271
FXUS63 KGRB 222346
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
646 PM CDT Thu May 22 2025

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Continued cool through Friday with highs mainly in the 50s. A
  few sprinkles may linger in eastern WI into early this evening,
  and a few more showers may develop in far northern Wisconsin
  and northern Door County late tonight into early Friday.

- Frost may be possible across northern Wisconsin at times through
  this weekend. Conditions look most favorable for widespread frost
  late Saturday night.

- A generally dry week is expected, along with gradually
  moderating temperatures from this weekend into next week. The best
  chance of rain occurs Tuesday into Wednesday.

&&

.DISCUSSION...
Issued at 317 PM CDT Thu May 22 2025

Widespread stratocumulus clouds and patchy light showers or
sprinkles in eastern WI should wane during the early evening,
with partly cloudy skies prevailing for much of the night. Another
batch of low clouds will arrive in northern WI late tonight, in
the wake of a weak cold frontal passage. Cold north flow off Lake
Superior could result in redevelopment of a few light showers or
sprinkles over far northern WI and northern Door County late
tonight into early Friday, but these should diminish as Canadian
high pressure builds into the region in the afternoon. Lows
tonight will be in the middle 30s to lower 40s. Highs on Friday
will be in the 50s to around 60 range.

An upper level trough over Canada will gradually sag south into
the region during the remainder of the forecast period, while
persistent Canadian high pressure ridges across the area.
This will lead to a cooler and drier period, with very small
shower chances occurring during daytime heating, or with the
passage of weak short-waves. The best chance of rain will occur
as low pressure tracks southeast of the region and an upper
trough moves through Tuesday into Wednesday. Most of this rain, if
it occurs, should be light and mainly impact C/EC WI. A gradual
moderation in temperatures is expected starting this weekend,
with slightly above normal readings possible by the middle of next
week.

Frost Potential: Only patchy frost is expected over northern WI
tonight, as surface/boundary layer winds stay up and low clouds
arrive late. Models suggest that clouds will also be present
across northern WI through much of Friday night. The best setup
for widespread frost appears to be late Saturday night as skies
clear and winds drop off.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 646 PM CDT Thu May 22 2025

VFR conditions prevailed across the region this evening with
SCT/BKN clouds of 6000-8000 ft AGL. Isolated light showers or
sprinkles were also observed in far NE WI and along portions of
the lakeshore. Anticipate these showers to end once the sun sets
this evening. The SCT/BKN clouds will continue through much of the
night before MVFR cigs drop into northern WI early Friday
morning, reaching RHI around 09z/Fri. Similar to today (Thursday),
the low clouds will become more extensive across all TAF sites
throughout the morning before lifting to VFR during the afternoon,
except near the Upper MI border.

Light northerly winds are expected tonight, increasing again
Friday morning with gusts up to 20 kts.

&&

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

&&

$$

DISCUSSION.....Kieckbusch
AVIATION.......Kruk