NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 191902
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
202 PM CDT Thu Mar 19 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Wintry mix tonight near the Michigan border. Minimal snow and
  ice accumulation expected.

- Areas of fog tonight into Friday morning central to north-
  central WI.

- Next chance of a wintry mix and snow (30-50%) Saturday night
  into Sunday, especially over northern WI.

- Temperatures surging above normal into Saturday, with the warmth
  peaking Saturday (mid to upper 50s). Snowmelt and increased
  flows and rising levels on rivers and streams are expected.
  Several rivers may reach bankfull or even minor flood stage
  beginning this weekend.

&&

.DISCUSSION...
Issued at 201 PM CDT Thu Mar 19 2026

NW flow will bring a couple of clipper systems to the region. The
first occurs tonight into Friday morning with a smattering of
light rain, snow and possible freezing rain near the immediate
border with Upper Michigan. Ice and snow accumulations look
minimal and sfc temps will be at or above freezing. Thus, impacts
look to be on the lower side. Late tonight into Friday, the
ongoing melting snow and warmer temps/dewpoints will support areas
of fog developing over central and north-central WI. Fog could be
locally dense. Given low temps remaining above freezing, roads
that are now clear of recent snow cover should just stay wet.

Friday will feature warmer temperatures as highs reach the 40s
across the Fox Valley and lakeshore, with around 50 across central
and north-central Wisconsin. A low pressure system developing
over the Plains will bring a surge of warm air to the region on
Saturday along with some small chances for rain across far north-
central Wisconsin. This will likely be the warmest day in the
next week as temperatures top out in the 50s across central
Wisconsin with a 30-60% chance of hitting 60 degrees south of
Highway 10.

The cold side of this low pressure system will track through the
area Saturday night, bringing colder temperatures and a rain/snow
mix as a cold front sinks south through Sunday. Chance of precipitation
is 30-50% with most of the precipitation occurring on Saturday
night. Probability of >2" of snow for the 24 hr period ending
Sunday evening is now around 20%, trending up slightly over last
few NBM runs.

High pressure will then provide dry weather to the area early
next week. Temps will start off at or slightly below normal, but
quickly rebound to slightly above normal by the middle of next
week. A clipper system will also be moving through the middle of
next week. This could bring a round of rain/snow later Wednesday
into Thursday. Higher-end precip with this system would be 0.5
inch of QPF. Top end snowfall (90th percentile) is around 2-3",
mainly near the Upper Michigan border. At this point, this clipper
represents the most notable system next week.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1246 PM CDT Thu Mar 19 2026

Scattered MVFR to VFR clouds for the rest of the day. Better
chance of bkn LIFR-MVFR clouds will be tonight, lowest in central
WI to north-central WI. A clipper will bring some light rain,
freezing rain and snow tonight, mainly along the Upper Michigan
border. Nighttime cooling and low-level inversion with ongoing
melting snow sets up potential for fog late tonight into Friday
morning central to north-central WI.

Winds will be light overall, but low-level wind shear (SW 40-50
kts veering NW to 30 kts) will develop all sites tonight into
Friday morning.

&&

.HYDROLOGY...
Issued at 201 PM CDT Thu Mar 19 2026

As temperatures warm later into the weekend, the snowmelt will
result in increasing fast flows and rising river levels. Some
rivers could reach bankfull or even minor flood stage. The lack
of a rapid, significant warmup points to a more gradual rise in
area rivers as opposed to widespread rapid rise flooding. That
being said, the flooding situation will be monitored closely given
how much water is locked up in the current snowpack across the
region. Latest Snow Water Equivalent (SWE) here at our office is
now 2.88 inches with a snow depth of 14 inches. This matches the
current NOHRSC snow depth and SWE analysis pretty well. Modeled
snowpack temperature from the NOHRSC site points to ripening of
snowpack (really starting the melting/runoff process) over
central WI as early as Friday, with more widespread ripening of
snowpack up over the area on Saturday.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......JLA
HYDROLOGY......JLA