Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Aug 07 2025 06:01:26 ACUS01 KWNS 070601 SWODY1 SPC AC 070559 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Thu Aug 07 2025 Valid 071200Z - 081200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF NORTH DAKOTA... ....SUMMARY... Scattered severe thunderstorms are expected later today into tonight. The most likely corridor is centered on North Dakota, where a few tornadoes, very large hail, and significant severe gusts are possible. ....Northern Great Plains... Significant severe storms capable of producing wind gusts of 75+ mph, very large hail, and possibly a few tornadoes are still expected in an area centered on ND later today into tonight. A mid/upper-level trough is forecast to amplify over parts of the Northwest/northern Rockies today as it moves eastward. One or more low-amplitude vorticity maxima may precede the larger-scale trough and move across the northern Great Plains during the afternoon and evening. A surface low is forecast to gradually deepen across the northern High Plains. Rich low-level moisture beneath steep midlevel lapse rates will result in strong to extreme buoyancy within the warm sector of this cyclone, and also near/north of a baroclinic zone that will extend east/northeast of the low. This instability combined with moderate deep-layer shear will result in a very favorable conditional environment for severe storms. Guidance generally depicts one or more intense storm clusters moving across ND sometime later today into tonight, but considerable spread remains regarding timing of the primary threat, and the duration and coverage of supercells. There is some potential for morning elevated convection to become increasingly organized with time, with renewed development during the afternoon possible near the surface low and baroclinic zone. Any supercells within this regime would pose a threat of very large hail, along with some tornado potential, especially near the baroclinic zone. A tendency toward clustering and MCS development is expected with time, increasing the threat for one or more swaths of significant severe wind, along with some potential for line-embedded tornadoes. The southern and eastern extent of higher-end severe potential remains uncertain, due to differences regarding storm timing and the position of the main baroclinic zone. Farther west, isolated to widely scattered supercells may develop within a moderately unstable post-frontal regime from central into eastern MT. Elongated hodographs and steep lapse rates will support severe hail and wind potential with these cells. Some clustering remains possible within this regime as well, and depending on the evolution of downstream convection, storms that initiate in MT may eventually spread into western/central ND late tonight with a continued severe threat. ....IL/eastern IA into WI and western upper MI... Some potential for strong to locally severe storms remains evident within a broad area from IL/eastern IA into WI and western upper MI, though uncertainty remains regarding the potential for a more organized threat somewhere within this broader area. Guidance varies regarding the evolution of morning convection across parts of IA/MO, and whether a well-defined MCV will emerge from this area. However, even a weak MCV or other low-amplitude vorticity maxima may aid in scattered to widespread storm development late this afternoon into the evening, within a modest low-level warm advection regime. Deep-layer flow will be relatively modest, but rich moisture and moderate to strong buoyancy will support a threat for at least isolated hail and damaging wind. ...Dean/Weinman.. 08/07/2025 $$ = = = 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) .