textproduct: Morristown

KEY MESSAGES

Updated at 758 PM EDT Sun Sep 27 2026

- Cool and dry conditions continue on Monday, but a notable warm up is expected Tuesday onward, with temperatures rising several degrees above normal.

- The forecast for Friday into next weekend remains uncertain. Does rain return by Friday, or hold off until late Saturday? Details aren't clear at this time.

DISCUSSION

Issued at 147 PM EDT Sun Sep 27 2026

Upper troughing will continue over the NE CONUS, with ridging from Texas NNE into the western Great Lakes region, through late Monday. This will keep dry conditions, with low afternoon RH and temperatures around or slightly below normal, in place across the forecast area. Speaking of low RH values, the NBM is once again too high with afternoon dewpoints, so a heavy handed dose of CONSShort and HRRR dewpoints were mixed in for this afternoon and Monday as well. By Tuesday the upper trough pulls away into the northern Atlantic, and the ridge shifts east towards the Appalachian, remaining there through the latter part of the week. Expect continued dry conditions, with a notable warm up Tuesday through Thursday, with afternoon temperatures rising several degrees above normal.

For the end of the week, there's mixed reviews on how the pattern evolves and how quickly rain chances return. The evolution of the pattern across the CONUS will be based on the interaction of an upper low that will move onshore in southern California and Hurricane Polo which is forecast to move NNE across the Baja peninsula, both of which occur on Monday. Previous model runs had those phasing into a closed upper over the desert southwest and more slowly shifting east across the southern CONUS through the week, with a weaker northern stream jet across southern Canada, yielding prolonged ridging over the southeast and a late Friday or maybe Saturday return of rain chances to our area. Trends in some guidance over the last 24 hours have been for a stronger Canadian jet, a quicker eastward movement of the upper low and subsequent weakening of the southeast ridge, and thus a quicker return of Gulf moisture and rain chances to the southern Appalachian. That's not universally the case though, as some guidance maintains a stronger ridge and slower progression of things, still putting rain off until late Saturday into Sunday. Suffice it to say, the forecast for Friday into next weekend is far from certain and there's plenty of time for significant shifts in the forecast. For right now, the forecast will reflect continued above normal temperatures for both Friday and Saturday (although closer to normal for Sat), with rain chances returning Friday afternoon and continuing into Saturday. I wouldn't be at all surprised if the slower timing is correct and the Friday rain forecast winds up being too pessimistic, but it's also not an unreasonable forecast for the moment either.

AVIATION

(00Z TAFS) Issued at 758 PM EDT Sun Sep 27 2026

VFR conditions will be predominant at KTYS and KCHA through the TAF cycle. Fog is expected to bring LIFR conditions to KTRI overnight into early Monday morning before a return to VFR mid to late morning and continuing into the afternoon. Winds will largely be from the north and 10kts or less tomorrow afternoon, though, occasional gusts 15-20kts cannot be ruled out.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 54 84 55 86 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 51 80 53 84 / 0 0 0 0 Oak Ridge, TN 50 80 53 83 / 0 0 0 0 Tri Cities Airport, TN 47 76 52 80 / 0 0 0 0

MRX WATCHES/WARNINGS/ADVISORIES

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