805
FXUS64 KOHX 262342
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
642 PM CDT Sat Jul 26 2025

...New UPDATE...

.KEY MESSAGES...
Updated at 636 PM CDT Sat Jul 26 2025

- A Heat Advisory is in effect for all of Middle Tennessee west of
  the Cumberland Plateau from tomorrow through Wednesday.
  Widespread heat index values of 105F+ are expected, especially
  from Monday through Wednesday. Temperatures will start to back
  off starting on Thursday.

- There are low to medium chances for afternoon/early evening
  storms this weekend and for most of next week.

- While the risk of severe storms is very low, any storms that
  develop may produce very heavy rainfall and frequent lightning,
  along with the potential for localized gusty winds.

&&

.UPDATE...
Issued at 636 PM CDT Sat Jul 26 2025

I hope you`re enjoying these "cooler" temperatures because
starting tomorrow, the heat is going to crank up again. I hope you
have a way to stay cool if you have outdoor plans tomorrow. For
the time being, a few showers are roaming around Middle TN, but
these should disappear in the next few hours as the sun sets.
Can`t rule out a rumble of thunder, but most look like just brief
showers. Outside of that, the rest of the night should be quiet
with some light patchy fog for anyone who gets a shower. I`ll talk
Heat Advisories and this week`s storm chances with this evening`s
full forecast package.

&&

.SHORT TERM...
(Rest of today through Sunday)
Issued at 1124 AM CDT Sat Jul 26 2025

We are getting to enjoy one day without a Heat Advisory today,
although it`s still plenty hot outside. Already, we are seeing
some "pinhead" cells pop up on radar, and the heat-driven
convection is likely to increase as we head into the afternoon.
High pressure at the surface and aloft is centered over the
southeast U.S., so we are definitely feeling the influence of a
maritime tropical air mass across Middle Tennessee. There is
plenty of moisture rotating around the periphery of the high.
Indeed, the morning sounding from OHX gives us a Precipitable
Water value of 1.96", which is just above the 90th percentile for
this date, and gives us a PWAT+ value of 123 (meaning that
today`s PWAT is 123% of the daily mean value). There is obviously
plenty of instability in the environment, as well. Adjusting the
12Z sounding for the forecast max temp, we get a CAPE of just over
2,000 J/kg and a Lifted Index of -6. The 700-500 mb lapse rate
remains a modest 5.5C/km, so the severe storm potential today is
greatly limited. But with a weak wind field aloft, we will
continue to have to be on the lookout for slow-movers producing
high rainfall rates. Tomorrow, a Heat Advisory goes into effect
for all of Middle Tennessee west of the Cumberland Plateau.

&&

.LONG TERM...
(Sunday Night through next Saturday)
Issued at 1124 AM CDT Sat Jul 26 2025

The aforementioned high center will retrograde westward during
the early part of next week, but that will do nothing to lessen
the heat nor bring drier air. In fact, Monday through Wednesday
look to be the hottest days, with max temps increasing to the mid
and upper 90s at BNA (and many other locations, as well). There
will likely be some areas that reach a heat index of 110F during
the Monday through Wednesday period. So there is the possibility
that some of the Heat Advisory will have to be upgraded to an
Excessive Heat Warning should those 110F values affect a large
enough area. While our rain and storm chances are likely to
persist throughout most of next week, the heat won`t; an east-west
oriented surface boundary approaching from the north looks to
close in on Middle Tennessee by Thursday. This will create a more
zonal flow, which would cut off our southerly flow and thereby
lessen the heat. The surface boundary might actually slip through
the mid state by week`s end, but we will have to see. It`s
extremely difficult to get a clean frontal passage in Middle
Tennessee this time of year. But it will sure come as a relief if
it actually happens.

&&

.AVIATION...
(00Z TAFS)
Issued at 623 PM CDT Sat Jul 26 2025

Storm activity will dissipate near CSV over the next hour and no
more activity is expected overnight. There is a low chance of fog
development at CSV after midnight. Scattered showers and storms
will develop again on Sunday but coverage is expected to be less
than today. Therefore, no mention of thunder was include although
there is a low chance (10-20%) a terminal is impacted. Winds will
be southwesterly around 7 kts or less.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      76  95  78  96 /  20  30  10  40
Clarksville    76  94  77  95 /  20  30  10  30
Crossville     69  88  71  90 /  20  40  10  50
Columbia       74  95  76  95 /  20  30  10  40
Cookeville     72  89  73  91 /  20  40  10  40
Jamestown      71  89  71  90 /  20  40  20  50
Lawrenceburg   73  93  74  94 /  20  30  10  40
Murfreesboro   74  95  76  96 /  20  30  10  40
Waverly        74  93  75  95 /  20  30  10  30

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM Sunday to 8 PM CDT Wednesday for
TNZ005>010-023>031-056>064-075-077-093>095.

&&

$$

UPDATE.......Unger
SHORT TERM...Rose
LONG TERM....Rose
AVIATION.....Reagan