014
FXUS64 KMRX 111820
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
220 PM EDT Tue Aug 11 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 218 PM EDT Tue Aug 11 2026

- Showers and thunderstorms will be possible each day through the
  end of the work week, with the best chance of rain during each
  afternoon.

- There will be potential for a few storms to become strong to
  severe each afternoon with damaging winds and localized flooding
  the main threats.

- Temperatures will be near normal through Friday, but trending
  slightly above normal for the weekend.

&&

.DISCUSSION...
Issued at 218 PM EDT Tue Aug 11 2026

The regional radar mosaic shows multiple areas of convection
upstream over the Ohio Valley and southern Great Lakes. The exact
evolution of these structures is uncertain, but the likelihood of
one of these structures to impact our area is high. There are a few
isolated thunderstorms developing across the southwest VA ahead of
the main MCS over N KY and W WV. These storms could produce isolated
winds and heavy rainfall. If we see repeated rounds of storms and
showers over any area, the potential for flooding and flash flooding
will increase and may require flood headlines in the future.
Forecast soundings across SW VA & NE TN highlight 2000-3000+ j/kg
CAPE with ~20 knots of shear. This is plenty for clusters of
thunderstorms to develop and produce isolated hail/wind damage.
Forecast soundings further west in SE TN highlight significant
instabilty available for thunderstorms to tap into. The general
consensus is that we`ll see the MCS or a portion of the MCS upstream
follow the instability gradient that goes through our eastern
forecast area of SW VA/NE TN. The instability in place will be
plenty for MCS maintenance and the structure itself will likely be
able to enhance the local shear environment to a more favorable
situation. The timing appears to be between 4 to 8pm for our NE area
with uncertainty on how far south/west it`ll continue. Additional
MCS over central Indiana should continue to move south-southeast and
should arrive in our northern area this evening. The exact evolution
of this is even more uncertain due to the unknowns with this
afternoon`s potential convection. There is reason to believe that
the second round should maintain some intensity and bring another
round of thunderstorms capable of producing damaging winds and heavy
rain. This structure does have some mid level support as an impulse
transits through the Ohio Valley this evening/tonight. This should
move through the area this evening and into tonight before we begin
to dry out. Given the general uncertainty and lower-than-normal
confidence with this forecast, please monitor the forecast if you
have any outdoor work or activities planned this afternoon - evening.

Wednesday through Friday... this period remains unsettled with the
potential for additional showers and thunderstorms each afternoon. A
strong ridge remains off to our west and a trough to our east over
the NE CONUS. This places us in a favorable area for daily
shower/thunderstorm chances through Friday evening. There will be a
non-zero chance for a few of these storm to become strong to severe
and able to produce heavy rainfall. There isn`t a clear signal for
any one area but rather a broad brush approach given the unstable
airmass and northwest flow aloft. The finer details won`t be
resolved likely until the day of given the lower confidence tied to
this pattern.

Saturday through Early Next Week... The western ridge axis will
build into the area this weekend. This will allow warmer
temperatures to settle in through the start of next week.
Precipitation chances will continue through the weekend, but the
chance of any organized convection will be much lower. If the ridge
builds in further east, we may even stay mostly dry Saturday/Sunday,
which would welcomed.

&&

.AVIATION...
(18Z TAFS)
Issued at 130 PM EDT Tue Aug 11 2026

Overall, VFR conditions are expected outside of any passing
thunderstorm. Showers and storms are expected in some capacity
through this afternoon and into the overnight hours. Confidence in
timing and coverage is low at the moment. Amendments may be
needed prior to the 00Z TAF issuance. If we do see a strong line
of convection move out of KY and down into TN, then TRI and
perhaps TYS may see 40 to 50kt wind gusts as this line moves
through. Again, low confidence as of now.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  93  74  94 /  40  30  20  20
Knoxville McGhee Tyson Airport, TN  73  90  73  91 /  40  40  30  30
Oak Ridge, TN                       72  90  72  91 /  40  30  30  30
Tri Cities Airport, TN              68  86  69  87 /  60  40  50  40

&&

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

$$

DISCUSSION...BH
AVIATION...99