SPC May 18, 2024 0600 UTC Day 1 Convective Outlook
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1245 AM CDT Sat May 18 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN NORTH FL AND SOUTH GA... ...SUMMARY... The most probable corridor for damaging winds is across the Florida Panhandle to the South Atlantic Coast, this morning into the afternoon. Isolated damaging winds and sporadic severe hail will be possible during the afternoon into the evening across much of the Southeast, and over parts of the Upper Midwest to eastern Kansas. ...Southeast... Increasing convective development is expected this morning across the northern Gulf Coast region from LA to the FL Panhandle. This should occur in response to isentropic ascent within the 700-mb baroclinic zone, amid a difluent upper flow regime in the right-rear quadrant of an intense upper jet advancing northeast over the Deep South to southern Appalachians. Outflow from a Friday evening MCS that decayed over south GA and north FL should serve as the primary downstream baroclinic zone later this morning as convection consolidates and spreads east-northeast. Amid a relatively nebulous surface pattern due to the lack of cyclogenesis, low-level flow outside of convective influences should remain weak. Southwesterly deep-layer speed shear will be favorable for occasional linear clustering through the morning into the afternoon before convection moves off the southern Atlantic Coast. Scattered damaging winds from strong to isolated severe wind gusts remain possible. Additional storms should form along the Florida Atlantic Coast sea breeze during the afternoon with an isolated severe threat possible. At least scattered afternoon thunderstorms are expected over the TN Valley to southern Appalachians ahead of the primary shortwave impulse embedded within the positive-tilt, southern-stream trough. Uncertainty exists over the degree of destabilization in the wake of the extensive morning convection farther south-southeast. With only moderate deep-layer shear expected between the trough and the mid-level jet near the Gulf Coast, have held severe wind/hail probabilities at level 1-MRGL. ...Upper Midwest to KS... A shortwave trough across the Prairie Provinces into the northern Great Plains will move east into far northwest ON by early Sunday. Attendant surface cyclone will track more north-northeastward as it occludes, with the trailing cold front shifting east of the Upper MS Valley and south in KS during the afternoon. Low-level convergence along the front should be sufficient for isolated to scattered thunderstorms, as a moderately unstable airmass with MLCAPE of 1000-2000 J/kg becomes established at peak heating. The bulk of strong mid-level west-southwesterlies will remain confined behind the front. Moderate deep-layer shear should overspread the Lake Superior region, as flow substantially weakens with southern extent. Isolated severe hail and damaging winds will be most likely across the Upper Midwest portion of the area. Locally strong to severe wind gusts and small hail may also occur within the weakly sheared environment along the front into KS. The severe threat will wane after dusk. ..Grams/Bentley.. 05/18/2024
