FXUS63 KGRB 270847 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 347 AM CDT Mon Oct 27 2025 Forecast discussion for routine morning forecast issuance .KEY MESSAGES... - Mainly dry conditions will persist through Thursday, courtesy of dominant Canadian high pressure. Rain chances Tuesday are minimal, as dry air should inhibit the eastward extent of the rain. - A Small Craft Advisory is in effect from 7 pm Monday to 7 am Wednesday for the nearshore waters of Lake Michigan from Rock Island to Sheboygan. Persistent east to southeast winds of 10 to 20 knots with gusts to 30 knots will create waves of 4 to 7 ft, resulting hazardous conditions for small craft. - High temperatures will generally be near or slightly above normal all week - High uncertainty exists for the timing of the next rain chance late in the week due to an upcoming pattern shift. && .DISCUSSION... Issued at 346 AM CDT Mon Oct 27 2025 Patchy fog (not as widespread as yesterday morning) was noted across portions of northeast Wisconsin early this morning, generally from Clintonville and Shawano north to near Iron Mountain. There was a wide range in temperatures early this morning ranging from 30 at Oconto to 47 at Manitowoc. Any lingering fog should burn off a few hours after sunrise, with mostly sunny skies with highs in the middle 50s to around 60 this afternoon. An approaching low-pressure system on Tuesday is expected to bring increasing cloudiness to the region. Latest model trends suggest the rain will hit a brick wall due to the dry Canadian high pressure system in place. We have very low confidence that any meaningful rain will make it into central or northeast Wisconsin, with the system likely shunted to the south Tuesday night into Wednesday. Highs on Tuesday will be in the 50s. High temperatures today and Tuesday has been raised a few degrees due to the cool bias in the MOS guidance. Dry weather will hold firm through Wednesday and Thursday as the high pressure remains entrenched. The weather pattern undergoes a significant shift beginning Friday, as the upper-level ridging breaks down and transitions to a more progressive west-northwest flow. This change introduces significant uncertainty regarding the timing of the next organized precipitation. Models suggest a chance for rain late Friday or over the weekend, but details are unclear. Temperatures are expected to remain near or slightly above normal throughout the period, and current guidance suggests highs may be slightly too cool and could be increased in later updates. On Lake Michigan, winds and building waves prompted the issuance of a Small Craft Advisory from 7 PM Monday until 7 AM Wednesday morning for the nearshore waters. On the bay, confidence was lower in meeting Small Craft criteria, thus held off on issuing for the bay at this time. Day shift will need to take another look at this. && .AVIATION...for 06Z TAF Issuance Issued at 1017 PM CDT Sun Oct 26 2025 Clear skies and light southeast winds should lead to fog development overnight, especially in the SE upslope region of far northeast WI, where boundary layer winds will be lightest and models show lowest vsbys. Prospects for fog have gone up in parts of the Fox Valley/lakeshore areas, where winds have been lighter and temperatures have dropped off quicker than anticipated this evening. Therefore, have increased fog in the GRB/MTW TAFs for the overnight period. Models show little signal for lake-enhanced stratus overnight (and there's no current evidence on satellite), and daytime cumulus development on Monday, so will forecast clear skies outside of any low stratus associated with fog. Fog is expected to mix out by around 14z/Mon. Light southeast winds will prevail overnight, increase to around 10 knots with gusts to 15 to 20 knots on Monday, then diminish to 5 to 10 knots by sunset. Some LLWS could develop over far north central WI (northwest of RHI) late Monday evening. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Eckberg AVIATION.......Kieckbusch