Carvers Gap

Man, the GEFS ensemble and deterministic after d8 are waaaaay out there on an island. The 18z GEFS going the deterministic run. The 18z GEFS ensemble has no support from any other ensemble run. The 18z AIGFS(which JB hates) is truly an awesome pattern by the end of its run. edit: Some halfway support from the 18z AIFS Euro. But the AIFS Euro looks pretty good. I think the cold will be centered back a bit further west than early December which is probably not a bad thing.

I also think the 8th is starting to be a trackable window. No guarantees, but it is showing up across modeling and at 500 on ensembles. With the NAO block likely in place, it is certainly a realistic option.

Kind of a minor event possible on NYD from the Plateau into SE KY, SW VA, and border areas of NE TN. Maybe we can cook something up per the 18z RGEM. I don't think anything more than a dusting or snow showers, but we have seen these trend south at the very last minute - as in the radar is the only thing that verified this far south.

The 18z GFS definitely trying to get in on the action. It has a storm which cuts into the forum area, but still manages to stay south. The good thing? It is the GFS at 10 days. The great thing? Good storm track.

I think the dry conditions(outright drought) in some areas of the forum is worth a continuing discussion. The southern edge of our forum is really dry as is west Tenn/eastern Arkansas. The southern Apps, as is typical w/ La Nina, are BN for rainfall. MBY is normal which has not been a usual occurrence of late. Thankfully, I think as we trend towards El Nino this summer....we will see a normal summer for temps, rain, and a reduced risk for endless summer next fall. If El Nino takes hold early enough, we could see cooler than normal temps later in spring.

That is a really good run of the Euro Weeklies(which are now dailies!). Ridge out west w/ it bridging across to Greenland. This is generally supported by some of the colder analogs. This pretty much holds throughout the run. Now, I have been doing this for a while....it likely won't hold for 6 weeks. The weeklies kind of just roll with week one and don't really move from that pattern sometimes. As @John1122notes, that storm track is a good one if it verifies. A word of caution: There has been no more fickle beast in wx modeling than LR modeling this winter. I wouldn't develop a long term attachment!!! I have 2x30day chunks at 500 posted. I mainly have done that, because each kind of tells a different story - both good for winter in the Tennessee Valley. I add two control images - you know I like the control. The temps map I think is a little bit less washed out, and it gets cold on that control run! The snow map is very similar to the ensemble, and that is likely a good sign. It is basically snow climatology, but I will take average vs none. But it gives us a good idea of the storm tracks possible - sliders, cutters, and inland runners. And if you need something to be concerned about if you like snow...I have that for you as well. Now, the good thing is that BN precip prob means it has been cold. I definitely am in the school of thought that we do a lot better when cold is in place. So, there is good and bad with this map. I don't have to explain the bad.

I use photobucket. @John1122mentioned a service he uses as well. I use photo bucket. I just upload the photo, and then grab a hosting link for it. Some hosting sites are free and some are maybe five bucks a month.

Also, ensembles are starting to honk that an Alaskan block is setting up. Now that....that would deliver cold.

The 12z AIFS Euro has three storms back-to-back-to-back. Easily the best suite of the year in terms of just synoptical setup.

5 day mean for the deterministic 12z Euro...~d6-11.

It is quiet in here to have such a good 12z suite. The 12z Euro looked loaded. Very nice run with plenty of chances and actual snow embedded in the run.

Winch chills here in Bristol are in the teens. Flurries are in the air. What a reversal in temps.

The 12z CMC has the EPO in place by Jan 6 with a nice pattern in place by the 8th - eastern trough.

I thought the 12z GFS was close with two storms on Jan 7 and Jan 11. Sure enough, the 12z CMC which doesn’t have a progressive bias…brought it. Good look. Big storm.

Really good example of a NA ridge retrograding at mid latitude w/ the HL ridge also doing the same. If that is stable, that is game on and very tough to break down. If it traps a piece of the TPV, even better for winter weather. Bottom up strat splits....do they affect the troposphere immediately? Good overall trends continuing on modeling overnight.

