006
ACUS11 KWNS 152201
SWOMCD
SPC MCD 152200
NEZ000-KSZ000-SDZ000-COZ000-WYZ000-160030-

Mesoscale Discussion 2068
NWS Storm Prediction Center Norman OK
0500 PM CDT Sun Sep 15 2024

Areas affected...portions of northeastern CO...western NE...eastern
WY...and southwestern SD

Concerning...Severe potential...Watch unlikely

Valid 152200Z - 160030Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms should increase in strength and coverage
while spreading/developing northward across the central/northern
High Plains into this evening. The strongest storms will be capable
of producing severe wind gusts and isolated large hail.

DISCUSSION...Latest water-vapor imagery depicts an embedded midlevel
impulse tracking northeastward across portions of northern CO this
afternoon, and regional VWP shows around 20-30-kt midlevel flow
accompanying this feature. Associated large-scale ascent will
promote an increase in thunderstorm development along the
central/northern High Plains -- generally focused on the moist side
of a lee trough. Steep deep-layer lapse rates (sampled by recent DEN
ACARS soundings) amid lower/middle 50s dewpoints are contributing to
sufficient buoyancy for gradual updraft intensification.
Additionally, the enhanced midlevel southwesterly flow atop
low-level southeasterlies is favoring 20-30 kt of effective shear --
sufficient for loosely organized clusters and brief supercell
structures. As as result, severe winds gusts and isolated large hail
will be possible with the strongest storms as they spread/develop
northward into this evening. Given the increasing large-scale ascent
and favorable environment for strong convective outflow generation,
there may be a tendency for localized upscale growth with time,
which would further increase the severe-wind risk.

Current expectation is for the marginal deep-layer shear to limit
overall convective organization and intensity, and a watch is not
currently expected. However, convective trends will be monitored
into this evening.

..Weinman/Guyer.. 09/15/2024

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

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

LAT...LON   39840198 39800232 40300445 40580467 41730491 42500495
            44300429 44540405 44610364 44500315 43990281 43460267
            42640275 41560262 40150177 39840198