Severe Thunderstorm Warning 185, NWS Nashville, TN

Area Forecast Discussion
National Weather Service Nashville TN
Issued by National Weather Service Morristown TN
617 AM CDT Tue May 20 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 614 AM CDT Tue May 20 2025

- There is an enhanced risk (level 3 out of 5) for severe storms
  today. All modes of severe weather are possible, including
  damaging winds, hail, and tornadoes.

- Much cooler and drier air will push across the area by mid-week
  continuing into the first half of next weekend.

&&

.SHORT TERM...
(Tonight through Tuesday Night)
Issued at 1014 PM CDT Mon May 19 2025

As a trough ejects onto the Great Plains, it's been responsible
for severe weather over that area. This activity is important to
note because it's this that will bring the first round of storms
into Middle TN early Tuesday morning. This first round of storms
looks to cross the TN River as a line by 7-8AM and so begins our
next severe weather event. While these storms should weaken as
they travel east overnight, our own environment will destabilize
through the morning. Forecast soundings show little in the way of
a cap so as our CAPE values rise after daybreak and bulk shear
increases to 35-45 knots, the environment will be supportive of
storms re-intensifying. Main threat with the morning MCS will be
damaging winds, but a low threat for hail and tornadoes will still
exist as forecast soundings show steep mid- level lapse rates and
curved hodographs.

The morning activity will push east out of Middle TN by early to
mid-afternoon, but it will be the next round of storms that poses
the greatest severe weather risk. Ahead of a cold front, an
additional line of storms will develop, likely starting to cross
the TN River by 2-4PM. Shear values increase through the
afternoon, and surface winds veer just enough compared to the
morning hours to allow for larger and more curved hodographs.
Lapse rates aren't great at around 6-6.5 C/km, but regardless, all
modes of severe weather are still on the table, including
tornadoes.

There are still some aspects of this event where forecaster
confidence is still not high. The first is what impact the morning
convection will have on our afternoon atmosphere. More widespread
activity Tuesday morning will limit the time the atmosphere has to
recover for the afternoon storms. Models do continue to show cloud
breaks and a mid-level dry slot that will help with
destabilization in the afternoon, but this will have to be watched
closely. The second is the potential for discrete supercells ahead
of the afternoon line of storms. CAMs show more discrete cells
developing ahead of this second line, and if this verifies, would
expect a higher tornado threat.

&&

.LONG TERM...
(Wednesday through next Tuesday)
Issued at 1014 PM CDT Mon May 19 2025

Thunderstorm activity will come to an end late Tuesday evening,
and a much quieter end to the week is in store. As an upper-level
ridge builds to our west, dry northwest flow sets up over Middle
TN. In the wake of the cold front, temperatures will also be
cooler with highs only in the 60s to 70s. Next chance for rain
comes this weekend, however, as a shortwave brings rain chances
Sunday and into early next week.

&&

.AVIATION...
(12Z TAFS)
Issued at 614 AM CDT Tue May 20 2025

Unsettled weather will move into the area this morning with
periods of MVFR/IFR due to thunderstorms. A line of showers and
thunderstorms moves in from the west after 13z and will push east
during the morning hours. Then a cold front will bring a line of
widespread thunderstorms 21z through 05z 5/21. Otherwise,
conditions will be VFR outside thunderstorms with SSW winds gust
to 25KT at times.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      85  63  79  59 /  90  60   0  10
Clarksville    83  61  77  57 /  90  40   0  10
Crossville     82  61  73  53 /  70  80  10  10
Columbia       84  61  79  59 /  90  50   0  20
Cookeville     83  63  74  55 /  90  80   0  10
Jamestown      83  61  74  52 /  90  90  10  10
Lawrenceburg   83  61  78  58 /  80  60   0  10
Murfreesboro   86  63  79  58 /  90  60   0  10
Waverly        81  58  77  56 /  90  40   0  20

&&

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

SHORT TERM...Clements
LONG TERM....Clements
AVIATION.....13