403
ACUS01 KWNS 090601
SWODY1
SPC AC 090600

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu May 09 2024

Valid 091200Z - 101200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM
CENTRAL/NORTH TX EASTWARD ACROSS THE SOUTHEAST INTO SOUTHERN SC...

...SUMMARY...
Very large hail with multiple supercells appears probable across
parts of central Texas into the ArkLaTex vicinity Thursday afternoon
and evening. A broader corridor of severe hail and damaging-wind
potential will extend from east Texas into the lower Mississippi
Valley and Southeast.

...Synopsis...
Another very active severe weather episode is possible later today,
with the main threat expected along a generally west-to-east
corridor from parts of north/central TX into the Southeast. Some
severe potential will persist across parts of AL/GA during the day,
with at least some risk of all severe hazards. Supercells capable of
producing very large to giant hail and possibly a couple of
tornadoes are possible across parts of central/north TX during the
afternoon and early evening. One or more fast-moving MCSs may move
eastward across parts of the Southeast tonight, potentially
producing a swath of damaging wind.

A large, positively tilted upper-level trough will cover much of the
CONUS on Thursday. An embedded mid/upper-level low will move slowly
and perhaps retrograde toward the eastern Great Basin, with moderate
to strong westerly midlevel flow extending eastward across the
southern Plains and Southeast. A cold front will move across parts
of the southern Plains and Southeast through the day, with the
frontal position potentially influenced by widespread antecedent
convection that will likely last into the morning.

...MS/AL/GA/SC during the day...
A cluster of strong to potentially severe storms may be ongoing
across parts of MS/AL/GA/SC at the start of the forecast period.
This convection may expand in coverage through the morning within
broad low-level warm advection, and generally spread
east-southeastward toward the coast. Downstream of this convection,
diurnal heating of a very moist airmass will support moderate to
potentially strong buoyancy, while favorable deep-layer shear will
continue to support organized convection. A mixture of supercells
and bowing segments will be possible, with an attendant threat of
damaging gusts, hail, and possibly a few tornadoes.

...Parts of central/north TX during the afternoon...
There is some signal for isolated storm development this morning
across western portion of the Edwards Plateau, on the western fringe
of deeper low-level moisture and strong instability. Any storm that
matures in this area could quickly evolve into a supercell with a
threat of very large hail and localized severe gusts.

If any early development persists northeastward, or else does not
disrupt the warm sector, then a supercell threat is expected to
evolve into parts of central/north TX during the afternoon, both
near the dryline/front intersection and also potentially to the cool
side of the front. Strong to extreme instability (with MLCAPE across
the warm sector potentially in the 3000-4000 J/kg range), favorable
deep-layer shear, and elongated/straight hodographs will support a
threat of very large to giant hail. Low-level flow/shear will be
rather weak, but some tornado threat could also evolve, especially
where storm and/or boundary interactions take place.

...Central/north TX eastward across the Southeast during the
evening/overnight...
A majority of HREF guidance and also some larger-scale guidance
(such as the NAM/GFS/ECMWF) depict potential for development of a
fast-moving MCS that would move from parts of central/north TX
across the Southeast into the overnight hours. The pattern generally
favors this scenario, with favorable downstream moisture/instability
and moderate to strong westerly flow aloft. If this scenario pans
out, then a long swath of damaging winds will be possible from TX
across much of the Southeast, including the potential for gusts of
greater than 75 mph, and possibly brief line-embedded tornadoes.
However, given the inherent uncertainty with late-period MCS
development, combined with uncertainty regarding the evolution of
diurnal convection into MS/AL/GA, no increase in unconditional wind
probabilities has been made with this outlook. The 30% wind area has
been expanded southward, based on the latest guidance.

...North Carolina into the Mid Atlantic and Ohio Valley...
Some early convection may persist into parts of NC and the Mid
Atlantic, with a threat of isolated damaging wind. Some
redevelopment will be possible into parts of IN/OH, where weak to
moderate buoyancy may persist in advance of a cold front. Deep-layer
shear will remain sufficient for organized convection, and a few
stronger cells/clusters capable of isolated hail and damaging wind
will be possible.

..Dean/Wendt.. 05/09/2024

$$