804 FXUS63 KARX 240555 AFDARXArea Forecast Discussion National Weather Service La Crosse WI 1255 AM CDT Wed Sep 24 2025
.KEY MESSAGES...
- Seasonable conditions the rest of the week with temps generally at/few degrees above normal. Apart from some morning fog the next couple days, dry conditions should prevail.
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.DISCUSSION... Issued at 127 PM CDT Tue Sep 23 2025
The upper trough that had a hand in yesterday`s severe weather chances has finally drifted east of our area, putting the region in weak northerly flow aloft. A weak upper low across the Central Rockies is starting to get shunted east as a ridge begins to build across the Pacific Northwest. This is creating a long trough axis that extends through the Upper Mississippi Valley and into the southern Ontario with the upper jet well to our north. As the trough axis begins to pivot counterclockwise into the Ohio River Valley, a string to weak surface lows will trek across the nations mid section. Guidance over the last day has trended further south with the track of these lows, nullifying rain chances across the region. Even with some weak shortwaves passing overhead in the cyclonic flow aloft, low level capping and overall issues with moisture depth should keep all rain chances at bay through the work week. Weak flow will prevail across the area this weekend with a weak ridge progressively building in. This looks to keep the forecast dry through at least early next week.
Temperatures overall will be mild but near normal through the week with highs generally in the 70s. Friday and Monday look to be the best chances to cross the 80 degree mark but otherwise most days should see minor fluctuations in temperatures overall.
Similar to today, we will see chances for fog the next couple of mornings with dew point depressions less than 4 degrees and overall moist soils from recent rains. The main limiting factor will be boundary layer winds being a little stronger than desired which would increase mixing. Should winds slightly under-perform current expectations, fog may be a little more widespread. If fog doesn`t materialize, saturation in the low levels will likely still lead to low stratus development overnight and into the morning hours before burning off.
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.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1255 AM CDT Wed Sep 24 2025
Fog and low stratus remain the primary aviation concern for tonight and into the morning hours on Wednesday as low-level moisture remains in places with a building nocturnal inversion. Currently, deterministic guidance has been backing off on lower vsbys and cigs considerably in the last few runs. However, given robust probabilities (50-90%) for MVFR cigs in the recent HREF have kept at least MVFR mention at KLSE with IFR mention at KRST. MVFR to IFR cigs and vsbys will linger throughout much of the morning until diurnal mixing begins to remove any low-level moisture towards noon. Winds will generally remain light through the TAF period at under 8 kts.
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.ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None.
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DISCUSSION...Barendse AVIATION...Naylor
NWS ARX Office Area Forecast Discussion