NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 011735
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1135 AM CST Sun Mar 1 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- A more spring-like pattern sets up this week with chances for
  mixed precip Monday night into Tuesday (20-50%), then mainly
  rain mid-week (15-30%) and again late in the week (40-60%).

- Below normal continue today, then a slow but steady warming
  trend begins on Monday and continues through the week. Ice
  jam/floe and minor flooding concerns may arise.

&&

.DISCUSSION...
Issued at 148 AM CST Sun Mar 1 2026

Precipitation & Fog Chances / Trends: As the pattern turns more
zonal across the CONUS, there will be periodic chances for precip
through the week. First chance arrives Monday night into Tuesday.
While models have trended a little weaker with this system, LREF
probs of more than 0.01" are still running between 40-70% south
of Hwy 29, with probs for more than 0.1" only 10-25%. So any
precip looks to be on the light side. Model soundings showing
temp profiles hovering around freezing from the surface to
~3000ft, so p-type could be a little tricky. With the weakening
trend, will hold PoPs to between 20-50% with a rain/snow mix for
now (NBM/LREF probs of 1+" of snow remain under 25%). While the
better moisture and dynamics are forecast to stay south of the
area, we will still need to monitor this system as any northward
shift and a little more phasing could increase chances for an
impactful snow/mixed precip event (actual piece of energy just
coming onshore on the West Coast early today).

Next chance for precip arrives mid-week, but model guidance not in
good agreement if/when this would occur with the ENS drier and
the GEFS holding on to some rain chances. Will keep the NBM PoPs
of 15-30% to cover this small chance of rain (possibly a little
snow mixed in over the north if precip can get into northern WI at
night). Better signals for rain arrive late in the week as a
couple shortwave troughs move into the Plains and Great Lakes. Too
early for any details, with timing/strength details still to be
ironed out. But a couple shots at rain appear likely, with amounts
depending on how much moisture can advect into the region, along
with when/if any cyclogenesis occurs. NBM PoPs of 40-60% look
reasonable. Thunder chances late in the week remain under 10% this
far north, but any northward shift of the higher temp/dewpoints
could bring some thunder chances into the picture.

Chances for fog will also increase through the week as dewpoints
increase and snow melt adds to the low level moisture. If/when
winds are light and skies are clear at night, fog will be
possible. This will especially be the case across central and
northern WI.

Temperatures: Another day of below normal temps is on tap for
today, with highs ranging from around 20 in north-central WI to
the mid 20s to near 30 for most other locations. Wind chills in
the single digits above and below zero are expected early this
morning and again overnight into Monday morning. Temps gradually
rise throughout the week as modified Pacific air spreads into the
Great Lakes. High temps should climb into the 40s mid week, and
into the 40s/50s on Friday (NBM probs of 50+ degrees 50-85% south
of Hwy 29).

Minor Flooding & Ice Jam/Floe Potential: Unless some unexpected
heavier rain occurs during the week, the overall flooding threat
will be very low, as a slow snow melt / compaction of the snow
pack should occur with above freezing temps during the day and
below freezing temps most nights. The ice jam threat will increase
through the week as many rivers are still fully or partially ice
covered and the warmer temps and increasing flows will promote
additional break up. Gusty south/southwest winds on Monday will
increase the threat for ice floes on Green Bay as well.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1135 AM CST Sun Mar 1 2026

Good flying conditions are expected for the remainder of the day
through tonight with mostly sunny/clear skies. The only exception
is some MVFR clouds moving over MTW early this afternoon for a
couple hours. Mid-level clouds will return over the area late
tonight into Monday morning.

Light and variable winds are expected today through late tonight.
Southerly winds increase mid-morning Monday, with gusts to 15-20
kts towards the end of this TAF period into Monday afternoon. LLWS
is anticipated late tonight through mid-morning Monday, mainly
across far northern WI (RHI TAF site), as winds around 1900 ft
increase from the SW to 35-40 kts.

&&

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

&&

$$

DISCUSSION.....Bersch
AVIATION.......Kruk