Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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800 FXUS63 KGRB 221643 AAA AFDGRB Area Forecast Discussion...UPDATED National Weather Service Green Bay WI 1043 AM CST Sat Nov 22 2025 New Information added to update section .UPDATE... Issued at 1042 AM CST Sat Nov 22 2025 Couple reports of light snow and/or graupel in northern WI and also over portions of central WI as warm air advection precip, with touch of mid-level instability, shifts across the region ahead of cold front. Added/expanded small mention of light rain/snow or sprinkles/flurries next few hours. Main area of concern from this precip impact wise would be over northern WI if ptype falls as rain (as it did upstream at IWD) as road temps in far northern WI are still just below freezing. Precip intensity is very light, so this should minimize the issue. No other changes of note to going forecast. && .KEY MESSAGES... - Mild with no significant precipitation expected until late Monday afternoon or evening. - A pattern change is expected in the middle of next week, with colder and blustery conditions, along with possible gale force gusts on the bay and lake. Some snow accumulation possible over northern Wisconsin Wednesday into Thursday. && .DISCUSSION... Issued at 326 AM CST Sat Nov 22 2025 Mid-level clouds were spreading into the forecast area as WAA increased ahead of a cold front approaching from the eastern Dakotas. In advance of the clouds, clear skies and light winds allowed temperatures to drop into the teens and 20s. WAA, mid-level FGEN and a weak short-wave trough may generate enough saturation for patchy light mixed snow/rain near the WI/Upper MI border today. The previously-mentioned weak cold front will move through the region this afternoon/evening. High pressure builds back into the region by Sunday, and lingers into Monday morning. Although clouds will hold back temperatures a bit today, abundant sunshine on Sunday should allow the typical warm spots to reach 50 degrees. Rest of the forecast: The remnants of a Southwest U.S. upper low will lift northeast toward the Great Lakes, bringing a chance of light rain to our western counties Monday afternoon, and widespread light to moderate rain to the entire region Monday night into Tuesday. A strong upper trough over the Northern Plains will then shift northeast and close off into an upper low as it moves through northern WI/Upper Michigan Tuesday night into Wednesday. This system will bring a mix of rain/snow Tuesday night, which should change to mainly snow on Wednesday. As the system shifts northeast Wednesday night into Thursday, gusty northwest winds should bring potential for lake-effect snow to the Lake Superior snowbelt, including Vilas County. Accumulating snow will be possible across northern Wisconsin during this period, with the highest likelihood of significant amounts occurring over Vilas County. Due to the strength of the system, there is increasing potential for northwest gales on Lake Michigan Wednesday into Thursday. Minor lake-effect may continue into Friday over the far north, but Saturday is looking mainly dry at this point. Temperatures: Normal to above normal temperatures are expected through Tuesday, with much below normal readings likely for the mid to late part of next week. && .AVIATION...for 12Z TAF Issuance Issued at 555 AM CST Sat Nov 22 2025 Mid-level clouds were overspreading the region early this morning, as WAA increased ahead of a cold front. This system may produce patchy light snow (mixed with rain in the afternoon) near the WI/MI border, but should not impact any of the TAF sites. A cold front will move through later this afternoon and evening, with a wind shift to west-northwest expected in its wake. Some low clouds off Lake Superior may drop into northern WI tonight, leading to a period of MVFR ceilings at RHI. Winds will be south-southwest and gusty this afternoon, then west-northwest after the frontal passage. Periods of LLWS will develop - see the individual TAFs for timing and details. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE.........JLA DISCUSSION.....Kieckbusch AVIATION.......Kieckbusch