textproduct: Morristown

KEY MESSAGES

Updated at 1258 PM EST Tue Jan 20 2026

- Confidence in a significant winter storm affecting the southern Appalachian region Saturday into Sunday is increasing. However, it must be stressed that details on where the axis of heaviest precipitation and resulting wintry precip totals remain unclear. This weekend's system should be monitored closely over the next couple of days.

- Cold air behind this weekend's storm will keep temperatures at/below freezing for at least a day or two. This will prolong the effects of any winter weather, with power outages possible as well.

DISCUSSION

Issued at 1258 PM EST Tue Jan 20 2026

Confidence continues to increase with regards to the potential for a high impact winter weather event affecting the southeast United States this weekend. As such, I'll devote nearly the entirety of the forecast discussion to that event.

Strong, deep troughing will remain over much of the central and eastern CONUS over the next several days, with quasi-zonal flow in place across the Gulf coast. One impulse embedded in the upper trough will drag a cold front into the region Wed night into Thu with some light rain expected across the forecast area. Afterwards a strong +1050mb surface high will drop out of Canada into the northern plains on Friday, reinforcing the front across the region and leading to some additional light precip on Friday possibly. However the main show is Saturday into Sunday. A very strong jet over the Ohio valley into the northeast, coupled with an upper low ejecting east from southern California, will result in widespread moderate to heavy precipitation across Tennessee and the surrounding areas. Timing wise, models agree fairly well on the bulk of the precipitation starting around daybreak Saturday and continuing through Sunday morning before tapering off Sun afternoon. Where there is still significant disagreement, revolves around precip types and amounts. Some guidance indicates a warm nose pushing north to the I-40 corridor while other guidance keeps it south of the Tennessee/Georgia border. The former would support significant icing in the south while central and northern areas get a significant snowfall event. The latter would support snow everywhere, with lighter totals further north and heavier amounts along and slightly south of the I-40 corridor. At this point in time, it's difficult to tell which scenario is more likely to play out. What is pretty clear though is that a highly impactful winter weather event seems set to play out across the southern Appalachian region Sat and Sun.

Regarding totals and precip types, it is worth noting that PWAT values for this event are well above climatological averages. That's significant since it's more likely to see unseasonably high PWATs in warm, heavy rain events versus cold winter weather events. Given the thermal profiles snow ratios aren't going to be crazy high, so I would expect the snow to be a heavier/wetter type. This coupled with the potential of some icing somewhere means that power outages will be a distinct possibility.

Lastly, whatever falls on Sat/Sun isn't going anywhere in quick fashion. Temperatures on Sunday through Tuesday are going to be quite cold and I undercut NBM guidance a bit on Sun/Mon to account for temperatures being impacted by whatever snowpack is present.

AVIATION

(18Z TAFS) Issued at 1237 PM EST Tue Jan 20 2026

VFR TAFs with no significant weather through the next 24 hours. Low risk of LLWS around daybreak tomorrow at KTYS, but winds aloft currently expected to remain below thresholds. A few gusts as mixing begins around 15z likely at KCHA as the wind field strengthens. Otherwise high level clouds will begin to increase by the end of the period.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 24 53 38 52 / 0 30 60 30 Knoxville McGhee Tyson Airport, TN 20 53 37 52 / 0 20 50 20 Oak Ridge, TN 21 50 35 50 / 0 30 50 20 Tri Cities Airport, TN 17 50 33 48 / 0 20 40 20

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...NONE. VA...NONE.