940
FXUS63 KGRB 041750
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1250 PM CDT Tue Aug 4 2026

.KEY MESSAGES...

- A few non-severe storms (30-60%) may impact mainly east-
  central into northeast Wisconsin late this afternoon/evening.

- There are intermittent 30-50% chances for storms Friday
  through early next week, but confidence in timing and
  potential severity are low at this time.

&&

.DISCUSSION...
Issued at 1250 PM CDT Tue Aug 4 2026

A cold front will pass southeast across the area this evening into
early Wednesday. Ahead of the front, the HREF surface-based CAPE
reaches ~1000 J/kg across east-central Wisconsin, although
synoptic forcing and deep layer shear are relatively modest.
Isolated to scattered storms may develop ahead of the front, but
the severe weather risk will be quite low. Additional showers
may persist north of the surface boundary overnight into
Wednesday.

A shortwave trough will drag a boundary south towards the area on
Friday with a 20-40% chance of storms. Over the weekend into early
next week, the local area will likely reside on the northern
periphery of a seasonably warm, moist and unstable environment.
Subtle shortwave troughs embedded in the seasonally strong mid-level
westerly flow  will interact with the low-level boundary and
instability to produce rounds of showers and storms across the
Midwest. However, predictability of storms at this range is low in
this type of pattern. Some weather risk could evolve given the
degree of flow aloft, but these trends will need to be evaluated in
coming days as confidence increases with the degree of instability,
timing of shortwaves, and boundary placement.

Otherwise, temperatures will trend seasonably warm late this week
into the weekend. Some smoke aloft from wildfires may lead to hazy
skies at times, but HRRR smoke model suggests low near surface smoke
concentrations through Wednesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1250 PM CDT Tue Aug 4 2026

A cold front move southeast this afternoon and tonight with
scattered thunderstorms most likely (40-60%) late this afternoon
and evening across east-central Wisconsin. The greatest window
for any storms was refined at KGRB, KATW and KMTW, but
additional adjustments likely will be needed in subsequent
updates. Showers may persist overnight into early Wednesday
north of the front, but with the thunder threat lower.
Southwest winds will shift west/northwest in the wake of the
front or become light overnight. With the light flow, areas of
IFR/MFR stratus may develop overnight into Wednesday morning.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement from 2 PM this afternoon to 10 PM CDT
     this evening for WIZ022-040-050.
MARINE...Small Craft Advisory from 2 PM this afternoon to 10 PM CDT
     this evening for LMZ541>543.

&&

$$

DISCUSSION...JM
AVIATION...JM

NWS GRB Office Area Forecast Discussion