-- Discussion containing changed information from previous version are highlighted. --
989
FXUS64 KMRX 130012
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
812 PM EDT Sat Jul 12 2025

...New AVIATION...

.SHORT TERM...
-- Changed Discussion --
(This evening through Sunday morning)
Issued at 141 PM EDT Sat Jul 12 2025

Key Messages:

1. Scattered showers and storms will continue this afternoon and
evening. A few may become strong to severe. Primary concerns with
any strong to severe storm will be damaging winds between 40-60 mph
and isolated flooding.

Discussion:

Upper trough across the Midwest and Great Lakes will provide
enhanced forcing which will support scattered showers and storms
through this evening. Bulk effective shear still in the 15 to 20kt
range per model soundings and RAP analysis. Rap analysis on the SPC
meso page shows MLCAPE values around 2,500 J/kg through the
afternoon. This mix of instability and minor shear will allow storms
to be loosely organized, compared to typical summer-time pulse.
Basically, this just means that there is a better chance for a few
isolated strong to severe storms today compared to yesterday. The
main hazards will any strong storm will be wind gusts up to 60 mph.
The risk for isolated flooding also remains due to the high PW
airmass.

Coverage of showers and storms will decrease by sunset but a few
isolated showers and storms may linger through the night due to some
slight enhancement in the 500 mb vorticity. Also, patchy dense fog
is possible tonight across any location that receives rainfall today.
-- End Changed Discussion --

&&

.LONG TERM...
-- Changed Discussion --
(Sunday through next Saturday)
Issued at 141 PM EDT Sat Jul 12 2025

Key Messages:

1. No change from previous forecast. Daily summer-time convection
continues through the long term. Still potential for increased
coverage by late week as a trough returns to the eastern U.S.

2. Hot conditions return as an upper ridges strength peaks in the
middle part of the work week. Heat indices in the mid 90s to near
100F will become more common across valley locations.

Discussion:

No real change to the long term. Upper trough will continue to
slowly pivot eastward Sunday through Monday with continued chances
for diurnal convection. Under weak flow, we will have limited
chances to see any severe storms. The best coverage each day will
continue to be focused along our high terrain areas. Expect heat
indices in the mid 90s to near 100F to become more widespread across
the southern and central valley by Monday, with values in the low to
mid 90s across northeast TN and southwest VA. The hottest days look
to be Monday through Wednesday. Slightly lower temps, back in the
upper 80s to low 90s expected thereafter.

Additionally, we are still keeping an eye on a late week trough that
has potential to bring increased coverage of afternoon shower and
storm activity across the area.
-- End Changed Discussion --

&&

.AVIATION...
-- Changed Discussion --
(00Z TAFS)
Issued at 748 PM EDT Sat Jul 12 2025

Convection previously impacting TAF sites is beginning to
diminish and depart east. An additional line of convection is
moving through western and central KY but the activity is
anticipated to wane before making it to any TAF sites. HREF
probabilities suggest KTRI has the highest chance of fog/low cig,
and they did observe moderate convection this afternoon. Opted to
include brief MVFR conditions because of this. Additional showers
and storms expected tomorrow afternoon but believe the coverage
will be more isolated in nature. Only included vicinity mention at
CHA where CAMs are in better agreement. It is possible mentions
may need to be included at other sites in future issuances.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  94  73  95 /  10  40   0  30
Knoxville McGhee Tyson Airport, TN  72  91  72  94 /  10  30  10  30
Oak Ridge, TN                       70  91  71  93 /  20  40  10  40
Tri Cities Airport, TN              68  87  68  89 /  30  50  20  30

&&

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

$$

SHORT TERM...
AVIATION...KRS