textproduct: La Crosse

KEY MESSAGES

- Rain chances return Thursday (20 to 50%), mostly impacting portions of northeast Iowa and southwestern Wisconsin with amounts generally around , however amounts remain below 0.1".

- Rain likely for Friday morning and thunderstorms for Friday evening. There is a 30 to 75% chance for at least 1" of rain to fall Friday into Saturday.

DISCUSSION

Issued at 104 PM CST Tue Mar 3 2026

Today-Thursday: Dry Early with Rain Chances Returning for Some on Thursday

Dry conditions for today and Wednesday as highs get into the upper 40s to low 50s on Wednesday. A low that is forming over the Intermountain West will shift into the Central Plains and portions of the Midwest on Thursday. This increases rain chances across eastern Iowa and western Illinois while also creeping into southeastern portions of our CWA in northeast Iowa and southwestern Wisconsin. Ensemble members from both the GEFS and EPS support this as the majority of the them (>90%) show measurable precipitation in Platteville, WI. Looking at the 00Z LREF probability of measurable precipitation, it is ranging from 30 to 80% across portions of northeast Iowa and southwestern Wisconsin with the highest probabilities in southern Wisconsin. Not much is expected for rain with this system as the probabilities for more than 0.1" drop off greatly compared to the measurable rain, with only a 20 to 40% for 0.1", mostly across Grant county.

Friday: Rain/Thunderstorms Likely in the Morning and Again in the Evening/Overnight

Heading into Friday morning, a trough begins to eject out of the Central Rockies and move into the Central Plains. Ahead of this trough, 850mb winds increase to the 35 to 45kt range and bring increased moisture to the region. The most recent NAEFS continues to indicate that this will be an anomalous amount of moisture with the PWATs reaching the 99th to 99.5th percentiles, around 1 to 1.25". NBM probabilities for greater than 1" occurring by 12PM Friday are between 30 and 50% for areas along and south of I-90. More rain chances are expected Friday evening/overnight as the low associated with the trough over the Plains moves into the Midwest. While showers and storms are expected, there remains quite a bit of uncertainty regarding storm strength, location of the low, and how far north the warm sector can get. Moisture transport remains good following the morning convection and even in the GFS it actually is stronger in the evening compared to the morning. The 12Z GFS continues its trend of moving the low further and further north, which in turn brings the warm sector further north into much of our CWA. The 06Z ECMWF is a little more progressive than the GFS and does not bring the warm sector as far north. While instability is not that high with MUCAPE for Friday remains in the 500 to 1000J/kg, there is decent low level shear, 25 to 40 kts. As a result of the potential for severe weather both CSU machine learning severe guidance and SPC have highlighted much of the forecast area in a 15% risk for severe weather to occur Friday evening and into the early overnight. While the severe weather threat is still uncertain, the heavy rain threat remains. NBM probabilities for at least 1" to fall by Saturday morning at 6AM are now between 50 and 75% for northeast Iowa, locations south of I-94 in Wisconsin, and portions of southeast Minnesota. We will continue monitoring this as we get closer.

Saturday- Early Next Week: Dry Weekend with Rain Chances Returning Tuesday into Wednesday

After a slight cooldown from Friday with highs in the mid 40s to low 50s, temperatures warm up as warm air advection pushes into the Upper Midwest for Sunday and Monday as highs get into the upper 50s to low 60s. Rain chances return Tuesday into Wednesday as a trough dips down into the northern CONUS. Ensembles favor this as the 00Z LREF shows a widespread footprint of 55 to 75% of measurable precipitation between Tuesday morning and Wednesday morning.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1112 PM CST Tue Mar 3 2026

LIFR to below airfield minimum vsbys are expected at KRST with areas of 1/4SM fog developing across portions of southeast MN and northeast IA prior to sunrise. Given the high probabilities (60-80%) in the recent HREF for 1/4SM at KRST in combination with calm winds, clear skies and a pronounced nocturnal inversion in the RAP/HRRR, thinking a period of 1/4SM is likely to occur. However, as daybreak occurs and diurnal mixing processes take place, expecting the fog layer to lift fairly quickly by mid-morning leaving behind VFR conditions. As you head closer to the Mississippi River, probabilities decrease for 1/4SM vsbys for portions of western WI with only low probabilities (20-30%) in the HREF at KLSE. As a result, have maintained IFR reductions from the previous forecast but there is some potential (40% chance) for no vsby reductions at KLSE. In any case, VFR conditions are expected after this fog lifts mid-morning across the area and likely stay VFR for the remainder of the TAF period.

ARX WATCHES/WARNINGS/ADVISORIES

WI...None. MN...Dense Fog Advisory until 10 AM CST Wednesday for MNZ086-087- 094>096. IA...Dense Fog Advisory until 10 AM CST Wednesday for IAZ008>011- 018-019-029.