Brokaw, Wisconsin Weather Forecast Discussion

069
FXUS63 KGRB 091916
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
216 PM CDT Tue Sep 9 2025
Forecast discussion for routine afternoon forecast issuance
.KEY MESSAGES...
- Rain and a few storms continue across far north-central
  Wisconsin. Additional rain (30-50% chance) arrives in the late
  evening for central Wisconsin.
- Additional potential (20-40% chance) for showers on Wednesday,
  mainly west and north of the Fox Valley and Green Bay areas.
- Conditions hazardous to small craft, along with dangerous
  swimming conditions, expected on the bay and Lake Michigan
  through this afternoon/evening.
- Chances for showers and thunderstorms return for the start of
  the weekend.
&&
.DISCUSSION...
Issued at 216 PM CDT Tue Sep 9 2025
Shower and storm activity continue across far north-central
Wisconsin at the leading edge of the warm air this afternoon.
Generally, the rain has made a slow shift east and south, but will
likely continue into the mid to late afternoon. The rain may see
more breaks develop in the evening as the sustaining low level jet
weakens, but kept at least some pops (20-40%) in the area to
account for lingering activity, especially with some signs of
additional development further to the west along the leading edge
of the warm air. Rain amounts under these storms could still get
to a few tenths, but will be heavily localized to the northwoods.
A cold front accompanied by an upper shortwave feature currently
visible on satellite and radar will also continue to work its way
towards the region by the late evening hours. Although this is
forecast to weaken on its way into our area, scattered (30-50%)
shower activity seems likely across central Wisconsin by Wednesday
morning. The rain across central and north-central Wisconsin will
also provide a window for fog development during the overnight
period, so kept fog in the forecast for much of central to north-
central Wisconsin.
Wednesday precipitation trends are less certain. Some guidance
suggests the weakening cold front and shortwave will lead to
precipitation departing the region by the late morning. That said, weak
surface instability on model soundings, ample moisture, and
lingering upper support as the shortwave crosses the region in the
afternoon does suggest at least scattered shower activity.
Therefore, leaned away from a dry forecast and kept at some low
pops (20-30% chance at any one location) in the forecast to
account for some lingering light shower potential. Overall, the
better probability remains north and west of the Fox Valley,
especially in the afternoon where again there are signs of maybe
a rumble of thunder for far northern Wisconsin. However, if
anything does stay organized a little longer, a brief sprinkle
will be possible across the Fox Valley as well.
High pressure builds into the region as the front shifts
southeast Wednesday night, and should bring dry weather through
most of Friday. The high pressure system will edge east Friday
night into Saturday, allowing the front to return as a warm
front. Scattered showers and thunderstorms are expected develop
as this occurs. Dry weather should return late in the weekend as
strong ridging aloft builds across the western Great Lakes.
Temperatures will remain close to normal through midweek, then
rise above normal Friday into Saturday, with highs reaching the
upper 70s and lower 80s in most areas.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1236 PM CDT Tue Sep 9 2025
A band of showers and thunderstorms will be around the northwoods
early this afternoon, impacting primarily RHI. Accompanying the
rain will be some MVFR ceilings. Elsewhere skies start off mostly
VFR with mid level cloud cover expected to expand across the
region through the afternoon and evening.
Showers will move in from the west tonight, crossing into central
Wisconsin. These showers are unlikely to get into the Fox Valley
by the early afternoon, so no mention of precipitation for our
east-central Wisconsin sites for now. The rain will also bring in
a good chance for fog, especially for RHI so expect some IFR or
even LIFR conditions for a time before sunrise Wednesday morning
in north-central Wisconsin.
Flying conditions then improve during the day Wednesday, but some
clouds will stick around, along with a isolated shower chance
during the afternoon period on Wednesday.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement until 10 PM CDT this evening for WIZ022.
Beach Hazards Statement until 7 PM CDT this evening for WIZ040-
050.
&&
$$
DISCUSSION.....Uhlmann
AVIATION.......Uhlmann

NWS GRB Office Area Forecast Discussion