Mt. Lacrosse Snow Report

146 FXUS63 KARX 150535 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 1235 AM CDT Thu Oct 15 2026 .KEY MESSAGES... - Rain expected across the entire area for much of the today with rainfall totals of around 1/2" to 1". No impacts are expected from this rainfall. - Breezy northwest winds with shower chances (30-50%) on Friday morning and afternoon. There is some potential for gusts to reach 45 mph, primarily west of the Mississippi River with ongoing showers. - Temperatures become much colder Friday night and Saturday morning with lows in the 20s to lower 30s. This may bring an end to the growing for some of the area, especially near and north of I-94 (60-90% chance for temperatures colder than 28 degrees). && .DISCUSSION... Issued at 1235 AM CDT Thu Oct 15 2026 Today: Rain Across Much of the Area Our next pair of synoptic features that will be responsible for widespread rainfall today can be noted on GOES-19 water vapor imagery and RAP 500mb heights as both an upper-level low situated over Colorado begins to phase with a northern stream upper- level trough moving into the northern Great Plains. As this occurs, much of deterministic guidance generally agrees on instigating surface cyclogenesis south of the local area at the exit region of this upper-level feature as it pivots through the region. Additionally, a fairly respectable plume of low- level moisture pushes just south of the local area with some increase in precipitable waters to around 1-1.5" this afternoon. Consequently, the recent HREF generally has respectable rainfall amounts with the inter-quartile range for QPF amounts across the region ranging from 0.5" to 1". As far as timing is concerned, much of the CAMs generally agree on bringing precipitation associated with this system into the region towards daybreak. As we head through the day, cannot rule out some weak convection south of I-90 where some weak MUCAPE is present in the RAP which may lead to some locally heavier rainfall amounts (higher percentiles of the HREF have some 1.5-2" amounts in Clayton and Grant Counties). Otherwise, the main cold front with this system swings through the region by mid-evening ending precipitation potential from west to east. Overall, should be a healthy rainfall event but not expecting much impacts from this rainfall. Friday: Breezy Conditions with Morning Showers Possible Behind the aforementioned cold front on Friday, the combination of an increasing surface pressure gradient and some mixing into a 40 kt low-level jet will allow for winds to increase to around 15-25 mph with gusts upwards of 35-45 mph, particularly west of the Mississippi River. While probabilities in the NBM are not overly high (10-30%) for wind gusts over 45 mph, some instability and steep low-level lapse rates are present in RAP soundings. As a result, this should allow for some showers to push through the region on Friday morning associated with the cyclonic flow of the upper-level trough overhead. Consequently, would not be surprised to see some local enhancement of winds as showers aid in momentum transferring down some stronger gusts to the surface where gusts reaching 45 mph would be possible. Friday Night - Saturday Morning: Frost/Freeze Likely By the time the nighttime hours roll around on Friday, the aforementioned surface pressure gradient begins to wane as surface high pressure begins to push into the local area. Consequently, expecting winds to decrease with clearing skies as well. Therefore, the setup looks fairly solid for an effective radiational cooling night across the region with the NBM having fairly high probabilities (60-100%) for lows to fall below freezing across the entire local area outside of river valley locations. As a result, Frost Advisories and Freeze Warnings will likely be needed during this period. The highest probabilities (60-90%) in the NBM for a killing freeze with lows below 28 degrees will generally be near and north of I-94, with lower probabilities elsewhere (10-40%). This Weekend & Early Next Week: Dry, Gradually Warming Up As we head into the weekend and early next week, upper-level ridging will push into the region allowing for increasing southerly to southwesterly flow in the low-levels. As a result, expecting the advection of a modestly warmer airmass into the region during this period. Consequently, temperatures warm into the 60s by Sunday with highs even jumping back into the lower 70s as suggested in the median high temperatures fields of the NBM by early next week. Overall with the upper-level ridging overhead, not seeing much for precipitation chances in ensemble guidance as the grand ensemble (GEFS/EC/Canadian ensemble) has very low (under 10% chance) measurable precipitation probabilities this weekend through Tuesday of next week. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1235 AM CDT Thu Oct 15 2026 MVFR conditions across much of the region this evening will give way to IFR conditions during the morning hours as a disturbance brings widespread rainfall with accompanying decreasing cigs and vsbys. IFR to LIFR cigs will persist throughout the daytime hours with vsbys hovering around MVFR to IFR thresholds. Rain generally exits the region around 00z to 03z Friday with some improvement in cigs to MVFR possible, especially west of the Mississippi River. Otherwise, winds will generally begin the TAF period light and from the east but will shift to northwesterly and increase to around 10-15 kts late this afternoon and evening. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Naylor AVIATION...Naylor