FXUS63 KGRB 222316 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 616 PM CDT Sat Aug 22 2026 Updated aviation portion for 00Z TAF issuance .KEY MESSAGES... - Isolated to scattered showers and storms (20-60% chance) north- central to eastern WI this afternoon. A strong storm could produce gusty winds and hail. - Dry weather returns Sunday and Monday, with a period of unsettled weather arriving for the middle of next week. - Slightly below normal temps this weekend, then a return to near normal readings for most of next week. Lows Sunday night may drop into the 30s north-central. && .DISCUSSION... Issued at 1242 PM CDT Sat Aug 22 2026 Near term through Sunday...Northwest flow and shortwave diving across this afternoon during peak heating will result in isolated to scattered showers through 7p, especially far northeast WI and on across Door County. While weak deep layer shear (less than 25 kts) limits overall storm organization and the severe threat, MLCAPEs up to 1000 J/kg, inverted-V soundings, very steep low- level lapse rates, and lower freezing levels will promote some gustier winds and small hail in the stronger showers/storms. Northwest winds will be breezy at 15 to 25 mph this afternoon, before diminishing this evening. Closer approach of sfc high will bring dry weather tonight into Sunday. Upper trough (cold air aloft) close enough to lead to another partly to mostly cloudy afternoon as fair weather cu blossoms. Northwest winds will be a little lighter on Sunday, but could still gust to 20 mph. Extended...Dry, but chilly Sunday night with high overhead and low PWATs allowing for good radiational cooling. MOS guidance already suggesting that typical cold spots up north could drop into the mid to upper 30s. Next chance for showers and some storms arrives Tuesday afternoon through Wednesday afternoon as a sharp mid- level trough and sfc cold front work through. If cold front is slower on Wednesday (ECMWF), there would be better chance for a few stronger storms over eastern WI that afternoon. Instability appears modest with this mid-week feature, keeping severe risk low. Machine learning is mixed at best on severe potential. Then, similar to today post fropa, steeper lapse rates and peak heating may yield another round of isolated to scattered showers and storms on Thursday. Temperatures...After the cooling this weekend into early Monday, temps return to near or even slightly above normal with highs mainly in the mid 70s to low 80s. Normal highs for the coming week start off in the 77-78F range, but by next weekend fall off into the mid 70s. && .AVIATION...for 00Z TAF Issuance Issued at 616 PM CDT Sat Aug 22 2026 Upper level disturbances within a sharp trough axis are shifting over northern Lake Michigan early this evening and taking showers and thunderstorms with them. Lingering fair weather clouds above 6 kft are observed on satellite behind the shortwave. These clouds will likely dissipate with loss of heating by 01-02Z. With a modest pressure gradient, MOS guidance shows little to no fog threat, but will monitor as climatology would suggest some patchy fog is possible across the northwoods where rain occurred this afternoon. Fair weather clouds will likely build with daytime heating 15-16Z Sunday. Cloud bases will remain VFR (5-6 kft) which will gradually rise through the afternoon. Northwest winds will remain breezy on Sunday with gusts 14-18 kts. && .MARINE... Issued at 1242 PM CDT Sat Aug 22 2026 Northwest winds of 10-20 kts with gusts to 25 kts expected tonight into Sunday morning behind re-inforcing cold front. Have hoisted Small Craft Advisory for the central Bay and for Lake Michigan nearshore waters north of Sturgeon Bay. Strongest winds will be near Death's Door and Washington Island. Offshore winds will limit waves to 1 to 3 ft for most spots on the bay and nearshore waters, with any 3-4 foot waves staying in the open waters. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....JLA AVIATION.......MPC MARINE.........JLA