596
ACUS02 KWNS 031731
SWODY2
SPC AC 031729

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1229 PM CDT Fri May 03 2024

Valid 041200Z - 051200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS IN THE PERMIAN
BASIN OF WEST TX...

...SUMMARY...
Scattered severe thunderstorms are expected across parts of west
Texas from late afternoon through the evening on Saturday. Several
storms may produce very large to giant hail, and a couple strong
tornadoes are possible.

...Synopsis...
A shortwave trough over the Upper Midwest will progress largely into
northern Ontario, while a deep closed mid/upper low moves inland of
the West Coast and reaches the CA/NV/OR border vicinity by early
Sunday. A near 100-kt southern-stream upper jet will shift east from
Baja/Gulf of CA across parts of northwest and north-central Mexico.

At the surface, a weak cyclone over the Upper MS Valley will move
northeast. A trailing cold front will arc southwestward and push
southeastward, likely from the Ozark Plateau to west TX by Saturday
afternoon. This boundary should stall for a time in the Permian
Basin/South Plains vicinity before being reinforced by convective
outflows Saturday evening.

...West TX vicinity...
A weak, lee surface cyclone will diurnally deepen in the Trans-Pecos
vicinity, within the left-exit region of the aforementioned upper
jet impinging eastward. As the cold front settles south and stalls
in vicinity of this low, a very rich western Gulf airmass to its
south will become strongly unstable with MLCAPE of 3000-3500 J/kg
expected by late afternoon. Convective initiation appears likely
north of the cold front in southeast NM to the South Plains and
farther south in the lee of the higher terrain of the Trans-Pecos.
Several, largely elevated, supercells should become established
north of the surface front. An elongated and nearly straight-line
hodograph within the buoyancy profile should foster splitting cells
with a threat for very large hail. Farther south, a few supercells
along and south of the front across parts of the Permian Basin will
also pose a threat for potentially giant hail as well while
low-level shear is initially modest. But shear will strengthen into
early evening, posing an increasing threat for a strong tornado or
two. 12Z HREF members are nearly unanimous in suggesting very high
updraft helicity values in at least one simulated warm-sector
supercell during this time frame.

Deeper into the evening, convection should increasingly consolidate
and become more widespread as low-level jet mass response continues.
This should favor a mix of severe wind gusts with embedded large
hail and tornado threats. These hazards will subside overnight, but
should linger on an isolated basis towards parts of central TX.

...Mid-MS Valley to the Ozarks/Ark-La-Tex...
A line of strong thunderstorms should be ongoing at 12Z Saturday,
just ahead of the aforementioned cold front, from northwest MO into
southeast KS. This activity should largely wane through the morning,
but locally damaging winds and marginal hail will be possible until
it decays.

Renewed thunderstorm development is expected during the afternoon,
especially late along parts of the cold front where adequate
boundary-layer destabilization occurs in the wake of the morning
activity. With the Upper Midwest shortwave trough progressing
northeast, strong mid-level southwesterlies will be displaced north
of the destabilizing warm sector. Deep-layer shear will be modest,
largely from 20-30 kts. This would be adequate for some small,
multicell clusters. Overall severe threat will probably remain
isolated and marginal with a mix of damaging winds and hail, largely
peaking in the late afternoon to early evening.

..Grams.. 05/03/2024

$$