Forecast Discussion for GRB NWS Office
658
FXUS63 KGRB 110353
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1053 PM CDT Thu Sep 10 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Chances for thunderstorms return on Friday night into Saturday
  morning. The severe weather threat is low.

- Potential for heavy rainfall and thunderstorms increases Monday
  into Tuesday as a stronger low pressure system tracks near the
  region, though forecast uncertainty remains high.

- Gusty south-southwest winds will generate high waves along Lake
  Michigan Friday afternoon through Saturday morning, causing
  hazardous conditions to small craft and dangerous swimming
  conditions at Lake Michigan beaches.

&&

.DISCUSSION...
Issued at 154 PM CDT Thu Sep 10 2026

Mostly clear skies are expected through Friday as high pressure
tracks through the western Great Lakes region.

Storm Chances Return Late Friday: Next chance for
showers/thunderstorms comes late Friday night into Saturday
morning as an upper trough drags a cold front across the region.
The risk for any severe storms is very low (less than 5%) as
forecast soundings show a stout capping inversion during the
period. Guidance also continues to the axis of greatest
instability and moisture remaining well west of the forecast area.
There is still some timing uncertainty with when rain may come to
an end Saturday as recent model guidance has come in slower with
the passage of the front which could lead to showers lingering
through the morning Saturday. Overall the trend with the
rain from this front has diminished from previous runs as some
models suggest the front could pass through with little to no rain
as the best dynamics stay to the north with the best instability
to the south. This is reflected in the latest NBM pops with a
small chance (

NWS GRB Office Area Forecast Discussion