Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 29 2024 19:56:18 ACUS01 KWNS 291956 SWODY1 SPC AC 291954 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Thu Aug 29 2024 Valid 292000Z - 301200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF MINNESOTA AND WESTERN WISCONSIN... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE UPPER MIDWEST AS WELL AS THE MID ATLANTIC.... ....SUMMARY... Severe thunderstorms are expected this afternoon and evening over portions of the Upper Midwest, with a threat for tornadoes, damaging winds, and sporadic large hail, especially across parts of Minnesota into western Wisconsin. Other severe storms are expected across the central Plains and Mid-Atlantic/Carolinas. ....20z Update... Minimal changes were made to the prior outlook. Thunder probabilities have been lowered across western parts of the central Plains behind the cold front. An isolated severe storm will be possible ahead of the front from the central Plains southward into the southern High Plains. Moderate buoyancy is supporting a fair amount of convection with some potential for damaging outflow winds or marginally severe hail. However, weaker deep-layer shear and modest large-scale ascent should keep the threat minimal prior to frontal passage later tonight. Across parts of the upper MS Valley and Midwest will maintain the Level 2/3 Slight/Enhanced as is. Scattered storms are ongoing and expected to increase in coverage through the afternoon and into this evening. Increasing deep-layer shear and partial heating ahead of the bands of storms near the cold front should allow for more robust/organized storms to gradually develop through the remainder of the afternoon. With the expected convective coverage, storm mode is trending toward more linear solutions, though moderate deep-layer shear and strong low-level turning with height may support a few embedded or semi-discrete supercell structures. Damaging winds are the primary threat, but occasional large hail and a couple of tornadoes are possible, especially near the warm front with any of the more persistent rotating features. Across the central Appalachians and Mid Atlantic, no changes were made to the severe risk area. The predominate hazard remains a few multi-cell clusters capable of damaging wind gusts. Convection ongoing over the higher terrain in western VA/PA and WV should gradually expand eastward, with some potential for consolidating outflow. See the prior outlook for more information. ...Lyons.. 08/29/2024 ..PREV DISCUSSION... /ISSUED 1147 AM CDT Thu Aug 29 2024/ ....Upper Midwest/Central Plains... Have upgraded portions of central/eastern Minnesota into western Wisconsin to Enhanced Risk for a perceived greater aggregate severe risk, highlighted by a transition to an increased damaging wind potential by evening. An upper-level trough will continue generally east-northeastward from southern Saskatchewan toward Manitoba and eventually far northwest Ontario late tonight, with southern-peripheral height falls and moderately strong southwesterly winds aloft as far south as the far eastern Dakotas and Minnesota into Wisconsin. Scattered thunderstorm development is expected by mid-afternoon along the front from northern Minnesota south-southwestward into southwest Minnesota and the central Plains including eastern/southern Nebraska into northwest Kansas. The most severe-favorable ingredients are expected across central/southern Minnesota, where 2500-3500 J/kg MLCAPE will coincide with 30-40 kt effective shear. Some initial supercells can be expected with large hail. Tornado potential should be maximized across central Minnesota and possibly far western Wisconsin in vicinity of a weak surface wave/warm front-related triple point, where low-level moisture/SRH will be maximized, somewhat analogous to the South Dakota/North Dakota border vicinity yesterday late afternoon and early evening. Storms should otherwise steadily grow upscale by early evening, with storm mergers leading to quasi-linear segments and possible bows with an increased damaging wind potential across Iowa, and especially eastern Minnesota into western Wisconsin. ....Carolinas/Mid-Atlantic including parts Virginia/Pennsylvania... Scattered multicell thunderstorms are expected to form this afternoon, offering isolated damaging wind gusts and marginally severe hail. This activity will develop in a plume of rich low-level moisture, with lower-elevation surface dewpoints in the upper 60s to low 70s F. That, along with diurnal heating offsetting modest mid-level lapse rates, should support MLCAPE in the 2000-3000 J/kg range. $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .