-- Discussion containing changed information from previous version are highlighted. --
152
FXUS64 KHUN 060003
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
703 PM CDT Sun May 5 2024

...New AVIATION...

.NEAR TERM...
(Tonight)
Issued at 319 PM CDT Sun May 5 2024

Mainly high clouds off an on still moving across northern Alabama.
Earlier showers and storms that were developing over the higher
terrain of northeastern Alabama have primarily dissipated.

The focus for storm development is shifting to convection
developing along a pre-frontal trough axis currently stretches
from near Columbus, MS northwest to near the Tupelo, MS area.
This area of convection is moving to the northeast around 30 mph.
Current low level lapse rates are very steep (7.5 to 8.5 degree/km)
and SBCAPE/MUCAPE is between 2000 and 3000 J/KG ahead of this
convection. Analysis is starting to show some effective bulk shear
between 30 and 40 knots moving into extreme northwestern Alabama
as well. Thus, we could see some storms become strong to severe
this afternoon into early this evening before instability wanes.
Main threats with any severe storms would be damaging winds and
large hail. At this time, do not believe a severe thunderstorm
watch will be issued, but a few severe storms could occur. Heavy
downpours with some of these storms could produce some ponding or
isolated flash flooding depending on how quickly the developing
convection moves northeast tonight.

Additional rain and thunderstorms should continue to develop
through daybreak on Monday, as a strong shortwave aloft continues
to move northeast into Kentucky and produces additional forcing
to aid convective development. Shear and instability should drop
off after midnight, so not expecting the threat for severe storms
to continue much past midnight.

&&

.SHORT TERM...
(Monday through Wednesday)
Issued at 319 PM CDT Sun May 5 2024

As the shortwave continues to weaken and move east towards the
Mid-Atlantic region on Monday, forcing weakens over the area.
Shear picks back up, but better forcing will be well north of the
area in Kentucky and Tennessee. However, strong to severe storms
given expected instability and around 35 knots of shear look
possible. A severe thunderstorm cannot be totally rule out, but
should be isolated if they occur.

Shear strengthens more on Tuesday with moderate CAPE redeveloping
in the afternoon. Not expecting organized severe storm activity
due to the weak forcing expected. This could be a bit more
organized that activity we see on Monday if forcing end up being
stronger. However, much of that forcing moves northeast of the
area. Regardless, if the convection can get going, a few severe
storms could occur. Main threats would be large hail and damaging
winds winds with any severe storms.

Overall, there has been very little change in guidance from the
global models, with any nocturnal storm clusters that survive as
far southeastward as the TN Valley early Wednesday morning
expected to dissipate rather quickly by mid-day along a stalled
boundary ahead of an approaching cold front. Attention will then
refocus to the northwest of our region, where explosive
development of convection is expected to occur on Wednesday
afternoon as a frontal wave shifts northeastward into MO. One
region of potential convective development will be downstream from
the path of the surface low (from eastern KS into central IL),
with another region of potential development along the trailing
cold front extending southwestward into northeastern TX.

This will keep low to medium chances of showers and thunderstorms
in the forecast Wednesday afternoon into Wednesday evening. Very
strong warm air advection is shown in models over the area south
of this boundary. 925 mb temperatures in guidance still climb to
between 22 and 25 degrees. Thus, highs in the upper 80s and maybe
lower 90s could occur. Shear picks up some to around 40 knots
during the afternoon hours. Mainly expect strong storms given weak
forcing, but can`t rule out a severe storm.

&&

.LONG TERM...
(Wednesday night through Sunday)
Issued at 315 PM CDT Sun May 5 2024

It still appears as if this activity will grow upscale into a
rather potent MCS that should track southeastward into our CWFA
late Wednesday night into the early morning hours on Thursday.
With mid-level WSW flow expected to easily be in the 45-50 knot
range at this point atop a southwesterly low- level jet of 30-40
knots, all severe hazards (including tornadoes) will be possible
with this convective system.

Yet another round of rain and thunderstorms may occur with the
passage of a cold front Thursday night, but at least low-level
shear will be weaker with this final round, and airmass recovery
may not be sufficient to support a risk of strong-severe storms. A
refreshing surge of cooler/drier continental air will spread
southeastward in the wake of the cold front, bringing dewpoints
into the 40s for much of next weekend.

&&

.AVIATION...
-- Changed Discussion --
(00Z TAFS)
Issued at 702 PM CDT Sun May 5 2024

The main line of thunderstorms have pushed through the terminals,
but showers will linger into the night keeping MVFR conditions in
place. Reduced the coverage of showers and storms for tomorrow
morning into early afternoon for this TAF issuance and introduced
a PROB30 instead  for isolated showers until the afternoon when
the low chances for thunderstorms returns.
-- End Changed Discussion --

&&

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

$$

NEAR TERM...KTW
SHORT TERM....KTW
LONG TERM....KTW
AVIATION...JMS