032 ACUS11 KWNS 232131 SWOMCD SPC MCD 232131 MTZ000-WYZ000-232230- Mesoscale Discussion 2104 NWS Storm Prediction Center Norman OK 0431 PM CDT Sun Aug 23 2026 Areas affected...portions of central and eastern Montana Concerning...Severe potential...Watch likely Valid 232131Z - 232230Z Probability of Watch Issuance...80 percent SUMMARY...Widely scattered thunderstorms (including some supercells) will continue eastward with a risk for severe gusts and isolated hail. A downstream Watch is likely needed. DISCUSSION...As of 2130 UTC, widely scattered thunderstorms were ongoing across central MT. New convection was also developing near the WY border. Ascent from an approaching upper trough should continue to support these storms and any new development this evening. Moisture is modest (40s and 50s F dewpoints), but strong diurnal heating has steepened low and mid-level lapse rates enough for moderate destabilization. This will support stronger updrafts as they move eastward over the next couple of hours. 40-50 kt of westerly flow aloft with supercells and some upscale growth into linear clusters. The dry sub-cloud layer and flow aloft will favor severe gusts, especially with clustering. Hail is also possible, especially with any persistent supercells. Given the increasing severe risk, a downstream Severe Thunderstorm Watch is likely needed soon. ..Lyons/Thompson.. 08/23/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...GGW...RIW...TFX... LAT...LON 49050884 49250603 49060504 48710487 48380473 47470496 46050568 45270625 44940708 44760872 44920911 45330913 46040889 48020883 49050884 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  016 ACUS11 KWNS 232149 SWOMCD SPC MCD 232149 NDZ000-SDZ000-232315- Mesoscale Discussion 2105 NWS Storm Prediction Center Norman OK 0449 PM CDT Sun Aug 23 2026 Areas affected...Parts of southwestern North Dakota Concerning...Severe potential...Watch likely Valid 232149Z - 232315Z Probability of Watch Issuance...95 percent SUMMARY...The risk of supercells and organized clusters capable of producing large hail and severe wind gusts will increase over the next few hours. A watch will be issued shortly. DISCUSSION...Thunderstorms are evolving along a lee trough in far southwestern ND -- potentially being aided by a passing midlevel wave farther north (evident in WV imagery). An elongated hodograph with clockwise curvature (around 30-40 kt of effective shear) and steep midlevel lapse rates atop lower/middle 60s dewpoints will support organized clusters and supercell structures capable of producing large to very large hail and severe wind gusts. Deep-layer shear oriented perpendicular to the lee trough will initially favor discrete cells, though localized upscale growth into small clusters is possible with time. A watch will be issued shortly. ..Weinman/Thompson.. 08/23/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...UNR... LAT...LON 46170398 47120400 47640394 47870360 47950260 47670210 46610204 46040230 45910282 45970382 46170398 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN