Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 22 2023 06:01:58 ACUS02 KWNS 220601 SWODY2 SPC AC 220600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Fri Sep 22 2023 Valid 231200Z - 241200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT PLAINS...AND LOWER TO MID MISSOURI VALLEY... ....SUMMARY... Thunderstorms, associated with large hail and wind damage, will be possible on Saturday across eastern parts of the Great Plains, and in the Lower to Mid Missouri Valley. Marginally severe storms will also be possible in parts of the Mid-Atlantic. ....Great Plains/Lower to Mid Missouri Valley... An upper-level low will move northeastward across the northern Plains on Saturday as an associated mid-level jet moves through the base of the trough. At the surface, a low will move quickly northward from eastern Nebraska into western Minnesota, as a cold front moves eastward through the central Plains. As surface heating takes place ahead of the front, scattered thunderstorms are expected to develop from parts of the eastern Dakotas south-southeastward into parts of the lower to mid Missouri Valley. Cell coverage will gradually increase in the late afternoon and early evening, with MCS development likely across parts of the region. By midday, a north-to-south corridor of moderate instability will likely be in place from eastern Kansas northward into eastern Nebraska, where MLCAPE is forecast to peak in the 1500 to 2500 J/kg range. Moderate to strong deep-layer shear will also be present along this corridor, with the strongest shear located beneath the mid-level jet in the mid Missouri Valley. The thermodynamic and kinematic environment should support supercell development, with the greatest supercell threat located from near the axis of the jet southward. This is forecast to be in far eastern Nebraska and western Iowa, where the combination of instability and shear is forecast to be the greatest. Supercells will have a threat for large hail and wind damage. Further north into parts of eastern South Dakota and western Minnesota, there is some uncertainty concerning how much instability will develop. The more aggressive solutions with instability suggest that supercells will be possible with a threat for large hail and wind damage. Because of the uncertainty concerning instability, the slight risk over far eastern South Dakota and southwest Minnesota is more conditional. ....Southern Plains... At mid-levels, west-southwesterly flow will be in place on Saturday across much of the Desert Southwest and southern Rockies, with northwesterly divergent flow located over much of the southern Plains. At the surface, a cold front will advance southeastward into the southern High Plains. Isolated to scattered thunderstorms are expected to form along and near the front by afternoon, as moderate to strong instability develops. Several storm clusters appear likely to become organized in the late afternoon, persisting into the early to mid evening. Forecast soundings ahead of the front, from Oklahoma City to Wichita Falls, suggest that MLCAPE will peak in the 2000 to 3000 J/kg range during the late afternoon. 0-6 km shear is forecast to be in the 35 to 45 knot range, with 700-500 mb lapse rates near 7.5 C/km. This environment will likely support supercells with large hail. Wind damage may also occur, especially with mixed mode cell clusters that become organized. The severe threat from far southern Oklahoma to west-central Texas will likely be marginal, due to a lack of large-scale ascent. ....Mid-Atlantic... A tropical system is forecast by the National Hurricane Center to move through eastern North Carolina on Saturday. To the east of the center, instability is forecast to increase during the day from eastern north Carolina into eastern Virginia. A marginal tornado threat may develop with bands of convection that move through the stronger instability. ...Broyles.. 09/22/2023 $$ = = = 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) .