451
FXUS63 KGRB 210514
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1214 AM CDT Thu May 21 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- A Frost Advisory is in effect for northern Wisconsin tonight
  where low temperatures around 30 degrees are expected.

- Frost headlines may also be needed Thursday night as lows fall
  into the low to mid 30s over the Northwoods.

- Below normal temperatures continue throughout the week, warming
  to above normal late this Memorial Day weekend into early next
  week.

- Dry weather is expected through at least early Friday with
  periodic rain chances throughout the Memorial Day weekend.

&&

.DISCUSSION...
Issued at 115 PM CDT Wed May 20 2026

Diurnally driven cumulus clouds continue across northeast
Wisconsin this afternoon. These clouds are expected to scatter out
this evening with the loss of daytime heating as drier air works
its way into the region. The combination of mostly clear skies and
light winds will allow temperatures to drop precipitously tonight,
as low temperatures range from around 30 across the north to the
middle to upper 30s across the rest of the region. The cold
temperatures across the north will trigger Frost Advisory
headlines for that area later tonight into Thursday morning.
Although temperatures could dip into the upper 20s across the far
north, the amount of time below freezing is expected to be too
brief for a Freeze Warning at this time.

Thursday will continue to be dry with continued below normal
temperatures expected. Lows Thursday night are once again expected
to drop into the lower to middle 30s across north-central
Wisconsin, where additional Frost Advisory headlines will be
possible. The rest of the region should be a bit warmer with lows
around 40 degrees.

High pressure will retreat from the region on Friday, which will
allowing two separate low pressure systems to approach the region
first from the south then from the west during the Memorial Day
weekend. Current model trends do not bring the brunt of these
systems through northeast Wisconsin, which means instead of a
prolonged wet showery weekend, periodic chances for showers and
thunderstorms will be possible at times. Additional shortwaves
will bring small chances (20-30%) for showers and thunderstorms at
times into the middle of next week.

Temperatues will be below normal through the end of the week,
then eventually warm to above normal by the second half of
Memorial Day weekend and last into the middle of next week.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1214 AM CDT Thu May 21 2026

Mid-high clouds (above 12k ft) will continue to spread across the
region overnight into Thursday, with only a few other lower
clouds possible at times. A stray sprinkle will be possible from
the mid-cloud deck, mainly across central and east-central WI, but
dry air in the low-levels will limit this activity and there
would be no impacts to aviation if any sprinkle were to occur.

Northeast to southeast winds will continue overnight, mainly
under 10 kts. Model soundings continue to show a period of 20-25
kt winds around 1000 ft in the late evening and early overnight
hours. Nighttime stability will limit the gustiness, but a few
gusts to ~15 kts are expected. East to southeast winds generally
under 12 kts are expected on Thursday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory until 8 AM CDT this morning for WIZ005-010>013-
018-019-021-073.
&&

$$

DISCUSSION.....Kurimski
AVIATION.......Bersch

NWS GRB Office Area Forecast Discussion