Met, how does that scoring system work? Blues, reds, yellow, points?

I should note that no records have been broken at TRI that I know of. Anyway, this is for posterity and future use. What a temp change to go from near record temps on Sunday to single digit wind chills tomorrow night and below zero winch chills in the mountains! National Weather Service Morristown TN 140 PM EST Sun Dec 28 2025 ...New DISCUSSION... .KEY MESSAGES... Updated at 1233 PM EST Sun Dec 28 2025 - Very warm this afternoon with possible record highs being broken again. - Showers and a strong cold front cross the area tonight and early Monday morning. - Strong gusty winds expected area-wide this afternoon through Monday, especially across the higher elevations tonight. Either Wind Advisories or a Special Weather Statement is in effect. - Much colder air moves in behind the front. Wind chills near zero are expected across the higher elevations Monday night, and highs in the 30s on Tuesday. && .DISCUSSION... Issued at 1233 PM EST Sun Dec 28 2025 One more day of well above average temperatures before a big pattern change beginning tonight. Low 70s are currently being reported across parts of the valley this afternoon already. Will include climate stats below. Daily Record High Maximum Temperatures: Date Chattanooga Knoxville Tri-Cities Oak Ridge 12-28 73(2015) 76(2015) 73(2021) 72(2021) Southerly to southwesterly winds are also occurring. Expect these to increase throughout the day and overnight tonight. A low center currently over Iowa and Illinois, will deepen through the day as it tracks towards the Great Lakes. A cold front will then develop and trail it to the southwest. Damming to the east under high pressure will kick-start the winds over the Southern Appalachians likely earlier than anywhere else because of increasing pressure gradient. This will not be a true mountain wave set-up for the Southern Appalachians given the flow direction with the frontal passage, but there will still be gusts to near 50 mph, as indicated by the Wind Advisory in place there. Wind Advisories were also added for the plateau and southwest Virginia counties. Upon looking at the latest guidance from HREF, RRFS, and others, winds appear they will generally remain below advisory level for the rest of the forecast area - valley and SW NC. A Special Weather Statement through Monday morning was issued there mentioning gusts up to 35 mph, with possible pockets of near 40 mph. After 7 am or so, winds will slowly decrease from west to east, but will hang on for the most part for the eastern higher terrain. The primary direction following the front will be from the west. The warmest temperatures tomorrow will likely occur near midnight for the forecast area, as the front makes its mark during the overnight hours. A line of showers will accompany the front, but the most we can expect are gusts translated down to the surface from aloft with any gusty showers. The strongest of any storms or severe weather threat, will remain close to the low`s center south of Michigan. It appears any influence of return- flow/northwesterly flow behind the low will remain to our north. With lows in the 20s and teens for the higher terrain forecast Tuesday morning and some winds persisting for the higher terrain as well, wind chills near 0 will be possible. Weather turns dry later tomorrow through Wednesday. High temperatures will rebound 10 degrees or so from Tuesday into Wednesday. A weak system will approach from the north Thursday into Friday, bringing a chance of light precipitation, with best chances across the northern part of the forecast area. By next weekend, precipitation chances increase from the south as the front stalls to our south. Where this sets up may determine how much precipitation we see. The southern valley and SW NC could sure use some beneficial rain to remove some of the moderate drought.

This front tonight and tomorrow is going to be powerful. Real feel temps will differ almost 40 degrees from one end of the forum to another. According to the 18z 3kNAM, wind gusts could reach 40mph as the front passes through. The 18z HRRR, has gusts up to 50mph on the Plateau. Behind the front, on Monday and Tuesday wind chills very well could be in the single digits. Actual temps tomorrow night and Tuesday night should be in the mid teens to upper 20s. Winter is about to come back with a roar. The 3k Nam is picking up on some light snow bands as this passes in eastern areas. It doesn't have much accumulation, but it wouldn't surprise me to see the usual places at higher elevations get some light amounts.

