Carvers Gap

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?

I don't know how I feel about the GEM para, but it isn't giving up its Arctic air to the GFS without a fight. Honestly, it probably looks the most sensible at 500 along w/ the AIGFS.

I will add that it might be worth watching that Jan3 system on the GEM. The GEFS(as bad as it has been) has had a slider or two in each of its ensemble members. Low and behold, there it is on the GEM...rain, but decently cold temps and still time for that to trend.

But really, if we can score this....we take it.

What do ye call this here ridge?

Well, I looks like models have returned thankfully to their typical biases (instead of random solutions which make zero sense). Right now, I would roll with the deterministic Euro and GEM runs at 0z. Their progression makes sense, even if it a bit wonky. The 0z GEPS, 0z EPS, 6z AIFS Euro, and 6z AIGEFS ensembles general support the determinist Euro and GEM from 0z. Though I won't toss it...the GFS/GEFS combo is an outlier at this point. Overall, good trends overnight. We can have good winters even if the cold in Canada is AN but polar - if it is January. Plus, there is a lot of snowpack up there, and I have my doubts(GFS) if it gets scoured for long(if at all). Great disco overnight - read back prior to this post. Get that EPO ridge in place, and Siberian cold would possibly plunge into North America.

Don't know if I trust ensembles or not...but the Euro AIFS ensemble and GEFS at 18z make a lot of sense, though different on several levels. The 18z Euro deterministic AIFS actually ends up w/ a strong EPO/PNA ridge with split flow. Maybe that is where this is headed. If so, Canada would restock w/ very cold air in days, and set the stage for Cosgrove's last third of January to be frigid. Those seeds seem to be in place in LR modeling. I think we have chances prior to that, but just commenting for Jan 15-31st. Either way, it looks some HUGE back and forth cold/warm swings could be in play....I still kind of think Jan 2 is being under modeled in regards to cold. I will try to update one more time as ensembles finish running....with individual members in an effort to sift through this.