Carvers Gap

This pretty much sums it up...models are all still all over the place. National Weather Service Morristown TN 606 AM EST Thu Dec 4 2025 ...New AVIATION... .KEY MESSAGES... Updated at 601 AM EST Thu Dec 4 2025 Dry weather today before increasing precipitation chances tonight into Friday. - Probabilities for minor impacts from ice and snow are trending upwards across the northern Cumberland plateau, southwest VA and extreme northeast TN for tonight into Friday morning - Very low probability of rainfall this weekend. && .DISCUSSION... Issued at 1240 AM EST Thu Dec 4 2025 Dry today with continued below normal temperatures. Increasing precipitation chances tonight into Friday morning. The good news is that the latest HREF probs mostly align with the previous forecast. The bad news, the last two runs of the HRRR are well above the HREF means in terms of snowfall amounts. This makes for a low confidence forecast. Latest HREF guidance shows probs for at least 0.5 inches across southwest VA are in the 30 to 50% range. Probs for at least 0.5 inches for extreme northeast TN are generally from 50 to 70%. There are also low probs, 10 to 20%, of at least 0.5 inches across the northern Cumberland Plateau and areas along and near the TN/KY state line. Upping the prob amounts to 1 inch yield much lower values, around 30%, but for very isolated locations for both southwest VA and extreme northeast TN. The LREF members shows slightly higher prob values, and with more spatial coverage, for the 0.5 and 1 inch prob values. LREF shows moderate probs of 1 to 2 inches across southwest VA and into extreme northeast TN. The REFS output aligns fairly well with the LREF ensemble probs. Then we have the HRRR. The latest two runs of the HRRR show even higher values than what the REFS and LREF ensembles means suggests. The HRRR wants to paint a solid 2 inches in across the northern Plateau, and 3 to 4 inches in across southwest VA and extreme northeast TN. Because of all this, uncertainty in snowfall amounts is high. These higher end amounts would result in travel impacts while the lower HREF amounts suggest little to no impacts. With this forecast package, have trended snowfall amounts slightly upward, above NBM, based on latest model data and trends. In addition to the snow, NBM also painting in some light icing across these same areas. Please stay tuned to the forecast as the snowfall forecast will likely continue to change given the current variability. Please plan ahead for potential impacts with this system. Areas from Knoxville and south should remain all rain through the event. The bulk of the precip will have ended by Friday afternoon, but a few light showers may linger into the evening hours. NBM still wants to hold on to some slight chance POPs for Saturday and Sunday but it seems warranted so will leave them in the forecast. Rain chances continue into next week as an active pattern will be in place across the country. As of now, Tuesday look like it should be dry though and is most likely to be the nicest day of the forecast period.

The 18z Euro has a light upslope clipper around the 8th....need to keep an eye on that one.

Some nice trends on both the NAM and RGEM if you like frozen. To me, this also bodes well for future systems. It looks like modeling under-did the NW shield of the precip. So this super dry sliders which follow tomorrow night...might have a bit more juice. Good luck on overnight modeling to everyone. I hope someone gets an early season snow!

Let’s see what MRX notes with their next update in regards to soundings.

HRRR looks like it is has some downslope over the eastern valley. Looks very similar to its 18z run.

What is crazy is that the Euro Weeklies had this timeframe as a bullseye before they infamously had an infinite loop of feedback over the Southwest...and pumped crazy temps into the East. Now, we are tracking a potentially light winter wx event for northern areas of the forum. I wouldn't be surprised for glaze to show up further south.

MRX noted in their disco that soundings indicate all snow in NE TN but light. Again, time of day is important. If this comes in at night, could be frozen for many areas.

Looks like a little lee side slp???

It would not at all surprise me to see this trend SE or NW. LOL. The cold could push more than expected...we have seen that trend on a lot of models at 18z. OTH, we have all seen systems jog northwest at the last minute. I need to look at the 500 vort map. The RAP is a good model. To some extent, we see that same setup on other models...just not as juicy. Plenty to track beyond this event as well. In the valleys, we are trying to get a head start on climatology.

This kind of shows the idea. The 3k name is decidedly SE of 12K. The 18z ICON is north. I am using the two models which serve me decently well at short range. They are just about where I can rely on them decently well The 18z RGEM is running now. Similar to 12z. It has more ZR. See MRX comments above.

The 18z HRRR has decent returns over @John1122's and @Shocker0's places. Mix ove TRI. Snow over SW VA and SE KY. If that stays the same, I would expect MRX and JKL hoist winter wx products tomorrow evening at the very lates...maybe tomorrow morning once the actual axis of precip is determined.

