Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Aug 06 2023 17:44:42 ACUS02 KWNS 061744 SWODY2 SPC AC 061743 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1243 PM CDT Sun Aug 06 2023 Valid 071200Z - 081200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR THE MID-ATLANTIC STATES INTO THE SOUTHERN APPALACHIANS AND CAROLINAS... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ....SUMMARY... Severe thunderstorms are possible Monday across portions of the southern Appalachians, mid-Atlantic and northeast U.S. Scattered swaths of damaging gusts are expected with this activity. Additional widely scattered thunderstorms are possible across the central High Plains, posing a risk for large hail and severe gusts. ....Synopsis... A potent mid/upper shortwave trough will move from IL to the central Appalachians during the period. A seasonally anomalous belt of strong west/southwesterly flow will move through the base of the trough and overspread the central/southern Appalachians into the Mid-Atlantic states. In the low levels, low pressure will develop east from northern IL to Lake Erie through evening. A cold front attendant to the surface low will sweep east/southeast across the Midwest during the day and reach the Appalachians and northern MS/AL late overnight. ....OH Valley to Mid-Atlantic to the southern Appalachians and Carolinas... Scattered showers and isolated storms are forecast to be ongoing over the OH Valley Monday morning with more widely spaced convection trailing west-southwest into the Mid South/Ozarks. Considerable cloud cover with northward extent over a large moist/warm sector will limit destabilization into portions of PA and north. Farther south, heating of a very moist boundary layer will yield a moderate to very unstable airmass (1500 to 3000+ J/kg MLCAPE) from PA southward into the southern Appalachians. Multiple bands and clusters will likely begin to develop towards midday over the upper OH Valley and central Appalachians. Less certain is convective timing over the TN Valley where a large spread of model solutions is currently depicted. Nonetheless, scattered thunderstorms will likely develop by early to mid afternoon and become quite extensive from northern AL/GA into PA/VA/WV/MD. A mix of semi-discrete cells and clusters are possible initially and a risk for all severe hazards is expected given favorable shear profiles for storm organization/low-level rotation. Upscale growth is expected as storms move into the northern VA/MD and Chesapeake Bay vicinity during the late afternoon/early evening where the wind risk will seemingly be maximized. Much of the activity will eventually move east of the Mid-Atlantic coast during the evening and areas farther south through the Carolina Piedmont and into the coastal plain. ....Central into the southern High Plains... Moderate mid/upper northwesterly flow will continue to stream across the central High Plains vicinity on Monday. Moderately cool 500 mb temps around -10 C will support steep midlevel lapse rates. Modest boundary layer moisture is forecast along a surface trough, with dewpoints generally in the 50s, supporting moderate instability. Strong vertical shear (effective shear greater than 45 kt) will foster organized updrafts, while elongated/straight hodographs suggest large hail will be possible and perhaps a narrow window for very large hail with initial supercells. A deeply-mixed boundary-layer with dewpoint depressions around 20 F also may foster strong gust potential. The latest models show some of this activity continuing into west-central KS after dark. Farther south, models are suggesting thunderstorms will develop on the southern fringe of stronger westerlies near the eastern NM/TX South Plains vicinity. Deep, well-mixed boundary-layer profiles will potentially support isolated severe gusts during the early evening. ....Northeast TX toward the Lower MS Valley... A surface boundary is forecast to extend west to east across the region. Differential heating along the boundary, and a very moist/unstable airmass will support isolated thunderstorm development. Vertical shear will be rather weak, but isolated strong gusts may accompany thunderstorms during the afternoon. Isolated coverage/longevity of this activity preclude higher risk probabilities. ...Smith.. 08/06/2023 $$ = = = 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) .