511 
FXUS64 KMRX 311932
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
332 PM EDT Fri Jul 31 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 215 PM EDT Fri Jul 31 2026

- One last dry day today with seasonable temperatures and
  relatively comfortable humidity. 

- A low chance for a few strong storms tomorrow afternoon into the
  later hours of the night. Damaging winds the main threat with
  localized flooding also possible. A tornado also cannot be ruled
  out, especially near the plateau.

- The wet pattern that begins tomorrow will persist into next
  week. Temperatures warm up towards next weekend.

&&

.DISCUSSION...
Issued at 215 PM EDT Fri Jul 31 2026

One last dry day today with a bit of an increase in humidity 
under shortwave ridging aloft and surface high pressure situated 
over the Appalachians. A fairly stout closed upper low will arrive
from the Northern Plains tomorrow vertically stacked above a 
surface low. Around Sunday, the trough axis and cut off low 
seemingly parks right over us, for the most part. There's still 
some uncertainty about how this will play out because of model 
discrepancies. It's not until Wednesday that the next trough rolls
in and absorbs the aforementioned low. Thereafter until the end 
of the forecast period, weak steering develops, and daily chances 
of showers and storms continue with temperatures pushing above 90 
again. Precipitation chances later in the week will be best over
the higher terrain.

Tomorrow will present a chance of strong to possibly a severe 
storm, as well as isolated flooding. There will be a couple of
rounds of storms tomorrow with the first between 7 am and 3 pm ET
and 4 pm until possibly after midnight for the second. Null
surface instability amid a low level inversion, will prevent the 
early day round from getting strong. There may be some 
thunderstorms, but it'll be mostly rain. The area with the
greatest threat of stronger storms will be the plateau/west of
I-40, where SPC has the area under a slight risk. A slim marginal
area to the east of that and then no severe for much of northeast
TN and southwest VA. This makes sense as southerly flow over the
terrain is trying to pull what we'd typically see in winter;
downsloping eradicating precipitation or just keeping it at bay.
The strongest winds over the higher terrain will be later in the
day tomorrow, but quickly dropping off into the overnight hours, 
so not like how true winter mountain wave events behave. Southerly
flow develops in the afternoon and turns out of the SW close to
midnight and after, which is why the downsloping shouldn't 
persist overnight. 

The strong to severe threat for later tomorrow  will surely need 
monitored with CAPE pushing 2000 J/Kg, deep layer shear around 35 
kt, PWATs nearing 2 inches, and DCAPE over 700. Tornadic activity 
also cannot be ruled out when surface winds will be at their most 
"southerly". 18z HRRR forecast soundings around the plateau area 
depict southerly or slightly backed winds at the surface, 
increased SRH, 0-1 shear over 20 kt, and 3CAPE around 70 or 
higher. This threat will only be limited to western parts of the 
forecast area (plateau), as the entirety of threats is forecast 
to drop off as it moves east, possibly being choked off by the 
downslope flow. Mainly, damaging wind gusts will be the concern 
with possible flooding tomorrow.

&&

.AVIATION...
(18Z TAFS)
Issued at 142 PM EDT Fri Jul 31 2026

Predominant VFR conditions and light winds continue this
afternoon. Increasing mid to low level VFR clouds and the chance 
for showers and storms will increase mid to late morning at CHA 
and TYS. This activity is associated with an approaching warm
front and could lead to periods of MVFR conditions under the 
heaviest convection. Less confidence in precipitation making it 
to TRI due to expected downslope drying in northeast TN. Winds 
will shift to a southerly direction behind the morning warm-front.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  86  72  87 /  20  90  90  40 
Knoxville McGhee Tyson Airport, TN  69  86  72  86 /  10  60  90  50 
Oak Ridge, TN                       69  84  70  85 /  10  70  90  60 
Tri Cities Airport, TN              64  84  69  83 /   0  30  60  80 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

DISCUSSION...KS
AVIATION...KRS


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