Joppa, Alabama Weather Forecast Discussion

539
FXUS64 KHUN 221045
AFDHUN
Area Forecast Discussion
National Weather Service Huntsville AL
545 AM CDT Mon Sep 22 2025
...New AVIATION...
.NEAR TERM...
(Today)
Issued at 304 AM CDT Mon Sep 22 2025
Bands of cloud cover and weak showers and thunderstorms can be
seen currently moving north across the area supported by the
nocturnal LLJ. With an approaching short wave adding additional
forcing, this trend is forecast to continue through the next
several hours.
The aforementioned shortwave is forecast to ripple though the TN
Valley today along and ahead of a mid level trough. At the surface
this will be competing with high pressure to the east with SSE
induced flow. The SE flow will support PWATS climbing back into
the 1.5" range, adding moisture to the areas ahead of the
shortwave. The passage of the shortwave will provide enough
support to trigger scattered strong to potentially severe storms
across the area, with best chances north of the TN River due to
proximity to the wave. Models again show damaging winds being the
primary threat with an inverted v sounding present this afternoon.
With higher PWATS to start the week, heavy rainfall and nuance
flooding will be secondary threats along with frequent lightning.
The current 3 AM question is how much instability can we procure
by midday. With additional clouds ahead of the short wave
translating east, this could cause some limitation in daytime
heating and destabilization if cloud cover lingers through the
morning. This would decrease our severe threat which currently
sits at a level 1/5 for areas north of the TN River. Likewise CAMS
differ greatly in coverage of storms for our area, only converging
on the fact that the best coverage and chances for severe storms
will be well to our north in Nashville`s area. Nonetheless, make
sure to remain weather aware through the afternoon.
&&
.SHORT TERM...
(Monday night through Wednesday night)
Issued at 1051 PM CDT Sun Sep 21 2025
Depending on the evolution and eastward movement of storms across
our region tomorrow, portions of northeast AL/southern TN may
still be experiencing this regime early Monday evening. However,
gradual weakening/dissipation is expected to occur within a few
hours of sunset as the axis of a mid-level trough progresses
further eastward and away from the TN Valley, inducing weak
subsidence aloft. After Midnight (and continuing throughout the
day on Tuesday), we will likely see additional clusters of
showers/thunderstorms approach our region from the west-northwest,
which may initiate either along remnant outflow boundaries or
within the low-level warm advection regime of a larger positive-
tilt trough (extending from eastern Canada into the central
Rockies). Although this activity will tend to travel east-
southeastward in the prevailing steering flow aloft, strengthening
broad scale subsidence across our forecast area will likely keep
the highest concentration of precip to our north and we will
advertise a low chance POP (~30%) north of the TN River, with a
lower 10-20% POP elsewhere. Should storms impact our forecast
area, CAPE will remain high enough to support a risk for strong-
severe winds (especially with mid-level flow gradually increasing
into the 20-30 knot range), but coverage is highly uncertain.
Latest short range model date suggests that an upper low will
begin to consolidate within the broader longwave trough on Tuesday
night (likely across the Mid-MS Valley), with this feature
predicted to slowly intensify but move very little on
Wednesday/Wednesday night. As the related surface low begins to
lift northeastward from the southern Plains into the Mid-MS Valley
(and eventually Lower Great Lakes), an MCS may evolve out of
convection across OK/KS Tuesday afternoon, that would subsequently
track east-southeastward, perhaps reaching western TN/northern MS
by 12Z Wednesday. Although this system may be on a weakening
trend as it enters our CWFA later Wednesday morning, rain and
embedded thunderstorms may begin to impact the region early in the
day. Of more concern (from a severe weather standpoint) is the
potential redevelopment of thunderstorms in the vicinity of a
surface trough that will be approaching the region from the west
on Wednesday afternoon before shifting slowly eastward Wednesday
night/Thursday morning. If sufficient airmass recovery can occur
to support deep updrafts, mid-level WSW flow increasing into the
40-50 knot range with time will yield a favorable environment for
organized multicells (and perhaps a few supercells), with an
attendant risk for damaging winds and large hail. Even with the
southwesterly low-level jet predicted to veer and weaken by 12Z
Thursday, magnitudes of 25-35 knots may also provide a low-end
tornado risk before this occurs. Regarding temperatures, highs
will remain in the u80s-l90s on Monday and Tuesday, before falling
back into the l-m 80s Wednesday. Lows will remain in the m-u 60s.
&&
.LONG TERM...
(Thursday through Sunday)
Issued at 1051 PM CDT Sun Sep 21 2025
Global models suggest that the coverage of rain and thunderstorms
will remain rather high across the TN Valley on Thursday, with
redevelopment of another band of convection possible during the
afternoon/evening as a weak cold front slides southeastward into
the forecast area. Although mid-level winds will remain in the
40-50 knot range and conducive for organized thunderstorms,
impacts from previous convection make instability highly
uncertain. Regardless, locally heavy rainfall will remain a
possibility given precipitable water values in the 1.8-1.9" range.
Present indications are that a drier and slightly cooler
continental airmass will finally work its way southeastward into
the region Thursday night/Friday morning, and although some low-
clouds and warp-around showers will be possible on Friday, the
remainder of the period appears to be dry at this point. Highs
will be in the u70s-l80s, with lows in the u50s-l60s.
&&
.AVIATION...
(12Z TAFS)
Issued at 545 AM CDT Mon Sep 22 2025
VFR  will be present at the start of the TAF period. Southerly
winds will pick up after sunrise with low rain and storm chances
arriving by mid afternoon. Confidence in timing and exact location
of storms is low. Any storms that do develop and move over the
terminal will be capable of briefly lowering ceilings and
visibilities. Rain and storm chances will decrease after sun set
with a low chance of additional impact overnight.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&
$$
NEAR TERM...RAD
SHORT TERM....70
LONG TERM....70
AVIATION...RAD

NWS HUN Office Area Forecast Discussion