143
FXUS64 KOHX 171630
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
1130 AM CDT Tue Jun 17 2025

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1130 AM CDT Tue Jun 17 2025

- Showers and thunderstorms continue to be the pattern for the
  upcoming week with low chances of severe weather and medium
  chances of flash flooding.

- Summer-like heat and drier weather makes an appearance across
  Middle Tennessee for next weekend. Heat indices climb to 100
  degrees Saturday through Monday.

&&

.MESOSCALE UPDATE FOR TODAY`S STORM POTENTIAL...
Issued at 925 AM CDT Tue Jun 17 2025

The morning sounding from OHX shows a wet environment with only
modest instability. The Precipitable Water is 1.91, which gives us
a PWAT+ of 148 (observed PWAT is 148% of the daily mean value),
and puts us close to a daily max and definitely above the 90th
percentile for this date. When modifying for the expected max
temp, we get a surface-based CAPE in excess of 1,300 J/kg and a
Lifted Index of -5. However, the 700-500 mb lapse rate is only
5.5C/km, and there is very little low-level wind shear. So the
big takeaway is a very low severe potential. The tall, thin CAPE
that were seeing pretty much rules out any large hail potential.
So were left with an isolated damaging wind threat and a heavy
rainfall potential. We will have to monitor for localized flooding
with any slow movers, as the high PWAT value suggests the
possibility of very high rainfall rates. Meanwhile, the 13Z HRRR
shows at least scattered activity occurring across Middle
Tennessee for the remainder of the morning and through the
afternoon, then diminishing after 00Z. The lack of any real
organization means that trying to highlight specific timing is
impossible; the storm threat will be ongoing for the next several
hours.

&&

.SHORT TERM...
(Rest of today through Wednesday)
Issued at 1130 AM CDT Tue Jun 17 2025

Low clouds are our story once again for this morning. The UL trough
and shortwave should push east today, but still provide the forcing
for thunderstorms across the area. Again, a low chance of severe
weather, but flash flooding remains a concern. SPC has placed most
of our area in a marginal risk for severe weather today (level 1/5),
highlighting wind gusts as the most likely hazard. Daytime heating
will play a role in the thunderstorms again, so most likely time
will be in the afternoon and evening. With these storms, in addition
to wind gusts, most likely hazards will be lightning, and heavy
rainfall. PWATs from this morning`s sounding here at the office are
around 1.90", which is close to our daily max and above the 90th
percentile for today. This airmass is extremely moist, and we have
already had above average rainfall this summer, which is why we are
concerned about flash flooding in the area today. Be weather aware
and know your action plan if a flash flood warning is issued.

Wednesday will be a slight lull, in the terms it will be true
diurnal thunderstorm activity without any UL forcing or support.
However, Wednesday night into Thursday morning will be another
story. SPC has placed our NW counties in a slight risk for severe
weather (level 2/5) with a marginal risk (1/5) across the remainder
of the area. Looking at the CAMs, 2 waves are shown. The first line
moves along the KY/TN state line in the evening hours Wednesday, and
is not really a threat to the rest of middle Tennessee. The second
wave is overnight into Thursday morning, and affects the entire
area. It seems stronger in the guidance west of I-65, and then kind
of fizzles out as it moves east. Some guidance shows discrete storms
ahead of the main lines, which would cause more severe weather
issues, but wind is our main threat Wednesday evening into Thursday,
followed by large hail, and a low tornado threat at this time.


&&

.LONG TERM...
(Wednesday Night through next Tuesday)
Issued at 1130 AM CDT Tue Jun 17 2025

One more day of thunderstorm chances on Thursday after the morning`s
activity, but with the timing shift to be more of an overnight into
the morning event, we will have to see how much the atmosphere can
rebound into the afternoon. If there is enough rebound, we could see
isolated thunderstorms, mainly in the eastern part of the area.
Hazards with these cells will be lightning, heavy rain, and windy
conditions.

The weekend looks largely dry, but humid and hot. A stout ridge will
take hold over the southeast US over the weekend and into next week,
which will limit our rain chances but crank up those temperatures.
Highs look to reach the mid 90s, and the airmass will remain humid
over middle Tennessee, bringing about heat index concerns as they
could creep into the triple digits. We`re monitoring for heat issues
into the weekend, but with the temporal extent, hard to say for
certain now. It looks pretty likely though.

&&

.AVIATION...
(12Z TAFS)
Issued at 630 AM CDT Tue Jun 17 2025

While we`ve been VFR most of the night at our mid-state terminals,
MVFR cigs will accompany morning showers at CKV/BNA/MQY that
should arrive around 13Z. While these will only last a few hours
and VFR should return around 17Z, scattered afternoon showers and
storms are expected at all terminals. Timing is on the lower
confidence side, so covered with PROBs and will have to adjust.
Southwest winds will be less than 10 kts through 16Z then become
breezy with gusts up to 20 kts until sunset.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      84  72  90  72 /  80  30  30 100
Clarksville    82  73  88  72 /  80  10  20  80
Crossville     80  66  83  67 /  80  70  70  80
Columbia       83  71  89  71 /  90  30  30  90
Cookeville     82  69  85  68 /  90  60  50  90
Jamestown      82  67  84  67 /  90  70  70  90
Lawrenceburg   83  70  88  70 /  90  40  30  80
Murfreesboro   85  71  90  71 /  90  40  40  90
Waverly        81  70  88  69 /  80  10  20  90

&&

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

$$

SHORT TERM...Holley
LONG TERM....Holley
AVIATION.....Unger