Severe Thunderstorm Warning 104, NWS Nashville, TN

Area Forecast Discussion
National Weather Service Nashville TN
624 PM CDT Tue Jul 21 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 618 PM CDT Tue Jul 21 2026

- A Heat Advisory is in place until 8 pm this evening with heat
  index temperatures reaching 105+ degrees.

- There is a slight risk (level 2/5) for severe weather now
  through tonight. Main impacts are damaging winds and flash
  flooding.

- Cooler and drier conditions arrive Wednesday and continue
  through the end of the week.

&&

.SHORT TERM...
(Rest of today through Wednesday Night)
Issued at 1113 AM CDT Tue Jul 21 2026

Hot and humid conditions are in place across the region with
temperatures approaching 90 degrees and dew points in the mid and
upper 70s. Highs will top out in the low to mid 90s which will make
it feel oppressive this afternoon with heat index values up to 110
to even 115 degrees. A Heat Advisory is in place until 8 PM.

The heat is the first course of hazardous weather today. A surface
front is moving south through Missouri into central Illinois this
morning ahead of a shortwave in the northwest upper flow. The
combination of lift and the ample instability and moisture at the
surface will allow storms to fire across southern Indiana and Ohio
over the next couple of hours. Some activity is already bubbling
across our northeastern counties and some heavy downpours can't be
ruled out this afternoon, but the main severe concern will be with
the activity coming out of Kentucky this evening as bulk shear
increases. Damaging winds will be the main severe storm threat this
evening and into early Wednesday along with a very low risk of a
tornado along the TN/KY state line. Instability and storm
organization will decrease the further storms move south and the
deeper we get into the overnight hours. The window of greatest
severe potential looks like 7 PM to around 1 AM.

In addition to the severe threat, some instances of flash flooding
will be a threat. PWAT values are around 1.9-2" across Middle
Tennessee, so very high rain rates can be expected with storms
today and tonight. HREF and associated CAMs show pockets of 2" of
rain with 90th percentile values showing the potential for over 4"
in isolated areas. With the wet July we've had so far, this would
be sufficient for flash flooding in those areas. The HREF shows
the higher probabilities of over 2" and higher 90th percentile
values along and east of I-65. A Flood Watch is in effect through
12z Wednesday.

By 12z Wednesday, the surface front will be draped across the area
from SW to NE. South of the surface front, additional showers and
storms will be possible Wednesday afternoon along the plateau.
Shear will be lower than tonight, so I don't expect any severe
activity Wednesday afternoon. Behind the front, lower dew points
will filter in from the northwest through the day and into
Wednesday night. The surface front will be through the entire area
by Wednesday night which will usher in a very pleasant night with
low dropping into the low to mid 60s.

&&

.LONG TERM...
(Thursday through next Tuesday)
Issued at 1113 AM CDT Tue Jul 21 2026

To start the long term period, we will be in the nicest airmass
we've had so far this summer. Dew points on Thursday will be in the
low to mid 60s with highs in the low to mid 80s. Friday will be
similar but a couple degrees warmer. A shortwave will ride northwest
upper flow and approach the area Friday night into Saturday which
will reintroduce some low to medium rain chances. Temperatures will
creep up over the weekend with the possibility of a couple more
shortwaves bringing additional storm storms chances going into early
next week. There is some uncertainty of how far east ridging
influences pushes which will affect our rain chances and
temperatures next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 618 PM CDT Tue Jul 21 2026

The first 6 hours of this TAF cycle will be riddled with TS and
gusty winds as a broken line of thunderstorms moves into TN from
the north. These should come to an end for all terminals by 05-06Z
this evening and while cats will improve after the storms for
CKV/BNA/MQY, MVFR cigs will return around sunrise Wednesday at
BNA/MQY. CSV/SRB will bear the brunt of longer MVFR cigs through
the night and sticking around after storms until lunchtime on
Wednesday. Winds outside of storms will be light and we will see a
shift to the northwest/north after storms pass. With storms, winds
may be gusty at times with northwest to north gusts of 30 to 40
kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      73  87  65  83 /  80  10   0   0
Clarksville    70  86  62  83 /  50   0   0   0
Crossville     69  82  60  80 /  80  60  30  20
Columbia       73  88  65  84 /  80  20   0   0
Cookeville     71  84  63  81 /  80  30  10   0
Jamestown      69  82  60  80 /  90  40  10   0
Lawrenceburg   73  86  65  83 /  70  30  10  10
Murfreesboro   73  88  65  84 /  70  20   0   0
Waverly        71  86  63  83 /  70   0   0   0

&&

.OHX WATCHES/WARNINGS/ADVISORIES...

Heat Advisory until 8 PM CDT this evening for TNZ005>011-023>034-
056>066-075-077>080-093>095.

Flood Watch through Wednesday morning for TNZ008>011-024>034-
056>066-075-077-078-080-093>095.

&&

SHORT TERM...Reagan
LONG TERM....Reagan
AVIATION.....Unger