SPC MD 497

MD 0497 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF THE CENTRAL AND SOUTHERN HIGH PLAINS. Mesoscale Discussion 0497 NWS Storm Prediction Center Norman OK 0251 PM CDT Wed Apr 22 2026 Areas affected...parts of the central and southern High Plains. Concerning...Severe potential...Watch unlikely Valid 221951Z - 222145Z Probability of Watch Issuance...20 percent SUMMARY...Isolated high-based thunderstorms are expected this afternoon and into the evening. Isolated severe wind gusts, and some hail are possible. Limited moisture and storm organization should preclude the need for a watch. DISCUSSION...As of 1945 UTC, visible imagery and radar analysis showed incipient thunderstorms developing along a weak dryline/surface pressure trough from parts of the central Plains (NE,SD, CO, into western KS and the southern High Plains). Strong diurnal heating of a modestly moist air mass, along with weak ascent from increasing southwesterly flow aloft transecting the Rockies has destabilized the air mass east of the boundary. Continued heating and ascent should support additional storm development this afternoon. Steep lapse rates (8-9 C km) and 30-40 kt of mid-level flow will support occasional stronger/organized updrafts with multicells or transient supercells. High LCLs around 3 km, owing to the limited boundary-layer moisture (generally 30s-40s F dewpoints) will promote strong downdrafts within established thunderstorms. The steep lapse rates and strong evaporative cooling may allow for a few stronger downdrafts with severe gusts possible. Some hail is also plausible owing to cooling mid-level temperatures, especially farther south and east where buoyancy is greater. Given the propensity for strong downdrafts, long-lived organized severe storms are unlikely. Confidence in sustained thunderstorm activity is highest across the central high Plains were synoptic ascent is more robust. However, strong heating and the dryline circulation could support at least isolated storm development farther south the TX/OK Panhandles this afternoon/evening. With the severe risk expected to remain isolated and short-lived, a WW currently appears unlikely. ..Lyons/Mosier.. 04/22/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...DDC...UNR...GLD...AMA...PUB...BOU... CYS... LAT...LON 37790236 40310248 42850350 43390338 43650220 43450112 43090076 41290003 39170047 37100084 36110151 35710209 36250228 36810231 37790236 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more