Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Apr 18 2023 12:51:23 ACUS01 KWNS 181251 SWODY1 SPC AC 181249 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Tue Apr 18 2023 Valid 181300Z - 191200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON THROUGH TONIGHT FROM NORTHWEST TX TO THE MID MO VALLEY AND EASTERN WY... ....SUMMARY... Isolated severe thunderstorms are possible from parts of the southern Great Plains northward into the Mid Missouri Valley and westward into Wyoming. Severe gusts and large hail will be the hazards with the stronger storms late this afternoon into tonight. ....Central/southern Plains this afternoon through tonight... Downstream from a lead shortwave trough that will progress from the northern Great Basin today to the Dakotas tonight, lee cyclogenesis will continue across the central High Plains. The deepening lee cyclone will induce strengthening southerly low-level flow and northward advection of a modifying air mass from the western Gulf of Mexico. The moist layer will consist of mid 50s to lower 60s dewpoints spreading northward beneath a warm elevated mixed layer, which will largely cap the boundary layer through much of the period. Strong surface heating and deep mixing along the dryline may allow for isolated thunderstorm development late this afternoon, mainly near the Caprock from northwest TX into the eastern TX Panhandle. If a storm or two does form in this corridor, the environment will favor the potential for high-based, slow-moving supercells capable of producing isolated large hail and strong-severe outflow gusts. Any storms will tend to weaken near sunset as convective inhibition increases. Farther north, a few storms could form this evening near the dryline/warm front triple point in northern KS, on the northwest edge of the returning moisture. The initial storms could produce isolated damaging winds and large hail. A strengthening low-level jet during the evening will contribute to warm advection and the potential for elevated storms to persist overnight into southeast NE and western IA. Steep midlevel lapse rates, MUCAPE of 1500-2000 J/kg and sufficient cloud-layer shear will conditionally support elevated supercells capable of producing large hail. The modest moisture return through this evening casts some doubt on storm coverage, so will maintain Marginal risk for this update. During the afternoon/evening, gusty outflow winds may also occur with weak, high-based convection in an inverted-v environment across WY and vicinity, along the path of the ejecting midlevel trough. ...Thompson/Gleason.. 04/18/2023 $$ = = = 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) .