Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
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968 ACUS01 KWNS 150601 SWODY1 SPC AC 150559 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Aug 15 2026 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE OHIO VALLEY SOUTHEASTWARD INTO THE CAROLINAS...AND IN THE CENTRAL HIGH PLAINS... ...SUMMARY... Thunderstorms with severe wind gusts and isolated large hail will be possible from late afternoon into the evening across the central High Plains. Severe wind gusts will also be possible this afternoon into the early evening from parts of the Ohio Valley southeastward into the Carolinas. ...Mid Mississippi and Ohio Valleys/Central Appalachians/Carolinas... At mid-levels today, a broad anticyclonic flow pattern will be in place over the eastern U.S. Within the flow, a shortwave trough will move eastward into the lower Ohio Valley. Ahead of this feature, a moist and unstable airmass will be located from the mid Mississippi Valley east-southeastward into the Ohio Valley and southern Appalachians. In the morning, a convective complex is forecast to move eastward into the southern Great Lakes, and will likely be associated with a potential for severe wind gusts. To the south of this complex, a quasi-stationary front and moist axis will be located from the lower Ohio Valley southeastward into the southern Appalachians, along which moderate instability will develop by afternoon. Low-level convergence near the front will be the focus for convective development. A new complex of surface-based thunderstorms appears likely to form near the front and move east-southeastward from western Ohio into the Virginias during the afternoon. Additional storms will develop along and near the instability axis over the western Carolinas due to topographical forcing. Model forecasts in the moist air suggest that MLCAPE will peak in the 2000 to 3000 J/kg range in most areas. Near the instability axis, precipitable water values in the 1.8 to 2 inch range and moderate deep-layer shear will likely support a threat for severe wet downbursts. This threat should persist into the early evening with any line segments that become sustained over the higher terrain of the southern and central Appalachians. ...Central Plains... West-southwesterly mid-level flow will be in place over the southwestern and central U.S. today. At the surface, a moist airmass will be located from the foothills of the Rockies eastward into the central Plains. By afternoon, moderate instability will develop over much of the region. Scattered thunderstorms will form in the higher terrain and move eastward into the lower elevations during the mid to late afternoon. Some RAP forecast soundings at 21Z from eastern Colorado northward into western Nebraska have 0-6 km shear near 35 knots with steep low to mid-level lapse rates exceeding 7 C/km. This environment will support a mixed mode with supercells and multicell line segments possible. Supercells should be capable of isolated large hail, while severe wind gusts will be possible with supercells and organized multicells. The severe threat should persist into the early to mid evening as a complex of storms moves eastward through the central High Plains. ..Broyles/Lyons.. 08/15/2026 $$