226
FXUS64 KHUN 080839
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
339 AM CDT Wed Oct 8 2025

...New NEAR TERM...

.NEAR TERM...
Issued at 339 AM CDT Wed Oct 8 2025

The previous discussion remains on track. Patchy, dense fog has
developed over portions of the Tennessee Valley, reducing
visibility to as low as 1/4 to 1/2 mile. This fog continues to be
monitored as we continue into the morning. If it becomes more
widespread, a Dense Fog Advisory will be considered. However, with
the front approaching from the north and subsequent increased
winds moving in, we expect the fog to begin to dissipate in most
areas before sunrise.

PREVIOUS DISCUSSION:
West-southwesterly flow aloft of 25-35 knots will gradually veer
to west-northwest over the course of the night, as the southern
end of a large northern stream trough digs southeastward over the
Great Lakes. At the surface, a weak area of low pressure
(initially across northern KY) will accelerate east-northeastward
into the Mid-Atlantic Coast by 12Z Wednesday. Although a broken
band of showers (associated with a prefrontal trough/streamline
confluence axis) has now spread southeastward and out of the
region, WSW flow of 10-20 knots will persist at the 850-mb level
through the early morning hours and could support redevelopment of
pockets of light rain (especially across the southeastern portion
of the CWFA) through 8-10Z before ending. Across the remainder of
the region, the primary concern will be development of fog as
lingering mid-level clouds dissipate through the early morning
hours. The combination of widespread wetting rainfall earlier
today, dewpoints in the 65-70F range and calm-light northerly
winds may even support the formation of locally dense fog in many
locations by sunrise as temps fall into the mid 60s.

During the day tomorrow, we expect north-northeasterly surface
winds to strengthen considerably as an anticyclone migrates
eastward across the Upper MS Valley and into the Great Lakes
(maintaining a 3-4 mb pressure gradient across the region). This
should allow early morning fog to gradually transition into a
broken layer of stratocumulus that will dissipate from NW-to-SE
over the course of the afternoon. Dewpoints will fall into the
55-60F range by late afternoon, with highs a bit cooler and in the
75-80F range.

&&

.SHORT TERM...
(Wednesday night through Friday night)
Issued at 1214 AM CDT Wed Oct 8 2025

Embedded within prevailing west-northwest flow aloft, a weak mid-
level disturbance (currently across the central High Plains) is
predicted to slowly become more amplified as it begins to approach
our region on Wednesday night. This will occur as the surface
high to our north strengthens and shifts eastward into southern
Ontario, inducing cold air damming east of the southern
Appalachians and development of a subtle convergence axis that
will enter our region from the east between 6-12Z Thursday. The
combined effect of these features will lead to redevelopment of
broken stratocumulus clouds and perhaps a few sprinkles of rain
(especially for the southeastern portion of the forecast area)
early Thursday morning. This regime will continue throughout the
day as the mid-level wave tracks southeastward over the TN Valley
and the surface convergence axis travels further westward.
However, by Thursday night, low-level easterly flow will advect a
much drier airmass into the region (highlighted by dewpoints in
the u30s-l40s in our eastern zones). Although this will end the
risk for light rain, lingering stratocumulus clouds will keep lows
in the l-m 50s (similar to values from Wednesday night).

Latest model consensus still suggests that the mid-level wave
(discussed above) will continue to gradually deepen as it advances
further southeastward into coastal portions of GA/SC by 12Z
Saturday. North-northwest flow aloft across our region will
strengthen into the 15-25 knot range as this occurs, allowing for
further drying of the atmospheric column. Under sunny skies, highs
on Friday will once again reach the l-m 70s (similar to
Thursday), with a pleasantly cool night expected on Friday night
featuring lows in the 45-50F range.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 334 AM CDT Wed Oct 8 2025

Global models continue to indicate that a developing 500-mb
trough (initially positioned along the southeastern Atlantic
Coast) will continue to intensify as it lifts north-northeastward
this weekend. This disturbance may then become absorbed within the
flow around a more compact northern stream trough digging
southeastward from the Great Lakes, with this evolution resulting
in the formation of a large closed low in the general vicinity of
the Mid-Atlantic Coast. With NNW winds aloft predicted to increase
into the 25-35 knot range between the low to our east and a
500-mb ridge extending from south TX into the Great Lakes, we
expect dry conditions to prevail through the period. Highs will
slowly warm from the 75-80F range on Saturday into the l-m 80s by
Tuesday, with lows also increasing from the 45-50F range Sunday
morning into the l-m 50s early next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 334 AM CDT Wed Oct 8 2025

As fog moves in through the morning hours, LIFR to IFR conditions
are forecast at both KMSL and KHSV due to visibility drops and low
ceilings. Fog should dissipate shortly after sunrise, however,
low ceilings will continue through the late morning into the
afternoon. VFR conditions are forecast to return Wednesday
afternoon coupled with gusty, northerly winds up to ~20 kts.

&&

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

$$

NEAR TERM...HC
SHORT TERM....70
LONG TERM....70
AVIATION...HC