Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
750 ACUS02 KWNS 110602 SWODY2 SPC AC 110600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Tue Aug 11 2026 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL AND NORTHERN HIGH PLAINS...AND ALSO FOR PARTS OF THE MIDWEST AND OHIO VALLEY... ...SUMMARY... Thunderstorms with severe gusts and hail will be possible Wednesday afternoon and evening across parts of the central and northern High Plains. Damaging gusts and isolated hail will also be possible across parts of the Midwest and Ohio Valley. ...Parts of the Midwest/Ohio Valley... Guidance continues to vary considerably regarding potential for early-day convection across parts of the Midwest and Ohio Valley. Any morning convection will in turn influence the position of an effective frontal zone that will generally extend from parts of the mid MO Valley into the lower OH Valley. Strong heating, rich low-level moisture, and generally steep lapse rates will result in strong to extreme buoyancy to the warm side of the front, with substantial MUCAPE possible to the immediate cool side of the front. Multiple scenarios are possible. There will be some potential for any early-day storm cluster to propagate southeastward through the day, with a damaging-wind and isolated hail threat. Diurnal development will be possible in the vicinity of the frontal zone, with sufficient deep-layer shear for initial supercell potential. Hail and possibly a tornado could accompany the strongest diurnal storms, though there may be a tendency for clustering and perhaps organized upscale growth, with increasing wind-damage potential. While uncertainty remains high, one or more rounds of organized-severe potential could evolve in the vicinity of the frontal zone, and a 15% wind area was added where guidance currently has the greatest signal for development. ...Parts of the central/northern High Plains into the lower/mid Missouri Valley... To the north of a surface low across southeast CO and an eastward-extending warm front, moist low-level easterly flow will support potential for moderate to locally strong destabilization across parts of western SD/NE into northwest KS/far northeast CO. Midlevel flow will be relatively modest, but veering wind profiles will result in sufficient deep-layer shear for storm organization. Initial isolated to widely scattered discrete development could pose a threat of hail and localized severe gusts. Some upscale growth and possible MCS development may occur during the late evening and overnight across parts of central/eastern NE and vicinity. Guidance varies regarding the organization of any nocturnal MCS, but at least isolated damaging-wind potential could spread eastward through the end of the period. ...Northern SD/southern ND into parts of MN/WI/MI... While the strongest instability will remain south of the region, moderate buoyancy is forecast to develop along/ahead of a front draped from near the ND/SD border into southern MN, WI, and Lower MI. Coverage of storms is uncertain within this regime, but moderate northwesterly mid/upper-level flow and favorable deep-layer shear will support organized convection, with a threat for strong to locally severe gusts and hail if any sustained storms develop. ...Carolinas/Southern Appalachians... The evolution of antecedent upstream convection will have a considerable influence on the position of the primary surface front and any organized severe threat across parts of the southern Appalachians and Carolinas region on Wednesday. At least isolated storm development will be possible near the front and also across favored terrain areas, with modest west-northwesterly flow aloft supporting potential for outflow-driven cells/clusters with a threat of wind damage. Any features favorably timed with the diurnal cycle (such as a persistent storm cluster or MCV) could result in a greater coverage of wind-damage potential, but confidence in the details is too low for more than 5% wind probabilities at this time. ..Dean.. 08/11/2026 $$