Chattanooga, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

880
FXUS64 KMRX 132309
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
709 PM EDT Wed Aug 13 2025

...New AVIATION...

.DISCUSSION...
Issued at 133 PM EDT Wed Aug 13 2025

Key Messages:

1. Decreasing rain chances and flooding threat through the rest of
the afternoon and evening.

2. Scattered showers expected with an upper trough passage tomorrow,
mainly in the afternoon.

3. Reduced coverage of diurnal shower/thunderstorm chances through
the weekend. Above normal temperatures and muggy conditions return
over the weekend and continue for the first half of next week.

Discussion:

A low pressure system over AL has been pumping Gulf moisture into
our area today, producing high precipitable water content and
efficient rainfall rates that have led to flooding. Radar trends
show decreasing overage and intensity over the last few hours, but
southern sections will maintain a threat of flooding through the
rest of the day. The low will progress eastward tonight across GA
and SC, shifting the 850-500 mb flow to a more westerly direction
tonight. With the reduction of deep moisture and lack of forcing,
most of the overnight hours should be dry. However, abundant low
level moisture in place will likely result in fog and low clouds
area wide overnight and into tomorrow morning. Fog could be dense
in some locations.

A shortave trough is located from the eastern Great Lakes to the
Ozarks today, and will be moving across our area tomorrow. We will
still have a good amount of moisture through the column, but PW
values drop into the 1.75-1.9 inch range, and MLCAPE stays under
1000 J/kg for most of the area. Forcing with the trough should
initiate convection in the late morning and early afternoon, with
the terrain areas being favored for the best coverage. The flooding
threat will be less tomorrow given the slightly drying column and
stronger steering winds aloft, but some localized flooding may be
possible in areas that had a lot of rain today.

A ridge over the Southwest will merge with the ridge over FL,
leading to a large, amplified ridge over the TN/OH Valley regions
over the weekend. This will provide mostly dry conditions for our
area, aside from a few isolated/scattered diurnal showers and storms
in the higher terrain areas. Temperatures will be rising above
normal, with highs in the lower and mid 90s by Sunday. This will
continue through the first half of next week as the ridge remains
nearly stationary over the region.

&&

.AVIATION...
(00Z TAFS)
Issued at 706 PM EDT Wed Aug 13 2025

VFR conditions will continue for much of the evening with
deteriorating conditions late tonight into the morning hours. IFR
is expected at all of the sites with periods of LIFR possible,
primarily due to fog. Light showers are possible around the
terminals, but most places are likely to stay dry for the night.
Gradual improvements to VFR are expected late in the morning
heading into the afternoon. Additional showers and storms are
possible again during the afternoon hours but with more limited
coverage.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             71  88  72  91 /  40  50  30  30
Knoxville McGhee Tyson Airport, TN  71  87  70  91 /  40  50  20  20
Oak Ridge, TN                       70  87  70  90 /  30  50  20  20
Tri Cities Airport, TN              68  83  67  87 /  40  50  20  30

&&

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

$$

DISCUSSION...DGS
AVIATION...BW