


Area Forecast Discussion
Issued by NWS La Crosse, WI
Issued by NWS La Crosse, WI
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355 FXUS63 KARX 161000 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 500 AM CDT Mon Jun 16 2025 .KEY MESSAGES... - Strong to severe storms this evening and tonight. Highest confidence west of the Mississippi River Valley, primary hazards of damaging wind and large hail. - Additional storm chances Tuesday through Wednesday and early Friday into Saturday morning. - Warm weekend on tap. && .DISCUSSION... Issued at 146 AM CDT Mon Jun 16 2025 Main forecast concern continues to be severe storm threat later today. Ongoing convection early this morning will help determine timing of local severe threat later today. A couple recent HRRR runs (16.02Z, 01Z, 00Z) exhibited an earlier QLCS affecting the forecast area this afternoon-evening resultant of a decrease in morning convection. The decrease allows an unstable airmass to build locally, better fueling the storm potential. This scenario will also be dependent on exact location of frontal boundary causing cyclogenesis across the forecast area. While this isn`t the highest confidence scenario, it could be the most severe scenario and therefore something to monitor. Highest Storm Confidence This Evening - Tonight: Aligned with previous forecasts, highest confidence in a later solution into the nighttime hours as the main low lifts northeast through northern Minnesota; slowly draping a west- southwest oriented frontal boundary southeast through the forecast area. Given the later timing, the highest severe threat would be farther west concurrent with peak diurnal heating and more unstable air; aligning with Enhanced Risk in SPC convective outlooks. Slight risk seen over locally western counties in northeast Iowa and southeast Minnesota. Speed and timing of convection will directly affect potential changes to these risk locations; i.e., earlier = farther east. Hazards & Accompanying Timing Impacts: While clouded by location and timing of mesoscale forcing, ample severe parameters (CAPE/Shear) await convection. With this earlier solution, the most recent F48 HRRR (16.00Z) increased 0-6km shear from 30 to 40 kts. While all high resolution members suggest increase in shear over previous runs, most limit it postfrontally or in minuscule spots of mesoscale influence. Accompanying long hodographs suggest large hail will be possible and damaging wind with increased low level flow. Overall tornado threat is quite conditional on /if/ the earlier QLCS takes shape. The earlier solution in the aforementioned HRRR runs would increase this possibility while previous runs and other models with a later solution limit overall surface based activity. Subsequent Storm Threat Tuesday: Subsequent strong storm threat expected to affect the local forecast area Tuesday, Tuesday night, and/or Wednesday morning. Unfortunately confidence is low due to today/tonight`s storm timing and resultant frontal location. The earliest solution (lowest confidence) would result from a strong, linear storm mode tonight, allowing instability to build farther north through Tuesday. Current confidence keeps frontal boundary to the south, advecting highest storm chances zonally along southern half of the forecast area. Storm Chances Wednesday: Furthermore, the exit of tonight`s low affects subsequent synoptic solutions for Wednesday. A surface low expected to lift northeast along a southwest-northeast oriented baroclinic boundary from the Southern to Central Plains; advecting the lingering frontal boundary north across the forecast area. LREF solutions which have exhibited slight variations over the last couple of runs: agreeing on a slightly slower solution through Wednesday morning, potentially providing some more unstable air farther north. Although, the EPS has strengthened the low while the GEFS has weakened, going to show the copious details requiring ironing out. Regardless, better shear will lie postfrontally to the north. Storm Chances Friday Into Saturday: Eventually mid level heights build (LREF 100% confidence) through Thursday, reducing widespread precipitation potential into the weekend. Precipitation potential will graze northern peripheral counties in central Wisconsin as a low advects zonally along the International Border Friday into Saturday. Warming Through The Weekend: Building heights through the end of the week (LREF 100% confidence) increases surface temperatures through the weekend. The warmest solutions seen in the EPS and GEPS with 60-100% confidence for the 80 degree isotherm enveloping the forecast area Friday warming into the upper 80s through the weekend. The GEFS on the other hand suggests a colder solution with 10-30% for 80 degrees on Friday and low 80s through the weekend. Will be dependent on the strength and western extent of the Bermuda High. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 500 AM CDT Mon Jun 16 2025 Challenging forecast with a variety of synoptic, meso and micro scale features that will all have roles to play in clouds and shra/ts production through tonight. Short term guidance having a very tough time in capturing the smaller scale features and can flip hour to hour in their predictive outcomes. Forecast confidence high that the region will see bouts of shra/ts through tonight. As for timing/location questions...confidence is lower. Will continue to paint with a broad brush, trying to highlight more likely outcomes based more on the synoptics and/or ongoing trends. There will be adjustments to cig and pcpn trends through the day as meso scale interactions become more evident. All said, going to lean into a VFR cig forecast into tonight with MVFR favored for a few hours moving into the overnight. Scattered to areas of showers/storms early this morning, with more shra/ts lined up along a cold front later this evening. Can`t rule out spotty convection for the afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...JAR AVIATION...Rieck