NWS-Green Bay Forecast Discussion
FXUS63 KGRB 171158
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
558 AM CST Tue Feb 17 2026
Forecast discussion for routine morning forecast issuance
.KEY MESSAGES...
- Precip arrives late this evening, with a wintry mix of freezing
rain, sleet, and snow across northern Wisconsin where a Winter
Weather Advisory is in effect and slippery travel is likely.
Farther south, mainly rain is forecast.
- Snow is possible area-wide late Thursday into Friday, with a
20-60% probability of at least 2" of snow.
&&
.DISCUSSION...
Issued at 555 AM CST Tue Feb 17 2026
Main change this morning was to issue a Winter Weather Advisory
for mixed precipitation across northern Wisconsin from this
evening through Wednesday morning. Surface low to track from the
Dakotas to central Minnesota tonight into Wednesday. This
coincides with some LL warm advection, mid-level shortwave, and
LFQ of upper jet--all adding sufficient lift to the setup. While
the surface feature stalls out Wednesday afternoon, the deeper
moisture and lift subsides across central and northeast WI. While
light precip may linger into Wednesday afternoon, the bulk of any
rain/snow/mix will occur earlier in the day.
Precip types remain a challenge due to boundary layer temperatures
near freezing for some location. Deterministic and probabilistic
output agree that central into east-central WI will be warm enough
to support mainly rain. Isolated thunder is also possible early
Wednesday morning in the far southern/southwest forecast area.
Northern Wisconsin remains the focus for mixed precip. The
greatest probabilities (30-50%) for a glazing of ice (at least
0.01") is north of a Merrill to Antigo to Marinette line.
Probabilities for at least a tenth of an inch are less than 20%,
aside from eastern Oneida and Vilas, northern Langlade, and Forest
counties where probabilistic guidance is highlighting this area
for the greatest ice accumulations. As for snow, This same area
has a 20-80% chance for at least 1" of snow, highest near Florence
County, where the chance for 4" of snow is 40%. Most of this mix
of snow, sleet, and freezing rain will occur late Tuesday evening
through Wednesday morning, making for a slowed and slippery
morning commute.
Remnants from this first surface low remain northwest of the
forecast area throughout Wednesday night and Thursday, which will
keep chances (20-40%) for light precip in the forecast from
Wednesday afternoon through midday Thursday. Ptypes would remain
mainly snow in northern Wisconsin, and rain elsewhere. Impacts
from any snow would be minor and limited, but some slippery
stretches on untreated roads could remain.
The next feature to watch is a low ejecting out from Colorado
Thursday, reaching Wisconsin on Friday. Temperatures would support
a mix of rain and snow across the area Thursday evening and
overnight, transitioning to all snow mid to late Friday depending
on location and system timing. A few changeovers from rain to snow
are possible as temperatures fluctuate. Current prob guidance
shows a 20-60% chance for at least 2" of snow, highest across the
north, and lowest from the Fox Valley east towards Lake Michigan
where more rain is forecast.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 1053 PM CST Mon Feb 16 2026
Main concerns in the TAF period will be some patchy fog near the
Lake Michigan shoreline and the northwoods tonight and the arrival
of an active weather system Tuesday night. Patchy fog has already
developed along the shoreline areas, so included a mention for the
fog in MTW and GRB. Confidence on fog for the northwoods has once
again increased, so brought back the a TEMPO for RHI to include
some lower visibility should fog return.
Better flying conditions are then expected for most of the day
Tuesday before active weather returns Tuesday evening. Expect
lowering ceilings by 00Z Tuesday, with rain spreading into the
area shortly after. This should bring conditions down to IFR for
the overnight period. Wintry precipitation could mix in at times
as well, beyond the current TAF with the best chance for a mix
occurring further north towards RHI. The onset of this system will
also see very strong winds arrive in the lower levels, so LLWS
will become a concern at all terminals Tuesday night.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 PM this evening to noon CST
Wednesday for WIZ005-010>013-019-021.
