047
FXUS64 KMRX 160656
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
256 AM EDT Sun Aug 16 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 236 AM EDT Sun Aug 16 2026

- Very hot Heat Index`s continue today and Monday, especially
  south and central valley areas. Then it will remain on the hot
  side through the week but likely a bit less oppressive.

- Next week, best chance for showers and storms will be Monday
  with some possibly being strong to severe with drier weather
  expected midweek.

&&

.DISCUSSION...
Issued at 236 AM EDT Sun Aug 16 2026

The mid/upper level ridge will retrograde and flatten out tomorrow,
keeping the MCS activity across the Ohio Valley and Great Lakes.
This shift in the ridge should bring in slightly drier air, with PW
values falling to around 1.5 inches. Forecast soundings also
indicate a stronger cap suggesting less afternoon convective
development compared to recent days. A few isolated showers or
thunderstorms remain possible across southwest VA and the TN
mountains.

With fewer clouds and a lower rain chance, diurnal heating will
allow temperatures to climb into the 90s for most locations.
Although boundary layer mixing should lower afternoon dewpoints
somewhat into the lower to middle 70s. Heat Index values of 105+
degrees are still expected across the central and southern TN
Valley. These conditions can lead to heat related illness,
especially for those spending extended time outdoors. Limit
strenuous activity during the hottest part of the day, drink plenty
of water, and take frequent breaks in air conditioning or shade.

On Sunday night, some CAMs indicate remnant MCS convection moving
across West Virginia, potentially clipping portions of southwest
Virginia. Given the overnight timing, the severe threat looks
limited.

Monday will see Heat Index values within the ballpark of what we`ve
experienced this weekend. There`s a chance that the boundary layer
mixing on Monday brings in lower dew points and the humidity is not
technically Heat ADvisory criteria... But it`s still going to be hot.
Will go ahead and extend the Heat Advisory through Monday for one
more day.

A shortwave trough and surface cold front will move through Kentucky
Monday morning, sparking off convection as the system approaches the
Plateau during the afternoon. The air mass ahead of the front should
remain capped into the early afternoon while helping to increase
instability. Some shear will also be present, particularly across
northern TN and southwest VA, with the NAM showing approximately 30-
40 kt of deep layer shear. An inverted V profile, steep lapse rates,
and a deep boundary layer would support strong downdrafts and
damaging wind gusts. DCAPE values of 1000+ J/kg further support this
concern. The RRFS depicts a fairly intense convective line moving
through the area between roughly 7 PM and 11 PM.

Given these factors, the potential exists for a more significant
severe weather event Monday afternoon and evening, with damaging
straight line winds being the primary concern. Large hail and an
isolated tornado cannot be completely ruled out. Those with outdoor
plans should have a reliable way to monitor changing weather
conditions.

The surface front will push through the area Monday night, bringing
slightly cooler temperatures and lower dewpoints for Tuesday. This
should end the dangerous heat potential, although temperatures will
remain near normal.

The ridge will continue to retrograde through the remainder of the
week, resulting in a broad trough across the eastern CONUS. This
pattern will increase rain chances through the week as embedded
shortwaves move through the larger scale trough and the jet stream
settles into the Ohio Valley. Showers and thunderstorms will
therefore remain possible, with locally heavy rainfall and lightning
continuing to be the primary concerns with stronger storms.

Overall, the most notable hazards through the forecast will be
dangerous heat through Monday, localized flooding from repeated
thunderstorms, and a potentially more significant severe weather
threat Monday afternoon and evening.

&&

.AVIATION...
(06Z TAFS)
Issued at 236 AM EDT Sun Aug 16 2026

Dense fog once again possible at TRI very early this morning. <6SM
and BKN CIG already being reported there. TYS and CHA likely to
remain calm under SKC or high CIG. Later today trends dry with
very low chances of showers or storms, therefore no mentioning in
TAF. Rather light SW-Wly winds this afternoon at all terminals.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             98  77  99  76 /   0   0  40  20
Knoxville McGhee Tyson Airport, TN  96  76  95  73 /   0   0  70  50
Oak Ridge, TN                       95  74  94  72 /   0   0  60  30
Tri Cities Airport, TN              90  71  89  69 /  10  30  60  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Heat Advisory until 8 PM EDT /7 PM CDT/ Monday for Anderson-
     Bledsoe-Bradley-Hamilton-Knox-Loudon-Marion-McMinn-Meigs-
     Morgan-North Sevier-Northwest Blount-Northwest Monroe-Rhea-
     Roane-Sequatchie-West Polk.

VA...NONE.
&&

$$

DISCUSSION...
AVIATION...KS