nrgjeff

That's not bad right above. 1-2 West. My conceptual model has 1-3 most of Mid-Tenn, except far southern. Then 3-5 looks reasonable Upper Cumberland into Kentucky. Upper Great Valley should do better than last time. Chart looks similar at higher elevations with 6-8. KCHA remains a big warm nose risk. Signal and Lookout get snow again though. GFS below must be forecasting some banding. Not unreasonable, somewhere in the Region.

I like the GFS/Euro blend. NAM is still probably too north the 12Z run. UK Met is with the other globals south of the NAM. Still blanks Chattanooga. However it looks really similar to Sunday night. Add more for Western Tenn. If we can get a more diffuse northern boundary then Kentucky remains well in play. Track may be broader north and west. South side (KCHA) still has warm nose issues. Also does not line up as well for North Alabama (still light snow but not nearly as much).

Add the Florida Gulf Coast to places that get more snow than Chattanooga. NYC got hammered right after comparing itself to HSV. See what I'm trying to do here?

UK and ECMWF join the chorus for I-40 and I-81 north on Thursday. Looks like all good straight east of Knoxville too. GFS has an odd southern solution; so yes, I'd go with the GEFS. OK in Chatty we are praying for the GFS Op. Cold air will be in place. Might not start below freezing, but it's not starting at 70. Starting around 40 is doable with an east wind, except for... you know. ECMWF weeklies in cold for three weeks. Could be a fun January. It has MJO support attm. AN rain Deep South and BN precip here is a good look. Snow holds less moisture.

Chart below is important enough to post twice. I just eyeball the convection on the Pacific satellite. The 200 mb divergence or 850 mb convergence or outgoing radiation all show the same thing. Why make it complicated though? Satellite is simple. Now one can look at forecasts of the other variables on the models, but satellite is by far my favorite diagnostic tool. One can also loop it to get an idea for the next couple days. With up to a 7 day lag for effects in North America, that goes pretty far. Oh yes convection is in a favorable area for cold in the Southeast. China chart is also favorable with Siberia ridge and South China storm track. See @jaxjagman above. Sometimes China and US weather go together - depending on what's going on in Alaska. I like 2-3 weeks of cold. Mild interlude sometime next week would not shock me. Northwest Canada ridging never really settles down, so I could go with the CFS 16-20 Day with another cold shot. Unfortunately that could be it. I'm joking spring starts after Martin Luther King Day. However if the mild interlude fades (to normal or cold) late next week that could be signs of a more durable cold pattern.

Yeah @Uncle Nasty we know the physics, but it's still a tough pill. I mean the picture right above is not that far away. Chattanooga is of course the lowest elevation; so, downslope does more here. Also the Mountains are directly east-northeast, so that just magnifies the relief over which the downslope travels when a surface low is pivoting. KCHA misses the critical time of snow. Cold air simply must be in place first. We've done it from mid-30s before, but I've never seen it starting above 40 with rain. Tri-Cities is always a pressure cooker. I mean at least in KCHA we can just set our expectations low - or go up Signal/Lookout where it snowed. Kingsport has to get going early on the east wind; otherwise, the north wind on the very back side is downslope. Johnson City often has to endure downslope crap before the wind turns around more. Parimutal racing metaphor. Kingsport is a breaker and JC is a closer. If Kingsport does not break it's over. JC just has to wait. Bristol seems to behave a little closer to the Norwegian cyclone model, unless warm nose hell which often delays.

Some crap never changes. Expected but still... Congratulations to everyone else who got snow. LOL Tuscaloosa but not Chattanooga. I understand the physics but I'm still shaking my head in disgust. Again, I'm happy for everyone else in the entire free World who got snow!

LOL Tuscaloosa gets snow and Chattanooga is blanked. Sh!t no wonder I like severe weather. Birmingham eventually change over? Otherwise Chattanooga needs a friend of misery.

Yeah it's nowcast time and the models add less incremental value. Knowing climo is why I'm so cynical in KCHA. We have a nice baroclinic leaf on both satellite and radar. It's not moving terribly fast either, since we are still pre-pivot. Except for Chattanooga proper, I think all systems are go. Signal and Lookout will definitely have snow. Last post of the night. Best to all!

SPC is licking the column in Chattanooga after the triple dare. Best thing about a Christmas Story is they did a good job with all that snow outside.

SPC Mesoscale discussion does not account for the Great Valley. I don't expect a micro-scale map, but that broad brush is pretty bad to be honest. Chattanooga in the heart of the heavy sticking snow? Um, no. That aside, SPC seems to be with the local WFOs. They see the trough pivoting negative. That will indeed cool the column in a hurry. Lower Great Valley won't benefit much due to typical downslope and oh my it's still warm! Still SPC makes good points about the rest of the system. More than Feb. 2020 it reminds me of an event back in Kansas during October. Don't ask how long ago, haha. Tight low came in while temps were above freezing. Low pivoted negative and dumped 1-2 inches per hour snow.

