


Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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221 FXUS63 KARX 171758 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 1258 PM CDT Fri Oct 17 2025 .KEY MESSAGES... - Periodic showers and potentially (20-30%) a few thunderstorms are expected into Saturday night. Rainfall amounts for most will likely (60-100%) stay around or below 0.50 inches with some higher amounts closer to 1 inch possible (10-20%) across far southwestern Wisconsin. - Warmer than normal temperatures are expected through Saturday ahead of a cold front. Seasonal, near normal temperatures return for next week. - Gusty west to northwest winds will be possible Sunday through Tuesday as progressive pattern brings multiple systems through the area. && .DISCUSSION... Issued at 1253 PM CDT Fri Oct 17 2025 Today - Saturday: Off and On Rain Chances, Warm Temperatures Highly isolated light showers are overspreading much of the Upper Mississippi Valley ahead of a cold front draped north to south across Minnesota, extending from a occluding surface low across southern Manitoba. In the upper levels, a weakening upper low is ejecting northeast towards the Hudson Bay with southwesterly flow continuing across much of the Upper Midwest. A jet max was located across much of Minnesota at 500 mb. This, along with increasing convergence along the frontal boundary and continued low level moisture transport into the area, will allow for continued shower and weak storm development through the afternoon and into the overnight hours tonight. Coverage is expected to be more scattered in nature, largely due to the low level warm air advection creating a capping inversion between 800-900 mb. This will also serve to limit instability with mean MUCAPE values from the 17.12 HREF no higher than 250 J/kg across the region. Rain chances will gradually shift east as the front slowly progresses through the area with most rain chances coming to an end by 12Z Saturday. Rain chances are not totally over though as the trough axis lags behind the upper low and doesn`t look to swing through our area until around 12Z Sunday. Late Saturday, as the main body of the trough moves in, some light rain chances look to overspread the area. An axis of heavier rain will be possible across far southwestern Wisconsin, where slightly better instability and lift could co-locate overnight into Sunday. Overall instability forecasts for Saturday have come down in the 12Z HREF but there should still be enough for some heavier showers. QPF totals should stay at or below 0.5 inches but there remains a low chance (less than 20%) some locations across far Southwest Wisconsin could see totals around 1 inch before all is said and done Sunday morning. Temperatures tomorrow will remain above average, though to a slightly lesser degree than today. Highs will remain in the mid 60s to lower 70s as the cold air advection doesn`t look to really kick in until the trough axis swings through late Saturday into early Sunday. Sunday - Late Next Week: Progressive Pattern with Gusty Winds Sunday Through Tuesday. Dry conditions are expected to prevail across the area Sunday and Monday with weak upper level ridging sliding in behind the exiting trough. Sunday could see some gusty conditions as a rapidly deepening surface low across the Great Lakes tightens the local pressure gradient. Temperatures both Sunday and Monday look to return closer to normal in the mid 50s to mid 60s. Attention quickly turns to the next trough and upper low that is expected to drop southeast out of Canada Monday into Tuesday. Its corresponding surface low is expected to deepen across North Dakota and northwestern Minnesota before moving east into the Northern Great Lakes. This will likely lead to continued gusty winds on Monday and especially Tuesday on the backside of the departing surface low. 17.12Z GFS soundings show the potential for deep mixing Tuesday afternoon bringing potentially 40 kt gusts to the surface. 17.13 NBM probabilities show a 30-50 percent chance of gusts at or above 40 mph across pretty much all of the Driftless Region for Tuesday. This will be something to monitor in the coming days with a wind headline potentially in the cards. Otherwise, the generally progressive pattern looks to continue through the rest of next week with off and on rain chances and temperatures moderating out in the 50s to low 60s. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1245 PM CDT Fri Oct 17 2025 Primary aviation consideration over the next 24 hours will be a broken line of showers that will develop over portions of the region associated with a weak frontal boundary later this afternoon and into the evening. Overall, probabilities for MVFR reductions are not overly impressive (20-50%) in the recent HREF guidance, however cannot rule out some vsby or cig reductions with any heavier showers that pass through. Otherwise, mid-level sky cover will gradually clear through the overnight leaving mostly clear skies through daybreak on Saturday. Winds will begin the TAF period from the south between 12-18 kts with occasional gusts to 25 kts west of the Mississippi River. However, winds will gradually decrease to under 10 kts this evening and overnight. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Barendse AVIATION...Naylor