Mesoscale Discussion 1907
Issued: · Valid: –
Summary
Thunderstorms developing in western South Dakota may intensify into a severe weather system this evening, bringing the potential for damaging wind gusts of 65 to 80 mph and possible tornadoes across southern South Dakota and north-central Nebraska.
Product Text
000 ACUS11 KWNS 102240 SWOMCD SPC MCD 102239 SDZ000-NEZ000-WYZ000-110045- Mesoscale Discussion 1907 NWS Storm Prediction Center Norman OK 0539 PM CDT Mon Aug 10 2026 Areas affected...Western South Dakota into north-central Nebraska Concerning...Severe potential...Watch likely Valid 102239Z - 110045Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms developing across western South Dakota may intensify into a robust MCS in the coming hours. If/when this occurs, the potential for severe winds will substantially increase downstream into southern South Dakota and north-central Nebraska. Watch issuance is probable if convection intensifies as expected. DISCUSSION...Large-scale ascent continues to spread east across the central and northern High Plains based on recent GOES imagery with several clusters of high-based thunderstorms emerging from eastern MT into eastern WY and CO. More recently, a cluster of high-based thunderstorms has developed across far western SD in proximity to the western fringe of a moist plume that extends from the central Plains into western SD around a weak surface low analyzed south of the Black Hills. Over time, this convection should intensify as it continues to spread east into the moist air mass where MLCAPE rapidly increases into the 3000-4500 J/kg range. Additionally, the combination of southeasterly low-level winds to the north of the low with 30-40 knot mid-level flow aloft is supporting around 40-50 knots of effective bulk shear across the warm sector. This will likely promote organization of deepening convection over the next few hours - most likely into an MCS as cold pools continue to amalgamate and deepen. If an MCS emerges, the downstream environment will likely support severe gusts as high as 65-80 mph, and potentially a few embedded circulations given strong westerly low-level shear. Most high-res solutions over the past several hours have depicted some form of an MCS emerging out of the Dakotas this evening, though considerable spread is noted on precisely when and where such an MCS will emerge. Based on these observed trends, this cluster may develop into the anticipated MCS. Trends will continue to be monitored, and watch issuance will likely be required if the cluster continues to intensify. ..Moore/Mosier.. 08/10/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...ABR...LBF...UNR...CYS... LAT...LON 42350100 43390398 43660419 44160422 44430415 44640385 44700351 44349913 43859875 43259880 42839910 42539963 42360032 42350100 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN