-- Discussion containing changed information from previous version are highlighted. --
639
FXUS64 KHUN 230455
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1155 PM CDT Sun Sep 22 2024

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 855 PM CDT Sun Sep 22 2024

Isolated shower activity that occurred over portions of the
forecast area earlier in the afternoon has for the most part
dissipated. A few showers however have remained on a slow
weakening trend NNE of Lynchburg and Winchester. Otherwise under
generally clear skies, area temperatures have cooled into the 70s
with light winds. This after high temperatures that rose into the
lower 90s.

This first day of autumn, with longer nights under clear skies
and light winds, a development of patchy fog is possible. Fog
formation is more probable in sheltered areas, as well as near
bodies of water. Lows should cool into the upper 60s to around 70.
The overall forecast has things handled well; thus no big changes
are needed.

&&

.SHORT TERM...
(Monday through Tuesday Night)
Issued at 254 PM CDT Sun Sep 22 2024

The upper ridge that influenced this weekend`s weather is
expected to be pushed southeast through early this week as an
upper trough digs down into the southern Plains and ArkLaMiss
region from the Midwest. At the same time, an area of surface low
pressure is expected to develop over Arkansas by Monday afternoon
and progress northeast up into the Ohio Valley by midweek. A cold
front associated with this feature looks to then slowly approach
the Tennessee Valley through at least Tuesday.

There remains uncertainty in how potent this surface boundary
will be as well as how far southeast it will progress. This will
have a significant impact on our rainfall chances and totals on
Tuesday and into Wednesday. At this point, anticipating low
(15-30%) chances of showers and storms generally along and north
of the Tennessee River again on Monday. This will then be followed
by low to medium (40-60%) chances over the northwestern portion
of our local area (northwest Alabama, southern middle Tennessee,
and portions of north-central and northeastern Alabama) on
Tuesday, with 30-40% chances over the southeast. Additionally,
guidance indicates instability values between 500-1500 J/kg with
30-40 knots of bulk shear Tuesday afternoon. Therefore, this will
be something to watch as these conditions may lead to a low chance
of a few strong to severe storms. However, at this time, we are
currently not outlooked for severe weather by SPC.

Highs are forecast to top out in the lower 90s on Monday, but
perhaps be a touch cooler, in the upper 80s to around 90 degrees,
on Tuesday due to increased cloud cover and shower/storm chances.
Meanwhile, lows will continue to be warm, with temperatures in the
upper 60s to lower 70s Monday night and mid to upper 60s Tuesday
night.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 438 AM CDT Sun Sep 22 2024

Latest extended range guidance from the global models indicates
that the remnant frontal boundary/low-level convergence axis will
remain positioned across our region on Wednesday/Wednesday night,
resulting in a continuation of medium chances for showers and
thunderstorms. Due primarily to clouds and precipitation, highs on
Wednesday should fall back into the u70s-l80s, with lows on
Thursday morning in the l-m 60s. Beyond this point in the
forecast, uncertainty increases considerably due to the potential
development of a tropical cyclone in the Gulf of Mexico. Aside
from the fact that the system has not even begun to develop, the
cyclone`s eventual path will likely be dictated by both the cutoff
low to our west and a subtropical high off the southeastern
Atlantic Coast, and the models currently offer a vast array of
solutions on where these features will be located and when. Thus,
we have deviated very little from blended guidance and indicated a
gradual decreasing trend in POPs through the end of the week,
with full acknowledgement that they could be increased
significantly or pulled out altogether in future forecast updates.
High temperatures will also be dependent on the amount of cloud
cover and precipitation in our region but should generally remain
in the u70s-l80s through Saturday.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 1155 PM CDT Sun Sep 22 2024

With a weak area of high pressure remaining layered across parts
of the region, VFR conds are generally expected thru the period.
The exception may be some -br/MVFR vis early Mon morning. Iso
shra/tsra are also possible later in the day Mon, but the prob is
not high enough to include in the TAFs attm.
-- End Changed Discussion --

&&

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

$$

NEAR TERM...RSB
SHORT TERM....26
LONG TERM....70
AVIATION...09