050
FXUS64 KHUN 151600
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1100 AM CDT Tue Jul 15 2025

...New NEAR TERM, SHORT TERM...

.NEAR TERM...
(Rest of Today and Tonight)
Issued at 1100 AM CDT Tue Jul 15 2025

A narrow mid-level ridge will extend from the northwestern Gulf,
east-northeastward across the Lower MS Valley/Gulf Coast states
and into the southern Mid-Atlantic Coast through the duration of
the near term period. Along the southern rim of the ridge, an
easterly wave will retrograde westward across the northern FL
peninsula and into the northeastern Gulf, and along the northern
rim of the ridge, a weak mid-latitude shortwave trough will lift
northeastward from the western Ozark Plateau into southern IL/IN
by 12Z Wednesday. In the low-levels, high pressure will maintain
light/variable gradient flow, with afternoon temperatures in the
l-m 90s, dewpoints in the u60s-m70s (and mostly sunny
skies/stagnant flow) resulting in an uncomfortably hut/muggy
afternoon with heat index values in the 98-105F range.

Although a few diurnally-initiated showers and thunderstorms will
be possible (especially in the higher terrain of northeast
AL/southern Middle TN), coverage of convective cells should be
higher both to our northwest (from the Ozarks into the central OH
Valley -- where the influence of the shortwave trough will be
greatest) and to our east (from the central FL Panhandle north-
northeastward into northern GA -- where a surface trough related
to the easterly wave will exist). Regardless of storm coverage,
the local thermodynamic environment will be characterized by
MLCAPE in the 2000-3000 J/kg range, DCAPE of 750-1000 J/kg and
PWAT in the 1.7-1.9" range. Thus, brief strong outflow wind gusts
(up to 40-50 MPH), frequent lightning and heavy rainfall will be
possible with stronger cells as they drift slowly east-
southeastward.

This evening, the surface trough to our east is predicted to
drift slowly west-northwestward and should reside across the
eastern portion of the CWFA by early Wednesday morning. A few
showers and thunderstorms will be possible throughout the night in
the vicinity of the trough, but mostly clear skies and dry
conditions are expected elsewhere. With calm winds and narrow
dewpoint depressions, patchy fog will also be possible in a few
locations around sunrise as temps fall into the l-m 70s.

&&

.SHORT TERM...
(Wednesday through Thursday night)
Issued at 1100 AM CDT Tue Jul 15 2025

During the period from Wednesday through Thursday night, the
western portion of the southeastern CONUS 500-mb ridge (discussed
above) will begin to weaken, with the configuration of the ridge
taking on a more zonal orientation from the Arklatex into the
southeastern Atlantic Coast (as it becomes conjoined with a
stronger subtropical high retrograding across the southwestern
North Atlantic). Although this suggests that there will be little
(if any) change in the general synoptic environment across our
forecast area through the duration of the short term period, the
presence of the surface trough (discussed above) should focus an
increase in the coverage of showers and thunderstorms across our
region beginning late tomorrow morning. With forecast soundings
indicating similar thermodynamic parameters in place tomorrow
(compared to today), storm impacts will be similar. However,
collapsing steering currents will result in even slower and more
erratic cell motions, perhaps increasing the risk for heavy
rainfall/minor flooding. In the event that early initiation of
showers/storms (and convective debris clouds) are not very
impactful, HI readings may warrant a Heat Advisory tomorrow, with
latest guidance now suggesting a fairly widespread coverage of
105-110F readings across the valley.

The increasingly ill-defined surface trough is predicted to
progress further northwestward and through the region on Wednesday
night/early Thursday morning, as southerly flow strengthens in
the low-levels between a Bermuda high building into the
southeastern Atlantic Coast and a weak area of low pressure over
the north-central Gulf, and this may support a continuation of
scattered showers and thunderstorms for much of the night. The
modest increase in southerly flow in the boundary layer will
continue on Thursday/Thursday night, with precipitable water
values expected to rise above 2" during this timeframe. Although
this will support an increase in the coverage of afternoon
thunderstorms across southern portions of the central Gulf Coast
states, our main source of convective initiation may come late
Thursday afternoon or Thursday evening as outflow spreads
southeastward across western/Middle TN from frontal precipitation
across the Mid-MS/Lower-OH Valleys. With highs once again
predicted to reach the l-m 90s (and slightly higher dewpoints), a
Heat Advisory may be warranted on Thursday as well.

&&

.LONG TERM...
(Friday through Monday)
Issued at 1017 PM CDT Mon Jul 14 2025

Our attention in the extended will focus on the progress of
Invest 93L that will be moving westward over the northern Gulf
during the middle of this week. Some guidance indicates this
system may develop tropical characteristics before it veers into
the LA/MS/AL coastline during a Thursday night to Friday
timeframe. All this would mean for the Tennessee Valley will be
the potential for a gradual increase in PoPs Friday and
potentially into the upcoming weekend. How widespread this
activity will be will depend on the eventual track of this system,
but long range ensembles are honing on at least medium chances
for showers and thunderstorms. This would especially be true if
this feature begins to interact with a weak frontal boundary
attempting to push southeast from the Ohio/Mid-Mississippi Valley.
Given the deep tropical moisture that will be present across the
Deep South, locally heavy rainfall and potentially flooding would
be the primary concerns. Thus, the track of this system and how it
evolves is something we`ll need to watch in the coming days.
Given the added cloud cover and potentially higher rain chances,
heat impacts don`t appear to be as high during this late week
timeframe.

&&

.AVIATION...
(12Z TAFS)
Issued at 603 AM CDT Tue Jul 15 2025

Patchy fog will continue to reduce visibilities into MVFR at KMSL
until ~14Z. Otherwise, VFR conditions will prevail through the
TAF period at KHSV and KMSL. A few thunderstorms are possible this
afternoon, however coverage will be isolated, so did not include
it in this TAF issuance.

&&

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

&&

$$

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