Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 19 2025 16:33:30 ACUS01 KWNS 191632 SWODY1 SPC AC 191630 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sat Jul 19 2025 Valid 191630Z - 201200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS...MIDWEST/GREAT LAKES...AND VIRGINIA/NORTH CAROLINA... ....SUMMARY... Scattered damaging winds are possible today across parts of the Midwest/Great Lakes and southern Mid-Atlantic. Scattered large to very large hail and severe gusts are possible, along with a potential tornado threat, across the northern/central Plains during the late afternoon and evening. ....Midwest/Great Lakes... An ongoing sub-severe MCS continues east-southeast across IL with an attendant warm advection cluster of thunderstorms downstream over the lower Wabash Valley. Considerable convective overturning coupled with convective cloud debris have acted to limit destabilization thus far across IL into western IN and northward into the southwest Great Lakes. Have reduced severe probabilities this outlook update for northern IL into WI due to limited destabilization, and models converging on limited storm coverage through the remainder of the day and their depiction of primary thunderstorm activity tonight occurring farther south/southwest over IA into central IL towards daybreak. However, downstream of the ongoing thunderstorm clusters over IL/IN, gradual heating will probably support some intensification of storms into the afternoon. Isolated to perhaps scattered damaging winds in small clusters appear to be the primary severe hazard. Other thunderstorm development is possible over Lower MI where a wind-damage threat may materialize with the stronger storms that develop this afternoon. Later this afternoon but more likely into tonight, additional storms are forecast to develop on the trailing outflow with an attendant risk for mainly hail/wind. ....Virginia/North Carolina... A west-east draped frontal zone resides over southern PA to the north of this region. However, a very moist low-level airmass featuring lower to mid 70s dewpoints will continue to heat/destabilize through mid-late afternoon and promote the development of moderate buoyancy. Despite weak mid-level lapse rates, high PW (around 2 inches) will promote water-loaded downdrafts capable of strong to severe gusts and scattered wind damage with the more organized cluster(s). Around 15-25 kt of mid-level westerly flow will favor eastward-moving storm activity. The severe risk is expected to concentrate during the 20-01 UTC period as storms move towards central VA and into eastern VA by this evening. ....Northern/Central Plains... Water-vapor imagery shows a mid-level impulse moving eastward across the northwest quarter of MT this morning. This will continue eastward towards eastern MT and the western Dakotas by early evening. Weaker mid-level westerly flow will remain farther south into the central High Plains. At the surface, a lee trough will extend southward from eastern MT to eastern CO. Generally low to mid 60s surface dewpoints should exist this afternoon along/east of the lee trough, with upper 60s to lower 70s F dewpoints present near a remnant front/boundary in NE. Scattered thunderstorms will likely develop initially over the higher terrain of the northern/central Rockies this afternoon, with additional development farther east along the lee trough. As this convection spreads eastward into a moderately to strongly unstable airmass across the northern/central High Plains, it should strengthen. Weak low-level winds are forecast to veer and increase with height through mid/upper levels, supporting strong deep-layer shear and the potential for supercells. Scattered large hail will be possible with any supercells that can persist, with most guidance indicating a greater concentration of severe thunderstorms across eastern MT into western ND, and separately across western/central NE. Given the presence of steep mid-level lapse rates and 40-50+ kt of deep-layer shear, isolated very large hail appears possible. Recent model guidance indicates a few supercells may develop across west-central NE late this afternoon into the evening. Some enlargement of the hodograph during the evening combined with moist low levels may support a couple hour window for a locally higher tornado risk compared to within this broader region. ...Smith/Weinman.. 07/19/2025 $$ = = = 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) .