390
FXUS64 KHUN 250832
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
232 AM CST Mon Nov 25 2024

...New NEAR TERM, SHORT TERM, LONG TERM...

.NEAR TERM...
(Today and Tonight)
Issued at 232 AM CST Mon Nov 25 2024

The upper level ridge will shift east today as a shortwave trough
swings over the Midwest and into the Great Lakes region. A
surface low pressure system will also pivot over the Great Lakes
and upper Ohio Valley this afternoon, with a trailing cold front
approaching the Tennessee Valley as well. Anticipating highs
reaching the upper 60s to around 70 degrees as moisture continues
to increase and warm air is advected into the region ahead of this
cold front. Rain chances will also increase (40-60%) by late this
afternoon/early this evening from the northwest. The line of
showers and potentially a few embedded, elevated storms will
quickly progress over north Alabama and southern middle Tennessee
through late tonight. Although there will be plenty of bulk shear
according to model guidance, instability will be meager and lapse
rates insufficient for severe storm development. Thus, the threat
for strong to severe storms is low to none. As previously
mentioned, this will be a fast-moving system and dry conditions
will return to the local area by late tonight into very early
Tuesday morning. With this FROPA, lows are then forecast to dip
into the lower to mid 40s.

&&

.SHORT TERM...
(Tuesday through Tuesday Night)
Issued at 232 AM CST Mon Nov 25 2024

On Tuesday will come a brief respite in rain chances as zonal
flow sets up aloft and surface high pressure traverses the lower
Ohio and Tennessee valleys. Cooler temperatures are also
anticipated in the wake of the aforementioned cold front. Highs
are forecast to only reach the mid to upper 50s Tuesday afternoon,
with lows dipping into the 30s that night. Furthermore, low dew
point depressions could lead to the formation of frost once again
Tuesday night. We`ll monitor trends in case a Frost Advisory
becomes necessary; however, it`s a good idea to plan to tend to
any sensitive plants by covering them or bringing them indoors.

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 232 AM CST Mon Nov 25 2024

The main focus in the long term period continues to be an upper
trough that will shift into the eastern CONUS later in the week,
bringing a strong cold front to the area on Thursday. As mentioned
in previous discussions, there had been some differences among
global models regarding the evolution of the sfc low and what, if
any, threats might materialize. The GFS which had previously
favored a more southern sfc low track has shifted slightly north
and now is more in line with the ECMWF. We want to emphasize that
while we prioritize ensemble guidance at this range, we have
waited for more consistency among deterministic guidance and for
now that is happening.

With the trend favoring a sfc low to our north, this increases
our time in the warm sector and could result in a few
strong/severe thunderstorms late Wednesday into early Thursday.
There are a few limiting factors to take into account when
assessing the potential for severe storms, and one limiting factor
will be the overnight timing. Cool-season events tend to be more
shear dominant and the amount of sfc based instability plays a key
part in whether or not updrafts will be strong enough to overcome
the strong winds aloft. LREF ensemble means suggest that there
could be at least a small amount of sfc based instability (100-400
J/kg) Wednesday night that would support thunderstorms, but
confidence in this being strong enough to sustain any decent
updrafts is low at this time. What may be the more likely scenario
is that instability is more elevated and would limit the severe
threat to damaging winds instead of the potential for a tornado.
These trends will continue to be monitored in the coming days in
case more aggressive messaging is needed ahead of the holiday.
Rainfall amounts continue to be around an inch or less, so
flooding is not a concern at this time.

The aforementioned cold front will move through the area during
the day on Thursday and will be followed by a sharp change in
airmass. We will definitely notice the difference by Friday as
highs will be limited to the 40s and overnight lows drop into the
low to mid 20s. This cold airmass will be here to stay for a
while, and wind chills may even dip into the mid to low teens on
some nights heading into early next week. Enjoy the milder temps
while they last, because winter is coming!

&&

.AVIATION...
(06Z TAFS)
Issued at 1142 PM CST Sun Nov 24 2024

VFR conditions are expected at both terminals through 8Z. Then
some MVFR VSBYS due to patchy fog development could occur at
KHSV. Believe winds will remain around 4 knots or higher at KMSL
most of the night, so none was included there. These MVFR
conditions at KHSV were included in a tempo group from 8Z to 12Z.
Winds should pick up around 11Z at KMSL to around 8 knots with
some gusts to 13 knots. Further east, this may hold off until
closer to 13Z. Winds should continue to strengthen after 15Z and
turn more to the southwest. Rain chances then increase late this
afternoon/early this evening, along with a return of MVFR CIGs.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

$$

NEAR TERM...26
SHORT TERM....26
LONG TERM....25
AVIATION...KTW/26