Cowan, Tennessee Weather Forecast Discussion

510
FXUS64 KHUN 211047
AFDHUN
Area Forecast Discussion
National Weather Service Huntsville AL
547 AM CDT Sun Sep 21 2025
...New AVIATION...
.NEAR TERM...
(Today)
Issued at 250 AM CDT Sun Sep 21 2025
Current satellite shows convection fueled by an approaching short
wave centered along the Arkansas/Missouri state line. High clouds
can be seen shearing off and ahead of this feature however as of 2
AM the TN Valley remains mostly clear. Under mostly clear skies a
few areas of patchy fog have developed in our valleys. Cloud cover
looks to increase through the early morning hours as the
aformentioned system pushes east, dissuading any additional fog
formation.
Meanwhile, to our east, a CAD set up continues to evolve placing
us solidly in SSE surface flow. As the approaching short wave
moves east, the SSE flow will aid in keeping the main convection
to our north through the day today. Even so, scattered storms
triggered by outflow from the system to our north are forecast
across the area. HREF models show us reaching convective temps by
midday and indicate the presence of an inverted v profile. This
will support a gusty wind threat among the strongest storms with
heavy rainfall and lightning being additional threats. Coverage is
expected to be slightly higher than yesterday with locations north
of the TN River having slightly higher chances (30-40%). A
majority of storms will wane with the loss of surface heating come
sun set with only low rain chances (10-15%) carrying into the
overnight hours.
&&
.SHORT TERM...
(Sunday night through Tuesday night)
Issued at 959 PM CDT Sat Sep 20 2025
Next week, we will start off with a trough centered over the
northern Great Lakes but extends down into the Lower MS Valley
and the northern Gulf. This will be slow moving and allow a
shortwave ejecting out of the Rockies to start and phase with it.
Will get a push of moisture into the region with southeasterly sfc
winds and increasing southwesterly mid level winds. Combined with
small shortwaves rounding the trough to provide lift, and decent
instability, will see low chances (20-50%) of showers and
thunderstorms Monday and Tuesday. Shear will remain weak, but
storms could produce gusty winds and heavy rainfall. The highest
PoPs will stay north of the TN River. Daytime highs will only be a
tad cooler with the increase in cloud cover and storms, reaching
the upper 80s to lower 90s. Overnight lows will be warm in the
mid/upper 60s on Monday night and could hit 70 in a few spots on
Tuesday night.
&&
.LONG TERM...
(Wednesday through Saturday)
Issued at 959 PM CDT Sat Sep 20 2025
Global models are in agreement in depicting a strengthening mid-
level trough (with an increasing negative-tilt) to track across the
east-central Plains and into the Mid-MS Valley on Wednesday/Wednesday
night. As this occurs, a deepening surface low will shift from the
Ozarks into the Lower OH Valley, with potential development of a
secondary wave to the south of the primary cyclone (across
southeastern AR/northwestern MS). As a 20-30 knot southwesterly low-
level jet (ahead of this system) gradually becomes more established
across the TN Valley throughout the day, scattered convection is
likely to develop within the increasingly moist airmass (highlighted
by a plume of dewpoints in the u60s-l70s).
Coverage of showers and thunderstorms within the open warm sector
across our region will begin to increase early Wednesday evening and
should remain rather high through Thursday morning. With CAPE
expected to remain sufficiently high overnight to support
thunderstorms, we will need to watch this timeframe very closely for
a risk of severe weather, as WSW flow in the mid-levels will
progressively strengthen into the 40-50 knot range creating a
favorable kinematic environment for organized multicell clusters and
perhaps even a few supercells. At the present time, the magnitude of
the low-level jet appears only marginally conducive for weak
mesocyclone development, but trends in this parameter will need to be
monitored as any increase would yield at least a low-end risk for
tornadoes in addition to damaging winds. With a moist/tropical
airmass expected to be in place (featuring PWAT values in the 1.8-2"
range), locally heavy rainfall and flash flooding will also be a
concern as indicated in the Day 5 ERO from the NWS Weather Prediction
Center.
During the period from Thursday-Saturday, the surface low is
predicted to advance northeastward through the OH Valley before
slowly decaying over the central Appalachians. A surface trough and
cold front attached to the low may initiate additional showers and
storms on Thursday as they track across our forecast area, and
although shear profiles will remain favorable for storm organization,
instability will be uncertain in the wake of nocturnal
precipitation. Light-moderate NNW flow in the low-levels will begin
to advect a slightly drier continental airmass into the region
following frontal passage, but due to the slow movement of the mid-
level low, periods of low clouds and showers may occur from Thursday
nigt-Saturday (mainly across the northeastern portion of the CWFA).
Highs will fall back into the u70s-l80s, with lows likewise dropping
into the u50s-l60s.
&&
.AVIATION...
(12Z TAFS)
Issued at 547 AM CDT Sun Sep 21 2025
Cloud cover will increase through the day with rain and storm
chances increasing after 18z. Confidence in exact timing and
location of storms remains low and will be refined if possible in
future TAF issuances. If a storms moves directly over the terminal
it could briefly drop ceilings and visibilities to MVFR. Any
storms that do develop look to clear by 6Z with VFR conditions
prevailing overnight.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&
$$
NEAR TERM...RAD
SHORT TERM....JMS
LONG TERM....70
AVIATION...RAD

NWS HUN Office Area Forecast Discussion