597 FXUS63 KARX 082300 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 600 PM CDT Tue Jul 8 2025 .KEY MESSAGES... - Spotty shower/storms chances for the rest of the afternoon-into early evening. - Rain chances Wed-Sat, but focused on Friday (70-80%). Stronger storms possible Fri with locally heavy rain. && .DISCUSSION... Issued at 140 PM CDT Tue Jul 8 2025 > REST OF THE AFTERNOON/EARLY EVENING: Shortwave trough dropping southeast across MN/northern WI per latest watervapor satellite imagery will continue to track southeast through the rest of the time. Another shortwave/MCV was churning just south of the local area and responsible for the early morning convection over parts of IA (and still continues across northern IL). RAP MLCAPE climb to 500-1000 J/kg across WI this afternoon, although relatively skinny profile. The mix could be enough to pop a few showers/isold storms from mid afternoon into early evening, mostly across WI. However, latest RAP/HRRR showing mid level capping - would allow for a few agitated cu but not much more than that. Not much for shear to support any updraft that gets going. For now, will hold with the small chances (20%) over WI and monitor trends. > WED-SAT: rain chances with Friday harboring the highest likelihood. Conditional strong (severe?) storm risk Fri. Locally heavy rain possible. GEFS and EPS continue to spin a shortwave trough from the southern rockies eastward Thu, lifting it east/northeast across the upper mississippi river valley Fri. Another shortwave follows quickly on its heels, dropping southeast out of southern Canada and pushing across northern reaches of the region Sat. The first shortwave may eventually merge/be absorbed into the 2nd feature, but generally favored after both swing back northeast into Canada (post the local area). Latest GEFS is trending a bit faster with the overall speed of both upper level features compared to the EPS. Meanwhile, medium/long range guidance is starting to suggest a thunderstorm complex will spark over the central plains late Wed night, taking the residual MCV east and potentially bringing a shot for showers/storms to southern portion of the forecast area. Clouds, boundaries etc will have some influence on how that first shortwave moves - perhaps more importantly to any strong/severe risk - how far north an associated warm front lifts. Not much clarity at a few days out, and might not get a better idea on evolution until track of the Wed night/Thu MCV is more evident. Pool of soupy/unstable air pools ahead of the initial shortwave (Fri). Again, how far northward the CAPE axis extends is uncertain as positing of the relevant features/forcers isn`t super clear (yet). Enough wind shear could/would overlap with the unstable airmass, aiding storm organization and heightening a strong (severe?) storm risk. What appears more certain is the potential/likelihood of locally heavy rain. PWs continue to push north of 2" with warm cloud depths of 4 to 4.5k. Mostly north-south orientation of the convection will limit repeat, time-resisdence enhanced accumulations, GEFS and EPS 25-75 percentiles sit roughly from 3/4 to 1 1/4". However, the high end outliers climb above 3". Not a widespread flooding scenario but certainly one that could impact urban areas (street flooding) if realized. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 600 PM CDT Tue Jul 8 2025 Isolated to scattered showers/storms that have developed this afternoon have largely begun to weaken and are expected to fully dissipate with sunset. Some concern for fog/mist remains for the overnight hours (< 30%), but thinking it should be confined to the low lying areas and valley locations that are most prone to fog/mist development. As such, still not confident enough to add into the TAFs. Light northerly winds persist tonight into Wednesday under clear to mostly clear skies with diurnal cumulus developing Wednesday afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Naylor AVIATION...Falkinham