210
FXUS64 KHUN 041718
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1118 AM CST Thu Dec 4 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 1014 AM CST Thu Dec 4 2025

 - Periods of rain start this afternoon and continue through late
   tonight with rainfall amounts up to 0.25-0.50 inches.

 - Fog development tonight into Friday morning and again Saturday
   morning may cause travel delays.

&&

.NEAR TERM...
(Rest of Today and Tonight)
Issued at 1014 AM CST Thu Dec 4 2025

Current radar imagery shows a broad swath of precipitation to our
south with a few swaths of light rain south of the TN river. This
is associated with a developing coastal low in the northern Gulf
underneath longwave troughing for the CONUS, both providing very
broad forcing for ascent. As we progress through the day,
temperatures will warm into the upper 40s underneath overcast
skies.

Areas of stratiform rain will enter the TN Valley from the
southwest this afternoon and evening as a shortwave trough ripples
through the longwave pattern aloft. Rain should start in the west
around 3 PM and most of the area will be rainy by 6 PM. A heavier
axis of rainfall will move in this evening along a trough axis
from the coastal low to our south. Rainfall totals will be between
0.25-0.50 inches, so flooding is not a concern.

Heading into the overnight period, confidence is increasing that
temperatures will stay above freezing for the TN Valley. Sub-
freezing temperatures to our north will result in a light wintry
mix in Middle Tennessee, but because the heavier precipitation
will be to the south, even if sub-freezing temps overperform and
push into the TN Valley, impacts are not expected. Overnight lows
will only drop into the mid to upper 30s.

Rain moves out between 2 AM and 6 AM. Lingering moisture and calm
winds will pose a threat for fog, despite overcast skies.

&&

.SHORT TERM...
(Friday through Saturday)
Issued at 1014 AM CST Thu Dec 4 2025

Any fog that develops overnight behind the areas of rain will have
the potential to linger as late as noon in sheltered valleys.
Early morning commuters should allocate extra time just in case
the fog becomes dense. A dense fog advisory is not expected at
this time, but subsequent shifts will continue to monitor the
potential.

Weak high pressure at the surface settles into the Ohio River
Valley, so limited subsidence will keep skies overcast throughout
Friday. As a result, high temperatures will peak in the upper 40s,
similar to today. Moisture will remain trapped underneath the
overcast skies and not wicked away because of light winds. As a
result, fog remains a concern for Friday night into Saturday
morning. Drier air in the mid levels moves in late Saturday,
allowing skies to finally clear heading into Saturday night.

&&

.LONG TERM...
(Saturday night through Tuesday)
Issued at 1113 PM CST Tue Dec 2 2025

Some clearing Saturday night, but guidance shows mostly cloudy
conditions returning around midnight and continuing through the
overnight hours. Lows in the 35 to 40 degree range look
reasonable.

The main feature to watch through the long term forecast will be
the passage of a 500 MB trough through the eastern CONUS. Through
the weekend, the trough will amplify and move from the Plains into
the eastern CONUS. In association a surface low pressure system
looks to pass through the area from Sunday and Sunday night.

Deterministic models maintain high uncertainty regarding if any
precip will be present with the frontal passage. As such, stuck
with blended guidance that reflects the low chances of rain (~20%)
from Sunday night. If we do receive precip, especially near
daybreak Monday morning, we will have to keep an eye on temps as
they will likely near or just below freezing which could produce
brief and hopefully non-impactful wintry precip. We have very low
confidence in this however, just an interesting (non-impactful)
tidbit to keep an eye on.

Through the beginning of the work week, zonal flow aloft paired with
high pressure influence will promote non impactful weather. Temps
will have the opportunity to warm slightly with highs in the 40s and
50s. The forecast becomes slightly more uncertain from Wednesday
forward as models struggle to resolve our next system.

&&

.AVIATION...
(18Z TAFS)
Issued at 1117 AM CST Thu Dec 4 2025

Main impact for aviation today will be associated with rain moving
in from the southwest this afternoon. Ceilings will drop heading
into the evening down to IFR. With more persistent rain areas,
could see vsby lower to 3 SM. Rain tapers off early Friday morning
but low clouds and fog will remain. While flight categories were
only lowered to IFR, there is a low chance (20-30%) that LIFR cigs
linger until 12-15Z. Conditions gradually improve heading into
tomorrow afternoon and should return to VFR just after this TAF
period.

&&

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

$$

NEAR TERM...30
SHORT TERM....30
LONG TERM....RAD
AVIATION...30