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Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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835 FXUS63 KARX 160842 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 342 AM CDT Fri Aug 16 2024 .KEY MESSAGES... - Showers and a few rumbles of thunder are likely (40-70%) this afternoon. These may (20-40%) return Saturday afternoon as well. - Sunday through Thursday feature temperatures a bit below average. Depending on how the details shake out, each afternoon could presumably feature a stray shower, but no particular day stands out at this time. && .DISCUSSION... Issued at 341 AM CDT Fri Aug 16 2024 Friday and Saturday: Additional showers and thunderstorms 08z WV satellite clearly depicts an upper low churning to our north over MN/WI. As the upper low slowly moves to the east today, multiple shortwaves will rotate around this feature and pass over the CWA. With a decent amount of moisture in place through the column, these shortwaves should kick off numerous showers, especially during the afternoon when surface heating, though restrained by cloud cover, reaches a relative maximum. Progged soundings depict skinny instability profiles suggesting thunder coverage will be more limited, so have limited thunder mentions to the isolated and scattered categories. As for other hazards, main thing to watch this afternoon will be the potential for funnels and a stray non-supercell tornado as the upper low approaches our northern forecast area. While latest guidance suggests a lack of larger scale surface boundaries and their associated surface vorticity in our area, will need to closely monitor any stronger updraft that develops on an outflow boundary this afternoon, particularly in Taylor/Clark Counties. Saturday, with the upper low slowly departing to the east, additional upper disturbances may kick off more daytime convection. While the risk for funnels should be lower, thunder remains possible Saturday afternoon. Sunday through Thursday: Below normal temperatures, low potential for stray afternoon showers Guidance continues to broadly depict northwesterly flow aloft through the middle part of next week. This pattern usually leads to temperatures running a bit below normal for mid to late August and relatively uneventful weather, an outcome borne out as expected by benign LREF joint CAPE/CIN/shear probabilities, longer term GEFS- based ML outlooks, and most GEFS/ENS components remaining near average. A stray afternoon shower or storm could presumably occur if any well-timed shortwaves arrive but this appears to be a remote possibility at this time. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1053 PM CDT Thu Aug 15 2024 Partly to mostly cloudy skies for the overnight period. Some areas of patchy fog will be possible, especially for areas along and east of the Mississippi. If enough clearing does take place, IFR and LIFR fog could develop, especially in the river valleys. There is currently between a 20 and 30% chance of these lower flight categories occurring overnight. Scattered showers and storms will be possible across the area from Friday late morning through the rest of the day. MVFR conditions are likely to occur during the afternoon with lower flight categories expected for Friday night due to low stratus clouds. Southwest winds will transition to northwest winds Friday afternoon with some gusts between 15 and 25kts, especially in southeast Minnesota and northeast Iowa. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Ferguson AVIATION...Cecava