435
FXUS64 KMRX 040539
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
139 AM EDT Thu Sep 4 2025

...New DISCUSSION, AVIATION...

.DISCUSSION...
Issued at 125 AM EDT Thu Sep 4 2025

Key Messages:

1. A cold front will bring increasing chances of showers and storms,
especially this afternoon and evening. A few storms may become
strong to severe with damaging winds the main hazard.

2. A second cold front will bring additional afternoon showers and
storms Saturday. Friday will be dry between the two systems.

3. Above normal temperatures are expected Friday. Seasonally cool
temperatures Sunday into early next week after a frontal passage.

Discussion:

In the upper levels, a deep trough is still over the Eastern U.S.
stretching all the way to the GOA/FL. At the surface, a
vertically stacked low is well to the north over Ontario with a
cold front stretching from Canada into the Tennessee and Ohio
River Valleys. This active pattern will bring scattered showers
and storms mainly this afternoon and evening with more isolated
activity this morning. This afternoon will have better instability
with ML CAPE around 1000 to 1400 J/KG. Effective shear will be 30
to 35 knots, indicating that storms this afternoon may be a bit
better organized. SPC has a marginal risk for severe for our whole
forecast area. The primary threat will be gusty winds but small
hail will also be possible. This does not look like a clean
frontal passage. This front will likely stall just north of our
region.

Friday looks dry and hot with increasing POPs Friday night and
Saturday as a cold front approaches. A few strong storms seem
possible during max heating but even then ML CAPE looks fairly low
around 200 to 600 J/KG. Effective shear looks decent around 30 to 35
knots. The best forcing will be much farther north near the Great
Lakes. This will be a clean frontal passage late Saturday bringing
cooler temps and lower dew points. Also, a noticeable wind shift to
northerly winds.

Sunday through early next week looks dry with high pressure over the
Eastern U.S. and below normal temps, especially Sunday and Monday.

&&

.AVIATION...
(06Z TAFS)
Issued at 125 AM EDT Thu Sep 4 2025

Isolated showers and storms will continue through the morning
hours. This afternoon/evening, showers and storms will be more
scattered and a few may be strong to severe. Patchy fog is
likely this morning. Dense fog is looking less likely with some
cloud cover in place.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             86  65  92  68 /  30  20   0  20
Knoxville McGhee Tyson Airport, TN  82  65  90  67 /  50  40   0  30
Oak Ridge, TN                       81  63  89  66 /  60  40  10  40
Tri Cities Airport, TN              78  61  85  62 /  50  30   0  20

&&

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

$$

DISCUSSION...McD
AVIATION...McD