SPC AC 120602 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0102 AM CDT Sun Apr 12 2020 Valid 121200Z - 131200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS SOUTHEAST AR...NORTHERN LA...MUCH OF MS...NORTHERN AND CENTRAL AL AND FAR NORTHWEST GA... ...SUMMARY... An outbreak of severe thunderstorms is likely today into tonight, with the greatest threat expected from Louisiana through much of the Southeast and Tennessee Valley. Strong tornadoes, widespread damaging winds, and large hail are all possible. ...Synopsis... An outbreak of severe storms is expected today across portions of the Lower MS Valley into the Southeastern U.S. Intense storms capable of widespread damaging winds, large hail, and several strong tornadoes are possible with several rounds of storms from late morning into the overnight hours. ...ArkLaTex into the Southeast... Initially, convection is expected to be ongoing across east TX this morning, in association with a lead shortwave perturbation. Storm mode may be messy with this area of convection as it spreads east/northeast across northern LA/southern AR into northern MS and the TN Valley vicinity. However, strong warm advection will bring upper 60s to low 70s F dewpoints as far north as I-20 by late morning/middday, as a 50+ kt southwesterly low level jet overspreads the lower MS Valley. As a result, any convection that is initially elevated above a modest EML should quickly become surface based. Additional convection is then expected to develop by early afternoon as a weak cap erodes across central and southern MS along a pre-frontal trough/confluence band. These storms will likely be more classic semi-discrete supercells, and spread eastward into AL by late afternoon, and northern GA during the evening. Large, curved hodographs and deep, rich boundary layer moisture in intense vertical shear will support long-lived supercells capable of producing significant tornadoes. Overnight, there is some potential for upscale growth into a LEWP/QLCS across eastern AL/GA into the FL Panhandle. Damaging wind and mesovortex tornadoes are possible with this convective mode as well. Further east, strong surface heating and increasing dewpoints will result in weak destabilization across the Carolinas in the vicinity of a weak surface trough. Upper forcing will remain weaker across this area, limiting storm coverage. However, a few cells could become intense, capable of a couple of tornadoes and severe wind/hail during the afternoon. ...Ozarks Vicinity to Lower OH Valley... Additional convection is expected to develop in association with the main mid/upper shortwave trough ejecting across the southern Plains through 00z, then northeastward across the OH Valley overnight. Storms are expected to develo across eastern OK during the afternoon and spread eastward into southern MO and AR. Some semi-discrete cells are possible initially, and will be capable of producing very large hail. However, low level shear will become veered and deep layer flow more parallel to a surface cold front, resulting in some upscale growth into one or more bowing segments. This could result in a corridor of intense, damaging winds from northern AR into western TN/KY during the evening/overnight hours. In addition to damaging wind potential, mesovortex tornadoes also will be possible with this activity. ...Mid-MS Valley into the Central Appalachians... Isolated thunderstorms are possible during the afternoon across northern MO into southern IA in strong warm advection ahead of the surface cold front. Marginally severe hail and wind will accompany these storms. During the evening and overnight hours, a surface low will continue to deepen as it lift northeast toward the Great Lakes. Additional storms will spread across the IN/OH and into portions of the central Appalachians posing a threat for locally strong wind gusts and isolated hail with the strongest cells. ..Leitman.. 04/12/2020 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z