100
ACUS11 KWNS 272018
SWOMCD
SPC MCD 272018
NEZ000-KSZ000-SDZ000-COZ000-WYZ000-272145-

Mesoscale Discussion 1447
NWS Storm Prediction Center Norman OK
0318 PM CDT Thu Jun 27 2024

Areas affected...Portions of the central and northern High Plains

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

Valid 272018Z - 272145Z

Probability of Watch Issuance...95 percent

SUMMARY...Monitoring the area for increasing severe-storm potential
this afternoon. A watch will be needed for parts of the area within
the hour.

DISCUSSION...Deepening boundary-layer cumulus is evident in the
vicinity of the Black Hills as well as far northeast CO into the NE
Panhandle this afternoon -- generally focused along a lee
trough/surface wind shift. During the next couple hours, the lee
trough will deepen as midlevel westerly flow strengthens across the
northern and central Rockies. This will support a gradual increase
in thunderstorm development over the next few hours, given diurnal
heating of a moist air mass (upper 50s to middle/upper 60s
dewpoints) and removal of MLCINH along the lee trough.

Storms should generally track eastward into the increasingly rich
moisture, where steep midlevel lapse rates are yielding moderate
surface-based instability. The 19Z UNR special sounding showed
around 30 kt of effective shear, characterized by a long/mostly
straight hodograph, and deep-layer shear should strengthen to around
40-50 kt with time. As a result, storms should organize into
semi-discrete supercells and organized clusters, with a risk of very
large hail (potentially up to 3 inches) and severe gusts.

A watch issuance is likely for parts of the area within the hour.

..Weinman/Hart.. 06/27/2024

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

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

LAT...LON   43520402 44730412 45490378 45760326 45860213 45770174
            45370112 44440058 42140017 40379993 39270005 38960071
            38860163 39110228 40230279 41450348 43520402