217
FXUS64 KHUN 170000
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
700 PM CDT Fri May 16 2025

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 157 PM CDT Fri May 16 2025

Both low and mid cloud cover has thinned significantly over the
last few hours east of the I-65 corridor. Further west, thicker
mid/high cloud cover has redeveloped. Most locations have reached
the lower to mid 80s across northern Alabama and southern middle
Tennessee. Still could see an upper 80 degree high near the I-65
corridor and mid 80s further east.

A very humid and unstable airmass (3000 to 4000 J/KG) is in
place. However, The good news is that there have been very little
signs of convective development a few models were hinting could
happen around 4 PM. The cap in place aloft and the drier air
between 850 mb and 700 mb seen in 7 AM Birmingham sounding, looks
like they will hold off any convection this afternoon. Both
satellite and radar trends seem to support this as well.

Models still show the main upper level forcing sagging southeast
into southern middle Tennessee and NW Alabama between 10 PM and 1
AM ahead of an approaching cold front. Enough MUCAPE or SBCAPE
(1000 - 2000 J/KG) lingers ahead of the front into the overnight
hours. However, strong shear continues to be shown ahead of the
front and 0-3 km helicity climbs to between 200 and 350 m2/s2 as
the best forcing moves into the area ahead of and with the front.
Expect there could be some embedded supercells (producing large
hail initially) that move into the area. Still thinking this will
form into a more widespread damaging wind threat with a few
tornadoes possible. The high low level moisture and cloudy
conditions tonight should keep lows very warm, only dropping into
the 65 to 70 degree range in most areas.

Overall timing of convective initiation hasn`t changed much.

1. Franklin (AL) NW Lincoln County (TN) - 10 PM to 2 AM
2. SW Lawrence County (AL) to Sewanee (TN) - Midnight to 3 AM
3. SE Cullman County (AL) to Fort Payne (AL) - 2 AM to 5 AM

If some convection does eventually form 4 PM to 8 PM (as those few
models were hinting), supercells and a larger hail/stronger
tornado threat could exist during that period. At this time, that
is not expected to occur.

&&

.SHORT TERM...
(Saturday through Monday)
Issued at 157 PM CDT Fri May 16 2025

Much drier air moves southeast into the area just after daybreak
on Saturday between 8 or 9 AM. The front should be far enough south to
keep rain chances out of the forecast by then. Highs should reach
the mid to upper 80s again across northern Alabama and southern
middle Tennessee on Saturday. Most guidance places the front
somewhere through central Alabama when it stalls. However, during
the late afternoon/early evening hours, several models move this
front northward into northwestern Alabama and then further
northeast overnight. Scattered showers and thunderstorms in the
evening should give way to more widespread activity overnight.
Strong shear pushes back into the area and with very moist low
level moisture moving back into the area behind the front,
instability will increase enough to warrant at least a low severe
threat. Main threats would be damaging winds and up to one inch
hail. High dewpoints and cloudy conditions tonight should keep
lows very warm, only dropping into the 65 to 70 degree range in
most areas.

As the front stalls near the southern portion of the forecast
area, cloud conditions and additional showers and thunderstorms
are expected on and off through the day into the early evening
hours on Sunday. Expect cooler conditions as well with highs only
climbing into the upper 70s to lower 80s. Again with strong shear
over the area and enough instability in place, a few strong to
marginally severe storms could occur.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 157 PM CDT Fri May 16 2025

Luckily, it looks like we see a break in high rain/thunder chances
Sunday night into Monday, as the front really pushes to the north
as a stronger warm front. At the same time, upper level ridging
builds over the area. Locations north of the Tennessee River could
still see scattered showers and thunderstorms, possibly a few
again strong to marginally severe. Highs will likely be similar
(though current guidance may be a tad too low), reaching the mid
to upper 80s. Monday night will still be very humid with lows
dropping into the mid to upper 60s.

A stronger storm system over the Rockies develops and moves slowly
east Monday night into Tuesday. The strength of the upper level
ridging and the northward placement of its associated warm front
should keep any shower or thunderstorm activity north of the area
Monday night. However, on Tuesday into  Tuesday night, it looks
like higher rain and thunderstorm chances move back into the
region. Strong shear and instability will return ahead of that
system. A bit more helicity is hinted at with model guidance. So
tornadoes may be more of a threat with this system. However, it is
still several days out, so alot can change. Again colder air
moves into behind this system, towards the end of next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 700 PM CDT Fri May 16 2025

The primary feature of concern for aviation interests this
evening and throughout the early morning hours on Sat will be one
(or perhaps two) lines of SHRA/TSRA which may evolve from
individual cells (currently developing within a zone from
southeastern MO into west-central AR). Although it is still
unclear how this will unfold, timing of potential storm impacts
(including AWWs) at the terminals appears to be from 4-8Z/MSL and
6-10Z/HSV, and TEMPO groups have been included for these
timeframes. Due to the existence of a strong low-level jet, LLWS
has also been included thru 8-10Z Saturday. Outside of convection,
conds will remain VFR, with a bkn-ovc coverage of mid/high-lvl
clouds this evening/overnight and more scattered coverage
tomorrow. Gusty SW sfc flow will veer to WSW and diminish in the
wake of the nocturnal convective lines.

&&

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

&&

$$

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