&&
$$
DISCUSSION.....KLJ
AVIATION.......Uhlmann
FXUS63 KGRB 171159
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
559 AM CST Tue Feb 17 2026
Updated aviation portion for 12Z TAF issuance
.KEY MESSAGES...
- Precip arrives late this evening, with a wintry mix of freezing
rain, sleet, and snow across northern Wisconsin where a Winter
Weather Advisory is in effect and slippery travel is likely.
Farther south, mainly rain is forecast.
- Snow is possible area-wide late Thursday into Friday, with a
20-60% probability of at least 2" of snow.
&&
.DISCUSSION...
Issued at 555 AM CST Tue Feb 17 2026
Main change this morning was to issue a Winter Weather Advisory
for mixed precipitation across northern Wisconsin from this
evening through Wednesday morning. Surface low to track from the
Dakotas to central Minnesota tonight into Wednesday. This
coincides with some LL warm advection, mid-level shortwave, and
LFQ of upper jet--all adding sufficient lift to the setup. While
the surface feature stalls out Wednesday afternoon, the deeper
moisture and lift subsides across central and northeast WI. While
light precip may linger into Wednesday afternoon, the bulk of any
rain/snow/mix will occur earlier in the day.
Precip types remain a challenge due to boundary layer temperatures
near freezing for some location. Deterministic and probabilistic
output agree that central into east-central WI will be warm enough
to support mainly rain. Isolated thunder is also possible early
Wednesday morning in the far southern/southwest forecast area.
Northern Wisconsin remains the focus for mixed precip. The
greatest probabilities (30-50%) for a glazing of ice (at least
0.01") is north of a Merrill to Antigo to Marinette line.
Probabilities for at least a tenth of an inch are less than 20%,
aside from eastern Oneida and Vilas, northern Langlade, and Forest
counties where probabilistic guidance is highlighting this area
for the greatest ice accumulations. As for snow, This same area
has a 20-80% chance for at least 1" of snow, highest near Florence
County, where the chance for 4" of snow is 40%. Most of this mix
of snow, sleet, and freezing rain will occur late Tuesday evening
through Wednesday morning, making for a slowed and slippery
morning commute.
Remnants from this first surface low remain northwest of the
forecast area throughout Wednesday night and Thursday, which will
keep chances (20-40%) for light precip in the forecast from
Wednesday afternoon through midday Thursday. Ptypes would remain
mainly snow in northern Wisconsin, and rain elsewhere. Impacts
from any snow would be minor and limited, but some slippery
stretches on untreated roads could remain.
The next feature to watch is a low ejecting out from Colorado
Thursday, reaching Wisconsin on Friday. Temperatures would support
a mix of rain and snow across the area Thursday evening and
overnight, transitioning to all snow mid to late Friday depending
on location and system timing. A few changeovers from rain to snow
are possible as temperatures fluctuate. Current prob guidance
shows a 20-60% chance for at least 2" of snow, highest across the
north, and lowest from the Fox Valley east towards Lake Michigan
where more rain is forecast.
&&
.AVIATION...for 12Z TAF Issuance
Issued at 558 AM CST Tue Feb 17 2026
A few sites in east-central WI seeing some fog this morning
resulting in MVFR/IFR vsbys, including KGRB and KMTW. Expect this
fog to continue for a couple more hours, and then erode by mid-
morning. The rest of the day expect VFR flying conditions, with
easterly wind gusts of 20-30 kts this afternoon.
Flying conditions deteriorate this evening and overnight as a
system approaches and precip arrives. Most TAF sites in the GRB
area are expecting rain, while northing Wisconsin will see a mix
of freezing rain, sleet, and snow tonight into Wednesday morning.
Along with the precip, LLWS develops tonight with winds of 45-55
kts at 2kft.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 PM this evening to noon CST
Wednesday for WIZ005-010>013-019-021.
&&
$$
DISCUSSION.....KLJ
AVIATION.......KLJ