FXUS63 KGRB 200755

AFDGRB



Area Forecast Discussion

National Weather Service Green Bay WI

255 AM CDT Wed Aug 20 2025



Forecast discussion for routine morning forecast issuance



.KEY MESSAGES...



- Patchy dense fog expected through daybreak, especially central 

  and north-central Wisconsin.



- Isolated showers are possible at times today, especially east-

  central Wisconsin and the lakeshore. The rest of the week will

  be dry with the next chance for showers and thunderstorms Friday

  afternoon into Friday night. Severe storms are not expected.



- Temperatures will be around normal for much of the upcoming 

  week, with the potential for well below normal temperatures late

  in the weekend into early next week.



&&



.DISCUSSION...

Issued at 255 AM CDT Wed Aug 20 2025



Very patchy fog across the region early this morning should burn

off shortly after sunrise. A weak shortwave trough embedded in 

northwest flow will bring a small chance (10-20%) for light 

showers or sprinkles today across east-central Wisconsin and the 

lakeshore.



High pressure will then keep the region dry tonight through Friday

morning. A cold front will bring the next chance for showers and

thunderstorms to the region Friday afternoon and Friday night as

it tracks through the western Great Lakes region. NWP models are

not all that bullish on QPF amounts as this cold front tracks

through the area, as the best dynamics will be to the north. The

potential for severe storms looks fairly low as instability looks

to stay below 1000 J/kg with around 20 knots of bulk shear. A

strong storm cannot be ruled out during peak heating, but that

looks to be the extent of the severe potential at this time.



Behind the cold front a much cooler airmass will push into the

region as daytime highs go from the 70s to around 80 to the 60s to

around 70 or about a 10 degree tumble in daytime highs for the

weekend and into early next week.



&&



.AVIATION...for 06Z TAF Issuance

Issued at 1053 PM CDT Tue Aug 19 2025



LIFR/IFR clouds are forecast to spread southwest across the area 

late this evening and overnight, with some MVFR ceilings likely 

prevailing over eastern WI. Fog is also expected to develop 

tonight as winds decrease and enough low-level moisture will 

remain in place. Mainly IFR/MVFR VSBYs are expected, with some 

LIFR VSBYs possible in central to north-central WI, where skies

will remain clear longer.



Some sprinkles or light showers will be possible at times

overnight into Wednesday, but should not create any worse flying

conditions than the lower clouds and fog.



On Wednesday, once the fog lifts, expect lower ceilings to

persist early in the day, with a slow improvement through the day

as conditions improve to MVFR/VFR. Fog will again be possible

Wednesday night into Thursday morning, but likely after 06z

Thursday.



&&



.GRB WATCHES/WARNINGS/ADVISORIES...

None.



&&



$$



DISCUSSION.....Kurimski

AVIATION.......Bersch