606 FXUS63 KARX 041135 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 635 AM CDT Sun Apr 4 2021 .SHORT TERM...(Today and tonight) Issued at 310 AM CDT Sun Apr 4 2021 Main forecast concerns today are on fire weather due to the combination of low afternoon relative humidity values and breezy conditions. The big forecast question for today is how deeply will the atmosphere mix. The depth of mixing will determine how low relative humidities go today and how breezy it could get. The RAP is by far the most aggressive showing mixing all the way up to around 600 mb and forecast soundings take on an inverted V profile. Have reduced dew point values in the forecast to account for the deep mixing, leaning toward HREF 2m AGL RH ensemble min values, which verified well yesterday. Expect near critical fire weather conditions today with min RH values falling into the upper teens to around 22 percent. The only limiting factor today to not be at critical levels is winds are a little on the light side out of the south/southwest at 11 to 17 mph with gusts up to 22 mph during peak afternoon heating. It will be a warm day across the area too, with highs climbing into mid to upper 70s, cooler across north- central Wisconsin where highs will mainly be in the 60s. Expect moisture to increase across the area during the evening as higher dew points start working into the region from the south. Also, warm air advection kicks in as a shortwave approaches from the northern plains, and a few showers are possible, and cannot rule out some thunderstorms as moisture moves in around 800 mb. If this moisture materializes, there could be elevated CAPE values of around 1800 J/kg, maybe enough for some isolated hail, will have to keep an eye on this potential. .LONG TERM...(Monday through Saturday) Issued at 310 AM CDT Sun Apr 4 2021 Main forecast concerns are on showers and thunderstorms Monday, with the potential for some isolated stronger storms, then focus turns to shower and thunderstorm chances through much of the week. Monday will feature a warm and noticeably more humid day across the area as low pressure moves into southern Minnesota, with a warm front situated over northern portions of the forecast area. Scattered showers and thunderstorms are expected across the area, especially Monday afternoon into Monday night. A few stronger storms are possible Monday afternoon into Monday evening with MLCAPE values of 800 to 1200 J/kg and 0-6 KM Bulk Shear of 25 to 35 kts. The strongest shear looks to be mainly across southeast Minnesota into west central Wisconsin, and this is where a few stronger storms could develop. Low pressure then deepens over the Central Plains late Tuesday into Wednesday and meanders east/northeast into the Upper Mississippi River Valley through the last half of the week with periods of showers and possibly a few thunderstorms. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) Issued at 635 AM CDT Sun Apr 4 2021 VFR conditions are expected through the TAF period. Plan on south winds increasing today into the 10 to 12 kt range with gusts to around 20 kts during the peak afternoon heating. Look for increasing clouds tonight as low pressure approaches from the Dakotas. && .FIRE WEATHER...Today Into Early This Evening Issued at 310 AM CDT Sun Apr 4 2021 Expect near critical fire weather conditions across the area today with afternoon relative humidity values falling into the upper teens to lower 20s and breezy southerly winds of 11 to 17 mph with gusts up to 25 mph during peak afternoon heating. These weather conditions combined with dry fine fuels across the area will produce near critical conditions this afternoon. Moisture starts to increase across the area tonight with RH values climbing into the upper 60s to upper 80s after midnight. Rain chances return on Monday into Monday night, then widespread rains are looking likely Tuesday night into Wednesday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Wetenkamp LONG TERM...Wetenkamp AVIATION...Wetenkamp FIRE WEATHER...Wetenkamp