MD 2068 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF NORTHEASTERN CO…WESTERN NE…EASTERN WY…AND SOUTHWESTERN SD
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
