271
ACUS01 KWNS 310600
SWODY1
SPC AC 310558

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Fri May 31 2024

Valid 311200Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...ARK-LA-TEX...LOWER MISSISSIPPI VALLEY AND
CENTRAL HIGH PLAINS...

...SUMMARY...
Scattered severe storms, associated with a wind-damage and isolated
tornado threat are expected today from parts of the southern Plains
into the Ark-La-Tex and lower Mississippi Valley.
A severe threat is also expected to develop over the High Plains
late this afternoon and early this evening, where isolated large
hail and severe wind gusts will be possible.

...Southern Plains/Ark-La-Tex/Lower Mississippi Valley...
An upper-level trough will move slowly eastward across the
south-central U.S. today. A moist and unstable airmass will be
located from the lower Mississippi Valley extending westward across
much of Texas. Along the northern edge of the moist airmass, a few
organized line segments should be ongoing at the start of the period
from north-central Texas eastward into the Sabine River Valley. As
surface temperatures warm across the moist airmass over central and
east Texas today, this convection is expected to gradually
intensify, with new convective development taking place on residual
outflow boundaries. Short-term model forecasts from the HRRR suggest
that a linear MCS could organize during the mid to late morning. If
this happens, then a wind-damage threat would be likely from parts
of the Texas Hill Country eastward into southeast Texas and
southwest Louisiana.

Further to the east into the Ark-La-Tex and lower Mississippi
Valley, low-level moisture advection will take place as the
upper-level trough approaches from the west. By afternoon, surface
dewpoints are forecast to be in the mid to upper 60s F from northern
Louisiana into Arkansas. Surface heating and increasing large-scale
ascent ahead of the trough will likely support scattered
thunderstorm development. By late afternoon, RAP forecast soundings
from east Texas into northern Louisiana have MLCAPE peaking near
2000 J/kg, with 0-6 km shear in the 30 to 35 knot range. This would
be enough to support a severe threat with the stronger cells. Some
short-term model forecasts suggest that cells will remain discrete,
and will have potential to rotate. If this occurs, then an isolated
tornado threat may develop in parts of northern Louisiana and
southern Arkansas, along the southern edge of the stronger low-level
flow. Across most of the region, wind damage will be the primary
threat, with this potential continuing into the early to mid
evening.

...High Plains...
A low-amplitude upper-level ridge will be move eastward into the
Rockies today, as mid-level flow over the High Plains remains mostly
from a westerly direction. A relatively narrow axis of moderate
instability is forecast to develop by afternoon from eastern New
Mexico northward into eastern Colorado. By mid to late afternoon,
scattered thunderstorms are expected to form in the higher terrain,
and move eastward into the lower elevations. RAP forecast soundings
by late afternoon to the east of Denver and along the Palmer Divide
have MLCAPE generally in the 1000 to 2000 J/kg range, with 700-500
mb lapse rates near 8 C/km. 0-6 km shear is forecast to be in the 45
to 55 knot range, which should easily support supercell development.
Severe wind gusts and isolated large hail be possible as the storms
mature over the plains of eastern Colorado during the early evening.
A conditional threat for hailstones greater than 2 inches in
diameter may also exist.

Further south across northeast New Mexico, thunderstorms are also
expected to develop in the higher terrain this afternoon. The
strongest instability is forecast over far eastern New Mexico, where
MLCAPE could peak near 2000 J/kg. The greatest potential for severe
convection will be in far northeast New Mexico, where moderate
deep-layer shear will be in place. Supercells with isolated large
hail are expected in the lower elevations during the late afternoon
and early evening. The severe threat should be more isolated with
southward extent over eastern Mexico, where deep-layer shear is
forecast to be considerably weaker.

..Broyles/Barnes.. 05/31/2024

$$