Yeah grassy areas are not melting if it's in the 20s, even if the soil is still 40s. Roads will probably quickly improve after it ends though. Obligatory back deck and grill pictures will be preserved most of the morning. Looking forward!

Arctic fronts are good at coming in quicker west of the Plateau. I think you're right. Unfortunately the Great Valley can not escape downslope, esp below Maryville, Tenn. Chatt temps are still nutty warm. Plateau blocks low level cold. Smokies double down with sinking motion out of the East. I'm not sure why MRX is so optimistic. I always love mention of the T-word though. Good for points north and east and west and even south. TROWAL!

Here are screenshots of video from near Muscle Shoals on New Year's Day. Two separate supercells produced rotating wall clouds, but I could not discern any touchdown. A middle second sup is not pictured because it was garbage. Thanks to @Fred Gossage excellent TV and radio commentary. First supercell near town about 3:30 pm Third supercell just south of town 5:00 pm

In Chattanooga we remember all the big strike-outs. Bottom of the Ninth Game 7 WS with RISP. All we need is a blooper. WhifX3! There was the Chattanooga Saturday miracle February 2020. Nice things before the Pandemic, lol!

Lock in that RAP. See Chattanooga forecast. Rest of y'all are good to go!

It's just the HRRR. In all seriousness probably some sleet. Eventually it's changing over and snowing for a few hours. DGZ ain't bad either. Can't always be perfect saturation. Hopefully inside 12 hours a Red Tag does not jinx it. Still thinking warm nose hell dusting or less KCHA. I like almost every other forecast point in our region.

So Tornado Warnings and Watches improve the effect over general thunderstorms. Just kidding! Regarding the Great Valley, it's definitely downslope. Cold air likes to get trapped. Warm air would rise through cooler air (instability) or just be static stable (all else equal). Of course with terrain it's not equal, and we get downslope instead.

Yes it was an excellent bowl game. Very entertaining for neutral fans and the national audience. Now I'm ready for basketball and other winter things. Red tag can't say the word for risk of a jinx.

Well @Holston_River_Rambler we might be able to enjoy some SREF plumes. I just saw the 12Z stuff for Sunday snow. So we can be disappointed on both the storm and winter side? I'll check that snow stuff later. Yes @Carvers Gap you make good points about UT. I was just stomping around the living room and barking at my TV.

Saturday will depend on the prefrontal trough. Main front is veered off with parallel upper level flow, not really a tornado machine. Mississippi and Alabama will start Saturday capped. However the cap will gradually erode. Prefrontal trough is forecast and will be there. Question is the cap. If the cap breaks down there, discrete supercells will bring their usual threats. They would probably go from rooted to tornado in an hour. That kind of shear, this time with low level flow, would spin up tornadoes rapidly. Would be MDT but too early to make the call now. That's only if the cap breaks. If the cap holds then it'll look a lot like Wednesday - which still had Sand Mountain tornado(es). However that's not a huge day across the region. SPC should hold with ENH on this afternoon's Day 2.

Always Sand Mountain @SmokeEater Also saw a report from Rainsville, another common event. It's almost the Cullman of the Mountain.

Well Tennessee is a sports betting state. ACC Refs could do it under the radar. Also UT play calling was atrocious late. Why pass when you can run up their gut? Unbelievable! @Bigbald we pulled off a Christmas miracle and skied Cataloochee, NC before these closures. I believe this is uncommon. They can usually make snow a majority of nights even in mild wx. The string of well above freezing nights is a deal killer. Good news those snow guns can make a ton of snow at night. What we see during operating hours is nothing. They can be open very quickly this week after just a few cold nights.

Boundary, clearing skies, and increasing surface winds has reached the Tennessee border with Mississippi and Alabama. Watch is valid. Another Southern event looks poised to over-achieve relative to 36 hours out. Still think Enhanced 10% hatched covers it. Not quite Moderate material, but it's getting close. I'd keep Enhanced. Word watches bluntly, but not strongly. In addition to the lifting boundary, appears a pre-frontal trough runs north to south in Mississippi. Could be a focus for robust new development.

Thanks MRX I'll look forward to that sh!t after dark. At least it'll still be evening, not late night. Remember even storm chasers don't like that crap after dark. Virtual chase target is northeast Mississippi to northwest Alabama, into southern Middle Tenn. That's hideous chase terrain so no real chasing. Lunch in Corinth, Miss. would offer options south into Miss. or back east into Bama. However the immediate tri-state (with TN) is completely unchasable terrain. Punt! Oh yeah, lots of college football on today too. Cheers!