Flash Flood Warning 20, NWS Nashville, TN

Area Forecast Discussion
National Weather Service Nashville TN
1249 PM CDT Fri Jul 17 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 1235 PM CDT Fri Jul 17 2026

- Daily rounds of scattered storms will continue through the
  weekend. Strong winds gusts and heavy rain causing localized
  flooding are possible. There is a marginal risk of severe storms
  for the Plateau through the weekend.

- Heat indices will reach the low 100s for many areas west of the
  Cumberland Plateau into early next week. Tuesday will be the
  hottest day of the period with heat indices nearing or exceeding
  105 degrees for much of the area.

- Slightly cooler and less humid air is expected late next week.

&&

.SHORT TERM...
(Rest of today through Saturday)
Issued at 1144 AM CDT Fri Jul 17 2026

Diurnally driven cumulus are already popping up across Middle
Tennessee on satellite this morning, with showers and thunderstorms
forecasted for today, yet again. Temperatures will barely get into
the 90s for highs today, with some areas on the Cumberland Plateau
sticking in the mid 80s. Triple digit heat indices are the name of
the game the next few days, so make sure you are staying hydrated if
you have any outdoor plans for the weekend.

Overnight we can expect some patchy fog to develop in Middle
Tennessee. Nothing too dense, but enough to drop visibility a bit.
Overnight lows will dip into the upper 60s to low 70s, and rebound
back into the low 90s with heat indices in the triple digits once
again.

There is a chance for isolated severe storms into the weekend, with
SPC highlighting portions of our area in a marginal risk (level 1
out of 5). Primary hazard with any stronger storms would be gusty
winds and heavy rainfall leading to localized flash flooding, given
the sheer amount of moisture in the atmosphere (with PWATs in
forecast soundings above 2"). The chance for severe weather is low
however, as we lack meaningful shear to sustain decent updrafts and
stronger storms, but an isolated strong storm cannot be ruled out.

&&

.LONG TERM...
(Saturday Night through next Friday)
Issued at 1144 AM CDT Fri Jul 17 2026

Into the work week, temperatures will only continue to increase as
WAA increases at 850mb. This will lead to triple digit heat indices
into early next week, some getting into Heat advisory territory. We
will have to evaluate the need for a heat product as we continue to
approach that point in time. Remember to stay hydrated and take
frequent breaks in the AC or shade if you work outside or have any
activities planned. Until the cold front comes through on Wednesday
bringing cooler and less humid air into Middle Tennessee, diurnal
thunderstorms will continue to be a daily threat. Most of these will
not be strong, but we could see some gusty winds and localized flash
flooding from stronger or training storms.

After the cold front on Wednesday morning, we will enter a quieter
period for the mid-week. Highs will be in the mid 80s for Thursday
and Friday, slowly warming back into the 90s into next weekend.

&&

.AVIATION...
(18Z TAFS)
Issued at 1235 PM CDT Fri Jul 17 2026

Expect mainly a persistence forecast across the airspace today.
High moisture content and instability has encouraged another
afternoon of scattered showers and thunderstorms, warranting
PROB30s for each site. Timing of this sporadic convection may last
a little after 01Z, but CAMs are in fairly good agreement on the
bulk of storms settling down by then. The Cumberland Plateau is
showing a pretty strong signal for fog and low ceilings (IFR to
LIFR), especially for CSV overnight. Current guidance suggests
improvement shortly after 12Z, but with the high humidity and
light winds, CSV and SRB may end up socked in through tomorrow
afternoon. More pop-up storms are on tap tomorrow afternoon as
well.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      73  92  75  91 /  30  30  30  70
Clarksville    74  92  74  91 /  20  20  30  60
Crossville     69  84  69  85 /  20  40  40  70
Columbia       72  92  73  91 /  20  20  30  70
Cookeville     71  87  71  86 /  30  50  50  70
Jamestown      69  86  69  85 /  20  50  70  70
Lawrenceburg   71  90  72  89 /  20  30  30  70
Murfreesboro   72  92  73  91 /  30  30  50  70
Waverly        72  91  73  91 /  20  10  40  60

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&

SHORT TERM...Holley
LONG TERM....Holley
AVIATION.....Dirkes