Mesoscale Discussion 1901
NWS Storm Prediction Center Norman OK
0353 PM CDT Wed Aug 14 2024
Areas affected...central South Dakota
Concerning...Severe potential...Watch unlikely
Valid 142053Z - 142300Z
Probability of Watch Issuance...20 percent
SUMMARY...A cluster of thunderstorms may continue to slowly evolve
to the west and northwest of the Pierre vicinity through 5-7 PM CDT,
accompanied by occasional small to marginally severe hail and
locally strong surface gusts. It is possible that the risk for
potentially damaging wind gusts could increase later this evening.
However, at least until then, it appears unlikely that a severe
weather watch will be needed.
DISCUSSION...Within lee surface troughing, inhibition is eroding
with continuing insolation, for a destabilizing boundary layer near
a modest low centered near Pierre. This is being aided by mid-level
cooling overspreading the high plains, associated with the leading
edge of troughing crossing the northern Rockies, which appears to be
providing support for an evolving line of convection to the west of
Mobridge into the Philip vicinity.
A gradual further upscale growth appears possible during the next
few hours, as convection acquires increasing inflow of unstable
boundary-layer air becoming characterized by CAPE up to 2000 J/kg.
In the presence of south-southwesterly deep-layer mean flow on the
order of 10-15 kt, storm motions will remain slow initially.
However, modest shear, aided by veering of wind fields with height,
might slowly contribute to increasing organization into early
evening, particularly as convective outflow supports an increasingly
prominent surface cold pool. Once this occurs, the risk for strong
to severe surface gusts may begin to increase. Until then, though,
more localized strong surface gusts and occasional small to marginal
severe hail appear the primary potential severe hazards.
..Kerr/Thompson.. 08/14/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...BIS...UNR...
LAT...LON 45990078 45659962 43939945 43900110 45490153 45990078
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