497
FXUS64 KHUN 010934
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
334 AM CST Mon Dec 1 2025

...New NEAR TERM...

.KEY MESSAGES...
Updated at 334 AM CST Mon Dec 1 2025

 - Cold rain will overspread the region this afternoon. A few
   snow flurries will be possible as precipitation ends late
   Tuesday morning.

 - Chances for rain beginning Thursday, with widespread rain on
   Friday.

 - Wind chill temperatures will be in the upper teens to mid 20s
   early this morning.

 - A low chance of freezing fog (20-30%) in some areas early
   Wednesday morning.

&&

.NEAR TERM...
(Today)
Issued at 334 AM CST Mon Dec 1 2025

A cold morning was in progress despite a rather thick veil of
high clouds streaming across the southern states. Temperatures
have fallen into the upper 20s to lower 30s at this hour with
north to northeast winds of 5-8kt. The first half of today will
remain dry, but a surge of isentropic ascent will develop as
south-southwest flow in low levels takes shape rapidly through the
day. Surface pressure falls will induce an inverted surface
trough across AL into middle TN by late afternoon. CAMS suggest
rain will rapidly develop across the ArkLaMiss region this
morning, spreading into northwest AL just after 18Z. The coverage
of rain will increase through the afternoon and especially into
early this evening.

Previous Discussion
Issued at 1105 PM CST Sun Nov 30 2025

In the mid/upper-levels, a pronounced ridge across the eastern
North Pacific will sustain broad scale cyclonic flow aloft across
much of North America for the duration of the near term period
(anchored by a cold core vortex across northern Hudson Bay).
Embedded within this flow, a positively-tilted shortwave trough
(currently extending from the central Rockies into the Great
Basin) is predicted to amplify as it shifts southeastward into the
southern Plains by the end of the period and partially phases
with a weaker disturbance to its north. As this occurs, westerly
mid-level flow of 45-55 knots across the TN Valley will gradually
back to southwest, resulting in a broken-overcast coverage of high
clouds throughout the night. At the surface, a 3-4 mb gradient
will continue across the local forecast area, as the center of a
modifying arctic high builds east-southeastward from the northern
Plains into the Lower Great Lakes/OH Valley. This will yield a
moderately strong NE wind throughout the night and persistent cold
advection in the low-levels, with overnight lows in the m-u 20s
and attendant wind chills in the l-m 20s.

Over the course of the day on Monday, the surface anticyclone (to
our north) will progress further northeastward into the New
England vicinity, resulting in a light easterly wind during the
morning hours. However, by tomorrow afternoon, south-
southwesterly flow at the 850-mb level will increase to 20-30
knots as the amplifying mid-level trough (mentioned above) digs
further southeastward into the Great Plains, with elevated warm
advection resulting in a broad axis of surface pressure falls
extending from the northwest Gulf Coast into the northern Mid-
Atlantic states. Sufficient lift and moisture transport in this
regime will allow light-moderate rain to quickly spread
northeastward across the entire CWFA between 20-24Z, with rapidly
descending cloud bases during this timeframe keeping daytime highs
in the u40s-l50s. Given the magnitude of warm advection aloft,
precipitation appears as if it will be entirely liquid at onset.

&&

.SHORT TERM...
(Monday night through Wednesday night)
Issued at 1105 PM CST Sun Nov 30 2025

Stratiform rain will continue to expand in coverage and intensity
across the region on Monday evening, as a mid-level trough
(initially across the southern Plains) advances northeastward into
the OH Valley. Although the trough will be dampening with time,
present indications are that it will acquire a neutral tilt,
supporting an increase in the southwesterly low-level jet to 30-40
knots during the 0-6Z timeframe. Furthermore, development of a
wave of low pressure across the north-central Gulf may enhance
low-level streamline confluence across the local forecast area,
resulting in enhancement of precipitation coverage/intensity
(although it appears as if the axis of heaviest rain will set up
to our southeast). Rain will largely end from NW-to-SE between
6-12Z as the developing surface low tracks northeastward into
southeastern GA, allowing cold/dry air into the low-levels to be
advected into our region once again as surface winds shift to NNW
and strengthen. Temperatures will advectively fall into the l-m
30s as this occurs, but this should occur after precipitation
ends. However, forecast soundings later in the morning on Tuesday
depict a layer of low-level stratus, which could yield pockets of
snow flurries even as rapid subsidence drying occurs in the
mid/upper tropospheric column. Due to lingering clouds and cold
advection, temperatures will struggle to surpass the u30s-l40s on
Tuesday afternoon.

During the period from Tuesday night-Wednesday night, zonal flow
aloft will return across the TN Valley, downstream from another
positive-tilt shortwave trough migrating across the Four Corners
vicinity. Although dry conditions are expected at this point, a
new round of stratiform rain may begin to expand northeastward
over the Lower MS Valley and central Gulf Coast early Thursday
morning, as a surface trough sharpens in this region. Should this
regime expand as far northeastward as our forecast area prior to
sunrise, forecast soundings appear conducive for sleet given a
strengthening warm nose aloft and high potential for evaporative
cooling below the warm nose. Finally, as mentioned in previous
forecast discussions, conditions appear favorable for the
development of freezing fog on Tuesday night/Wednesday morning
with expectations of abundant ground moisture and calm winds. With
lows in the l-m 20s, any development of fog could be quite
impactful and may deposit a thin glaze of ice on bridges and other
elevated surfaces.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 1105 PM CST Sun Nov 30 2025

Extended range guidance from the most recent suite of global
models suggests that a mid-level shortwave trough (initially
across the Four Corners) will weaken considerably as it ejects
northeastward into the OH Valley by 0Z Saturday. Nevertheless, a
similar setup (compared to what we will experience earlier in the
week) will unfold, with a developing southwesterly low-level jet
downstream from this feature resulting in northeastward expansion
of stratiform rain into the region early Friday morning as a weak
wave of low pressure evolves across the north-central Gulf.
Depending on the onset time of precipitation, ice pellets or light
snow may occur initially, but forecast soundings appear
supportive of a rapid transition to rain. Periods of light-
moderate rain will continue for much of the day, before ending in
the east Friday evening, as a new surface low organizes along the
Mid-Atlantic Coast.

Beyond Friday, the progression of individual waves within broad
scale cyclonic flow across North America becomes increasingly
unclear, but latest data indicates a drier pattern becoming
established from Saturday into Sunday, with a slight warming trend
as well.

&&

.AVIATION...
(06Z TAFS)
Issued at 1108 PM CST Sun Nov 30 2025

VFR flight weather conditions will last through most of today. By
21-22Z, ceilings will lower to around 050agl with areas of -RA
developing. By 00-01Z, ceilings will lower below 010agl (IFR) as
-RA becomes widespread. Visibility may drop to 3-4SM at times as
well. These conditions will persist through the end of the period.

&&

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

$$

NEAR TERM...17
SHORT TERM....70
LONG TERM....70
AVIATION...17