Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 09 2023 19:43:46 ACUS01 KWNS 091943 SWODY1 SPC AC 091942 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0242 PM CDT Sun Apr 09 2023 Valid 092000Z - 101200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE SOUTHERN HIGH PLAINS... ....SUMMARY... Isolated severe thunderstorm gusts and large hail are possible across portions of the southern High Plains this afternoon and evening. ....20z Update - Southern Plains... The previous forecast remains on track and no changes have been made with the 20z update. Isolated thunderstorms have developed this afternoon within the Marginal risk area, with one severe-warned storm currently across southwest OK. These storms may briefly become severe, producing strong gusts and near-one inch hail. Severe potential is expected to remain sporadic/marginal. ...Leitman.. 04/09/2023 ..PREV DISCUSSION... /ISSUED 1128 AM CDT Sun Apr 09 2023/ ....Southern High Plains... A low-amplitude, southern-stream shortwave trough will continue advancing slowly eastward over the central/southern High Plains today, before gradually weakening and becoming absorbed into a more-pronounced northern-stream midlevel trough this evening/overnight. As this feature continues eastward, modestly enhanced midlevel westerly flow will gradually veer to northwesterly by this evening, while a related surface lee trough remains nearly stationary over the High Plains. East of the lee trough, two weak mesoscale lows have developed in response to early-morning/ongoing convection -- one over the TX Panhandle and the other near the TX South Plains. Along the southern/eastern peripheries of the northern mesoscale low/outflow boundary, lower 50s surface dewpoints are spreading northward in conjunction with filtered diurnal heating. As MLCINH erodes, additional surface-based convection should focus along this boundary over the southern TX Panhandle into far southwest OK this afternoon. Steep midlevel lapse rates and elongated mid/upper-level hodographs should favor a couple loosely organized, splitting supercell structures capable of large hail and locally severe gusts. Similarly, diurnal destabilization/steepening low-level lapse rates along/ahead of the southern mesoscale low/outflow boundary should favor additional convective development this afternoon. Given the steep deep-layer lapse rate environment and long/generally straight hodographs (30-40 kt of effective shear), isolated large hail is expected -- especially with the early/cellular development. From the afternoon into the evening/overnight hours, convection will generally spread/expand southeastward as midlevel flow veers on the backside of the weakening shortwave trough. Continued outflow generation amid slightly stronger deep-layer shear could support localized upscale growth/convective clustering and an increasing potential for severe gusts. Eventually, convection will impinge on increasing nocturnal boundary-layer stability and a residual midlevel capping inversion with southward extent, with a corresponding decrease in severe potential during the overnight hours. $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .