Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri May 12 2023 05:56:55 ACUS01 KWNS 120556 SWODY1 SPC AC 120555 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1255 AM CDT Fri May 12 2023 Valid 121200Z - 131200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSOURI VALLEY... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN PLAINS... ....SUMMARY... Strong to severe thunderstorms are expected to develop this afternoon across the mid Missouri Valley, where a few tornadoes, very large hail and wind damage will be possible. Strong to severe storms are also expected to develop in parts of the southern Plains this afternoon, with a potential for very large hail and wind damage. ....Mid Missouri Valley... An upper-level low will move northeastward today across the central Plains. Mid-level flow ahead of the system will be from the south. At the surface, a low and an associated warm front will move across southern and eastern Nebraska. Along the front, surface dewpoints in the 60s F combined with surface heating, will likely result in moderate to strong destabilization by afternoon. MLCAPE is forecast to reach the 2000 to 3000 J/kg range along a relatively narrow northwest-to-southeast corridor over the mid Missouri Valley. Thunderstorms will develop near midday across north-central Nebraska, with additional development taking place southeastward across eastern Nebraska during the afternoon. These thunderstorms will move in a northward direction and will be associated with a severe threat during the afternoon and early evening. Although the upper-level system will not be associated with strong mid-level jet, some speed shear will be evident in the mid-levels, with directional shear also in the boundary layer. This wind profile will support supercell development. The wind profile on RAP forecast soundings in the mid Missouri Valley this afternoon have 0-6 km shear near 40 knots, with 0-3 km storm relative helicities near 250 m2/s2. This, combined with steep low to mid-level lapse rates will support supercells and large hail. The more intense updrafts may produce hail greater than 2 inches in diameter. Tornadoes will also be possible with supercells. At this point, tornado coverage is somewhat uncertain, and could depend upon how many cells can remain discrete as low-level flow gradually increases during the late afternoon. A wind-damage threat will also be possible with supercells and along the leading edge of the more organized line segments. ....Southern Plains... Flow at mid-levels will be relatively weak across the southern Plains today. At the surface, a moist airmass will be in place across most of Texas and Oklahoma, where strong instability is likely to develop by afternoon. Scattered thunderstorms will form within this airmass during the afternoon, with multiple cell clusters or line segments moving eastward across the region. Due to the relatively weak low to mid-level flow, there may be numerous cell mergers. Wind-damage will be possible as these interactions take place. If a cold pool can organize during the late afternoon, then a wind-damage threat will be possible along the leading edge of the more intense parts the line segment. While an enhanced risk associated with wind damage will be possible across parts of the southern Plains, the potential is conditional and the exact areas with greater risk are uncertain. ...Broyles/Weinman.. 05/12/2023 $$ = = = 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) .