####018004202#### ACUS01 KWNS 111253 SWODY1 SPC AC 111252 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Thu Apr 11 2024 Valid 111300Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR EASTERN OHIO AND NORTHWEST WEST VIRGINIA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR FAR SOUTHERN GEORGIA INTO NORTH AND CENTRAL PARTS OF FLORIDA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple of tornadoes are possible in far southern Georgia into central Florida, mainly this morning through early afternoon. ...Synopsis... Water-vapor imagery this morning shows a potent mid-level low/trough centered near the AR/MS/TN border with an upstream trough over the Upper Midwest forecast to phase with the Southeast trough. A cyclone near the TN/MS border will deepen as it develops north-northeast into the Lower Great Lakes by early evening. A trailing surface cold front will push east across portions of the Southeast/southern Appalachians during the day, before clearing the Southeast coast by early Friday morning. ...Upper OH River Valley... Considerable uncertainty remains for this forecast in terms of the magnitude of destabilization across the OH Valley late this morning through the afternoon. This uncertainty is primarily due to low cloud cover and weak capping resulting in scattered showers/low-topped thunderstorm activity and the potential to remain relatively cool in the boundary layer. However, mid-level dry air evident in water-vapor imagery is wrapping through the base of the mid-level low/trough over TN, and this mid-level dry intrusion forecast to spread northeast into portions of the Upper OH Valley. Weak instability coupled with some enlargement of the hodograph can support an environment in which discrete cells and semi-discrete clusters evolve into supercells. A few tornadoes are possible if stronger updrafts/supercells manage to develop, in addition to an accompanying threat for damaging gusts and perhaps marginally severe hail. ...Florida/Georgia... Ongoing pre-frontal broken band of strong to severe thunderstorms over north FL and the eastern Gulf of Mexico will gradually shift east across the northern half of the Peninsula through the morning and into the afternoon. The northern rim of rich low-level moisture (upper 60s to lower 70s deg F surface dewpoints) have advected into north FL early this morning. Although lapse rates will remain modest, it appears the richer moisture will contribute to adequate surface-based buoyancy (500-1250 J/kg MLCAPE) across the northern half of the Peninsula today. The Jacksonville and Tampa 88D VAD wind profiles are quite strong this morning and will likely remain so through the early afternoon as the larger-scale mid-level trough pivots eastward over the FL Peninsula by early evening. The risk for a couple of tornadoes and damaging gusts will likely maximize through the midday before the thunderstorm band moves offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ...Mid-Atlantic states into Carolinas... A less focused and more conditional severe risk seems evident for the Carolinas later this afternoon and northward into the Mid-Atlantic states this evening as the upper trough encroaches on the general region. A broad warm-air advection regime north of the FL/GA early-day MCS will slowly destabilize today, aided in part by lower 60 deg F dewpoints north, mid to upper 60s south. Long hodographs will favor storm organization with any robust updrafts. Isolated to widely scattered strong to severe storms capable of a threat for damaging gusts and a couple of tornadoes are possible, mainly over parts of western VA, with lower coverage expected farther east over the coastal plain/Delmarva. ..Smith/Mosier.. 04/11/2024 $$