FXUS63 KGRB 270330

AFDGRB



Area Forecast Discussion

National Weather Service Green Bay WI

1030 PM CDT Sun Oct 26 2025



Updated aviation portion for 06Z TAF issuance



.KEY MESSAGES...



- Locally dense fog is expected again late tonight into early 

  Monday, reducing visibilities to under 1/2 mile.



- Light rain chances (15-40%) arrive Tuesday into Tuesday night

  and again late in the week.



- Seasonal temperatures for most of the week. 



- Persistent east/southeast winds will bring a prolonged period of

  high waves and gusty winds, especially on Lake Michigan, from 

  Monday night into Wednesday.



&&



.DISCUSSION...

Issued at 327 PM CDT Sun Oct 26 2025



Tonight and Monday: High pressure will remain in control of the 

western Great Lakes as it slowly slides eastward, bringing dry 

conditions. Daytime cumulus clouds will continue to fade late this

afternoon. Clear skies are expected for much of the evening, then

similar to last night, expecting low clouds and fog to form 

overnight into Monday morning, especially over northern WI. Setup

looks similar to last night with light southeast surface winds 

(upsloping), clear skies, and cross-over temps being reached. But 

some winds just off the surface could keep some of the denser fog

from forming. HREF/SREF and other models support the most 

widespread fog northwest of the bay, so have ramped up fog and 

cloud cover there. More patchy ground fog is favored elsewhere.

The patchy dense fog will reduce visibilities, impacting the 

morning commute in some spots. Lows should drop into the 30s for 

most locations, with some upper 20s over northern WI and some low 

40s near Lake Michigan. Any low clouds and fog will burn off by 

around 9am on Monday, with only a few fair weather daytime cumulus

expected through the day. Highs will climb into the 50s for most 

locations.



Rest of the week into next weekend: Model blend has slowly backed

off on chances for rain Tuesday into Tuesday night as a large, 

slow moving trough will become cut off to our south. The low will

be battling with a strong high pressure system across eastern

Canada, which will filter in drier air. This dry air looks to 

keep far northeast WI dry, with the best chances for rain west of 

a Rhinelander to Oshkosh line, but still only between 15-40%. As 

the cut off low drops south, it will drag the precip chances 

south of the area. As the low shifts up the eastern U.S., 

northeast WI could get clipped with western precip shield, but

better chances look to stay in MI. Another system will be diving 

southeast towards the Great Lakes in the Friday/Saturday 

timeframe, which looks to bring additional chances for light 

precip. Seasonal temps are expected for most of the week.



&&



.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.....Bersch

AVIATION.......Kieckbusch