


Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
079 ACUS03 KWNS 101929 SWODY3 SPC AC 101928 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 PM CDT Thu Jul 10 2025 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN THE LOWER MI VICINITY... ...SUMMARY... Scattered damaging winds are possible across the Lower Michigan vicinity on Saturday afternoon. A broad swath of isolated severe thunderstorms is anticipated from the Great Lakes to the southern High Plains, mainly Saturday afternoon/evening. ...Great Lakes... A shortwave trough should be centered on the MB/ON to the Dakotas/MN border at 12Z Saturday. An embedded impulse should take on an increasingly negative tilt as it ejects through the basal region of the trough. This will help broaden the belt of moderate mid-level (30-45 kts at 500 mb) southwesterlies across most of the Great Lakes. Large spread, typical for this time of year, exists with the handling of downstream MCVs and related flow/ascent enhancements, as well as mesoscale placement of the effective outflow boundary from prior day convection. The most likely corridor for ample buoyancy development should be from southern/eastern Lower MI southward in the Midwest. Stronger deep-layer shear will overlap the synoptic cold front farther west in central/eastern WI and western Upper MI. However, the degree of destabilization in this corridor is uncertain. An ensemble of D3 CAM guidance and ML severe probs suggests that the Lower MI vicinity will have the best chance at clusters capable of scattered damaging winds during Saturday afternoon. ...Mid-MS Valley to the Southern High Plains... Multiple areas of general thunderstorms are expected to be ongoing at 12Z Saturday from the Ozarks to the southern High Plains. With only peripheral influence of the Upper Midwest shortwave trough, afternoon to evening severe potential will be tied to the influence of remnant MCVs embedded within generally weak deep-layer shear. Greater concentration of thunderstorms that may grow upscale into a slow-moving MCS on Saturday evening seems plausible across a portion of the southern High Plains. Mesoscale predictability warrants broad, low severe probabilities at this time. ..Grams.. 07/10/2025 $$