280
FXUS64 KMRX 072230
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
630 PM EDT Tue Oct 7 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 554 PM EDT Tue Oct 7 2025

- Beneficial rainfall through early Wednesday morning. Rainfall of
  1/4 to 1/2 inch across much of the area.

- Lows are expected to drop into the mid to upper 30s across the
  higher elevations of the far east Tennessee mountains for the
  latter half of the week.

- More fall-like temperatures and dry weather expected from Thursday
  onwards through this weekend. A slight warming trend Sunday
  into next week.

&&

.DISCUSSION...
Issued at 131 PM EDT Tue Oct 7 2025

Currently, an area of light rain is moving across the northern
half of Tennessee and southwest Virginia. This is due to a 30
knots 850mb jet producing isentropic lift across much of the area
today. Rainfall amounts have been light and will move north of the
area this afternoon.

For this evening, the jet dynamics associated with 300mb jet
streak over the Ohio valley will have moved northeast of the area.
A pre-frontal trough over middle Tennessee will move into the
Plateau and east Tennessee. This boundary along with marginal
instability (CAPES of 500-750) will produce scattered showers and
embedded thunderstorms.

For tonight, models are in agreement with isentropic forcing in
the 305-310K layer. As the frontal boundary approached the area a
band of showers and possibly thunder will move across the region.
Overall, rainfall amounts will average 1/4 to 1/2 inch.

For Wednesday, showers will end with drier air moving back into
the region with sky cover diminishing. Mainly the far east
Tennessee mountains will have a chance of showers in the afternoon
and evening.

For Thursday, another wave moving into the Tennessee valley and
southern Appalachians will produce an inverted surface trough
across the area. There is a slight chance of showers mainly in the
mountains and southeast Tennessee, otherwise dry.

For Friday through early next week, ensemble analysis and
deterministic models are in agree with an upper ridge over the
mid-section of the nation with and upper trough along the east
coast. Overall dry conditions and more seasonal fall temperatures
are expected. Lows for the latter half of the week will fall into
the mid to upper 30s across the higher elevations of the far east
Tennessee mountains.

A gradual warming trend is expected early next week as the upper
ridge builds into the Tennessee valley.

&&

.AVIATION...
(00Z TAFS)
Issued at 554 PM EDT Tue Oct 7 2025

MVFR cigs become prevailing at all sites overnight as rain showers
overspread the region ahead of a cold front. A few thunderstorms
will be possible in the vicinity of CHA and TYS where prob30
groups were added. Brief IFR conditions are possible within the
heavier convection this evening. The cold front moves east of the
region by Wednesday morning with a wind shift to the north at
10-15 kt. Cigs gradually improve to VFR by late Wednesday
afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             68  80  58  72 /  80  10  10  10
Knoxville McGhee Tyson Airport, TN  67  76  55  73 /  90  20  10   0
Oak Ridge, TN                       66  75  53  72 /  90  10   0  10
Tri Cities Airport, TN              63  72  48  70 /  80  40   0   0

&&

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

$$

SHORT TERM...99
LONG TERM....99
AVIATION...JB