NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 202349
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
649 PM CDT Wed May 20 2026

Updated aviation portion for 00Z 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 00Z TAF Issuance
Issued at 648 PM CDT Wed May 20 2026

Daytime cumulus clouds will continue to fade late this afternoon
and early evening with the loss of daytime heating. Mid and high
clouds (above 12k ft) will continue to spread across the region
tonight into Thursday. A stray sprinkle will be possible from this
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 it were to occur.

Light north winds will continue to shift to the east this evening
as the lake breeze continues to move west. Model soundings show
a period of 20-25 kt winds around 1000 ft later this evening,
with some of that trying to mix down, so added a period of gusts
to around 15 kts, but nighttime stability should limit the
gustiness. East to southeast winds generally under 10 kts are
expected on Thursday.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from midnight tonight to 8 AM CDT Thursday for
WIZ005-010>013-018-019-021-073.
&&

$$

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