SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Jun 22 2023 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE MISSOURI VALLEY... ...SUMMARY... Severe thunderstorms are possible across the Middle Missouri Valley vicinity on Saturday. Very large hail is currently expected to be the primary threat. ...Synopsis and Discussion... A shortwave trough is expected to progress through the northern periphery of the upper ridging over the Plains on Saturday, moving across the Dakotas and NE into the Upper Midwest. Surface low attendant to this shortwave will take a similar path, tracking from central SD northeastward to the northern MN/WI border vicinity. An associated cold front will move eastward across SD and NE during the afternoon, before then continuing eastward across southern MN and IA during the evening and overnight. A very moist air mass will precede this shortwave trough across the Mid MO and Mid MS Valleys, with afternoon dewpoints likely in the mid to upper 60s. Northeastern extent of the steeper mid-level lapse rates will also extend into this region. The resulting combination of moist low levels and steep mid-level lapse rates will support strong buoyancy during the afternoon and evening. A belt of stronger mid-level flow is expected to spread into the region as well, supporting 40 to 50 kt of deep-layer vertical shear. Thunderstorm development is anticipated along the front once convective inhibition erodes by the late afternoon. The strong buoyancy and shear will support severe thunderstorms, some of which could produce very large hail. Overall convective evolution has low predictability at this forecast range, but some upscale growth appears possible. Low probabilities were extended into the Ozark Plateau to account for this possibility. ..Mosier.. 06/22/2023
