MD 1209 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PARTS OF CENTRAL AND EASTERN SOUTH DAKOTA AND ADJACENT PORTIONS OF THE NORTHERN GREAT PLAINS
Mesoscale Discussion 1209
NWS Storm Prediction Center Norman OK
0132 PM CDT Thu Jun 22 2023
Areas affected...parts of central and eastern South Dakota and
adjacent portions of the northern Great Plains
Concerning...Severe potential...Watch unlikely
Valid 221832Z - 222130Z
Probability of Watch Issuance...5 percent
SUMMARY...Increasingly widespread thunderstorm development is
possible through late afternoon. While some of this may pose a risk
for marginally severe hail and wind, it appears unlikely to become
well-organized.
DISCUSSION...Moderate mixed-layer CAPE with increasingly negligible
inhibition appears focused within a corridor along a weak surface
frontal zone, particularly near a weak low east of the Pierre, SD
vicinity. Widely scattered thunderstorm development is already
underway, and various model output has been suggestive that
convection will become more widespread through 20-22Z, perhaps aided
by forcing for ascent associated with a weak convectively generated
perturbation.
Deep-layer south-southwesterly mean wind appears generally less than
20 kt, with vertical shear also modest to weak. However,
thermodynamic profiles with initially steep lower/mid-tropospheric
lapse rates may provide support for marginally severe hail and
locally strong downbursts. As convection begins to grow upscale,
gusty winds may become more widespread along the leading edge of
consolidating outflows, but this probably will remain mostly below
severe limits.
..Kerr/Hart.. 06/22/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FSD...ABR...UNR...
LAT...LON 44959985 45789863 45719719 44519774 43409899 43049974
43190085 44959985
