Mesoscale Discussion 1908
Issued: · Valid: –
Summary
Severe thunderstorms capable of producing large hail and damaging winds may develop across southeast Montana and move into southern North Dakota and South Dakota this evening. If storms initiate, they are expected to become organized clusters with the potential for significant wind gusts and large hail.
Product Text
000 ACUS11 KWNS 102315 SWOMCD SPC MCD 102315 SDZ000-NDZ000-MTZ000-110115- Mesoscale Discussion 1908 NWS Storm Prediction Center Norman OK 0615 PM CDT Mon Aug 10 2026 Areas affected...Far southeast Montana into far southern North Dakota and northern South Dakota Concerning...Severe potential...Watch possible Valid 102315Z - 110115Z Probability of Watch Issuance...40 percent SUMMARY...Satellite trends are being monitored for thunderstorm development across southeast Montana. If thunderstorms can develop they will likely move into an air mass very favorable for severe convection. Watch issuance is possible if this can occur. DISCUSSION...Latest GOES imagery depicts a growing cumulus field across southeast Montana in proximity to a weak surface low/confluence zone. Although broad-scale forcing for ascent across this region is weaker compared to areas further south, the nearby thermodynamic environment appears supportive of thunderstorms with limited capping and around 2500 J/kg MLCAPE. It remains uncertain whether or not ascent across this region will be sufficient to initiate and maintain deep convection, and recent guidance shows considerable uncertainty on whether or not storms will develop (though a few RRFS solutions do hint at this potential). However, if convection can develop and be sustained, it will likely migrate east/southeast into an increasingly moist air mass where MLCAPE values increase to around 3000-4000 J/kg. Additionally, the KBIS VWP continues to sample 50-55 knot 0-6 km BWD, which will favor organized convection. Storm mode would likely transition from semi-discrete cells into an organized cluster/MCS given the relatively dry low-level air mass and weak near-surface flow within the zone of initiation, both of which would favor deep/expanding cold pools. If initiation and clustering occurs, a threat for large hail and severe winds will likely emerge across far southern ND and into northwest/north-central SD. Convective trends will continue to be monitored, and watch issuance will be considered if robust/sustained convection becomes more imminent. ..Moore/Mosier.. 08/10/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR...BYZ... LAT...LON 44400125 45150445 45380464 45880468 46190453 46460414 46510385 45979976 45649953 45259953 44859970 44530021 44390065 44400125 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