Sign me up for this. Keep your fingers crossed. BN heights east or north of Hawaii(maybe a Kona Loa low???), ridge out west, trough in the east -NAO hooked into the EPO ridge, storm signal on the EC. If you were to design a winter pattern for our area...that is it. Most modeling has some iteration of this, but this is by far the best look. Notice the four quadrants in the northern hemisphere of cold and warm - 4 blues and 4 yellow/orange. Notice the HL blocking over North America.? Notice that Europe is also cold? That map teleconnects well. I don't really trust modeling right now, but this map doesn't have the craziness. The ridge over the EC today retrogrades into the West.

Seems like a much cooler suite. It could just be ebb and flow, but a lot of cold is present(even if AN at times) in Canada when compared to earlier runs. If the BN temps remain in Canada w/ an EPO/NAO couplet....it should come SE. Remember that 84-85 analog map(should be in the December thread) of the December warm-up in 84? While I don't think we see that type of flip, we could certainly see a lot of cold air headed south if trends continue. When I was growing up and spent some time on a farm, we generally enjoyed warm-ups at this time of year...but we knew what was likely coming next. Maybe the thing which is most encouraging is that ensembles are catching up now. If they are under playing the pattern(as they have for most of the season regarding cold), this could be a very cold pattern upcoming. I still want a 3-4 more days of model runs for things to get dialed-in though.

AMAZINGLY(and I use that word sparingly), models kind of settled down today after 300. Check out the 12z Euro and GFS at 360. That is a really great pattern. The good thing is the Euro gets there pretty quickly. With the Jan 2 trough, the Euro never really lets the ridge come back East. It simply retrogrades the ridge further west with each passing vortex -> that is probably the most likely scenario. Simply put the map in motion at 500, and watch the ridge keep popping up further west. If we can manage an EPO ridge which couples w/ the NAO block(and traps cold under it....better than 70/30 chance in my mind)...we might like where the surface pattern goes.

The 12z Euro eventually traps cold air "under" (latitude speaking) the block. It gets a bit wonky, but (and it might be wrong still) it kind of makes more sense than the other stuff we have been seeing. That IMHO makes a lot more sense than the tendency for an Alaskan vortex that deepens to a point that it is creating a temporal vortex which rips space and time, and empties Canada of cold.

Now, I look at this map, and everything kind of fits and makes sense. There isn't a lot of feedback (edit, well the NAO is pretty strong). The -NAO is still there. The trough on the West Coast probably wants to slide east...and then a western ridge "should" rebuild right after it. That is perfect placement for an NAO. Any low road slp w/ that block in place has to be watched. That is a very good look in my book.

If that EPO ridge hits and holds around Jan 10th, I think we are in business. Dec 28-10th has always seems kind of like a back and forth pattern to me. But yeah, modeling is just wild right now. I would suspect during the second half of January, we possibly could see some very cold weather if not before then. Right now, when I see model feedback(deep reds or deep blues), that run is toast from that point forward...but still fun to watch. With that NAO block in place, really anything after Jan 2nd is fair game to track. I am just hanging out and watching the LR pattern until we get to that point. Depending on which model and which run...this could be a really wild pattern or a dud. I have no idea which...but I lean towards cold and stormy the deeper into January that we get. With models struggling to "see cold," my money is they aren't seeing some cold fronts right now. As for the MJO, low amplitude and all over the place. I am not sure it will drive the bus for a bit. I am banking on the QBO and HL blocking running the show. As long as we don't stall in 6, I think we can over-ride it. The good thing is that we are likely exiting the chinook pattern tonight when that howler of a cold front announces its arrival....

I am back from my early Knoxville run today....there is one way to get rid of feedback from the Alaskan vortex, and that is to replace it with feedback from an EPO ridge. LOL. 384 from the 0z GFS today. I don't know what is going on w/ that model, but the juice is loose with it. Somebody slip some DGEX code into the GFS programming?