SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1229 AM CDT Sun Aug 29 2021 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN LOWER MICHIGAN AND OVER THE CENTRAL GULF COAST IN ASSOCIATION WITH HURRICANE IDA... ...SUMMARY... Isolated strong to severe storms are possible across portion of the Upper Great Lakes this afternoon. Additionally, tornadoes may occur within the right-front quadrant of Hurricane Ida over the central Gulf Coast. ...Upper Great Lakes... Notable short-wave trough currently located over the northern Plains is forecast to advance into the upper Great Lakes region by 18z. Strong mid-level height falls will spread across Lake Superior/UP of MI into Ontario by late afternoon. Southern influence of this feature, along with increasing 500mb flow, will skirt northern lower MI enhancing the possibility for a few strong/severe thunderstorms ahead of the progressive cold front. Forecast soundings suggest surface-based parcels will become buoyant by 18z, and isolated thunderstorms should develop along the wind shift within a flow regime characterized by surface-6km bulk shear on the order of 35kt. Modest boundary-layer heating will be noted across the warm sector extending across lower MI into northern IL. As temperatures warm through the 80s it appears convection should gradually develop southwest across southern Lake MI into IL by late afternoon/early evening. While this activity will be more removed from the short wave, a few strong/severe storms may be noted. Wind is the primary concern, though marginal severe hail threat also exists. ...Hurricane Ida... Hurricane IDA continues its west-northwest movement toward the LA Coast. Outermost bands of convection are beginning to affect the FL Panhandle, west along the central Gulf Coast. With no appreciable change expected to earlier forecast track, previous thoughts regarding tornado potential continue. IDA is forecast to advance inland to a position near southwestern MS by the end of the period. Have opted to extend SLGT Risk a bit farther north into central MS to account for increased shear across this region late in the period. ..Darrow/Wendt.. 08/29/2021 Read more LIVE: spc.noaa.gov
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