048
FXUS64 KHUN 130536
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1236 AM CDT Mon Oct 13 2025

...New AVIATION...

.NEAR TERM...
(This Evening through Monday)
Issued at 1039 PM CDT Sun Oct 12 2025

North-northeaserly flow aloft of 20-30 knots will remain in place
across the TN Valley this evening, to the west of a 500-mb trough
(with a slight positive tilt) positioned along the southeastern
Atlantic Coast. However, during the early morning hours, winds
aloft will gradually back to NNW as the trough begins to move
slowly eastward and our region becomes more influenced by a
strengthening subtropical high that will build northeastward from
northern Mexico into southeastern TX by the end of the near term
period. Although this evolution may allow a few thin/translucent
cirrus clouds to overspread the region prior to sunrise, they
should have no impact on an otherwise favorable environment for
radiational cooling. With a light NNE to calm wind expected along
the southern periphery of a surface high centered over the
southern Quebec/New Brunswick vicinity, overnight lows will be in
the 45-50F range once again (l-m 50s near large water sources),
with patchy mist and fog expected to develop (especially in the
valleys of northeast AL/southern TN).

The high to our northeast will weaken over the course of the day
on Monday, with a surface low off the Mid-Atlantic Coast also
predicted to become less defined as the parent mid-level wave will
quickly become absorbed in the flow around a more compact trough
over the northern Mid-Atlantic states. Nevertheless, we will
remain in a light-moderate NNE flow regime in the low-levels,
which will support development of a deep/well-mixed boundary layer
as temperatures progressively warm into the u70s-l80s. Thus, we
expect dry conditions to continue, with only a few fair-weather
cumulus clouds during the afternoon.

&&

.SHORT TERM...
(Monday night through Wednesday night)
Issued at 1039 PM CDT Sun Oct 12 2025

Latest short range forecast data suggests that light-moderate NNW
flow aloft will persist across the TN Valley throughout the short
term period. This will occur as a subtropical high (initially
strengthening across east TX Monday night/Tuesday) begins to
weaken over the Red River Valley Tuesday night/Wednesday before
translating southeastward into the central Gulf Coast by Wednesday
night. In the low-levels, light-moderate northeast flow will
continue as an upstream surface high (initially along the
U.S-Canadian international border) spreads east-southeastward into
southern Ontario and the northern Great Lakes, weakening with
time. Due to the combined influences from the ridge aloft and
reinforcement of dry advection at the surface, we anticipate no
precipitation through the period. Although deterministic model
guidance suggests that highs will remain in the u70s-l80s for much
of the region, conditions will be favorable for a deep mixing
layer each afternoon and for this reason a few readings (perhaps
as high as the upper 80s) may occur (especially in the west).
Overnight lows will be in the l-m 50s.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 1039 PM CDT Sun Oct 12 2025

The extended portion of the forecast period will begin with an
amplified mid-level ridge extending northward into the Gulf Coast
states from a weakening subtropical high to its south. Although
the ridge axis will shift eastward across the region on Thursday
night (allowing southwesterly flow aloft to return on
Friday/Friday night), dry conditions will continue as onset of
southerly return flow in the boundary layer will initially have
little impact on dewpoints.

However, during the period from Saturday-Sunday, chances for rain
and thunderstorms will increase region-wide as deep-layer
southwesterly flow strengthens ahead of an amplifying mid-level
trough approaching the region from the west, allowing PWAT values
to quickly rise back into the 1.5-1.7" range. At this point, there
remain substantial differences in the global models regarding
both the evolution and speed of the mid-level trough (and related
cold front), which will have large impacts on both timing/coverage
of precipitation and the potential for organized convection. For
example, the ECMWF model suggests a more amplified disturbance in
the southern portion of the trough which (for our forecast area)
would result in stronger southwesterly flow aloft/bulk shear but
weaker lapse rates/CAPE. On the other hand, the GFS model
indicates that the northern stream will remain dominant, with
weaker shear accompanied by steeper lapse rates and higher
instability. Regardless, this is a system that we will need to
monitor over the coming days for perhaps a low threat of strong-
severe thunderstorms. As a result of clouds and precip, highs will
fall back into the l-m 70s by Sunday as lows rise into the
u50s-l60s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1236 AM CDT Mon Oct 13 2025

There have been no changes to previous aviation forecast
reasoning, as VFR conditions featuring clear skies and a light NNE
wind will continue at the MSL/HSV terminals early this morning.
If winds temporarily become calm, development of patchy BR/FG will
be possible at both airports btwn 8-12Z, and a TEMPO group for
MVFR vsby reductions has been included during this timeframe. A
few fair-weather Cu will develop by 15Z Monday (beneath an
increasing coverage of Ci), with NNE winds strengthening to 5-10
kts around this time, as well.

&&

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

&&

$$

NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...70/DD
AVIATION...70/DD