Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Apr 17 2023 07:34:14 ACUS03 KWNS 170734 SWODY3 SPC AC 170733 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0233 AM CDT Mon Apr 17 2023 Valid 191200Z - 201200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT PLAINS AND MID MISSOURI VALLEY... ....SUMMARY... Severe thunderstorms with potential for large hail and wind damage will be possible Wednesday into Wednesday night across parts of the central Plains, mid Missouri Valley, into parts of the southern Plains. ....Central Plains/Mid Missouri Valley... Mid-level flow will gradually increase in strength across the Great Plains on Wednesday, as an upper-level trough approaches from the west. At the surface, a cold front is forecast to move southeastward across eastern Nebraska and central Kansas, as a surface low deepens over southwest Kansas. The moist sector will be relatively narrow, positioned from eastern Kansas into south-central Iowa by afternoon, with surface dewpoints generally in the lower to mid 60s F. This will contribute to moderate instability by afternoon ahead of the cold front. As low-level convergence increases along the front and surface temperatures heat up, convective initiation is expected along and near the front from central Kansas northeastward into western Iowa. The storms will likely track northeastward across the central Plains and mid Missouri Valley during the late afternoon and evening. NAM forecast soundings just ahead of the front at 00Z from Salina northeastward to just south of Omaha have MLCAPE generally around 2000 J/kg, with 0-6 km shear near 40 knots. In spite of the favorable environment for severe, a capping inversion will be in place through part of the day. As the cap weakens during the late afternoon, scattered thunderstorms are expected to develop, and supercells will become likely. The thermodynamic environment, including mid-level lapse rates near 9.0 C/km, will be favorable for efficient large hail producers, and hailstones of greater than 2 inches in diameter will be possible with the more dominant supercells. An isolated wind-damage threat is also expected to materialize, especially in the early to mid evening as the storms mature and cell mergers occur. ....Southern Plains... West-southwesterly mid-level flow will be in place across the southern Plains on Wednesday, as an upper-level trough approaches from the west. At the surface, a dryline will become sharply defined during the day from west-central Texas northward into western Oklahoma. Surface dewpoints to the east of the dryline will be in the 60s F, which will contribute to moderate instability by afternoon. A capping inversion will prevent convective initiation through much of the day. However, the cap may weaken enough for isolated convective initiation during the late afternoon. A few thunderstorms could become organized and persist into the early to mid evening. NAM forecast soundings at 00Z along and to the east of the dryline, have MLCAPE reaching the 1500 to 3000 J/kg range. 0-6 km shear is forecast to be near 40 knot, which should be favorable for supercell formation in locations where convection can initiate. 700-500 mb lapse rates near 8.0 C/km will be favorable for large hail. Isolated wind damage could also occur. Although a severe threat appears likely with storms that can develop, the cap is expected to suppress convective initiation across most of the southern Plains Wednesday evening. ...Broyles.. 04/17/2023 $$ = = = 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) .