Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jan 19 2023 19:34:31 ACUS01 KWNS 191934 SWODY1 SPC AC 191932 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0132 PM CST Thu Jan 19 2023 Valid 192000Z - 201200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF OHIO... ....SUMMARY... Low-topped thunderstorms are expected to develop over eastern Indiana and move rapidly east across Ohio this afternoon into early evening. Scattered severe wind gusts from 60-80 mph are most likely through about 7 PM EST from western into central Ohio. ....Ohio and surrounding areas... Convection is just now forming over Indiana, with an increase in lightning noted. Visible satellite imagery shows clear skies ahead of the cold front, and continued heating should yield a few hundred J/kg of SBCAPE by late afternoon. Pressure falls are expected to accelerate just ahead of the front as shallow convection amasses. Forecast soundings show appreciable cooling will continue around 700 mb which when coupled with surface heating will yield increasing updrafts. Wind speeds around 50 kt are noted at 850 mb in upstream VWPs, which appears to be a likely value for gusts along the developing line of thunderstorms. As temperatures are warming into the 60s F, boundary-layer lapse rates are becoming steep. Indeed, latest observations indicate temperatures commonly 3-4 F above point forecast sounding values. As a result, outflow production may be enhanced with isolated gusts over 65 kt possible. Despite the low dewpoints, strong shear/veering winds with height and increasing low-level parcel buoyancy may support transient areas of rotation, resulting in enhanced wind-gust corridors or perhaps a brief/weak tornado. More information can be found in mesoscale discussion 78. ...Jewell.. 01/19/2023 ..PREV DISCUSSION... /ISSUED 1022 AM CST Thu Jan 19 2023/ ....Eastern IN and OH... A potent mid-level vorticity maximum over IL, embedded within the broader central CONUS trough, will eject east into OH through this evening. This feature will aid in sharpening an associated surface cold front that will rapidly progress east. Low-topped thunderstorms are expected to initiate across eastern IN towards early to mid-afternoon in a broken arc along the front. Within the exit region of an intense mid-level jet, this convection is expected to race east across OH through the afternoon. While SBCAPE will likely be meager, holding at or below 500 J/kg, nearly full insolation across the Lower to Middle OH Valley will yield steep 0-3 km lapse rates. This should support downward momentum transport of 50+ kt low-level winds as convection matures. Some 12Z HREF members (HRW-ARW, HRRR, and NAM-Nest) suggest boundary-layer max winds may reach 65-70 kts within rear inflow, supporting peak surface wind gusts across western to central OH. The arcing convective band will weaken after sunset as surface-based instability dwindles, but strong gusts may persist until convection dissipates in the western to central PA vicinity. $$ = = = 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) .