Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Sep 13 2025 00:47:56 ACUS01 KWNS 130047 SWODY1 SPC AC 130046 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 PM CDT Fri Sep 12 2025 Valid 130100Z - 131200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN WESTERN SD AND FAR SOUTH-CENTRAL ND... ....SUMMARY... Large hail and isolated severe gusts remain possible tonight across parts of the northern Great Plains and Black Hills. ....Northern Great Plains... Despite limited severe hail reports thus far, a few supercells along the south-central ND/north-central border area had impressively large MRMS MESH signatures. These supercells have remained anchored along a southwest/northeast-oriented surface trough amid weak low-level winds but around 40-kt effective bulk shear. This nearly straight-line hodograph structure conducive for splitting supercells, coincident with MLCAPE near 3000 J/kg per the 00Z BIS sounding, should support large hail potential over the next couple hours. An arc of convective outflow spreading north to east across northeast WY to far southwest SD will eventually impinge on the MLCAPE gradient that runs southwest to northeast across western SD. Cells along the outflow should intensify as they spread northeast of the Black Hills and north of the Badlands later this evening. 15Z and later CAMs indicate potential for a few sporadic supercells, which would yield a large hail threat. Severe gusts are also possible, but these may remain localized and transient given the modest motion of the outflow and supercell wind profile. ....Southeast AZ/Southwest NM... Earlier severe wind/hail storms across southeast AZ should diminish over the next hour or two as they attempt to spread into southwest NM where prior overturning has occurred. A cooler downstream boundary layer and weaker tropospheric lapse rates will further marginalize storm intensity after dusk. ...Grams.. 09/13/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .