Capshaw, Alabama Weather Forecast Discussion

181
FXUS64 KHUN 261630
AFDHUN
Area Forecast Discussion
National Weather Service Huntsville AL
1130 AM CDT Fri Sep 26 2025
...New AVIATION...
.NEAR TERM...
(Rest of Today and Tonight)
Issued at 1049 AM CDT Fri Sep 26 2025
A positively-tilted mid-level trough (positioned to our immediate
northwest) is predicted to evolve into a cutoff low and drift
slowly southeastward across northern/central portions of AL over
the course of the short term period. As this occurs, steering
currents will collapse as southwesterly flow aloft of 15-25 knots
becomes light/variable for a brief period of time, before veering
to the north by 12Z Saturday. At the surface, a prefrontal wind
shift axis currently lies across the southeastern portion of the
CWFA, with the leading edge of a diffuse cold front (separating
dewpoints in the u50s-l60s to its northwest from dewpoints in the
l-m 60s to its southeast) positioned across far northwest AL. With
abundant deep-layer moisture still in place across the region
(highlighted by PWAT values in the 1.2-1.4" range), weak mid-
level ascent provided by the trough should be sufficient to
generate scattered showers and some thunderstorms to the southeast
of the cold front from late this morning through the afternoon.
Presuming that surface temps warm into the u70s-l80s (even with a
broken layer of stratus clouds), CAPE in the 1000-1500 J/kg range
with steep lapse rates in the boundary layer suggest that wind
gusts up to 40 MPH and lightning will be the most significant
storm impacts. However, given weak steering flow and saturated
soils from recent rainfall, flash flooding may also become a
concern.
Present indications are that diurnally-enhanced convection will
largely end across our southeastern forecast zones shortly after
0Z this evening. However, due to the slow-moving nature of the
cutoff cyclone aloft and remaining presence of two surface
boundaries in the region, it would not be surprising to see
additional development of light-occasionally moderate showers
throughout the night (primarily across the eastern portion of the
forecast area). Across the remainder of the region, a combination
of low stratus clouds and light fog is predicted to evolve after
Midnight, with lows in the u50s-m60s.
&&
.SHORT TERM...
(Saturday through Monday)
Issued at 1049 AM CDT Fri Sep 26 2025
During the period from Saturday-Sunday, a cutoff mid/upper-level
low will weaken and lift northeastward into western NC, with
northerly flow of 15-25 knots expected to maintain the advection
of dry air into the forecast area aloft. At the surface, light
north-northeasterly winds will persist during the day tomorrow, as
the region will remain situated between a high centered over the
Ozarks and a weak area of low pressure across southern AL/GA and
adjacent portions of the FL Panhandle. However, by Saturday
night/Sunday, low-level NNE flow will begin to increase as a
reinforcing dome of high pressure (currently across the northern
Rockies) merges with the original anticyclone to its southeast.
Although a subtle gradient in low-level moisture will remain in
place across our region (which may support the development of a
few additional afternoon showers across the east on Saturday),
drying profiles aloft will lead to a lower coverage (compared to
today), with POPs dropping below mentionable levels on Saturday
night and Sunday.
Latest short range model solutions suggest that the cutoff low to
our northeast may begin to retrograde southwestward into the TN
Valley once again on Sunday night/Monday, but in a more
unorganized state (perhaps as an open trough). In the low-levels,
dewpoints will begin to increase region-wide as a developing area
of low pressure tracks north-northwestward off the southeastern
Atlantic Coast, and this (along with low-level forcing for ascent
provided by a surface trough/wind shift axis) will lead to a minor
increase in the coverage of showers and thunderstorms (especially
Monday). Afternoon highs will remain in the u70s-l80s tomorrow,
before rising into the l-m 80s on Sunday/Monday. Overnight lows
will remain in the u50s-m60s through the period.
&&
.LONG TERM...
(Monday night through Friday)
Issued at 843 PM CDT Thu Sep 25 2025
A dry forecast continues through the first half of the work week
as an upper level ridge and subsequent sfc high pressure filters
into the Tennessee Valley from the west. Low rain chances creep
back into NE Alabama by mid week as the aforementioned cold front
shifts back to the NE and stalls over the Carolinas. However,
confidence in this is low as we continue to watch how the tropics
unfold off the eastern coast. Therefore, maintained a mostly dry
forecast through the end of the long term period. Highs during
this time are forecast to reach the 80s with overnight lows in
60s.
&&
.AVIATION...
(18Z TAFS)
Issued at 1130 AM CDT Fri Sep 26 2025
Light NNE winds (in the wake of a weak cold front) will continue
to advect a slightly drier airmass southward into portions of
northwest/north-central AL from late this morning into the
afternoon. However, sufficient low-level moisture will remain
present for a sct-bkn Cu field in the 2.5-4 kft layer. Present
indications are that showers and a few thunderstorms will remain
concentrated invof a prefrontal trough lying to the SE of the
terminals, and we will not include any precip in the forecast
attm. However, amendments or AWWs (for lightning) may be required
on short notice as dictated by radar data (especially for HSV).
Although clouds will partially clear this evening, redevelopment
of low stratus and light fog is expected early Saturday morning
(particularly across northeast AL). Due to some uncertainly
regarding the western extent of low cigs and vsby reductions, we
have not mentioned anything in the forecast at this point, but
this may be introduced in future updates. Otherwise, a sct Cu
field will redevelop by 16Z Saturday.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&
$$
NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...HC
AVIATION...70/DD

NWS HUN Office Area Forecast Discussion