National Weather Service Morristown TN 117 PM EST Wed Dec 3 2025 ...New DISCUSSION... .KEY MESSAGES... Updated at 115 PM EST Wed Dec 3 2025 - Dry weather today and Thursday before increasing precipitation chances Thursday evening into Friday. - Moderate chances for light snowfall across extreme northeast TN and southwest Virginia early Friday morning. Minor impacts are possible. Elsewhere, will get rain Thursday night into Friday. - Very low probability of rainfall this weekend. && .DISCUSSION... Issued at 115 PM EST Wed Dec 3 2025 In the upper levels, nearly zonal flow or slight troughing will be over the region through the weekend as a big, broad trough dominates the Central and Eastern U.S. At the surface, high pressure will be over the region through Thursday. Thursday night into Friday, a Gulf Low moving eastward along the Gulf Coast will bring overrunning moisture into the region. Rain is expected for most of the region Thursday night into Friday. Temperature profiles support light snow Thursday night into Friday morning for Southwest Virginia and extreme Northeast Tennessee. Freezing rain probabilities are low in SW Virginia and extreme NE Tennessee and model soundings show a deep enough cold layer to support snow. By mid Friday morning temps will warm enough for a changeover back to rain. The lower elevations may get up to half an inch accumulation and the higher elevations may get up to an inch of accumulation. Minor travel impacts will be possible during the morning commute Friday but will be confined to SW Virginia and extreme NE Tennessee. The Tri-Cities area may see a few flakes but little to no accumulation is expected there. HREF guidance through 12Z Friday have snow totals below one inch. The Tennessee Valley won`t see any frozen precip with this system. HREF guidance doesn`t cover this whole event yet so hopefully the next forecast cycle will bring more confidence. Rain chances will be very low for the weekend and into early next week. One or more shortwaves may move through the pattern but moisture will be limited. Rain or possibly even a brief snow will be possible at some point but there is too much uncertainty to nail down specifics at this time. Widespread travel impacts are unlikely this weekend.

The 3k/12k NAM at 18z look decent for NE TN and SW VA. The 18z RGEM has not run for whatever reason.

We didn't start Carey in the second half. That cost us the game. 'Cuse blew our doors off when he was out. When they put him back in, we came all the way back, but it took too much effort. The good thing is...I think we have our starting lineup now. Ament, Boswell, Gillespie, Carey, and Estrella(when he returns). That group can score. Then we have Abrams and Brown coming off the bench. Domes are weird places to shoot - lots of air balls until the 3 gets dialed in over time. Barnes noted that Carey and Brown is(are?) the best offensive combo in the post until Estrella returns. We came back when those guys were banging in the paint. Ament will get there. He just isn't used to getting jostled. He will toughen up and be good. Even 5 star HS recruits often have to earn their stripes!

The 12z CMC is also trying to pop a coastal. As is, it would create light frozen precip/mix for the 8-9th. NC would stand the best chance with the CMC setup, and those folks have not had a lot of snow in recent years. Good for them if so. If that is a real slp, look for it to maybe continue to trend northwest. A lot on the table at 12z...nothing big at this time, but fun to track for this early in the season. It is important to note that the GFS can be a bit progressive in these setups. I would expect it to be on the SE envelope of options at this range for the 8-9th.

I have hated to even say it out loud, but that scenario has been on modeling for days...just a bit to our SE. Now, things are trending a bit northwest. It is a narrow boundary for that to occur and a bit early in the season for the valleys, but I could see places above say 1800' scoring with this.

@Holston_River_Rambler, I do think the RGEM looks a bit too cold. Time of day is key I "think." For ice in the eastern valley, the cold air has to get trapped. Usually for that to happen, we need a clear sky to start the evening and temps drop. Then cloud cover slides over between 2-4AM and traps the cold air in the valley. I just am not sure. I do think SW VA looks prime for good snow as is SE KY and prob the Plateau if the precip can make it back that far. NE TN is a crap shoot. What interests me is the slp popping to the SE.

Very close to a Nor'Easter w/ the 8-10th system. The ICON just about pulled it off. The 12z GFS pops a coastal over eastern NC.

Let's try this one more time...the 12z GFS has a second wave of frozen precip Monday for areas along the northern Tenn border, KY, and SW VA. The 0z CMC had this as well - waiting for its 12z run.

We are close to having to start a thread for this weekend. The 12z RGEM has ice over much of the eastern valley. The 12z GFS is less formidable, but has snow for SW VA and NE TN. The 12k(edit) NAM has snow over the Plateau and SW VA/E KY. Very close call, and getting dicier with each run.

And that CFSv2 at 6z sure looks a lot like the GEFS ext last night for December.

JB mentioned that all of the predicted stalls of the MJO have not occurred yet. He said modeling is having to adjust to the idea that the MJO is just continuing on around. Now, FTR I am not opposed to the Euro idea of a stalled MJO in 8-1! I really don't know honestly. I do think the MJO is going to reload though and rotate around once again. I found the CFSv2 seasonal this AM to be reasonable for DJF. This fits with a weak Nina. I have noticed multiple models w/ the NAO beginning to fire. To me this implies that cold drops into the Plains, very cold air at times. Then, the cold pushes south eastward. Basically this goes in sequence....cold -> thaw -> very cold.

No wonder models are all over the place....

The good thing that I see with regards to the mid-month ridge rolling through is that it is temporary on all ensembles this morning. It is always in the realm of possibility that the ridge is a pattern change, but for now it looks transient at best(3-4 days at the longest). That ridge, as long as it rolls through, could very well set the stage for the coldest air of the season(so far) to fill that trough behind it. There are pretty strong mechanisms in place to deliver cold air d10-15.

The 0z 3kNAM and 0z RGEM show frozen precip over NE TN and SW VA over the weekend. Just something to keep an eye on....