Subj : DAY2SVR: Marginal Risk To : All From : Mike Powell Date : Wed Aug 16 2023 07:25:00 ACUS02 KWNS 160634 SWODY2 SPC AC 160633 Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0133 AM CDT Wed Aug 16 2023 Valid 171200Z - 181200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS LOWER MICHIGAN AND THE OHIO VALLEY... CORRECTED FOR TYPOS ....SUMMARY... Isolated strong to severe thunderstorms are possible across Lower Michigan and the Ohio Valley on Thursday. ....Synopsis... A shortwave trough is expected to extend from central Ontario south-southwestward through WI early Thursday morning. This shortwave, and accompanying strong mid-level flow, are forecast to progress eastward across the Upper Great Lakes and Ohio Valley throughout the day, continuing into the Lower Great Lakes and northern Mid-Atlantic by early Friday morning. Cold front associated with this shortwave will push eastward just ahead of the wave, ending the period arcing from eastern NY across eastern PA and back into the TN Valley. Thunderstorms are expected along this front as it moves eastward. Afternoon thunderstorms are also possible within the moist airmass from coastal Carolinas into FL. Farther west, expansive upper ridging, initially extending from the southern High Plains through the Four Corners and into the northern Intermountain West, is expected to drift eastward towards the Plains while dampening. Afternoon thunderstorms are likely beneath this ridge, predominantly over the higher terrain from northern CA across the Great Basin and into the central/southern Rockies. ....Lower MI into the OH Valley... Thunderstorms will likely be ongoing along the front as it progresses eastward across the Upper Great Lakes early Thursday morning. Upper 50s to low 60s dewpoints are expected to be in place ahead of the front across Lower MI. Abundant cloud cover across the region will limit pre-frontal heating, but moist profiles will still have modest buoyancy. This modest buoyancy will temper overall storm strength, but strong low to mid-level flow could still support damaging gusts. Airmass destabilization is possible in the wake of this initial front amid low 70s temperatures, mid/upper 60s dewpoints, and cold mid-level temperatures (i.e. -12 to -14 deg C at 500 mb). Isolated thunderstorms are possible within this destabilized airmass, initiated by persistent large-scale forcing for ascent associated with the shortwave trough. Isolated hail and/or damaging gusts are possible within the strongest storms. ....Northern CA and NV... Afternoon thunderstorm development is anticipated across northern CA and NV, ahead of a subtle shortwave trough emanating from the upper low over the central CA coast. Buoyancy will be modest, but enhanced mid/upper level flow will extend across the region and a few strong to severe storms could develop within this regime. However, any strong to severe storm would be relatively short lived, mitigating the overall severe potential. ...Mosier.. 08/16/2023 $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .