755 
FXUS64 KMRX 231848
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
248 PM EDT Wed Sep 23 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 247 PM EDT Wed Sep 23 2026

- Numerous showers and storms will continue this afternoon into the 
evening. Localized flooding due to heavy rainfall is possible, in 
addition to gusty winds. 

- Cooler and drier conditions are expected through the weekend
  before a warming trend early next week. 

&&

.DISCUSSION...
Issued at 247 PM EDT Wed Sep 23 2026

Currently, a shortwave is moving through the area overhead with an 
upstream jet approaching from the west and inverted surface 
troughing. This has put the region in the left-exit region of the 
jet, leading to large-scale lift. When combined with PWAT values of 
1.3 to 1.4 inches, this has and will continue to provide support for 
showers and storms during the afternoon and evening. Morning 
convection and clouds has limited heating and destabilization in 
some areas, but up to 1,000 J/kg of MLCAPE is expected. With 
freezing levels of 14,000 feet or higher and recent rain for some, 
efficient warm rain processes continue to emphasize localized flash 
flooding as the main concern. Some gusty winds are possible but not 
to the same degree as flooding. CAMs differ on how much coverage 
lasts overnight, but intensity will be lessened as instability is 
lost. By Thursday, troughing will have moved off to our east, 
leading to less upper support. Still, inverted surface troughing and 
lingering moisture will keep at least low-end chances for rain in 
the area. During this time, a low in the Atlantic will be deepening 
as upper troughing moves overhead. 

By Friday, the low in the Atlantic will deepen into a Nor'easter as 
it moves along the New England coast. This will lead to broad 
northwesterly flow across the region, pulling down cooler and drier 
air associated with high pressure to the north. Dry and more fall-
like weather can be expected with widespread highs in the 70s 
expected through the weekend. Radiational cooling, especially Friday 
night, will allow lows to drop into the 50s and upper 40s in the 
northeast. Another warming trend is expected early next week as 
heights rise and another surface low develops in the Great Plains, 
leading to a southerly shift in winds. 

&&

.AVIATION...
(18Z TAFS)
Issued at 100 PM EDT Wed Sep 23 2026

The main aviation impact through the period will be continued
showers and storms, already being seen to the west of TRI and TYS.
All sites have improved back to VFR with these conditions expected
to remain for at least a couple of hours before rain fills back in
through the afternoon. Timing will be earliest at CHA and latest
at TRI but with a potentially shorter duration at CHA. Activity
will continue into the evening and possibly overnight at TRI,
leading to prolonged MVFR reductions. Fog is also possible at TRI
and TYS with MVFR or lower likely at all sites by early morning.
Conditions will gradually improve into Thursday. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             64  80  61  80 /  70  30  20   0 
Knoxville McGhee Tyson Airport, TN  63  76  58  75 /  80  40   0   0 
Oak Ridge, TN                       62  76  57  76 /  80  40   0   0 
Tri Cities Airport, TN              57  70  49  72 /  90  30   0   0 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...Flood Watch until 10 PM EDT this evening for Lee-Wise.

&&

$$

DISCUSSION...BW
AVIATION...BW


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