Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Sun Mar 22 2026 Valid 221630Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR EASTERN OHIO AND WESTERN/CENTRAL PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms appear likely this afternoon and evening across parts of the Ohio Valley into the Mid-Atlantic, particularly from far eastern Ohio into central Pennsylvania. Large to very large hail and damaging winds should be the main threats, but a tornado or two may also occur. ...Ohio Valley into the Mid-Atlantic... Early-morning soundings reveal a plume of steep mid-level lapse rates (i.e. greater than 8 deg C per km from 700 to 500 mb) extending from the southern Plains northeastward into the Upper OH Valley. This plume of steeper lapse rates is largely oriented along and west of a cold front that extends from a low in south-central KS to another low in western NY. The airmass preceding this front is seasonally warm and moist, with temperatures in the 70s and dewpoints in the 50s across much of the OH Valley. The expectation is for continued airmass modification today as moisture advects northeastward. However, this moistening will be offset by strong mixing, with dewpoints likely ranging from the upper 50s across the Lower OH Valley into the low 50s across western/central PA. This low-level moisture, combined with temperatures in the upper 70s/low 80s, should result in an erosion of surface-based convective inhibition ahead of the front from eastern OH through central PA. Additionally, given the steep mid-level lapse rates in place, weak instability (MLCAPE around 500-1000 J/kg) is expected to develop ahead of the front. Current expectations are for robust thunderstorms to develop by 19-21Z from eastern OH into western/central PA along and just ahead the front, forced by low-level convergence along the front and in the vicinity of a weak surface low moving across the region. An initially discrete mode is anticipated, with strong deep-layer shear favoring the development of supercells. Long/straight hodographs and steep mid-level lapse rates suggest that large to very large hail (up to 1.5-2.5 inches in diameter) is the main threat with these supercells. High LCLs and steep low-level lapse rates also support the potential for strong downbursts as well as trend towards upscale growth and a more linear mode as it moves east-southeastward across PA through the evening. Primary severe threat should transition from hail to damaging gusts throughout the evening. Given the high LCLs and limited low-level moisture, the tornado risk appears low, although not zero given the supercell mode anticipated. Farther west across the low to mid OH Valley, thunderstorm initiation should occur a bit later (i.e. closer to 00Z) as modest ascent attendant to a low-amplitude shortwave trough augments low-level convergence along the front. Much of this convection may tend to become elevated along/north of the undercutting cold front. Even so, steep mid-level lapse rates and strong shear will support a continued risk for large hail. Some isolated very large hail is possible with the initially more cellular development across southern IL, central IN, and west-central OH. A trend towards more linear structures is expected with time, and warm/dry low to mid-levels could still support some strong gusts despite the elevated storm structures. ..Mosier/Weinman.. 03/22/2026Read more
