492 FXUS63 KARX 251728 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 1228 PM CDT Thu Sep 25 2025 .KEY MESSAGES... - Unseasonably mild conditions through the middle part of next week (approx 10 degrees above the late Sep normals). Some locations likely to push north of 80 degrees starting Friday - especially along/south of I-90 and in the Mississippi River Valley. - Staying dry into the start of next week, but could linger until the following weekend. && .DISCUSSION... Issued at 115 AM CDT Thu Sep 25 2025 Positively tilted upper level trough axis with closed low over the great lakes early this morning will finally get a kick east today, showing some weakening as it moves over the new england states by Fri morning. Broad upper level ridging builds across the upper mississippi river valley post the trough, working to shuffle any west-east moving shortwave activity north of the region. Moving into the weekend and early next week the GEFS and EPS have continued to move toward a sharper, stronger upper level ridge building across the region. The WPC clusters also mimic, and have shown this trend over the past several days. There is an Omega block look to it. Some progression to the upper level pattern for the latter half of next week in the EPS and GEFS - both suggesting the ridge could shift east with a trough moving in by the weekend. Forecast confidence low in this stead as strength of the omega-ish blocking pattern isn't certain. Upshot to all of this? The forecast area is going to stay dry into the middle part of next week with above normal temps (but not crazy warm). > RAIN CHANCES: as mentioned above, the ridge/blocking pattern will act as strong deterrent to shortwave encroachment as we move through the weekend into next week. Long range guidance starts to suggest rain chances could work in by the latter half of next week with a stronger southerly fetch/shortwave interaction. Again, a ton of uncertainty here. All in all, look for dry conditions into *at least* the start of the new work week. > TEMPERATURES: a mild/warm stretch of days on the horizon thanks to the upper level ridge. Grand Ensemble paints 70-100% chances for 70+ degree highs through the middle part of next week. Same ensemble suggests 10-50% likelihood to reach 80+ degrees from I-90 southward, including locations within the Mississippi River valley. Roughly 10 degrees above the late Sep normals. So, not "hot", but certainly warm for this time of year. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1221 PM CDT Thu Sep 25 2025 Overnight into early morning fog, mainly along and east of the Mississippi River, continues to be the focus of the aviation forecast. Think the chances are pretty good for additional development tonight but some guidance is pointing toward a bit stronger winds aloft compared to the previous few nights which would inhibit formation of valley fog and potentially stratus to boot. Due to this uncertainty, have retained BCFG and a SCT group at LSE with a view toward refinement with the 00z and 06z cycles. Outside of the fog, a few fair weather cumulus around 4 kft are possible this afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Rieck AVIATION...Ferguson