textproduct: La Crosse

KEY MESSAGES

- Periodic storm chances initially this evening and overnight into Wednesday morning returning for Wednesday. Low confidence in storms although damaging winds due to evaporative cooling of moist air into drier low level air remains a concern.

- Above normal temperatures continue through the weekend.

DISCUSSION

Issued at 1257 AM CDT Tue May 26 2026

Warmer Than Normal Temperatures Continue:

A persistence forecast expected through midweek with high confidence for above normal temperatures due to 90th to max percentile mid level heights observed in 26.00Z soundings across the central CONUS. While confidence for warmth is high, local confidence in degree of warmth is lower, due to interdependence on low confidence precipitation/storm probabilities. Highest confidence for warmest temperatures seen well west of the Upper Mississippi River Valley through the Northern Plains into the Rocky Mountain West potentially seeing triple digit daytime highs today through Friday. Local confidence for near 90 degree daytime high temperatures remains lower due to bias correcting models causing sizable, 5-10 degree warm tails, on top of low confidence storm chances.

Periodic, Low Confidence Storm Chances:

A little moisture convergence currently present over northern Iowa and southern Minnesota will slowly shift east early this morning. With minimal shear to work with, these showers and storms will be quite pulsey. There is some uncertainty on how far east these storms can get, as some model guidance has these storms getting into northeast Iowa and portions of southeast Minnesota over the next several hours. While closer to the forecast area, increased low level moisture is also expected to remain slightly upstream of local forecast area, solidified by a synoptic low level stretching axis extending from the southern Great Lakes through southern Canada through midweek.

Combination of subsidence along this stretching axis attempting to solidify drier, anticyclonic flow locally with incoming moisture advection attempting to entrain within the anticyclonic flow affects local precipitation chances this evening into the overnight. Although, drier air doesn't go far, providing a potential sharp cutoff in storms/precipitation. This synoptic setup also means shear values are nearly absent, limiting storm confidence while steeper mid level lapse rates suggest some instability for storms to initiate off the surface. Therefore, inverted V soundings do suggest strong winds from evaporative cooling will be possible should/where storms form through this evening and night.

While similar low confidence for storms Wednesday evening and night, more, albeit minimal shear values slightly increase concern for damaging winds where storms form.

Persistent Forecast Into The Weekend:

The area of anomalous heights intensifies through the lower levels (SPC RAOB Climatology at MPX) into Thursday, ushering in a backdoor cold front and tightening a near meridional moisture boundary across the forecast area. Long term global ensembles and accompanying deterministic members suggest an Omega block solidifying this boundary potentially through the weekend, keeping any confidence in precipitation minimal and temperatures warm.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 603 AM CDT Tue May 26 2026

A band of showers and storms is currently along and west of I-35. The expectation with these showers and storms is that they will slowly push east and and dissipate over the next few hours. These showers and storms may impact (15 to 30%) portions of northeast Iowa and southeast Minnesota, basically west of a Rochester to New Hampton line. Scattered storms then develop later this afternoon and continue into the early overnight. The main hazard with these storms would be gusty outflow winds. All precipitation chances diminish between 09Z and 12Z. Light southwest winds continue through the afternoon. Once storms get going and produce outflows, winds will be variable at most locations. CIGS mostly stay between 6kft and 10kft this afternoon and into the overnight.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...None. IA...None.