629
FXUS63 KGRB 271801
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
101 PM CDT Tue Oct 27 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Rain likely (50-90%) with a chance (15-40%) of non-severe storms
  Wednesday evening into early Thursday. Another chance (15-30%)
  for scattered showers this weekend, and again early next week.

- Record temperatures possible on Wednesday, with temperatures
  staying above normal into next week.

&&

.DISCUSSION...
Issued at 100 PM CDT Tue Oct 27 2026

Precip and thunder chances...Broad warm air advection regime will
continue to support a few showers or sprinkles into tonight. Rain
will end late. Maybe a touch of stratus/fog late tonight based on
wealth of stratus upstream this morning. Shortwave trough currently
over Pacific Northwest swings across northern Plains on Wednesday
into Wednesday night. Strongest forcing and primary surface low
with this tracks from Minnesota into Ontario Canada. Weak cold
front tied to the low crosses Wisconsin late Wednesday and Wednesday
Night. Periods of showers (70-100%) expected for our area and with
elevated instability over 500J/kg, a few non-severe embedded
thunderstorms will occur. Bulk of rain occurs on Wednesday night.
Effective shear and greater instability and even some surface
based instability from MO-IA into MN may support a higher severe
risk there, which lines up with Machine Learning output. Lingering
showers exit eastern Wisconsin Thursday morning, with dry weather
returning late Thursday into Thursday night.

Rainfall totals from Wednesday afternoon through Thursday morning
still look to remain on the light side, with probabilities of
over 0.25" 50-80% highest from central to north-central Wisconsin,
and probabilities for over 0.50" 30-50%, highest in far north-
central Wisconsin. Any rain will help with the ongoing drought
across northern WI.

Unsettled weather returns this weekend, including for Halloween
activities. Some scattered light showers around, but not a washout
by any stretch, with NBM/LREF probabilities for more than 0.05"
30-60%, highest over central Wisconsin. Looking farther ahead, a
lot uncertainty but some indications at least off and on of a
stronger system that may impact Wisconsin for Election Day with
gusty winds and rain.

Temperatures...Plan on a quick rebound in temperatures from this
early weeks chill. Warm sector living will boost highs into the
upper 60s to lower 70s on Wednesday. Some record highs could be
broken, but if low clouds linger longer into the day that would
put a crimp into that. Record highs for Wednesday (10/28) are 70
at Green Bay (1946), 71 (1986), and 78 (1927). Slight cooling on
Thursday behind the weak front, most notable in the north. Highs
elsewhere still reach the mid 60s. Average highs for late October
are in the low 50s. On into the weekend, no cool down is in sight.
Highs will be in the upper 50s to lower 60s, depending on clouds
and coverage of showers. Temperatures may cool into the 50s next
week, especially if the stronger system ends up verifying over
the region as the ECMWF has shown recently and is hinted at by
LREF precip and wind gusts probabilities.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 100 PM CDT Tue Oct 27 2026

As high pressure moves east and low pressure lifts across the
northern Plains, Wisconsin will be within warm air advection
regime through Wednesday afternoon. Better chances for showers and
even some thunder move into the area on Wednesday night ahead of
cold front tied to the low. A few light showers or sprinkles could
occur into tonight, but these look too few and far between to
include any mention in TAFs.

IFR to MVFR cigs have been slow to dissolve today and extended
them a few more hours before they mix out this afternoon.
Conditions will then be VFR tonight into most of Wednesday. Only
exception could be scattered-broken brief MVFR possible on
Wednesday morning central to north-central WI on edge of stratus
field over the northern plains that may try to edge eastward late
tonight.

East-southeast winds up to 10 kts with gusts 15-20 kts expected
into this evening, before becoming light from the southwest late
tonight into Wednesday. A brief period of LLWS may form this
evening over north-central, but have opted to not include right
now. Greater chance of LLWS occurs late Wednesday afternoon into
Wednesday night as the core of low-level jet shifts into the
region.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion