


Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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000 FXUS63 KARX 110551 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 1251 AM CDT Fri Jul 11 2025 .KEY MESSAGES... - Light showers persist into early evening. Storm potential on the southern periphery of the rain/cloud for late afternoon/ evening (20- 40%). Widespread rain and a few storms more likely overnight into Friday morning, but generally south of I-90. Locally heavy rain possible. - Friday rain chances could be confined to just the morning hours as placement, evolution of the complex mix of weather variables trend toward holding most of the storm chances south/southeast and farther west. - Trending cooler by the middle part of next week with below normal highs in the 70s. && .DISCUSSION... Issued at 130 PM CDT Thu Jul 10 2025 > THiS AFTERNOON-EARLY EVENING: persistent light showers. Scattered storm potential for northeast IA/southwest WI into early evening. MCV spawned by overnight/early morning convection was churning over southeast MN early this afternoon, continuing to pinwheel areas of light rain around it. The clouds/showers will persist moving through the rest of the afternoon - knocking off several degrees from expected high temps and also working against the storm potential for later afternoon/evening. Without much sun/daytime heating, instability is being held in check. If the cloud mass continues to rotate/move per latest satellite trends, might get enough late day clearing over southern fringes - including northeast IA/southwest WI - to increase instability and the convective threat. Otherwise, the convective chances won`t increase until later into the night when the low level jet kicks and shortwave tracks in from the west. > REST OF TONIGHT-SATURDAY: periods of showers with locally heavy rain, Storm chances - a few could be strong, but higher severe risk lies farther south. Shortwave trough still on track to move out of the southern rockies, spinning east across IA overnight, likely riding the WI/IL border Fri as it exits across the western Great Lakes. The evening rain/storms will likely result in a west to east sfc front lying across IA - where this shortwave can interact with. In addition, short term guidance increase the low level moisture into the boundary, but mostly parallel to it (limiting additional lift). While what happens for the rest of this afternoon/evening will have an impact on setup for later tonight into Friday, the CAMS models showing pretty good agreement on developing another round of convection with the incoming shortwave, aligning along the front and the stream of low level moisture. PWs near 2" and warm cloud depths or 4-4.5 kft still favorable for heavy rain. If storms can repeat over a location, localized flooding (likely mostly urban and small streams) could/would become a concern. If this scenario holds true, resulting outflow/rain cooled region will further push the west-east running sfc boundary south/southeast. While pcpn is likely to be lingering in the morning across mostly southern parts of the forecast area, the focus for afternoon/evening storms (and accompanying severe risk) would be along the front - and south of the local area. Another shortwave trough, this dropping southeast out of southern Canada, will be sliding over the northern plains Fri afternoon, swinging its axis across the upper Mississippi river valley Sat afternoon. A sfc cold front will precede the trough, and it`s along this boundary that convection is favored to fire by mid/later afternoon. Ribbon of instability to work with but the bulk of the deep wind shear holds westward. Current timing would bring the line toward southeast MN well after 00z Sat. With decreasing instability trend would be downscaling the convection both in intensity and areal coverage. A few CAMS suggest it could diminish completely before working into western parts of the forecast area. Rain chances will persist Sat morning until that trough axis moves east, The instability is shifting into eastern WI though, taking with it much of the storm risk. > NEXT WEEK: rain chances Tue into Wed. Turning cooler (below normal) by mid week, potentially hanging around through the weekend. GEFS and EPS remain in good agreement with driving a shortwave trough/cold front out of Canada and across the region in the Tue/Wed time frame. The bulk of both ensembles` members lay down some QPF. Much cooler air will flow in post the front - 850 mb temps currently progged to drop from 20 C at 00z Wed to 8 C by 18z Fri. 75% of the GEFS and EPS members drop highs back into the 70s, but the lower 25% of the suites suggest highs won`t warm out of the 60s on a few days. Quite a change to the string of warm, humid summer days - if the scenario holds true. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1250 AM CDT Fri Jul 11 2025 With light surface winds and low-level saturation, patchy fog has begun developing across much southeast Minnesota, northeast Iowa, and western Wisconsin. This fog is expected to linger through much of the overnight. There is some uncertainty if this fog becomes more dense or if the mid-level clouds moving overhead impede dense fog and a MVFR/IFR stratus deck forms instead. Currently have 3SM and 1/2SM for KLSE and KRST respectively. If better saturation occurs at the surface then expect the fog to become more dense and approach IFR/LIFR. The best chance for the lowest visibilities to occur (LIFR) would be in portions of southeast Minnesota, including KRST, and northeast Iowa. The best chance (40 to 60%) for showers and thunderstorms to occur will mainly impact areas along and south of I-90 today. Light and variable winds are expected today. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Rieck AVIATION...Cecava