112
FXUS64 KOHX 050159
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
859 PM CDT Thu Jul 4 2024

...New UPDATE...

.UPDATE...
Issued at 859 PM CDT Thu Jul 4 2024

Most convective activity over last hour or so has been confined
to locations around and south of I-40 Corridor Region and around
and west of I-65 Corridor Region with a diminishing convection
strength trend. This area continues to support CAPE values within
a 3,000-4,000 J/KG range, instantaneous precipitation rates of 3-4
inches an hour, with total rainfall amounts in some locations
approaching 1.5 inches, as a subtle upper level shortwave digs
across this portion of mid state region this evening. A general
lean toward latest HRRR precipitation guidance taken per best
initialization with belief that convection will continue across
this area but continue to weaken as remainder of evening hours
progress. Will keep a slight chance pop for remainder of mid state
through evening hours, but it generally looks like, other areas
of mid state region will remain dry through remainder of evening
hours, including Nashville Metro Area. With a southwest to
northeast upper level flow pattern, current cloudiness across
western portions of mid state region will shift northeastward as
evening hours progress with some clearing of skies noted. Latest
Infrared satellite imagery showing an area of upper level
cloudiness developing as blow off from convection to southwest of
Nashville Metro Area presently and it may slide across Nashville
Metro Area as next hour or so progresses. Tweaked hourly
temperature, dewpoint, wind speed/direction, and sky conditions
grids blending them with associated previously forecasted hourly
late evening gridded values. Current regional temperature trends
support forecasted overnight low temperatures. Look for shower and
thunderstorm chances to increase after midnight from the
northwest. Remainder of forecast continues to be on track.

&&

.SHORT TERM...
(Rest of today through Friday)
Issued at 1136 AM CDT Thu Jul 4 2024

Happy 4th of July, Middle Tennessee! A heat advisory remains in
effect through 7pm tonight, so if outdoors today, it is
encouraged to stay hydrated with water, wear light clothing, and
take frequent breaks. Outside of the heat, the Independence day
forecast for storms looks to have improved over the last 24 hours.
We`ve been monitoring a complex of thunderstorms associated with
a shortwave trough across western Kentucky this morning. Those
storms will stay north of Tennessee, however, any outflow
boundaries that may push out from those storms will serve as a
trigger mechanism for scattered thunderstorms to fire along.
Models continue to show ample CAPE across the area this afternoon
with values reaching near 2000 J/kg. This is no surprise with how
hot it is and how warm our dew points temperatures are. The other
parameters of interest are shear and mid-level lapse rates, which
both appear to stay on the lower side today, meaning severe
thunderstorm potential will be limited. So what it comes down to
is we`ll be watching for thunderstorms to pop-up along any
boundaries hanging over the area this afternoon. Any storms that
do develop will have the potential to dump very heavy rain with
PWAT values nearing 2" this afternoon, produce gusty winds and
frequent lightning. As we move into the evening hours,
thunderstorm chances greatly diminish as instability values tank
with loss of daytime heating and any lingering boundaries move out
of the area.

A cold front will push through Friday in response to a deep upper-
level low kicking out that aforementioned shortwave. Rain and
thunderstorm chances will fire back up overnight tonight into the
early morning hours Friday and will become more widespread
across the area as the day progresses. Models aren`t showing much
in the way of severe potential, but an isolated strong storm or
two is possible late morning. The biggest thing with this front is
that it will provide us with a much needed break from the heat.
Increased cloud cover and rain will push temperatures down into
the upper 80s tomorrow with drier air filtering in after frontal
passage Friday evening. Drier air = lower relative humidity.

&&

.LONG TERM...
(Friday Night through next Thursday)
Issued at 1136 AM CDT Thu Jul 4 2024

We will be on the back side of the trough come Saturday and this
will continue to usher in sinking, cooler air. It will no doubt
still be warm with highs both Saturday and Sunday in the upper
80s for most and low 90s for some, but with the drier air being
present, the feel-like temperature will be much closer to the
actual temperature as dew point temperatures drop back into the
low 60s. As we move into the second week of July, winds will turn
back out of the south Monday due to a trough building in from an
upper-level low over the Midwest. This will bring moisture back
into the area as well as rain and thunderstorm chances. These
chances will stay in the forecast each day next week and will
generally be on the low-to-medium (30-50%) side each day. Models
show our mid-level winds turning westerly during the week and this
will aid in streaming in disturbances throughout the week. As of
now, nothing alarming in terms of severe potential in the long
term.

&&

.AVIATION...
(00Z TAFS)
Issued at 636 PM CDT Thu Jul 4 2024

Scattered storms will impact some terminals this evening.
Visibilities could be reduced to IFR if a terminal is impacted by
a storm. Storm coverage will decrease late this evening into
tonight. Some models bring a line of showers and storms into
Middle Tennessee from west to east close to dawn into Friday
morning. Confidence in this solution is increasing so tried to
give best first guess for initial timing of thunderstorms. Will
likely need to adjust with next set of TAFs. Winds are generally
light and even light and variable over the Upper Cumberland, but
with any storm this evening, gusts to 30 mph or greater are
possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      77  92  71  90 /  50  90  10   0
Clarksville    75  89  66  87 /  60  70   0   0
Crossville     71  86  65  85 /  40  90  40  10
Columbia       75  91  68  90 /  80  90  10   0
Cookeville     73  86  67  84 /  40  90  30  10
Jamestown      72  85  66  83 /  40  90  30  10
Lawrenceburg   75  90  68  89 /  80  90  20  10
Murfreesboro   76  92  68  90 /  40  90  20   0
Waverly        74  88  66  88 /  80  80   0   0

&&

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

$$

UPDATE.......JB Wright
SHORT TERM...Baggett
LONG TERM....Baggett
AVIATION.....Cravens