Expires:No;;311401 FXUS63 KARX 271143 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 543 AM CST Sat Dec 27 2025 .KEY MESSAGES... - Confidence is increasing for impactful winter storm Sunday morning into Monday morning. Highest snowfall totals of 4" to 6" forecasted along and north of Interstate 90 from southeast Minnesota into western and central Wisconsin. Winter Storm Watches for accumulating snowfall and blizzard conditions have been issued. - Cold temperatures through the end of the week may reach Cold Weather Advisory Criteria, overall confidence remains dependent on evolution of early week storm system. && .DISCUSSION... Issued at 337 AM CST Sat Dec 27 2025 Persistent Drizzle & Fog Today: The low level moisture of the holiday week increases through today as the low level ridge axis traverses the forecast area this morning and return flow advects a filament tied to Gulf moisture towards the Upper Mississippi River Valley. Therefore, have continued drizzle/rain additions over /most/ forecast model guidance today and tonight. While isentropic upglide will be a sufficient forcing mechanism, thickness of low level moisture realizing fog vs. drizzle will be determining factor. Regardless, while recent temperature forecasts have run a couple of degrees warmer than observations, expect above freezing surface temperatures across the forecast area to limit overall impacts. Winter Storm Impacts Sunday Through Monday Morning: Confidence in impactful winter storm continues to increase as confluence within the synoptic pattern causes rapid surface cyclogenesis from the Mid Mississippi River Valley Sunday morning. Deeper, slightly more southern solutions to the surface low increased local snowfall impacts from more enhanced low level frontogenesis lingering through Sunday night over the forecast area. Besides accumulating snowfall, the resultant tightened pressure gradient with enhanced low level cold air advection will increase northwest winds (25+kts sustained HREF) exacerbating visibility concerns within an already thick DGZ residence. Winter Storm Headlines Issuances: Current confidence for strongest cold air advection causing flash freeze concerns combined with HREF probabilities for increased wind gusts primarily affects locally western most counties from southeast Minnesota into northeast Iowa. Therefore, have issued Winter Storm Watch for Blizzard in these counties in collaboration with neighboring forecasts offices (DMX/MPX). A default Winter Storm Watch was issued elsewhere, in southeast Minnesota counties adjacent to the Mississippi River and western into Central Wisconsin, where confidence for 4"+ of snowfall aligns with flash freeze potential and strong winds along Interstate corridors during the holiday weekend travel period. Forecast Confidence & Potential Impacts: While confidence for impactful snow is high, the rapid evolution of the parent extratropical cyclone over the forecast area persists /some/ uncertainty regarding location of highest impacts. The south- southwest shift in LREF members over previous runs increases local forecast and impacts, should the southwest trend continue then higher impacts will likely be realized. Further headline complications arise regarding wind speeds as current high resolution model soundings, HREF/LREF confidence, and NDFD forecast which was increased from NBM in collaboration with neighboring forecast offices, support advisory speeds along and west of the Mississippi River Sunday night into Monday morning. Should the fatter flakes, broken up by the stronger winds, be too wet to blow after reaching the ground and not cause widespread visibility concerns (Blizzard), further headline assessment will be required. Colder Through End Of The Week: The Polar airmass sags southeast across the forecast area through midweek with daytime highs bottoming out in the single digits Thursday (LREF) and single digits overnight lows Wednesday night through Friday night/Saturday morning. While current confidence in temperatures is moderate (30-50%), wind speeds will require additional confidence regarding apparent temperatures and potential cold weather headline concerns mostly Thursday and Friday mornings. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 532 AM CST Sat Dec 27 2025 Further moistening to an already saturated low level air mass perpetuates LIFR-VLIFR impacts through much of the 27.12Z TAF period. Confidence in ceiling impacts remains high across the forecast area while visibility impacts are less certain. Lower elevation sites within river valleys (e.g., KLSE) have mostly been spared from LIFR visibilities. Where LIFR visibilities are occurring, increasing surface winds may provide sufficient mixing for better visibilities in a short window this afternoon. Have accounted for this at KRST TAF site from 19Z to 23Z albeit IFR or LIFR ceilings remain likely. Subsequent impacts from precipitation initially expected at 27.12Z TAF period terminus, lasting through Monday morning primarily in central Wisconsin. Initial rain switches to snow from northwest to southeast through Sunday. A deepening low pressure system will result in strong northwest winds sustained near 30 kts west of the Mississippi River, gusting near 40 kts at times. Blizzard conditions will be possible west of the Mississippi River. Highest snowfall amounts expected along and north of Interstate 90 locally in southeast Minnesota and western into central Wisconsin. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Winter Storm Watch from Sunday morning through Monday morning for WIZ032-033. Winter Weather Advisory from 3 PM Sunday to noon CST Monday for WIZ053>055. Winter Storm Watch from Sunday afternoon through Monday morning for WIZ017-029-034-041>044. MN...Dense Fog Advisory until noon CST today for MNZ079-086>088- 094>096. Winter Storm Watch from Sunday morning through Monday morning for MNZ079-086>088-094-095. Winter Storm Watch from Sunday afternoon through Monday morning for MNZ096. IA...Dense Fog Advisory until noon CST today for IAZ008>011-018-019- 029-030. Winter Storm Watch from Sunday morning through Monday morning for IAZ008-009-018-019. Winter Weather Advisory from 3 PM Sunday to noon CST Monday for IAZ010-011. && $$ DISCUSSION...JAR AVIATION...JAR