Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 08 2025 06:03:37 ACUS01 KWNS 080601 SWODY1 SPC AC 080600 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Fri Aug 08 2025 Valid 081200Z - 091200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN DAKOTAS INTO MUCH OF MN AND NORTHWEST WI... ....SUMMARY... Scattered severe thunderstorms are possible later today and tonight across parts of the Upper Midwest. Scattered damaging winds, large hail, and couple tornadoes are possible. ....Synopsis... A seasonably deep upper-level trough will move eastward into the northern Great Plains later today into tonight. In conjunction with this trough, a cold front will move across parts of the northern/central Plains into parts of MN/IA. The stronger mid/upper-level flow associated with the trough will generally lag the cold front, though there is some potential for increasing deep-layer flow/shear to impinge on a strongly unstable environment during the afternoon and evening. ....Dakotas into MN and northern WI... Elevated convection and possibly a remnant MCS will likely be ongoing at the start of the period somewhere from the eastern Dakotas into northern MN. These storms could pose a threat of isolated damaging wind and hail. The influence of the early-day convection results in considerable uncertainty regarding storm evolution later in the day. Convection may persist through much of the day behind the front, and also potentially along/north of an outflow boundary that will likely be in place somewhere across northern MN. Warm-sector development along the cold front will be possible by late afternoon, though stronger large-scale ascent attendant to the approaching trough will not overspread the region until evening, when widespread storm development will become possible. Steep lapse rates atop rich low-level moisture will support strong to extreme buoyancy along/ahead of the cold front, and to the warm side of any outflows. Deep-layer shear will become sufficient for supercells, though deep-layer shear generally parallel to the cold front could result in a quick transition to cluster or linear mode. Any sustained warm-sector supercells could pose a threat of large hail and a tornado. Damaging winds may become the primary threat as storms increase and spread eastward through the evening into late tonight. Greater severe probabilities may eventually be needed for part of the region, if uncertainties regarding the influence of early-day convection and potentially late timing of redevelopment are resolved. ....Black Hills into northeast CO and the NE Panhandle... Guidance varies regarding the potential for post-frontal storm development from the Black Hills into northeast CO and the NE Panhandle. Steep lapse rates and moderate deep-layer shear would conditionally support supercells within this regime, with a threat of hail and strong to severe gusts. However, some guidance is rather aggressive with drying behind the front, resulting in limited storm coverage. This area will be monitored for greater hail probabilities, if trends support development of multiple sustained cells. ....Southern High Plains... High-based convection is expected to develop this afternoon within a hot and well-mixed environment across the southern High Plains. Deep-layer flow will generally remain weak, but may be sufficient for development of small outflow-driven clusters capable of localized severe gusts. ....Northern Lower MI... Similar to Thursday, a few strong storms may develop this afternoon and evening across parts of northern lower MI, along the northeast periphery of the substantial buoyancy reservoir centered over the central Plains and Midwest. Modest northwesterly flow aloft will provide sufficient shear for some storm organization, with a threat for isolated hail and damaging winds. ...Dean/Moore.. 08/08/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .