Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jan 03 2025 19:55:07 ACUS01 KWNS 031954 SWODY1 SPC AC 031953 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0153 PM CST Fri Jan 03 2025 Valid 032000Z - 041200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Sporadic lightning flashes remain possible this afternoon and evening over parts of the coastal Pacific Northwest and northern California. Severe thunderstorms are not expected. ....20Z Update... A mid-level trough continues to approach the Pacific Northwest shoreline this afternoon, resulting in increasing deep-layer ascent and cooling aloft, which will promote isolated thunderstorm potential later this afternoon and evening. As such, the previous forecast (see below) remains on track. ...Squitieri.. 01/03/2025 ..PREV DISCUSSION... /ISSUED 1007 AM CST Fri Jan 03 2025/ ....Synopsis... Surface high pressure from the Rockies to the Southeast will result in a dry and stable airmass for much of the CONUS, precluding thunderstorm activity. The exception may be along portions of the Northwest coastal vicinity. Isolated thunderstorms are possible this afternoon and evening across coastal OR into northern CA as a strong upper trough moves over the Northwest. Cold temperatures aloft and modestly steep midlevel lapse rates will support minor instability. Low-topped convection in the wake of a surface cold front may produce sporadic lightning flashes. A few instances of small hail and gusty winds may also accompany this activity, but weak instability and modest vertical shear will limit severe thunderstorm potential. $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .