831
FXUS63 KGRB 101708
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1208 PM CDT Sun May 10 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- A Frost Advisory remains in effect for areas over central
  Wisconsin and west of the Fox Valley for this morning.
  Additional frost is likely tonight into early Monday morning.

- Elevated fire weather conditions are expected today and Monday
  to do low humidities and drying fuels.

- High probability of rain on Tuesday (greater than 80%). A few
  isolated thunderstorms are possible over central and northeast
  Wisconsin as the system passes.

&&

.DISCUSSION...
Issued at 135 AM CDT Sun May 10 2026

Mostly clear skies tonight has allowed temperatures to drop into
the 30s in locations where the wind has gone calm, but a few
locations are still in the low 40s due to a light breeze. Expect
winds will still go calm/be light enough over the next few hours
for readings to fall into the upper 20s to middle 30s, with the
Frost Advisory in place for central WI until 8:00 AM.

Precipitation: Surface high pressure starts building in from the
northwest today, while upper low continues to spin across
northeast Ontario, which sends some shortwave energy across
northern WI. The atmosphere is still very dry, but similar to
Saturday, there may be just enough to get a brief shower or
sprinkles, particularly across northern and northeast WI closer to
the shortwave. CAMs also highlight some speckled development from
mid- morning through the afternoon. Any accumulation would be a
hundredth or two.

Models remain in agreement in sending a clipper across Wisconsin
on Tuesday into Tuesday night. Trends have been consistent with
rain chances greater than 80% in most locations (lowest in central
WI). LREF probabilities of getting at least 0.10" of rain range
from 70-90%, with probabilities of exceeding half an inch around
5-15%, highest across the north. So while rain is likely, amounts
are not high enough to raise any flooding concerns. There is some
modest instability with CAPEs around 300 J/kg and mid-level lapse
rates around 7.0 C/km, which would result in isolated
thunderstorms, but severe storm potential appears low at this
time.

On and off rain and thunderstorm chances return Friday and next
weekend as a progressive weather pattern develops, but specific
timing details are not certain this far out.

Temperatures: A couple more below normal days today and Monday
with highs mainly in the 50s, and lows in the upper 20s and 30s,
leading to frost formation and necessary headlines where the
growing season has started. Readings bounce around normal through
the midweek, then we eventually see a shift to southwest flow by
late week, bringing in a warmer air with highs in the 70s to low
80s Friday into next weekend.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1208 PM CDT Sun May 10 2026

Upper level disturbances will pass across far northern Wisconsin
and the Upper Peninsula this afternoon, bringing broken VFR cloud
cover and scattered light showers and sprinkles. Cloud bases will
generally be above 6 kft at the terminals, but could fall as low
as 3500 ft near the U.P. border.

Clearing skies are anticipated this evening then clear skies
overnight until about 15z before fair weather clouds pop with the
heat of the day.

Gusty northwest winds 20 to 25 kts will subside early this
evening. Winds will then be light and variable overnight through
Monday morning with high pressure in control.

&&

.FIRE WEATHER...
Issued at 135 AM CDT Sun May 10 2026

Elevated fire weather conditions will persist from the late
mornings through the afternoons the next couple days. For today,
another day of deeper mixing will bring down some 20 to 25 mph
gusts at times. Minimum relative humidity this afternoon will
range from 25 to 35%. On Monday, the surface high moves across
northern WI which will result in much lighter winds around 5 to 10
mph. Minimum RHs of 22 to 30% are forecast north and west of the
Fox Valley, and in the lower 30s across the Fox Valley and east-
central WI away from Lake Michigan where a lake breeze is likely
to bring in more humid air.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from midnight tonight to 8 AM CDT Monday for
WIZ022-030-031-035>040-045-048>050.
&&

$$

DISCUSSION.....KLJ
AVIATION.......MPC
FIRE WEATHER...KLJ

NWS GRB Office Area Forecast Discussion