Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jul 25 2023 00:52:17 ACUS01 KWNS 250052 SWODY1 SPC AC 250050 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Mon Jul 24 2023 Valid 250100Z - 251200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE OHIO VALLEY... ....SUMMARY... Thunderstorms associated with damaging wind gusts and hail will be possible this evening across parts of the Ohio Valley, Northeast and upper Mississippi Valley. A few damaging wind gusts may also occur in the Intermountain West. ....Ohio Valley... The latest water vapor imagery has northwesterly mid-level flow over much of the Great Lakes region and mid Mississippi Valley, with an upper-level trough located in the Ohio Valley and southern Appalachians. At the surface, an axis of maximized low-level moisture is located from the mid Mississippi Valley into the lower Ohio Valley, where dewpoints are in the upper 60s F. Moderate to strong instability is analyzed along this corridor, with the RAP estimating MLCAPE in the 2500 to 3500 J/kg range. Scattered thunderstorms are ongoing within this pocket of instability across southern Indiana, Ohio and Kentucky. These storms will move eastward toward the western Appalachian foothills this evening. In the vicinity of the storms, the WSR-88D VWP at Wilmington Ohio currently has 0-6 km shear near 35 knots, with some directional shear in the low to mid-levels. In addition, low to mid-level lapse rates are between 7 and 7.5 C/km according to the RAP. This environment will support multicells with wind-damage potential. Hail will also be possible. The severe threat appears likely to persist into the mid to late evening, in areas where the strongest instability is located. ....Northeast... An upper-level trough is currently moving through the lower Great Lakes, Ohio Valley and southern Appalachians. Southwest mid-level flow is in place ahead of the trough across much of the Northeast. An axis of maximized low-level moisture and instability is located from east-central Pennsylvania into southern New York, where isolated to scattered thunderstorms are ongoing. Regional WSR-88D VWPs near this axis of instability suggest that 0-6 km is between 25 to 30 knots, and that 0-3 km lapse rates are in the 7 and 7.5 C/km range. This could support an isolated wind-damage threat associated with the stronger multicells. The severe threat is expected to persist for a couple more hours. ....Upper Mississippi Valley... Latest water vapor imagery shows a subtle shortwave trough embedded in northwesterly mid-level flow, moving southeastward through Wisconsin. An axis of instability is analyzed by the RAP from eastern Minnesota into north-central Wisconsin, along which isolated to scattered thunderstorms are ongoing. In addition, a speed enhancement at 500 mb is located near the trough, with wind speeds from the northwest at 35 to 40 knots across western Wisconsin. This is evident on the La Crosse WSR-88D VWP, which suggests moderate deep-layer shear is in place across much of the upper Mississippi Valley. This should be enough for a marginal severe threat this evening with cells that move south-southeastward across western and central WI. The primary threat will be isolated wind damage. ....Intermountain West... A mid-level anticyclone is located across the Desert Southwest and Rockies. Mid-level flow is southwesterly across much of the Intermountain West, where isolated to scattered thunderstorms are ongoing. Surface dewpoints in the Intermountain West are generally in the 50s F, which has resulted in weak instability in most areas. In addition, RAP analysis shows a mid-level speed max from Utah into southeast Idaho and western Wyoming. This feature is creating moderate deep-layer shear, which will support a few marginally severe multicells this evening. This, combined with steep low to mid-level lapse rates, will continue to support an isolated wind-damage threat. ...Broyles.. 07/25/2023 $$ = = = 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) .