846
FXUS64 KMRX 052335
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
735 PM EDT Sat Sep 5 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 722 PM EDT Sat Sep 5 2026

- Isolated severe storms possible through early evening, mainly
  along and south of interstate 40. Damaging winds and frequent
  lightning are the main concerns.

- Heat Indices of 100+ across the southern Tennessee valley but
  below criteria for a Heat Advisory for Sunday.

- Scattered storms again Sunday, mainly east of interstate 75, and
  Today, and isolated storms Monday, mainly along and west of
  interstate 75.

- Drier conditions return for much of next week, until the later
  half.

&&

.DISCUSSION...
Issued at 230 PM EDT Sat Sep 5 2026

Currently, an outflow boundary is moving south across the southern
half of the Tennessee valley and southern Plateau. Scattered storms
continue to develop along this boundary. MLCAPES of 2500 and DCAPES
of 900-1100. Microbursts parameter of 5-7 so isolated damaging winds
from these storms are possible.

Satellite and SPC meso-analysis shows airmass has stabilized over
east Kentucky, northern half of Tennessee, southwest Virginia so
expect these areas to remain dry the rest of today.

Areas along and south of the outflow boundary remain very hot with
heat indices over 100 degrees. North of the boundary conditions
are much better. However, given the outside events we will
continue through expiration.

Most clear sky, calm wind, and recent rains will allow for areas of
fog development tonight some dense, especially near area waterways.

For Sunday, another MCV or short-wave will move southeast across the
area. Another round of scattered showers and thunderstorms
anticipated mainly along and east of interstate 75. Airmass will be
favorable for localized damaging winds, frequent lightning and
locally heavy rains.

For Monday, an inverted surface trough across the Plateau and
western Tennessee valley will support isolated convection mainly
along and west of interstate 40. Again, strong/gusty winds and
frequent lightning will be the main concern.

For Tuesday and Wednesday, upper ridging builds back over the
Tennessee valley and southern Appalachians producing hot and dry
conditions. Dewpoints will be in the middle and upper 60s which will
limit the heat indices below heat advisory criteria.

The upper ridge flattens for Thursday as a short-waves and frontal
boundary approaches the area. Scattered showers and storms are
expected. The boundary moves south of the area for Friday.

For Saturday, return southerly flow around surface ridge east of the
Appalachians will bring moisture and instability back into the area.

&&

.AVIATION...
(00Z TAFS)
Issued at 722 PM EDT Sat Sep 5 2026

A few showers and storms are lingering near TYS but activity is
decreasing. A few isolated showers and storms will be possible
this evening and overnight. Some fog development is likely near
TRI. There is some uncertainty about how low visibility will get.
Showers and storms will be isolated tomorrow. The best chance will
be near TRI but overall chances are low.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             74  96  72  91 /  20  10  20  40
Knoxville McGhee Tyson Airport, TN  71  91  69  89 /  20  20   0  40
Oak Ridge, TN                       71  91  68  89 /  20  20   0  40
Tri Cities Airport, TN              67  86  65  85 /  20  30  10   0

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Heat Advisory until 8 PM EDT /7 PM CDT/ this evening for
     Anderson-Bledsoe-Bradley-Campbell-Claiborne-Grainger-
     Hamblen-Hamilton-Hancock-Hawkins-Jefferson-Knox-Loudon-
     Marion-McMinn-Meigs-Morgan-North Sevier-Northwest Blount-
     Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
     Roane-Scott TN-Sequatchie-Union-West Polk.

VA...NONE.
&&

$$

DISCUSSION...DH
AVIATION...McD