FXUS63 KGRB 250359 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1059 PM CDT Fri Apr 24 2026 Updated aviation portion for 06Z TAF issuance .KEY MESSAGES... - Isolated to scattered showers with a rumble or two of thunder will be possible through this afternoon. Additional rainfall amounts will be light. - Another round of moderate to heavy rain with embedded storms is forecast for Monday into Tuesday. Locally heavy rainfall between 1 and 2" will be possible. - Rivers will continue to rise into next week following several rounds of heavy rain, which would exacerbate ongoing flooding. && .DISCUSSION... Issued at 1102 AM CDT Fri Apr 24 2026 Recent surface obs and satellite imagery show the cold front out over Lake Michigan as of this afternoon, leaving only showery activity over eastern Wisconsin in its wake. As such, temperatures are slightly cooler than they were at this time yesterday, maxing out in the upper 50s to mid 60s in/around the Fox Valley. Temperatures should continue to warm by a couple degrees over the course of the next couple of hours as low clouds scatter out. Much drier air has also moved in behind the front, with dewpoints dropping down into the 30s and 40s. Slight chance (15 to 30%) showers will be limited mainly to areas along the lakeshore for the remainder of the afternoon. Rain/storm chances early next week... Another bout of moderate to heavy rain remains on track for the Monday into Tuesday timeframe following a brief dry spell over the weekend. Dynamics with this system look slightly more impressive, with amplified synoptic flow and a wide open Gulf bringing an abundance of moisture. Precip onset should hold off until late Monday morning or even early afternoon as a Hudson Bay high continues to stream dry air into the region, with the majority of the QPF falling Monday afternoon into Monday night. PWATs remain steady at a respectable 1 to 1.25" (90th percentile relative to climo) along the front, with NBM probabilistic guidance showing a broad 30 to 60% chance for receiving one inch of rain. 10 to 25% signal for two inches remains unchanged from the previous forecast cycle. Current thinking is that severe weather potential would be rather limited with only a narrow window of maximized instability. This being said, would not be surprised to see a marginal risk up into our southern tiers of counties for elevated hail given 35 to 40 knots of deep layer shear and modest mid-level lapse rates. Regardless, expecting at least some rumbles of thunder Monday evening into Tuesday. Extended... The remainder of the extended will be characterized by a cooler and cloudier pattern as a blocking upper low sits and spins over the Great Lakes. Several shortwaves pivoting around the parent low may bring some showery activity throughout the week, though QPF will remain minimal. Highs will average in the mid 50s to low 60s. Overall, widespread rain and thunder chances look to be absent through the majority of the week following the Monday/Tuesday system. && .AVIATION...for 06Z TAF Issuance Issued at 1058 PM CDT Fri Apr 24 2026 The MVFR cloud deck continued across far northeast and east- central WI late this evening, while clear skies prevailed elsewhere. However, some breaks in the MVFR clouds began to develop from north to south. Based on cloud trends, anticipate the clouds to become scattered at the east-central WI TAF sites between 06z and 09z. There are still some indications the MVFR cigs may return at the ATW/GRB/MTW TAF sites Saturday morning, but confidence is still not high enough to include in the 06z TAF issuance. Patchy fog was beginning to develop in some spots across far north-central WI late this evening. Continued to include a TEMPO group at RHI for the potential reduced vsbys. Any fog will burn off soon after sunrise Saturday morning. Light and variable winds are expected at most terminals throughout the TAF period, with light northeast to east winds at the east- central WI TAF sites Saturday afternoon. && .HYDROLOGY... Issued at 1102 AM CDT Fri Apr 24 2026 Minor flooding continues on several rivers, namely the Wolf and Menominee. While the overall trend still shows water levels receding due to rainfall underperforming last evening, this is likely to change as we get another round of moderate to heavy rain Monday into Tuesday. Per RFC forecasts and HEFS guidance, it appears that the Menominee River could return to recent crests in major flood stage later this week into this weekend, though there is only a 10 to 25% chance of this occurring. However, increasing snow melt from the Upper Peninsula would lend some confidence for at least a return to moderate flood stage. A signal also exists for the Wolf River to continue rising into moderate or even major flood stage. Additionally, levels on the Lake Winnebago system continue to rise due to inflow from the Wolf and Fox Rivers, with minor flooding already occurring from Lake Poygan to Winnebago and minor flooding forecast to occur through the weekend. Those living near rivers or streams should continue to monitor the latest Flood Warnings and statements from the National Weather Service in Green Bay. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Goodin AVIATION.......Kruk HYDROLOGY......Goodin