262
FXUS63 KGRB 241730
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1230 PM CDT Thu Sep 24 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Patchy fog, locally dense, may again be possible late tonight
  into early Friday morning.

- High pressure will maintain mostly dry weather through early
  next week.

- Next widespread rain chances arrive during the middle of next
  week.

&&

.DISCUSSION...
Issued at 1200 PM CDT Thu Sep 24 2026

Latest surface and radar obs show a broad area of light rain
impinging on northwest Wisconsin this afternoon where mid-level
shortwave and weak moisture convergence reside. Scattered showers
should make it to northeast Wisconsin by this evening, though any
QPF we manage to squeeze out should top off at a few hundredths of
an inch as precip encounters a wall of dry air. Signal then once
again exists for patchy fog development late tonight in the wake
of the showers as winds decouple and remnant moisture gets trapped
under near-surface inversion. Have a sneaking suspicion that fog
may end up overperforming similar to this morning, so will bear
monitoring.

Models continue to back off on rain chances over the weekend as
Hudson Bay high dominates the synoptic pattern. As such, PoPs
are held down to around 10 to 20% mainly over central and north-
central Wisconsin where models show the greatest chance for
showers. Strung out surface low then ejects off into northern
Canada early Friday morning, resulting in showers splitting to our
north and south.

Next chances for widespread stratiform rain remain on track for
the middle of next week as low pressure organizes over the central
Plains and deepening trough passes over the region. Though
ensembles still diverge on exact timing of precip, consensus shows
PWATs reaching near 90th percentile relative to climo, increasing
confidence in at least a soaking rainfall. Probabilistic guidance
currently shows a 40 to 50% signal for receiving one inch of
rainfall, though trends will need to continue to be monitored.
Otherwise, seasonal temperatures in the 60s to low 70s prevail
for the extended.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1200 PM CDT Thu Sep 24 2026

MVFR cu field with bases at around 2.5 to 3.5k ft has begun
popping this afternoon across portions of central and north-
central Wisconsin, which should lift to VFR in the next few hours
and eventually scatter out this evening. There is a low chance (<
20%) for light showers moving into central Wisconsin late this
evening into tonight, though better chances will be that all
terminals remain dry. However, main impacts to aviation during
this TAF cycle will revolve around patchy dense fog development
late tonight into early Friday morning. Vsbys may drop down to
LIFR or even VLIFR mainly across the north, though confidence is
low in this occurring. For the time being, have included TEMPO
groups for BR at RHI, AUW, and CWA. Otherwise, middle and high
clouds will continue to pass over the region at times through
Friday afternoon.

Southeast winds remain under 10 knots through this afternoon,
becoming light and variable overnight.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Goodin
AVIATION.......Goodin

NWS GRB Office Area Forecast Discussion