Hartselle, Alabama Weather Forecast Discussion

187
FXUS64 KHUN 210300
AFDHUN
Area Forecast Discussion
National Weather Service Huntsville AL
1000 PM CDT Sat Sep 20 2025
...New NEAR TERM, SHORT TERM, LONG TERM...
.NEAR TERM...
(Rest of tonight and Sunday)
Issued at 959 PM CDT Sat Sep 20 2025
Currently have mostly clear skies in place across the TN Valley
with temps in the in the upper 60s to lower 70s. Combined with
light to calm winds, we could see patchy fog early tomorrow
morning as lows reach the 60s. Any fog development will dissipate
with sunrise.
Tomorrow, we will see an increase in cloud cover with a low chance
(15-30%) of showers and thunderstorms during the afternoon hours.
Daytime highs will be warm once again, reaching the upper 80s to
lower 90s, which is several degrees above normal for this time of
year. Heat index values will be negligible, only slightly above
the temperatures. Shear remains weak, but any storms that
develop will be slow moving and capable of producing gusty winds
and heavy rainfall.
&&
.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...
(00Z TAFS)
Issued at 640 PM CDT Sat Sep 20 2025
Will hold onto VFR conditions for most of the night until a low
chance of MVFR fog, ~5-7 mi, develops again in the early morning
hours tomorrow. Will monitor obs for any amendments needed. Will
see an increase in cloud cover before a low chance (20%) of
showers and thunderstorms during the afternoon hours.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&
$$
NEAR TERM...JMS
SHORT TERM....JMS
LONG TERM....70/DD
AVIATION...JMS

NWS HUN Office Area Forecast Discussion