Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon May 19 2025 06:00:21 ACUS01 KWNS 190600 SWODY1 SPC AC 190558 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Mon May 19 2025 Valid 191200Z - 201200Z ....THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF CENTRAL AND EASTERN OKLAHOMA INTO THE WESTERN OZARKS... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN APPALACHIANS... ....SUMMARY... Significant severe weather is likely from the central/southern Plains into the the Ozarks today into tonight. All severe weather hazards are expected, to include tornadoes (some potentially strong to intense), very large hail, and severe winds. ....Synopsis... A highly amplified large-scale trough will move gradually eastward from the Rockies across the Plains through the period. Within the base of the trough, an embedded shortwave trough and accompanying 70-kt midlevel speed maximum will overspread the southern and central Plains. In response, a surface cyclone will deepen over north-central Oklahoma, while a focused low-level jet gradually strengthens along/east of a dryline extending southward from the surface cyclone (west of the I-35 corridor). ....Central/Southern Plains into the Mid Mississippi Valley... Along/east of the dryline, rich boundary-layer moisture (lower 70s dewpoints) beneath steep midlevel lapse rates accompanying an EML will contribute to strong/extreme surface-based buoyancy -- aided by diurnal heating within cloud breaks. Ascent along the dryline, augmented by the increasing midlevel ascent, will support convective development during the early afternoon west of the I-35 corridor. Storms should quickly intensify into a mix of supercells (from far southern KS southward) and organized clusters/line segments (further north) as they encounter the extreme instability and 50+ kt of effective shear. All severe hazards will be possible with this activity, including very large hail, damaging winds, and tornadoes (some possibly strong to intense). Similarly, warm-sector storm development is expected farther east across eastern Oklahoma and vicinity, given weak inhibition, rich boundary-layer moisture, and the aforementioned large-scale ascent. Despite the potential for scattered to numerous storms, the high-end environment will support long-track, semi-discrete supercells and organized clusters capable of all severe hazards. While overall convective evolution is somewhat uncertain, a 50-kt low-level jet and related large clockwise-curved hodographs (200-300+ 0-1km SRH) should support an increasing risk of strong/intense tornadoes during the late afternoon into the evening hours. Storms will generally spread/develop east-northeastward into the Mid-Mississippi Valley into the overnight hours, and gradual upscale growth into several organized clusters is possible -- with a continued all-hazards severe risk. ....Southern Appalachians... Along the northern periphery of shortwave ridging over the Southeast, a midlevel jet streak will cross the southern Appalachians during the afternoon. Here, an influx of steep midlevel lapse rates atop rich boundary-layer moisture will yield strong surface-based instability along/south of a warm front draped across the region. Scattered thunderstorms will spread east-southeastward along/south of the front from TN into the southern Appalachians, where the favorable buoyancy and around 40-50 kt of effective shear will promote organization into clusters and a couple splitting supercell structures. Damaging winds and large hail will be possible with the strongest storms. ...Weinman/Darrow.. 05/19/2025 $$ = = = 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) .