215
FXUS64 KMRX 021115
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
715 AM EDT Tue Sep 2 2025

...New AVIATION...

.DISCUSSION...
Issued at 132 AM EDT Tue Sep 2 2025

Key Messages:
1. Patchy areas of fog early this morning, mainly near area
waterways and river valleys, such as the Sequatchie Valley.

2. Increase chance of showers and thunderstorms Wednesday and
Thursday, and again for Saturday. Main concern will be locally
heavy rainfall especially for Thursday.

Discussion:

Early this morning, satellite fog produce and area observations
are showing development of fog. Locally dense fog is expected. The
fog will be mainly near area waterways and river valleys, such as
the Sequatchie valley.

The ensemble cluster analysis shows a series of short-waves moving
across the Tennessee valley and southern Appalachians for tonight
and Wednesday, and again Thursday. Instability is marginal with
MLCAPES up to 1000-1500. As westerly flow increases with these
waves 0-6km shear does increase to 30 knots so better organization
to the convection is expected. PWs and 850mb transport winds
increase as well so locally heavy rainfall expected especially for
Thursday. Overall, strong storms are possible Thursday but overall
severe threat is limited but will need to watch for localized
runoff issues.

For the extended periods, ensemble cluster analysis and
deterministic models show a unseasonably deep upper trough over
the Great Lakes and Ohio valley. A frontal boundary moves across
Friday night or Saturday with increases chance of showers and
thunderstorms. MLCAPEs of 1000-1500. Overall isolated strong storm
possible.

Surface ridging builds into the area for Sunday.

&&

.AVIATION...
(12Z TAFS)
Issued at 708 AM EDT Tue Sep 2 2025

Isolated showers have developed across the northern Plateau and
central Tennessee valley due to isentropic lift. Included prob30
for TYS through 15Z

Isolated showers are expected near the TAF sites, especially TRI
and TYS late this afternoon into the evening hours. As a short-
wave approaches the area overnight scattered showers will continue
at TRI and TYS

Otherwise, VFR conditions expected at all of the TAF sites.
Periods of mainly mid and high clouds will move across the region.
Pressure gradients are weak with winds remaining light.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             81  62  83  64 /  20  20  50  30
Knoxville McGhee Tyson Airport, TN  79  61  81  62 /  20  40  40  30
Oak Ridge, TN                       78  60  80  61 /  30  40  50  20
Tri Cities Airport, TN              78  56  76  57 /  20  30  60  10

&&

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

$$

DISCUSSION...DH
AVIATION...DH