Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed May 15 2024 12:59:30 ACUS01 KWNS 151259 SWODY1 SPC AC 151258 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 AM CDT Wed May 15 2024 Valid 151300Z - 161200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN HIGH PLAINS... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST... ....SUMMARY... Severe thunderstorms are expected across the southern Plains this afternoon and evening, accompanied by severe wind gusts, large hail, and perhaps a couple of tornadoes. Scattered severe thunderstorms are also possible this morning into the afternoon over parts of the central/northern Florida Peninsula, as well as the Carolinas. ....Central/northern Florida Peninsula... Thunderstorms will likely continue to focus along, and perhaps later redevelop a bit north of, a modestly convergent effective baroclinic zone that extends southwest-northeastward across the region. A warm and moist (at least middle 70s F surface dewpoints) air mass resides across much of the Peninsula. On the southern periphery of moderately strong cyclonically curved westerlies, related to a Tennessee Valley-centered upper trough, a moderately unstable environment and 40+ kt effective shear have been supportive of several embedded supercells in the pre-dawn hours. A further increase in convective coverage and intensity appears likely through the morning as the boundary layer warms, with some semi-discrete supercells expected. Damaging winds and large hail will be possible aside from a tornado risk. For additional short-term details, see Mesoscale Discussion 790. The overall severe risk seems likely to diminish/focus offshore by late afternoon. ....Carolinas... Ahead of the weak surface low, adequate boundary layer heating and moistening should occur beneath 6.5-7 C/km mid-level lapse rates, supporting a marginally unstable but uncapped airmass by afternoon. The combination of surface heating, and some dynamic lifting induced by the approaching mid-level trough, will support late morning/early afternoon thunderstorm initiation. Stronger westerly flow aloft from the mid-level trough will overspread the warm sector, contributing to 30-40 kt of effective bulk shear. Surface temperatures warming into the low 80s F amid mid 60s F dewpoints will boost MLCAPE to at least 1500 J/kg. Given relatively elongated, straight hodographs, splitting supercells and merging multicells should occur through the afternoon, accompanied by a severe wind and hail risk. ....Southern Plains... A weak triple point will become increasingly established near the Oklahoma/Kansas border vicinity into this afternoon, with a moist/moderate unstable air mass to the east of a surface trough/dryline extending southwestward toward the Texas Panhandle and Texas South Plains. The region may be further influenced by a subtle northeastward-developing mid-level speed max later today. Multiple zones of sub-regional thunderstorm development and intensification are expected during the mid/late afternoon. This includes high-based thunderstorm development across west/northwest Texas within a deeply mixed environment. Ample evaporative cooling within the deep, well-mixed boundary layer will yield the development of deep, strong cold pools with a tendency to merge through evening. Other storms should develop this afternoon in vicinity of the Raton Mesa in an evolving low-level upslope flow regime, and near and east of the Oklahoma/Kansas border vicinity triple point. Supercells are most probable (potential and duration thereof) with any development near/east of this surface triple point, and with the evolving post-frontal upslope flow regime from far northeast New Mexico into the Oklahoma/northern Texas Panhandles. Large hail will be possible especially within the first few hours of deep convective initiation, but severe-wind-producing clusters are expected to rapidly propagate from the Texas/Oklahoma Panhandles into northwestern Oklahoma and eventually far southern Kansas by late afternoon/early evening, preceded by richer low-level moisture and a strengthening low-level jet. Storms should gradually weaken overnight as they either become undercut by cold pools, or they outpace the buoyancy axis by the time they reach far eastern Kansas and northeast Oklahoma. ....Southern High Plains... Farther south, more isolated thunderstorms may initiate along a diffuse dryline across west/southwest Texas toward the Rio Grande. Given overall weak forcing, confidence in thunderstorm development and sustenance is not overly high, but any storm that can form and mature may become supercellular, accompanied by severe wind and hail. ...Guyer/Dean.. 05/15/2024 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .