Hampton Cove, Alabama Weather Forecast Discussion

434
FXUS64 KHUN 220351
AFDHUN
Area Forecast Discussion
National Weather Service Huntsville AL
1051 PM CDT Sun Sep 21 2025
...New NEAR TERM, SHORT TERM, LONG TERM...
.NEAR TERM...
(This Evening through Monday)
Issued at 1051 PM CDT Sun Sep 21 2025
A gradually amplifying 500-mb trough (initially across the
central Plains) will continue to advance eastward overnight and
will cross the middle/lower MS Valley tomorrow afternoon.
Southwesterly flow in the mid-levels will remain in the 15-25 knot
range as the trough approaches, and with a similar increase in
the south- southwesterly low-level underway this evening,
sufficient deep- layer ascent will be present to sustain clusters
of showers and a few thunderstorms as they spread northeastward
from the central Gulf Coast. Although storms will be neither
strong nor severe, occasional lightning and a brief period of
heavy rainfall may occur in small portions of the forecast area
for much of the night as this regime may not dissipate until
sunrise (or perhaps even later Monday morning). In spite of an
abundant coverage of mid/high-level stratus clouds, development of
patchy mist/fog can also be expected in wind-sheltered locations
as temperatures slowly descend into the m-u 60s.
As the axis of the mid-level trough approaches our region from
the west tomorrow, a narrow axis of surface pressure falls will
contribute to a lengthy axis of subtle streamline confluence which
should extend from the central OH Valley southward into MS/AL.
Presuming that sufficient destabilization can occur in the wake of
morning clouds/precipitation, thunderstorms should redevelop in
the vicinity of this feature by early afternoon and spread
eastward with time. Even with high temps a degree or so cooler
than today, it still appears as if steepening lapse rates aloft
will support CAPE similar to today (1000-2000 J/kg), and for this
reason we will continue to advertise locally damaging winds up to
60 MPH and small hail with the most intense cells. However, the
overall coverage of storms will be notably higher from the TN
River northward (where the approaching trough will be a bit more
amplified and height falls more pronounced), warranting a Marginal
Risk Day 2 convective outlook in this region.
&&
.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...
(00Z TAFS)
Issued at 700 PM CDT Sun Sep 21 2025
Although VFR will be the prevailing condition at the HSV/MSL
terminals this evening and overnight, a strengthening SSW low-
level jet will sustain scattered showers (and perhaps a few TSRA)
as they spread northeastward from southern portions of MS/AL for
much of the night (and perhaps into the late morning hours on
Monday). Coverage will likely remain too low to include in either
a TEMPO or PROB30 group, but an AWW for lightning is not out of
the question at either airport. Otherwise, a moist boundary layer
and light SSE wind should create MVFR vsby reductions in lgt BR/FG
btwn 9-13Z (especially as both terminals received a bit of rain
today). For the second half of the TAF period, a sct-bkn Cu field
will redevelop by 16Z, with perhaps an even greater coverage of
thunderstorms tomorrow afternoon (compared to today). This
activity will occur along and east of a sfc trough positioned to
our west, and PROB30 groups to address convective impacts have
been included at both HSV/MSL from 18-22Z.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&
$$
NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...70/DD
AVIATION...70/DD

NWS HUN Office Area Forecast Discussion