Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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881 FXUS63 KGRB 301730 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1230 PM CDT Thu Jul 30 2026 Forecast discussion for routine afternoon forecast issuance .KEY MESSAGES... - Chance (30 to 50%) for showers or storms today, mainly north of Highway 29. No strong storms are expected. - Wildfire smoke may reach the surface at times today and tonight. A drop to moderate (yellow category) air quality is expected. - Greater chances (50 to 70%) for showers and storms return Friday into Friday night. No severe weather is expected. && .DISCUSSION... Issued at 1035 AM CDT Thu Jul 30 2026 Rain/storm chances... CAMs are still showing a signal for diurnal showers/storms percolating over the north this afternoon into this evening where modest instability (1,000 to 1,500 J/kg) builds. Agitated cu has already begun popping as of early this afternoon, though remain unsure whether or not elevated smoke will hinder further shower development. Regardless, no strong or severe storms are expected, with most areas especially south of Hwy 29 remaining dry with ridging overhead. Next chances for more widespread rain/thunder arrive Friday morning, continuing into Saturday. Remain pessimistic about excessive rainfall potential given a more southerly solution presented by 12Z suite of model runs, with higher PWATs (1.75"+) holed up closer to the surface low. Additionally, dry air from departing high pressure persists to around 10k ft through Friday afternoon, delaying top down saturation of the profile. NBM continues to show broadbrush 40 to 60% chances for receiving 0.5" of QPF confined along/south of the Hwy 10 corridor, which doesn`t lend confidence to a forecast of widespread soaking rainfall. Convective activity should remain minimal due to weak shear (< 20 knots) and limited forcing. Overall, signs point toward a period of light to moderate stratiform rain Friday and Friday night. Expect light rain to persist through Saturday morning as the cold front continues to sag south. Dry weather should then settle in through around the mid-week timeframe as high pressure and upper ridging build. Smoke... Expect air quality readings in the moderate (yellow) category today into Friday as subsidence from high pressure brings an elevated smoke plume near the surface. Per upstream obs, little to no deterioration in visibility are expected. Overall air quality impacts are not expected to be as drastic as earlier in the month. && .AVIATION...for 18Z TAF Issuance Issued at 1035 AM CDT Thu Jul 30 2026 Some spotty MVFR cigs showing up this afternoon due to agitated cu field, though VFR conditions prevail for the most part through the end of the TAF period. Elevated wildfire smoke will continue to affect northeast Wisconsin through tonight, though vsbys should remain VFR if current obs hold. FEW to SCT showers/storms will be possible later this afternoon and evening mainly over the north as weak instability builds; have thus included a PROB30 mention of -SHRA in the RHI TAF. A more widespread round of stratiform rain/embedded thunder then arrives at the very end of the forecast period. Winds will remain under 10 knots through Friday afternoon, though locally higher gusts will be possible with any shower or storm activity. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Goodin AVIATION.......Goodin