974
FXUS64 KMRX 311751
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
151 PM EDT Thu Jul 31 2025

...New DISCUSSION, AVIATION...

.DISCUSSION...
Issued at 145 PM EDT Thu Jul 31 2025

Key Messages:

1. Increased convective coverage today and tomorrow ahead of/along
an incoming front. Severe chances look low, but high PWATs and slow
storm motions means isolated flash flooding still a possibility.

2. Cooler temperatures, even below seasonal norms, expected through
the weekend and into early next week. Rain chances persist, but
expect less coverage after the weekend.

3. There`s a possibility of a system lifting north from the central
Gulf coast midweek, ahead of an approaching trough. That would bring
widespread rain chances to the forecast area late in the period.

Discussion:

A front will push into the forecast area from the west/northwest
later tonight. Ahead of this front, fairly widespread shower and
thunderstorm activity is once again expected this afternoon. Severe
chances look to be low overall, although forecast soundings as a
whole support stronger convection than yesterday with the
possibility of an isolated report of damaging winds not being out of
the question. PWATs are a touch lower than yesterday but still high,
with storm motions that are very slow. As such, isolated flash
flooding will continue to be a concern this afternoon and evening.

The front will be part of a pattern change as upper troughing
becomes increasingly influential over the eastern CONUS through the
weekend and into the first part of next week. Temperatures Friday
through at least Monday look to be around or even slightly below
normal, especially Friday. Rain chances don`t truly exit the
forecast as there`s not a sweeping air mass change behind the front,
and H85 flow becomes southeasterly by Saturday, so convection over
the elevated terrain, possibly drifting into the valley during the
evenings, seems plausible Sat and Sun. Early next week may be dry as
surface high pressure will be situated to our north and PWATs drop
notably into early next week, but even then there`s plenty of
support in guidance for some afternoon storms.

The latter parts of the period look to be fairly wet. A post-frontal
CAD setup will be in place by early next week (a point in favor of
possible dry conditions), but return flow begins to push back in by
Tue/Wed as a more pronounced trough moves east from the Ozarks.
Isentropic analysis favors low level ascent back into the southern
parts of the area Wed for sure, with most global models showing a
system lifting north from the Gulf coast during the midweek time
frame, bringing widespread rain back to the forecast area by the end
of the period.

&&

.AVIATION...
(18Z TAFS)
Issued at 145 PM EDT Thu Jul 31 2025

Main concern for the 18z TAF period will be SHRA/TSRA affecting
terminals. An area of TSRA will affect KTYS and KCHA over the next
2-4 hours, with additional showers expected later tonight at those
sites plus KTRI with the frontal passage. Fog potential seems
pretty high at KTRI again tonight given expected rainfall and
cooler temperatures. Confidence in thunderstorm coverage tomorrow
not high enough to include in the TAFs at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             74  91  71  84 /  20  50  10  70
Knoxville McGhee Tyson Airport, TN  73  87  69  84 /  30  50  10  60
Oak Ridge, TN                       73  86  68  84 /  30  40  10  50
Tri Cities Airport, TN              70  83  65  80 /  40  60  30  40

&&

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

$$

DISCUSSION...CD
AVIATION...CD