Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jul 12 2023 07:17:46 ACUS03 KWNS 120717 SWODY3 SPC AC 120716 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0216 AM CDT Wed Jul 12 2023 Valid 141200Z - 151200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ....SUMMARY... Thunderstorms associated with large hail and wind damage will be possible across parts of the central Plains on Friday. Marginally severe storms could also occur outside of the Slight Risk in parts of the central U.S., and from the Mid-Atlantic into southern New England. ....Central Plains/Ozarks/Mid Mississippi Valley... An upper-level trough is forecast to move eastward through the central U.S. on Friday, as a cold front advances southward through the central Plains. Along and to the south of the front, surface dewpoints in the upper 60s to near 70 F will contribute to the development of moderate instability in areas that heat up the most. Thunderstorms are expected to form along and near the front, with convection moving southeastward across southern Kansas during the late afternoon and early evening. NAM forecast soundings from near and just south of the front late Friday afternoon have MLCAPE peaking in the 3000 to 3500 J/kg range, with 0-6 km shear between 35 and 40 knots. Surface temperature-dewpoint spreads are forecast to be large, which will result in high-based storms with wind-damage potential. Isolated large hail could also occur. The severe threat is expected to be maximized during the late afternoon as low-level lapse rates become the steepest. Although there is uncertainty at this range, both the 00Z NAM and 00Z ECMWF have a maximum in CAPE over southern Kansas late Friday afternoon. Both solutions suggest that MCS development will be possible in southern Kansas on Friday. Also, the last several runs of the NAM have been consistent with the front position at 00Z/Saturday. For this reason, confidence is high enough to introduce a Slight Risk over southern Kansas for this outlook. Further to the east-southeast into the Ozarks and mid Mississippi Valley, surface dewpoints in the upper 60s and lower 70s F will contribute to the development of moderate instability in areas that heat up the most. Thunderstorms that form in the late afternoon, when low-level lapse rates are steepest, may have potential for marginally severe winds. ....Mid-Atlantic/Southern New England... A subtle shortwave trough is forecast to move northeastward into the Northeast on Friday. A moist airmass is forecast from the Carolinas northward into southern New England. Moderate instability may develop along parts of this corridor by afternoon. Scattered thunderstorms will likely form in the Appalachian foothills around midday and move eastward toward the coast during mid to late afternoon. Steep low-level lapse rates will likely contribute to a potential for marginally severe wind gusts. Hail will also be possible with cells that form near the strongest instability. ...Broyles.. 07/12/2023 $$ = = = 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) .