394
FXUS63 KGRB 272220
AFDGRB

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

Updated aviation portion for 00Z TAF 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 at Wausau (1986) and 78 at Rhinelander
(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 00Z TAF Issuance
Issued at 512 PM CDT Tue Oct 27 2026

IFR/MVFR CIGS across the north most problematic for the next
6-12 hours. With the warm front lifting northward later tonight,
uncertainty exist in when the IFR/MVFR CIGS will lift. For KRHI,
they may lift for awhile the sink back towards IFR conditions
between 06z-12z. Confidence is low this will occur, thinking
IFR CIGS may stay through the night. Scattered showers will linger
into the evening hours, thus will have tempo groups for a few
hours this evening. Any low clouds should lift Wednesday morning
with gusty south winds to around 20 knots expected by late morning
and afternoon. It will be mild with record or near record warmth
expected.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion