textproduct: La Crosse

KEY MESSAGES

- With temperatures in the mid 20s to mid 30s, little cloud cover, and light winds, frost/freeze headlines have been issued for areas along and east of the Mississippi River for tonight. Another frost/freeze headline likely needed for Friday night as well.

- Cooler temperatures heading into the weekend with highs generally in the upper 40s to mid 50s. Temperatures warm back up for early next week with highs in the mid 60s to low 70s. - Low rain shower chances (10 to 25%) for north central and southern Wisconsin this afternoon, northeast Iowa and southeast Minnesota tonight. Scattered rain showers possible (10 to 25%) for Friday afternoon.

DISCUSSION

Issued at 222 PM CDT Thu Apr 30 2026

Cooler Temperatures Going into the Weekend then Warming Up for Early Next Week:

West to northwest flow aloft will continue to be the dominant flow pattern over the next week at least. Ensemble guidance favors the longwave trough currently parked over the Great Lakes to continue sitting there before gradually moving off to the east by the end of next week. With this flow pattern bringing in cooler air, temperatures over the next couple of days will be 10 to 15 degrees below normal with highs in the upper 40s to mid 50s for today and Friday with a slight increase on Saturday as highs get into mid 50s to low 60s. EFI values for Friday are in the -0.7 to -0.8 and the low for Friday night has values between -0.5 to -0.7. These low EFI values give a good explanation of how cold temperatures will get compared to climatological normal. Conditions for tonight compared to last night as relatively similar for cloud cover, but the winds are looking a little lighter. Forecasted low temperatures for tonight are in the mid 20s to mid 30s and so as a result of all these conditions, a Freeze Warning has been issued for most of central and western Wisconsin with a Frost Advisory for the counties along the Mississippi River. With forecasted low temperatures in the mid 20s to low 30s for Friday night and mostly clear skies with very light winds, widespread frost and freeze headlines will likely be needed once again.

Heading into Sunday and Monday, while northwest flow aloft continues, southwest flow returns for the lower levels. This will help to warm up the region as highs get into the mid 60s to low 70s. After another cold front moves through on Monday night, cooler air remains through at least midweek with highs generally in the 50s.

Periodic Precipitation Chances:

For much of the forecast period, there will be periodic precipitation chances as the upper level pattern remains mostly in northwest flow. There are quite a few vorticity lobes and shortwaves that move through the Upper Midwest providing just enough lift for showers to form. There is even a low chance of seeing some snow showers in north central Wisconsin as temperatures get down into the upper 30s this evening and do not get above 40F until Friday afternoon. With little impulses moving through during this timeframe and low level temperatures staying below -6C until ~3000ft, light snow showers could occur. The next best chance for widespread precipitation chances is looking like Monday afternoon and evening. There remains some timing issues on when the cold front arrives on Monday which as led to initiation differences for rain. With the southwest flow returning, we also build a little instability on Sunday and Monday so some thunderstorms could be possible. After Monday, we return to northwest flow being the dominant flow pattern and have multiple shortwaves passing through the region giving us more rain chances.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 631 PM CDT Thu Apr 30 2026

Diurnally driven cloud cover wanes this evening and into the overnight hours across the region. SCT-BKN cloud cover between 5-10kft increases again after 05z, mainly west of the Mississippi River where a low chance of light rain exists into Friday morning, 10-20% per the 30.18z REFS. Ceilings around 5kft develop again areawide by Friday afternoon, again bringing the potential (10-30%) for some isolated showers into the evening. Winds remain out of the northwest through the TAF period, becoming light overnight before picking back up to around 10KT by the late morning Friday.

ARX WATCHES/WARNINGS/ADVISORIES

WI...Frost Advisory from midnight tonight to 8 AM CDT Friday for WIZ032-041-054-061. Freeze Warning from midnight tonight to 8 AM CDT Friday for WIZ017-029-033-034-042>044-053-055. MN...Frost Advisory from midnight tonight to 8 AM CDT Friday for MNZ079-088-096. IA...Frost Advisory from midnight tonight to 8 AM CDT Friday for IAZ011.