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SPC AC 120451

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK 1151 PM CDT Fri Oct 11 2024

Valid 131200Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE SUNDAY AFTERNOON AND EVENING ACROSS MUCH OF WEST VIRGINIA...PARTS OF EASTERN KENTUCKY...SOUTHWESTERN VIRGINIA AND ADJACENT PORTIONS OF SOUTHERN OHIO...SOUTHWESTERN PENNSYLVANIA AND NORTHEASTERN TENNESSEE...

...SUMMARY... Strong thunderstorms may develop in a corridor across West Virginia, and perhaps into portions of eastern Kentucky and southwestern Virginia, late Sunday afternoon and evening. Some may be accompanied by small to marginally severe hail and potentially damaging wind gusts.

...Synopsis... Mid/upper flow across the northern mid-latitudes of the Pacific into North America will remain amplified through this period, with further amplification of large-scale troughing forecast across the Upper Midwest and Great Lakes into the Ohio Valley. Models indicate at least of couple of vigorous short wave perturbations digging within this troughing, one of which may contribute to modest surface cyclogenesis along a frontal zone across the Ohio Valley into the Northeast by late Sunday night.

In lower latitudes, a residual mid-level shear axis across the central Gulf of Mexico and Florida Peninsula will generally demarcate the northern periphery of higher moisture content air. However, a continued gradual moistening of the boundary layer ahead of the interior U.S. front may contribute to a corridor of modest destabilization across parts of the Ohio/Tennessee Valleys into the western slopes of the Appalachians by late Sunday afternoon.

...West Virginia into eastern Kentucky/southwest Virginia... There remains variability among the models concerning the evolution of surface cyclogenesis across the Ohio Valley into the Northeast Sunday through Sunday night. However, there still appears a general consensus that a moistening, but well-mixed, boundary layer will become characterized by CAPE on the order of 500-1000 J/kg by late Sunday afternoon, within at least a narrow pre-frontal corridor across Tennessee/Kentucky into West Virginia. It appears that peak destabilization will coincide with strengthening westerly deep-layer wind fields, including to 50+ kt in the 700-500 mb layer. Forcing for ascent in advance of stronger mid-level height falls, which may not begin overspreading the region until after dark, remains more unclear. However, a developing pre-frontal low-level upslope flow component may aid thunderstorm initiation across parts of West Virginia, and perhaps into eastern Kentucky and southwestern Virginia by early Sunday evening. If this occurs, the environment probably will be conducive to a few stronger storms posing a risk for hail and potentially damaging wind gusts.

..Kerr.. 10/12/2024

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