Subj : MESO: Mesoscale Discussion 1684
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Fri Jul 19 2024 21:51:16

ACUS11 KWNS 192151
SWOMCD
SPC MCD 192150=20
NEZ000-SDZ000-COZ000-WYZ000-192345-

Mesoscale Discussion 1684
NWS Storm Prediction Center Norman OK
0450 PM CDT Fri Jul 19 2024

Areas affected...southwest South Dakota and west-central Nebraska

Concerning...Severe potential...Watch possible=20

Valid 192150Z - 192345Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms should gradually increase in coverage and
intensity this afternoon/evening. A risk for hail and damaging gusts
may evolve. A WW is possible.

DISCUSSION...As of 2140 UTC, regional radar and satellite imagery
showed isolated thunderstorms developing near a frontal zone across
southern SD, northern NE and eastern WY. Warming afternoon surface
temperatures in the 80s to 90s F with 50s and 60s F dewpoints are
supporting moderate buoyancy of 1500-2500 J/kg across southern SD
and western NE. Enhanced mid-level flow ahead of a weak perturbation
was observed on area VADs, with effective shear of 35-45 kt.
Isolated organized storms, including supercells, appear possible
given the favorable CAPE/shear overlap. While mid-level lapse rates
are not overly steep (7-7.5 C/km), the moderate buoyancy and
potential for updraft rotation suggest a risk for hail with the
stronger storms. Damaging gusts are also possible with LCL heights
above 2,000 m.

Additional storm development/intensification will remain possible
late this afternoon and into the evening as weak ascent continues to
overspread the central High Plains. Exact storm coverage remains
uncertain given the relatively narrow zone of buoyancy and cloud
debris from earlier convection. Still, some CAM guidance suggests a
cluster or storms may eventually evolve with the potential for hail
and damaging winds across parts of southwest SD and west-central NE.
While convective evolution and the degree of severe risk remains
unclear, conditions will be monitored for a possible WW.

...Lyons/Gleason.. 07/19/2024

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!6lySsJlZknz7V8O1We1PHvF6GC1UM-teiPeW6PP7mVzxvpIcdObTpL_hRqFECygKOy_J-wEAU=
JKRwaJwlg4XrLjK9K8$  for graphic product...

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

LAT...LON   41130338 43940444 44580391 44430294 42640044 41980025
            41370043 40930153 41050308 41130338=20


=3D =3D =3D
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