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Mesoscale Discussion 1101
NWS Storm Prediction Center Norman OK
0322 PM CDT Thu Jun 09 2022

Areas affected...Western Nebraska and southwestern South Dakota

Concerning...Severe potential...Watch possible 

Valid 092022Z - 092215Z

Probability of Watch Issuance...60 percent

SUMMARY...Thunderstorms may develop across parts of western NE and
southwestern SD in the co*ing hours. Severe wind/hail, and perhaps a
few tornadoes, will be possible, and a watch will likely be needed
to address this potential.

DISCUSSION...Gradual destabilization is noted in GOES visible
imagery across portions of west Nebraska into far southern South
Dakota as a previously homogeneous mid-level stratus deck begins to
break apart into more agitated cumiliform clouds as temperatures
climb into the low 80s and richer boundary-layer moisture (denoted
by dewpoints in the 60s) surges northward. Latest mesoanalysis
suggests that MLCAPE has increased to 1000-2000 J/kg across western
NE, though some inhibition likely remains given some lingering
stratus. Surface observations and upper-air analyses show that this
region resides within a broad warm frontal zone, which is supporting
weak elevated convection on the periphery of the better buoyancy. 

More robust, surface-based convection is probable in the co*ing
hours as inhibition continues to decrease and a subtle mid-level
perturbation (noted in water-vapor imagery moving across WY) moves
over the region. Recent hi-res guidance suggests that convective
initiation could occur the next few hours, but may occur as late as
00-01 UTC. Regardless of timing, initially discrete cells are
expected given the weak forcing for ascent. Storms developing across
western SD (most likely off the Black Hills) will likely intensify
as they move into NE, though development along the surface warm
front is possible closer to 00 UTC. 

Recent KLNX and KUDX VWP data show a nearly uni-directional
northwesterly wind profile above 3 km, which will support the
potential for supercells. Large to very large hail and severe winds
will be the predominant hazards, though enough low-level helicity is
in place across western NE to support a tornado or two given an
initially favorable storm mode and adequate boundary-layer moisture.
Eventual upscale growth into one or more organized clusters is
possible later this evening as storms propagate to the
south/southeast along the buoyancy gradient, but when/where this
transition will occur remains uncertain. A watch will likely be
needed in the co*ing hours once observed trends suggest robust
convective initiation is imminent.

..Moore/Guyer.. 06/09/2022

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ABR...GID...LBF...UNR...GLD...BOU...

LAT...LON   40090173 40380201 41630212 42970210 43500247 43890293
            44390349 44760396 45430400 45700378 45600309 44940176
            44670103 44350045 43540024 42449994 41189989 40229983
            40100017 40050091 40090173