FXUS63 KGRB 051718 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1218 PM CDT Tue May 5 2026 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - Cooler temperatures are expected for the rest of the week, with overnight lows approaching freezing. There is a 30-80% chance for frost from central to east-central WI Tuesday and Wednesday nights (highest in central WI, lowest near the lakeshore). - Minor precip chances this week with little to no impacts. && .DISCUSSION... Issued at 236 AM CDT Tue May 5 2026 Surface cold front is southeast of the state now which will allow winds to subside overnight, and marks the start of a cooler pattern. The main impacts over the next few days will be frost/freeze potential during the nights. There are minor precip chances, but amounts and impacts will be minimal. Temperatures: Highs today will be about 15 to 20 cooler than Monday, in the upper 40s to middle 50s. Similar readings persist on Wednesday and Thursday, and then return closer to seasonal normals on Friday and this weekend, in the upper 50s and 60s. Overnight lows will be the numbers to watch, as temperatures approach freezing Tuesday night through Thursday night. This will likely warrant frost or freeze headlines for central and east- central WI (these products have not yet begun for northern WI). NBM probabilities show a 30-100% chance of reaching 36 degrees or cooler Tuesday and Wednesday nights, with the lowest probabilities in east-central WI near the lakeshore. Frost potential is less certain Thursday night, with probabilities of 5-60% in central and east-central WI. By the weekend, overnight lows look to stay warm enough to avoid frost where the growing season has started. Precip: A few precipitation opportunities throughout the week, but impacts from any precipitation will be minimal. Upper low will spin northward across Ontario and Hudson Bay the next couple days, which will keep northeast Wisconsin in northwest flow and send a few shortwaves through the area. Today's shortwave is likely to be dry, with only the HRRR showing a few spits of precip. NBM probabilities for 0.01" of rain are around 5%. Similar situation on Wednesday, with a 10-20% probability of measurable precip across northern WI. The potential is best on Thursday (20-40%) for some measurable rain, again not amounting to much more than a few hundredths. && .AVIATION...for 18Z TAF Issuance Issued at 1214 PM CDT Tue May 5 2026 VFR conditions are expected through the TAF period. SCT-BKN VFR stratocumulus should scatter out this evening, then redevelop later Wednesday morning. Gusty west winds will diminish by early evening, then pick up again late tomorrow morning, though not as strong. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....KLJ AVIATION.......Kieckbusch