Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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452 FXUS63 KGRB 141717 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1217 PM CDT Mon Sep 14 2026 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - Chilly temperatures in the mid 30s will cause widespread frost across northern WI early morning. - A round or two of heavy rain and storms is expected this afternoon through Tuesday. Rainfall amounts of 1 to 3 inches are possible across central and east-central WI. The severe weather threat is low. - Hazardous conditions for small craft return this afternoon and continue into Tuesday. Small Craft Advisories or a Gale Warnings are in effect this afternoon and tonight. A Small Craft Advisory is in effect Tuesday morning, ending during the late afternoon. - High waves will lead to an increased risk of rip currents at Lake Michigan beaches this afternoon into Tuesday afternoon where a Beach Hazardous Statement is in effect. && .DISCUSSION... Issued at 158 AM CDT Mon Sep 14 2026 Forecast for a a round or two of heavy rain this afternoon through Tuesday morning remains on track. A strong low pressure system is evident on WV imagery over the northern Rockies early this morning. This system will progress east into the northern Plains today with strengthening southerly flow ahead of the low drawing seasonally high moisture into the region. Expect rain to initially push into central WI during the early afternoon, however, the exact timing for the onset of precipitation remains somewhat uncertain as forecast soundings do show dry air in the low-levels that will need to be overcome. This initial round will likely be light to moderate widespread rain that spreads across the area by afternoon. A second round of rain is then expected beginning this evenings over central WI as a strong LLJ pushes noises into the region. This second round is expected to bring a more focused area of moderate to heavy rain to central and east- central WI late this evening and overnight. Between these two rounds of rain HREF LPMM 24hr rainfall totals show a corridor of 2-3" totals south of a line from Wausau to Sturgeon Bay with 0.5 to 1" north of that line. The exact placement of this higher end corridor may still shift north or south slightly. A few embedded thunderstorms are possible with this system, but weak instability keeps the severe threat low. Rain will come to an end from west to east Tuesday morning high pressure them bringing dry conditions for the remains of Tuesday and much of Wednesday. For the remainder of the week a baroclinic zone is expected set up over or just south of the forecast area. This will keep a 40-70% chance for showers and occasional thunderstorms Wednesday afternoon through next weekend, however, it will likely not rain that entire period. Temperatures will hover near to slightly below normal next week depending on where the boundary sets up each day. && .AVIATION...for 18Z TAF Issuance Issued at 1204 PM CDT Mon Sep 14 2026 Tranquil early this afternoon with rain and a few thunderstorms moving northeast into the region during the mid to late afternoon hours and early this evening over far northeast WI. Rain and a few thunderstorms will continue into early Tuesday morning, gradually ending from northwest to southeast overnight into early Wednesday morning. VFR CIGS will fall into the IFR/MVFR category later this evening and overnight. CIGS should rapidly improve Wednesday morning. As for winds, south to southeast winds will continue to increase this afternoon. Low level wind shear will develop during the late afternoon or early this evening from 180-190 degrees at 40-50 kts which will veer to the southeast tonight. Surface winds will remain up tonight, with some guidance indicating gusts close to 30 knots this evening across eastern WI. The cold front will push across the area late tonight into Tuesday morning, with gusty west winds behind it that will linger into Tuesday afternoon. && .MARINE... Issued at 158 AM CDT Mon Sep 14 2026 Strengthening southerly winds today will lead to hazardous boating conditions on Lake Michigan and Green Bay. Strongest winds, with gale force gusts are expected late this afternoon through Tuesday morning. During the period waves on Lake Michigan may reach 12+ ft. While winds won`t be as strong Tuesday afternoon gusts of 20-25kts will continue to create conditions hazardous to small craft. With the high waves strong rip currents are also expected to create dangerous swimming conditions at Lake Michigan beaches. && .GRB WATCHES/WARNINGS/ADVISORIES... Beach Hazards Statement from 7 PM CDT this evening through Tuesday evening for WIZ022. Beach Hazards Statement from 4 PM CDT this afternoon through Tuesday afternoon for WIZ040-050. && $$ DISCUSSION.....GK AVIATION.......Eckberg MARINE.........GK