795
FXUS64 KHUN 251730
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1230 PM CDT Wed Jun 25 2025

...New AVIATION...

.NEAR TERM...
(Rest of Today and Tonight)
Issued at 1115 AM CDT Wed Jun 25 2025

High pressure at the surface and aloft over the eastern Lower-48
was controlling our general weather situation. Area temperatures
at 11 AM have soared mostly into the lower 90s with light and
variable winds. Nearby morning soundings had critical temperatures
in the upper 80s and around 90, thus cumulus was forming over the
area. Given current temperatures and a +10 added to the current
readings would have our highs around 100. But the cumulus forming
will put a damper on that, keeping high temperatures in the mid to
upper 90s.

Areal precipitable water amounts of 1.6 to 1.7 inches, and
temperatures into the mid 90s will produce CAPE values in the
2500-3500 J/kg. With high pressure in place, overall vertical
shear values are low. Despite that, there is a risk for strong and
severe thunderstorms, with damaging outflow winds and large hail
the main threats. The current Day-1 Convective Outlook has our
eastern half in a Marginal (1/5) risk. It is possible that a
larger area will be in that or a higher risk as the day
progresses. Unlike yesterday, upper level capping is weaker. With
very warm temperatures, expect shower and/or storm initiation in
the next couple of hours.

Any shower activity that forms should gradually dissipate as we go
into the late evening and overnight. Low temperatures should range
in the low/mid 70s. Much of the MOS guidance was forecasting late
night fog before daybreak Thursday. Fog that forms should be more
likely in/near sheltered valleys, and near locations that receive
moderate to heavy rainfall today.

&&

.SHORT TERM...
(Thursday through Saturday)
Issued at 1115 AM CDT Wed Jun 25 2025

Another feature of note is an upper level low over the northern
Bahamas and east of Florida. This feature will continue heading
to the NW, and bring additional moisture towards this region. The
clouds and moisture will bring slightly cooler temperatures to the
area. High temperatures on Thursday should rise into the low/mid
90s, and in the lower 90s Friday. But with still high dewpoints
(low/mid 70s), heat index values will remain very close, to above
criteria for advisory. So we will extend our Heat Advisory through
7 PM Friday. Lows Thu/Fri night should range from the upper 60s to
lower 70s.

And with the heat, there will be more chances of mainly afternoon
and early evening showers and thunderstorms. These storms could
become strong to severe, with a Marginal Risk for the entire area
Thu, and about 1/2 of the area Fri. Damaging winds, and maybe
large hail are the main threats posed by the stronger storms.
Areal precipitable water amounts should range around 1.4 to 1.7
inches, which would support locally heavy rainfall from the
stronger storms.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 828 PM CDT Tue Jun 24 2025

An upper low will meander over the Southeast through the weekend. By
Monday, an upper shortwave trough will traverse the Midwest and then
swing over the Ohio Valley on Tuesday. At the surface, high pressure
will persist over the Appalachians for the weekend; however, this
will then be pushed towards the eastern seaboard early next week as
a low pressure system slides over the Great Lakes and its associated
cold front approaches the Tennessee Valley. With this pattern, expect
daily chances of showers and storms (30-60% chance), especially
during peak heating in the afternoon/early evening. By Tuesday, rain
and storm chances are forecast to increase (40-70%) as the
aforementioned surface front approaches the region.

Model PWATs range between 1.7-1.9 inches from Saturday through
Monday and, when compared with BMX Sounding Climatology, fall within
the 75-90th percentiles. PWATs increase to over 2 inches by midweek,
which would be greater than the 90th percentile. Thus, showers will
be efficient rainfall producers and could outperform current forecast
rainfall totals for the long term. At least nuisance flooding will
therefore be possible this weekend through early next week. As for
any chance of severe storms, instability will be sufficient but bulk
shear values are low. So, confidence is low in severe storm
occurrence.

The good news is that with the return of shower/storm chances will
come cooler daytime temperatures. Highs in the upper 80s to lower 90s
are anticipated from Saturday through Monday, with mid to upper 80s
on Tuesday due to the higher rain chances. Lows, however, will
remain in the upper 60s to lower 70s each night.

&&

.AVIATION...
(18Z TAFS)
Issued at 1230 PM CDT Wed Jun 25 2025

High pressure over the region at the surface and aloft, will
control the Tennessee Valley`s weather for the TAF. Light winds
are expected for the TAF. Strong daytime heating could result in
isolated to scattered shower and thunderstorm development this
afternoon and into the late evening.. Confidence is too low to
include a shower mention in the TAF at or near a terminal. But
have higher confidence that late night fog is probable, especially
in sheltered locations and near areas that had recently received
rainfall. Fog that develops should quickly dissipate after
daybreak Thu. Strong heating will produce more cumulus development
in the late morning, with possible convection near the end of the
TAF.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory until 7 PM CDT Friday for ALZ001>010-016.

TN...Heat Advisory until 7 PM CDT Friday for TNZ076-096-097.

&&

$$

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