903
FXUS64 KMRX 301804
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
204 PM EDT Sat Aug 30 2025

...New DISCUSSION, AVIATION...

.DISCUSSION...
Issued at 201 PM EDT Sat Aug 30 2025

Key Messages:

1. Seasonable temperatures continue through the weekend, with cooler
temperatures making a return and persisting through next week.

2. Isolated to scattered precipitation will favor the mountains into
far northeast Tennessee and southwest Virginia Sunday. Limited
thunder chances.

3. Greatest precipitation chances (30-40%) will favor the Cumberland
Plateau Monday and Tuesday. Increasing precipitation chances are
expected with an associated cold front in the Wed-Thu timeframe.

Discussion:

A pair of stationary boundaries remain displaced to our south with
surface high pressure centered atop Lake Ontario. The high pressure
influence extends into the southern Appalachians where mostly sunny
skies and seasonable temperatures are on-going. A very dry airmass
with PWAT values around the 25% percentile will continue to promote
quiet weather through the evening with very limited chances for an
isolated shower(20% or less), mainly across higher terrain.

A shortwave will traverse through upper troughing across the Ohio
Valley and southern/central Appalachians tomorrow. This will amplify
the nwly H3 jet to between 60-80kts. Weak jet coupling and vort
maxima will combat the upper level subsidence, increasing chances
for isolated to scattered precip. Most of this activity will remain
across higher terrain once again, though some activity may spread
into far northeast TN & southwest VA in closer proximity to the
shortwave. NAMBufr soundings depict MLCAPE 1000J/kg or less and just
modest mid-level lapse rates around 6C/km suggesting no significant
weather. Though, effective shear near 20kts will maintain the
potential for a few lightning strikes with some of the activity.
Something to be aware of if spending time outdoors for the holiday
weekend.

An additional shortwave swinging into the Ozarks will broaden the
troughing influence across southeastern CONUS Monday and into the
new work week. The main impact will be a return of cooler
temperatures owing to decreasing H5 heights. NBM has begun to trend
downward with precipitation chances Monday and Tuesday, with hints
that the trough axis remains displaced to our west. This generally
confines the best chances(30-40%) along the Cumberland Plateau. A
more notable impulse will rotate through the positively tilted
longwave trough mid-week with an expected frontal passage during the
Wednesday to Thursday timeframe. Increasing chances of showers and
storms are expected with the frontal passage. While shear will be
enhanced, instability may be the limiting factor for potential of
any stronger convection. High pressure will build into the region
post FROPA with a return of drier weather late week. Temperatures
will generally remain 5-10degrees below normal through the week with
just minor fluctuations on a day-to-day basis.

&&

.AVIATION...
(18Z TAFS)
Issued at 201 PM EDT Sat Aug 30 2025

VFR conditions, light winds, and FEW/SCT afternoon cu field will
prevail through the TAF period. Expect isolated to scattered
precipitation across portions of the southern Appalachians
tomorrow afternoon. Future shra mention may be need at KTRI for
this activity but low confidence on expected coverage so have
opted for no mention at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             62  86  63  83 /   0  10  10  20
Knoxville McGhee Tyson Airport, TN  60  84  61  81 /   0  20  10  20
Oak Ridge, TN                       60  84  60  81 /   0  10  10  30
Tri Cities Airport, TN              57  78  56  79 /   0  30  20  10

&&

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

$$

DISCUSSION...KRS
AVIATION...KRS