


Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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350 FXUS63 KGRB 062329 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 629 PM CDT Sun Jul 6 2025 Updated aviation portion for 00Z TAF issuance .KEY MESSAGES... - Areas of fog possible in the Wisconsin River Valley late tonight. - Seasonal summer weather is expected over the next week. Shower and thunderstorm chances expected Monday night into Tuesday, and again Friday into Friday night. && .DISCUSSION... Issued at 255 PM CDT Sun Jul 6 2025 Rain associated with a short-wave trough was finally moving out of eastern WI this afternoon, and clouds were gradually clearing. North to northeast winds were gusting to around 20 mph in eastern WI. Temperatures ranged from the middle 60s near Lake Michigan to the 70s and lower 80s inland. Fog Potential Tonight...High pressure will ridge into the western Great Lakes tonight, resulting in partly cloudy skies and decreasing winds. Conditions will be most favorable for fog in the Wisconsin River Valley (NC/C WI), where boundary layer winds will diminish to around 5 knots. Farther east, there should be just enough wind to prevent any significant fog development. Although patchy dense ground fog is likely, do not anticipate any need for fog headlines. Precipitation Trends...Rainfall chances will occur in association with a couple short-wave and frontal passages this week; mainly during the late Monday night through Tuesday and Friday through Friday night periods. Current indications suggest only marginal instability for both events, so the severe threat is uncertain. The late week system appears to have a bit more dynamic forcing and a more moist air mass, with PWATs increasing to 2+ inches in some areas. Will need to keep an eye out for heavy rainfall potential Friday into Friday night. Seasonal temperatures are expected through the extended forecast period. && .AVIATION...for 00Z TAF Issuance Issued at 629 PM CDT Sun Jul 6 2025 The pesky MVFR clouds have finally exited far east central WI late this afternoon, with mainly VFR conditions expected for the rest of the TAF period. The exception will be if fog can develop tonight. Chance for widespread fog remains under 20%, but with the recent rain, would expect at least some patchy ground fog to develop overnight across parts of central and north central WI (especially in/near the Wisconsin River Valley), where winds are the lightest (under ~5 kts). Have continued with TEMPO groups between 08z-12z/Mon for fog at RHI/AUW/CWA. Across eastern WI, there was more rain over the past 24-36 hours, but winds in the boundary layer are a little stronger (5-10 kts), so it will be more of a challenge to get fog to form. Will hold off on any TEMPO groups at GRB/ATW/MTW for now and monitor trends this evening. Monday is looking dry with light winds. Chances for showers and storms return Monday night into Tuesday morning. Some elevated smoke could make for a hazy sky at times through the TAF period. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kieckbusch AVIATION.......Bersch