ZCZC SPCSWOMCD ALL
ACUS11 KWNS 271809 
SPC MCD 271809 
NEZ000-SDZ000-COZ000-WYZ000-272045-

Mesoscale Discussion 1305
NWS Storm Prediction Center Norman OK
0109 PM CDT Tue Jun 27 2023

Areas affected...western Nebraska...adjacent northeastern
Colorado...southeastern Wyoming and southwestern South Dakota

Concerning...Severe potential...Severe Thunderstorm Watch likely 

Valid 271809Z - 272045Z

Probability of Watch Issuance...80 percent

SUMMARY...Rapidly intensifying scattered thunderstorm development
appears possible as early as 2-4 PM MDT, with strongest storms
becoming capable of producing very large hail and severe wind gusts.

DISCUSSION...Modest low-level moistening on south-southeasterly
near-surface flow into lee surface troughing is ongoing.  This is
contributing to increasing potential instability, beneath very steep
mid-level lapse rates associated with a plume of warm elevated
mixed-layer air advecting east of the Front Range and Laramie
Mountains vicinity.  With continued insolation, mixed-layer CAPE is
forecast to become maximized in a corridor across western Nebraska
by 20-22Z, as forcing for ascent accompanying a short wave impulse
progressing east of the higher terrain contributes to weakening
inhibition.

As southwesterly mid-level flow strengthens in excess of 50+ kt
(around 500 mb), the environment appears likely to become conducive
to scattered supercell development.  Once storms initiate,
intensification may be rapid with a few becoming capable of
producing very large hail and severe wind gusts.

..Kerr/Grams.. 06/27/2023

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

ATTN...WFO...LBF...UNR...GLD...BOU...CYS...

LAT...LON   43600146 40770070 40160135 40550248 41210285 42190412
            43760342 43600146 

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