NWS-Green Bay Forecast Discussion
FXUS63 KGRB 191737
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
1137 AM CST Mon Jan 19 2026
Updated aviation portion for 18Z TAF issuance
.KEY MESSAGES...
- Bitter cold wind chills as low as 15 to 25 below this afternoon,
with colder wind chills returning to all areas tonight into
Tuesday morning. Cold Weather Advisories extended until 10 am on
Tuesday.
- Snow chances trending higher Tuesday night south of Highway 29
(chances 50-70 percent).
- Another wave of bitter cold Friday into next weekend. This bout
of cold will be more extreme that is occurring early this week,
with chances of seeing wind chills down to 40 below zero 70 to
80 percent over central WI. Chances for daytime highs staying
below zero all areas up to 60-90%.
&&
.DISCUSSION...
Issued at 320 AM CST Mon Jan 19 2026
Arctic air arriving this morning with gusty winds. Areas of blowing
and drifting snow expected this morning. Bitter cold early this
week, relaxes some mid week, but then resurges late this week into
next weekend.
Snow and Blowing/Drifting Snow Today...
Lighter lake effect, with lower SLRs, persists over Vilas County
early this morning. Still a few hours of light to at times
moderate snow, so no change to the going Advisory there.
Otherwise, upper level trough with 850mb temps down to -25c digs
across and pressure gradient is tightening behind arctic front.
Wind gusts thus far have been 25-30 kts over central WI with vsby
reductions noted, but nothing too widespread. Despite traffic
webcams not showing anything too low in terms of vsby, call to
Marathon County did turn up lower vsby in more open western
Marathon County. Winds in the 1000-925mb layer do increase farther
east, with 40kts at top of mixed layer over eastern WI 9z-15z
teamed with cold air advection in that layer. Wind gusts of 30-40
mph in those areas will cause areas of blowing and drifting. Worst
conditions will be across Door County with stronger winds
forecast to mix off the bay and also as area of snow drops across
this morning. Have extended the Winter Weather Advisory from
Waushara northeast to southern Oconto and filled it in all the way
to the lakeshore. Strongest winds and most of the BLSN/DRSN will
be 4a to 9a, right in line for the morning commute. Main impacts
will be low vsby down to less than 1 mile at times and drifting
snow leading to snow covered and slippery roads. Will cover areas
not in any type of winter advisory in an SPS for the lower vsby.
Expect winds and BLSN/DRSN to back off this afternoon. Any
lingering light snow or flurries should shift to only Door County
by that time.
Bitter Cold into Tuesday...
Wind chills are dropping toward -25 over central WI early this
morning and readings 20-25 below will shift over the rest of the
area through late morning. Modest modification this afternoon even
as air temperatures stay below zero central to north-central and
stay in the lower single digits, but the colder wind chills return
tonight to all areas, including Door County, and last into Tuesday
morning. Have issued a Cold Weather Advisory for Door, and extended
the remaining advisories until 10 am Tuesday. High temperatures on
Tuesday afternoon will barely break zero central to north-central,
and will reach near 10 above elsewhere.
Clipper Snow Tuesday Night into Wednesday...
Shortwave in base of broad upper trough crosses the region Tuesday
night into Wednesday. Based on forecast soundings showing saturation
in the cold airmass, see no reason most of the area will not see snow.
See the last few days for a reference. Snow amounts at this point look
minor with chances for 0.1" up to 60% south of highway 29, while
the chances for 1" are 20-50% only over the southern portion of the
area (south of highway 10). Trends are up, and some models are liking
the higher end of ensembles (2-3" toward Oshkosh and Manitowoc).
Will be worth watching as the morning commute on Wednesday would
be impacted. Wouldn't be surprised if light snow/flurries linger beyond
this system into Thursday.
Extreme Cold Friday into the Weekend...
Arctic high pressure of 1050mb over the plains arrives later
Friday into the weekend. As mentioned yesterday, sharp trough with
very cold air is nearby, and now today is shown to drop over the
western Great Lakes region. 850mb temps -30c before slightly
moderating into Saturday. Result is better agreement that Friday
is very cold with chances of seeing subzero highs area-wide 60 to
90%, and chances for seeing wind chills less than 30 below
50-95%. If these colder trends hold up, we will need Extreme Cold
Warnings for all areas Thursday night right through Saturday. Wind
chills drop to -10 late Thursday and don't return to readings
warmer than that until Sunday afternoon. We're starting to message
this next bitter cold snap.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1134 AM CST Mon Jan 19 2026
Clouds have cleared across much of the region late this morning
with the exception along the WI/Upper MI border where MVFR cigs
and snow showers prevailed. However, the sunshine has allowed for
FEW or SCT clouds around 1500 to 2500 ft AGL to develop across the
region. Confidence is not high enough for the coverage of these
clouds to become BKN this afternoon, but included a TEMPO group at
RHI where there are additional lake-effect clouds/moisture
upstream. These lower SCT clouds may linger into this evening
before clearing occurs after midnight through the remainder of the
TAF period.
The northwest to west winds will continue to gust to 20 to 30 kts
early this afternoon, mainly for the east-central WI TAF sites,
and gradually subside to 10 to 15 kts around 06z Tue. Westerly
winds will increase Tuesday morning/afternoon with gusts of 15 to
20 kts.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until 10 AM CST Tuesday for WIZ005-010>013-
018>021-030-031-035>040-045-048>050-073-074.
Winter Weather Advisory until noon CST today for WIZ022-031-
037>040-045-048>050-074.
Cold Weather Advisory from 6 PM this evening to 10 AM CST
Tuesday for WIZ022.
&&
$$
DISCUSSION.....JLA
AVIATION.......Kruk