Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jun 27 2023 06:00:29 ACUS01 KWNS 270600 SWODY1 SPC AC 270558 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Tue Jun 27 2023 Valid 271200Z - 281200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN KS/NORTHERN OK INTO EXTREME NORTHWEST AR/SOUTHWEST MO... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHERN SD AND NORTHERN NE... ....SUMMARY... Storms producing severe winds (possibly in excess of 75 mph) are most probable in a corridor from southwest Kansas and the Oklahoma Panhandle, and potentially into the Ozark Plateau. Sporadic severe hail will be possible over parts of the northern Plains, with locally damaging gusts over parts of the Mid Atlantic. ....Synopsis... An upper ridge will remain anchored over the southern Great Plains today, with upper troughs persisting over the western and eastern CONUS. Within the western trough, a notable embedded shortwave and attendant mid/upper-level jet is forecast to crest the ridge into parts of the central Plains. Meanwhile, the eastern trough is forecast to gradually weaken through the day. At the surface, a cold front is forecast to move offshore of the Carolinas, while the western extension of the front will lift northward as a warm front from the southern into parts of the central Plains. ....Southern KS/northern OK into the Ozark Plateau... Confidence continues to increase in the potential for a long-lived MCS this evening that could produce a swath of severe winds (possibly greater than 75 mph) from southern KS/northern OK into parts of the Ozark Plateau. Initial storm development this afternoon is expected near the intersection of a dryline and the retreating warm front somewhere across the northern TX into the OK Panhandle, and also potentially into southeast CO along a surface trough. Strong buoyancy and effective shear increasing to 40+ kt in association with increasing mid/upper-level flow will favor the development of a few supercells, with a threat of very large hail. A tornado or two will also be possible if any surface-based supercells can be sustained near the warm front. With time, storm consolidation is expected over southwest KS/northwest OK, with CAM guidance and pattern recognition suggesting the potential for MCS development along the northern periphery of the upper ridge. A swath of severe wind, which may include gusts to greater than 75 mph, appears possible from northern OK/southern KS potentially into the Ozark Plateau, though the timing and intensity of the MCS becomes increasingly uncertain by the end of the forecast period. ....NE/southern SD and vicinity... A notable mid/upper-level shortwave trough is forecast to approach the northern High Plains this afternoon. A relatively narrow zone of low-level moisture return and moderate destabilization is expected into parts of west/central NE and southwest SD. Isolated to widely scattered supercell development is possible by late afternoon into the early evening, with an initial threat of hail (possibly golfball-size or larger). Some modest upscale growth is possible into parts of northeast NE/southeast SD, which may result in an increasing threat of severe gusts later tonight before storms move east of the more favorable instability and weaken. ....Mid Atlantic/Northeast... Scattered thunderstorms are again expected along/east of a cold front from the Mid Atlantic into parts of the Northeast. Deep-layer shear will generally be rather weak across the region, but modest instability may support a few stronger storms capable of locally damaging gusts and possibly some marginal hail. Areas that see somewhat stronger heating/destabilization may have a locally greater risk of damaging gusts, but uncertainty in this scenario remains too high for anything greater than 5% wind probabilities at this time. ...Dean/Lyons.. 06/27/2023 $$ = = = 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) .