FXUS63 KGRB 271818

AFDGRB



Area Forecast Discussion

National Weather Service Green Bay WI

118 PM CDT Mon Oct 27 2025



Updated aviation portion for 18Z TAF 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 18Z TAF Issuance

Issued at 118 PM CDT Mon Oct 27 2025



Southeasterly flow and low-level moisture has allowed a SCT/BKN

afternoon cu field to develop following this morning's

fog/stratus. While this cu field will dissolve throughout the

afternoon and skies will remain clear into the evening, high

clouds from an approaching system will increase from the

southwest overnight. However, forecast soundings indicate a

shallow layer of low-level clouds will develop/move into portions

of the region after 08z Tue into Tuesday morning. Winds will turn

more easterly on Tuesday and increase with gusts of 15 to 20 kts.



&&



.GRB WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION.....Eckberg

AVIATION.......Kruk