MD 1977 CONCERNING SEVERE THUNDERSTORM WATCH 637… FOR SOUTHWESTERN THROUGH SOUTH CENTRAL SOUTH DAKOTA
Mesoscale Discussion 1977
NWS Storm Prediction Center Norman OK
0910 PM CDT Sat Aug 12 2023
Areas affected…southwestern through south central South Dakota
Concerning…Severe Thunderstorm Watch 637…
Valid 130210Z – 130415Z
The severe weather threat for Severe Thunderstorm Watch 637
continues.
SUMMARY…Thunderstorms posing some risk for strong wind gusts may
remain possible into the 10-11 PM CDT time frame, north of the
central Nebraska/South Dakota state border vicinity. However, it is
not clear that this will require a new severe weather watch.
DISCUSSION…Downstream of a short wave trough digging into eastern
Montana, warm advection driven convection continues to gradually
spread across and east-southeast of the Black Hills vicinity.
Scattered stronger storms are generally focused on the
southern/southwestern periphery of this regime, from the Pine Ridge
Reservation vicinity into the Rapid City area, supported by a
continuing inflow of moist unstable boundary-layer air characterized
by sizable CAPE. However, as boundary-layer cooling progresses, the
risk for severe hail seems likely to gradually wane during the next
few hours.
It is possible that a strengthening southerly jet around 850 mb
could still focus an area of stronger lingering convection across
the Mellette, Todd, and Tripp county vicinity, which could be
accompanied by a period of increasing strong wind potential.
However, it is not clear that this will require a new severe weather
watch.
..Kerr.. 08/13/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…FSD…ABR…LBF…UNR…
LAT…LON 44380289 43770193 43690030 43199921 42860018 42900175
43040253 43760362 44380289
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