textproduct: Morristown

KEY MESSAGES

Updated at 736 AM EDT Tue Sep 1 2026 - Hot and humid conditions will worsen with highs well into the 90s and heat indices reaching or exceeding 100F for most Wednesday through Friday. Take frequent breaks and drink plenty of water when outdoors this week!

- Other than isolated storms in the mountains the next few days, rain chances do not return area wide until the weekend.

DISCUSSION

Issued at 226 AM EDT Tue Sep 1 2026

If today is the start of meteorological fall, Mother Nature was not given the memo. An oppressive 500 mb ridge will be parked over much of the Mid South through this week, reaching above the 90th percentile and flirting with the maximum values for this time of year. As a consequence, high temperatures down here at the surface are increasing as we head into the middle of the week, with highs in the mid to upper 90s commonplace for much of the Tennessee Valley and northern Plateau. Wednesday and Thursday carry a 45% chance of hitting 100F at Chattanooga, and Thursday the NBM has a 50% chance in Knoxville of doing the same. Heat indices will climb as well, with maximum values around 105F in the middle of the week. Forecast temperatures alone will flirt with a couple of daily records, namely on the 2nd and 3rd of September.

Daily Record High Maximum Temperatures

Date Chattanooga Knoxville Tri-Cities Oak Ridge 09-01 100(1957) 100(1951) 98(1953) 101(1953) 09-02 100(2011) 98(2011) 96(1943) 99(1953) 09-03 100(1954) 98(2011) 96(2011) 99(2011) 09-04 102(1954) 101(1954) 99(1954) 100(1954)

The upper ridge will get shunted to the west as we go into the weekend. The degree of heat relief will depend on how significant of an east coast trough we see, the GFS seems to have a more outlier significant solution versus the Euro/EC-AIFS. Any weakening should yield some relief outright, and maybe help initiate more storms to provide quicker diurnal relief.

Rain chances are slim for much of this week. The overall oppressive ridge won't lend much to vertical CAPE profiles this week, and we should see even less convection today as a result of the increasingly hotter airmass. The degree to which we see more widespread low chances of showers/thunderstorms over the weekend into next week will depend on the depth of the upper trough and how far west the upper ridge is pushed. For now much of the area has a low rain chance returning each afternoon beginning on Saturday, when even the Euro has a weak northwest flow shortwave to help spark better coverage. Until then, the most significant weather hazard is the anomalously high temperatures, with fairly regular humidity pushing the combined heat indices to near or at heat advisory thresholds for a couple days this week.

AVIATION

(12Z TAFS) Issued at 736 AM EDT Tue Sep 1 2026

LIFR conditions have developed at TRI this morning, however this should only last an hour or so. VFR conditions with light winds are expected again this afternoon. Latest high-resolution NAM does suggest a few spotty showers may develop across the central/northern areas this afternoon, but expected coverage is too low to include any mention at this time. Additional patchy fog is expected to develop across the region tonight, with TRI maintaining the best chance for brief impacts.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 98 75 100 75 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 95 72 98 74 / 0 0 0 0 Oak Ridge, TN 95 73 97 74 / 0 0 0 0 Tri Cities Airport, TN 91 69 95 69 / 0 0 0 0

MRX WATCHES/WARNINGS/ADVISORIES

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