Subj : DAY2SVR: Nws Storm Predic To : All From : Mike Powell Date : Sat Jul 01 2023 18:18:00 ACUS02 KWNS 011730 SWODY2 SPC AC 011728 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Sat Jul 01 2023 Valid 021200Z - 031200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SUNDAY INTO SUNDAY NIGHT ACROSS MUCH OF TENNESSEE...KENTUCKY...WEST VIRGINIA...VIRGINIA...MARYLAND AND DELAWARE...PARTS OF SOUTHERN OHIO... PENNSYLVANIA AND NEW JERSEY...WESTERN NORTH CAROLINA...NORTHERN GEORGIA...ALABAMA AND MISSISSIPPI...AND EASTERN ARKANSAS... ....SUMMARY... Scattered strong thunderstorms, and a couple of evolving clusters of storms, will pose a risk for severe wind and hail in a corridor from the Mid South and lower Ohio and Tennessee Valley east-northeastward into the Mid Atlantic region Sunday through Sunday night ....Synopsis... Models indicate that split flow across the eastern Pacific into western North America may become more amplified into and through this period. Within this regime, significant cyclogenesis is forecast to proceed later today through Sunday across the Canadian Prairies, with a trailing cold front advancing southeast of the international border, across much of the Northwest and northern Rockies into the northern Great Plains by 12Z Monday. While mid-level ridging builds downstream of the cyclone, across northwestern Ontario, southern Hudson and James Bays into adjacent portions of Quebec, positively tilted mid-level troughing in a branch to the south is forecast to shift slowly east-northeastward across the lower Great Lakes and Ohio Valley. It appears that this will be accompanied by a broad weak surface low, migrating along a diffuse surface frontal zone (initially extending from the northern Mid Atlantic and Ohio Valley into the southern Great Plains), and developing surface troughing to the lee of the Blue Ridge. ....Mid Atlantic/Ohio and Tennessee Valleys into Ark-La-Tex... Along and just south of the weak frontal zone, the boundary-layer may be initially impacted by a considerable amount of remnant convective outflow. How the associated outflow boundaries evolve through midday Sunday remains unclear, but insolation along and to their south likely will contribute to steepening low-level lapse and moderate to large CAPE in the presence of seasonably high moisture content. This appears likely to occur beneath a belt of 30-40+ kt (perhaps stronger where augmented by prior convection) west-southwesterly flow in the 850-500 mb layer, which may prove conducive to renewed strong and organizing convective development Sunday afternoon and evening. Isolated supercell structures are possible initially, posing a risk for severe hail, before potentially damaging wind gusts with evolving clusters becomes the more prominent hazard. ....High Plains... A mid-level perturbation digging within modest to weak northwest flow probably will contribute to scattered thunderstorm development to the lee of the southern Rockies Sunday afternoon and evening. Aided mostly by steep lower/mid-tropospheric lapse rates, a couple of storms may pose a risk for severe hail and wind. ....North Dakota/Minnesota... Large mixed-layer CAPE may develop within pre-frontal surface troughing near the state border vicinity by late Sunday afternoon. However, stronger mid/upper forcing for ascent and shear may remain mostly displaced to the north of the international border, resulting in mainly highly conditional severe weather potential for this period. ....Southern Montana... Moistening post-frontal upslope flow might contribute to sufficient destabilization to support isolated supercell development to the north of the Big Horn Basin, perhaps aided by large-scale forcing for ascent associated with warm advection late Sunday afternoon and evening. ...Kerr.. 07/01/2023 $$ --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .