Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
048 ACUS03 KWNS 220730 SWODY3 SPC AC 220730 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Wed May 22 2024 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OKLAHOMA AND THE OZARKS NORTHWARD TO THE SOUTHERN LAKE MICHIGAN VICINITY... ...SUMMARY... Isolated strong to severe thunderstorms are possible on Friday from eastern Oklahoma and the Ozarks, northward to the southern Lake Michigan vicinity. ...Eastern OK to southern Lake Michigan Vicinity... Friday begins with shortwave upper ridging over the Upper Great Lakes vicinity. This ridge will dampen as it shifts east toward the lower Great Lakes and a shortwave upper trough over the northern Plains develops east to the Upper Midwest. To the south across the southern Plains to the TN Valley vicinity, low-amplitude westerly flow around 30-40 kt will prevail. At the surface, low pressure over the eastern Dakotas will lift northward into Manitoba/western Ontario while a cold front progresses eastward across the mid/upper MS Valley and portions of the Ozarks. A seasonally moist airmass will be in place with low to mid 60s F dewpoints across parts of the Lake Michigan vicinity, increasing with southwest extent into OK/AR (upper 60s/low 70s F). Moderate to strong destabilization is expected, aided by steepening midlevel lapse rates. While stronger large-scale ascent will be focused over the Upper Midwest, the progressive cold front will be a focus for thunderstorm development through the period. Vertical shear will be modest, with deep-layer flow mostly parallel to the front. Clusters of thunderstorms pose a risk for strong/damaging gusts and possibly hail. Given a lack of stronger height falls until the nighttime hours and limited large-scale ascent with southward extent, severe thunderstorm coverage and evolution is a bit uncertain. Greater severe probabilities may become necessary in later outlooks if a corridor of greater potential becomes apparent as mesoscale details become better resolved. ...TN Valley to the Carolinas... A very moist and unstable airmass will be in place on Friday. Low-amplitude westerly flow will overspread the region, with large-scale ascent somewhat nebulous. There is some potential that a convectively enhanced vorticity maxima from remnant convection in the Day 2/Thu period will float through westerly flow. If this occurs, this could provide a focus for more organized convection in a weakly sheared environment. Uncertainty and the conditional nature of the threat at this time frame precludes severe probabilities, but strong storms are a possibility. ..Leitman.. 05/22/2024 $$