755 FXUS63 KARX 211050 AFDARXArea Forecast Discussion National Weather Service La Crosse WI 550 AM CDT Sun Sep 21 2025
.KEY MESSAGES...
- Scattered showers and thunderstorms possible through Monday. Some storms may become strong during the afternoon and evening hours, bringing primarily a risk for hail.
- Temperatures stay near normal with highs in the low to mid 70s through much of the upcoming week.
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.DISCUSSION... Issued at 245 AM CDT Sun Sep 21 2025
A short reprieve in cyclonic gyres traversing the Upper Mississippi River Valley limits local precipitation chances through this morning. A tight cyclonic rotation over North Dakota on early morning GOES water vapor imagery will reintroduce precipitation and storm chances later today as a perturbation along its southern periphery traverses the forecast area overnight. Initial storm and precipitation chances reach our western peripheral counties in southeast Minnesota this afternoon/evening, initializing on the nose of a low level jet streak with sufficient instability (500+ J/kg) accompanying the 60 degree surface isodrosotherm currently seen on surface observations over southwest Minnesota. Overall impacts will be dependent on lingering mid level warmer air and associated weaker lapse rates with meager, albeit severe sufficient, deep layer shear of 30kts from 0 to 6 km. Hail will be the main hazard while damaging winds are not able to be ruled out. Strong storms may continue overnight upon re-intensification of the low level jet.
Little progress in the synoptic pattern and frontal boundary along our western periphery through Monday persists strong to severe storm potential locally. Similar to Sunday, overall limiting factor will be meager, albeit severe storm capable, deep layer shear of 20-30 kts from 0 to 6 km.
Subsequent synoptic forcing through the work week will be a broad upper level trough extending southwest to northeast across the CONUS (LREF Probabilities) with todays aforementioned cyclonic rotation lingering over the Great Lakes. Meager progressivity in the global pattern suggests this setup is a precursor to an omega blocking pattern through next weekend seen in long term global deterministic models (GFS/ECMWF).
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.AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 547 AM CDT Sun Sep 21 2025
While there is a small (
NWS ARX Office Area Forecast Discussion