NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 201214
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
614 AM CST Fri Feb 20 2026

New Information added to update section

.UPDATE...
Issued at 614 AM CST Fri Feb 20 2026

Pretty complex situation early this morning. Main update was to
expand the Winter Weather Advisory into rest of north-central WI
as moderate to heavy snow will persist there through at least mid
morning on the northwest edge of pivoting deformation/fgen zone.
Farther east, rain and freezing rain switching to snow has occurred
as far east as Wautoma to Waupaca to Clintonville. This is as the
sfc low has reached southern Lake Michigan. Expect warm layer aloft
to collapse rather quickly as the low tracks east-northeast this
morning. All areas except the immediate lakeshore likely see
switch to snow by 8-9 am. Minor slushy snow could occur over the
Fox Valley as the change occurs, especially since temperatures
will still be only a few degrees above freezing into mid morning.

&&

.KEY MESSAGES...

- Mixed precipitation switches to heavy wet slushy snow over
  central WI early this morning. Snowfall rates over 1 inch per
  hour, resulting in a potentially hazardous morning commute.
  Moderate snow extends into northern WI as well through the
  morning.

- Rain, with some freezing rain and sleet elsewhere, switches to a
  rain and snow mix through the morning. Minor snow and ice
  accumulations.

- Turning colder with periodic light snow tonight through the
  weekend. Additional light snow accumulations, especially tonight
  in Door County, and later in the weekend over northern WI due
  to lake effect.

- Another warming trend by middle of next week.

&&

.DISCUSSION...
Issued at 335 AM CST Fri Feb 20 2026

Complex storm system impacting the state this morning. Main issue
early on has been temperatures staying around freezing as leading
rain is occurring from east-central to northeast WI. Already
expanded the Winter Weather Advisory earlier to include areas to
the north of Green Bay into Door County. Expect light icing on
especially elevated surfaces. Untreated roads could see some
slippery spots. Eventually the rain/freezing rain and sleet will
switch to rain/snow as colder air works in aloft, but this could
take until late morning. Though it should not last as long, could
see patchy freezing rain over east-central WI as well early this
morning. Earlier calls indicated that roads conditions were mainly
just wet as observed road temps are still in the upper 30s. A bit
of ice could occur on elevated surfaces before temps start to warm.

TROWAL feature to northwest of 700mb low is poised to shift into
central WI soon. Thus far over central WI, ptype has been mix of
freezing rain and sleet. Expect that to change as dynamic cooling
results in precip changing to what appears to be a very decent
thump of heavy wet snow roughly 5 am through 9 am over especially
Wood and Portage counties where pivot point of mid-level fgen
resides. Snowfall rates could push 1-1.5" per hour and this snow
will be very wet and heavy. Very narrow band could see snow totals
5-7" locally higher. Enough evidence in latest guidance and
upstream obs to upgrade Wood and Portage to warning. At this
point, Waushara/Waupaca should be just far enough east to stay in
the more moderate snowfall totals, but this will be close. As the
deep 990mb sfc low tracks from southern WI into central Lk
Michigan this morning, expect snow to expand on into northern WI
where advisory was already in place. Another pivot point for the
TROWAL may occur over Forest/Florence, so this could be another
spot for locally higher amounts. Some guidance pulls snow out
pretty quickly by midday, so will let the advisory hold there for
now. This too will have to be watched through the morning.

All headlines are set to expire at noon today. Based on latest
guidance, that looks good.

One last item to mention in the near term. With the moderate rain
overnight (thus far 0.40 to 0.60 east-central) and recent rainfall
increasing flows on rivers, will have to be on the lookout for
ice jams as ice continues to shift around and break up as flow
will just further increase. Hydrographs this morning showing some
signs of this at a few of the river gauge sites.

Moving into Tonight and Saturday, decent agreement that mid-level
convergence zone will linger over far northeast WI into Door
County to the west of the departing low pressure system. Expect
light snow with this and have increased pops right into Saturday
with this feature. Snowfall amounts could tally an inch or two
over northern Door County. Elsewhere some periodic light snow will
linger to the south of this trough, especially northern WI. Highs
on Saturday will cool down over northern WI, with readings in the
20s. Readings will stay in the low to mid 30s for the rest of the
area.

Colder the rest of the weekend in wake of mid-level trough
tracking through from the northern Plains. In the wake of the
trough, NNW winds and cold air crossing western Lake Superior
should aid in developing lake effect snow showers for northern WI.
Soundings show a deep DGZ late Saturday night into Sunday. That
implies fluffy, efficient snow for snowbelts of Vilas County and
flurries farther south from northern WI into central WI.
Probabilities for over an inch of snow are quite low, but a
reasonable high-end amount from the ensembles is currently around
3 inches in far northern Vilas. Highs below 30 for most on
Sunday, then temps will be colder than they have been in a while
Sunday night with readings in the single digits to teens. Compared
to recent warmth, will be a chilly start to the work, school week
on Monday. Next clipper system bringing some warmer temps along
with some snow moves through Tuesday into Wednesday.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 559 AM CST Fri Feb 20 2026

Complex aviation forecast this morning as strong low pressure
tracks across southern WI into central Lake Michigan, then
eventually into northern lower Michigan. Warm air aloft has
resulted in rain and freezing rain over eastern and northeast WI,
while snow is increasing over central and north-central WI. For
CWA/AUW/RHI carried TEMPO groups for 1/2SM vsby through 14z before
the snow begins to diminish. Eastern TAF sites will see change to
snow 12z to 16z from west to east. MVFR vsby may lower to IFR as
the switch to snow occurs. This will need to be monitored.
Otherwise, cigs will prevail at IFR this morning, lifting to MVFR
this afternoon and tonight. Only mention of snow tonight was at
GRB as area of lingering light snow from Upper Michigan to Door
County may graze that TAF site this evening.

Northeast winds gusting to 25-30 kts will back to the north the
rest of this morning, then shift northwest this afternoon as the
sfc low departs to the east. Gusts to 25 knots will remain possible
into this evening, before gusts diminish overnight.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST today for WIZ005-010>013-
018>022-030-031-037-045-073-074.

Winter Storm Warning until noon CST today for WIZ035-036.
&&

$$

UPDATE.........JLA
DISCUSSION.....JLA
AVIATION.......JLA