM was flirting with it. With it being January, an EPO ridge in place, and blocking over the top....there is definitely a risk of very cold air getting trapped under that block and sent south. I don't see a clear signal yet, but deterministic runs are flirting with it. Not sure I want any part of that.

The 12z Euro traps a piece of the TPV. That is one thing we have noted as a possibility. Crazy cold at the end of that run.