Subj : MESO: Mesoscale Discussion 1974 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 12 2023 23:07:15 ACUS11 KWNS 122307 SWOMCD SPC MCD 122306=20 SDZ000-NEZ000-130100- Mesoscale Discussion 1974 NWS Storm Prediction Center Norman OK 0606 PM CDT Sat Aug 12 2023 Areas affected...southwestern South Dakota Concerning...Severe Thunderstorm Watch 637... Valid 122306Z - 130100Z The severe weather threat for Severe Thunderstorm Watch 637 continues. SUMMARY...An isolated supercell may be maintained with a continued slow southeastward propagation into the Pine Ridge Reservation through 6-8 PM MDT, accompanied by large hail, locally strong surface gusts and perhaps some increasing risk for a tornado. DISCUSSION...An isolated supercell is in the process of propagating southeast of the Black Hills, embedded within a rather modest (around 20 kt), but strongly sheared westerly deep-layer mean flow.=20 Likely aided by lift forced by a zone of enhanced lower/mid tropospheric warm advection, and moderately strong southeasterly near-surface inflow characterized by mixed-layer CAPE around 2000 J/kg, it appears this activity will be maintained for at least several more hours.=20=20 A slow southeastward propagation across the Badlands into the Pine Ridge Reservation should persist, accompanied by a continuing risk for large hail and locally damaging wind gusts. Some strengthening of south-southeasterly ambient flow around 850 mb through 00-02Z may contribute to at least some risk for a tornado. ...Kerr.. 08/12/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8_ExNNUI-C_MEvvhYw1FWl2bpcjVDLrlbM59AdGGUByfEspudmmHiJdFp3HgNkZ73o2QQCdq4= c_oodgSKfy_4TKtAuo$ for graphic product... ATTN...WFO...LBF...UNR...CYS... LAT...LON 43950263 43160153 42930260 43040309 43290333 43950263=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .