434
FXUS63 KGRB 160022
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
622 PM CST Thu Jan 15 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- There is a 50-90% chance for snowfall accumulations greater than
  2 inches across most of the area from this afternoon through
  Saturday. Snow-covered and slippery travel will occur at times.
  Also, there will also be breaks in the steadier snow through
  Saturday.

- Bitterly cold temperatures arrive late in the weekend and early
  next week, with a 60-90% chance of wind chills colder than 20
  below zero on Monday and Tuesday mornings.

- A clipper system may bring light snow and the potential for
  hazardous travel Sunday, and then possibly again during the
  middle of next week.

&&

.DISCUSSION...
Issued at 209 PM CST Thu Jan 15 2026

The latest RAP analysis and satellite/radar imagery show potent
shortwave energy digging southeast across southern Saskatchewan
and Manitoba early this afternoon. Downstream, high pressure is
centered over the central Great Lakes resulting in a very dry
airmass below 10 kft across northeast Wisconsin. This dry air has
held off precipitation thus far today despite thickening cloud
cover. Meanwhile, warm advection is increasing into the northern
Mississippi Valley ahead of the approaching shortwave, with the
leading edge of this moisture producing light snow over northeast
Minnesota and northwest Wisconsin. Visibilities within this snow
have been dropping to around 2 miles.

Warm advection snow will slide southeast across the region late
this afternoon and evening. Most hi-res guidance shows snow
reaching north-central Wisconsin by mid-afternoon and northeast
Wisconsin by late afternoon or early evening. Saturation to -10C
may struggle initially over central Wisconsin, which could allow
for a brief period of freezing drizzle to mix in early this
evening. Otherwise, this quick-moving swath of light snow is
expected to produce a half inch to one inch of accumulation,
creating slippery travel for the evening commute.

Following a brief break in the activity, a second and steadier
round of snow will move through from midnight tonight through
Friday morning. Confidence is somewhat lower regarding the exact
coverage and intensity of this round as model guidance remains
spread, but a general model blend suggests an additional 1 to 1.5
inches of snow. This will lead to slippery and snow-covered roads
for the Friday morning commute, with the highest confidence for
impacts located over east-central Wisconsin. While a winter
weather advisory was considered, lower confidence in the fine
details and minimal wind impacts led to holding off for now. Minor
instability up to 30 J/kg develops Friday afternoon, and while
snow squall parameters are flagging, the lack of strong winds and
a sharp arctic front should limit the threat to simple convective
snow showers rather than organized squalls.

A slow-moving low pressure system will track across the northern
Great Lakes Friday night through Saturday. Forcing appears broad
and weak within the cyclonic flow, but light snow is expected to
continue at times. The probability of an additional inch of snow
during this 24-hour period ranges from 30 to 50 percent, with the
best chances over central and east-central Wisconsin. High
temperatures tomorrow will be the warmest of the next week,
reaching the upper 20s to lower 30s before a significant cooling
trend begins.

Another clipper system is on track to bring measurable snow to the
region Sunday into Sunday night. While snow is likely, the most
significant impact will be the arrival of an arctic airmass and
gusty winds behind the shortwave. 850mb temperatures are forecast
to plunge into the -25C to -30C range Sunday night and persist
through Tuesday. Combined with 850mb winds of 40-50 knots, surface
wind gusts of 30-40 mph are expected into Monday. This setup will
produce dangerous wind chills ranging from 20 below to 35 below
zero. These values align with top CIPS analogs and the typically
high- performing ECMWF guidance for arctic intrusions. Monday and
Tuesday will need to be monitored closely for excessive cold
headlines. Conditions may begin to moderate late Tuesday into
Wednesday as the core of the arctic air shifts east and another
clipper brings additional chances for light snow.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 622 PM CST Thu Jan 15 2026

VFR conditions will persist across much of the region. Most
recent surface trends show none of the current snow shown on radar
reaching the surface, so removed visibility impacts from the TAF
for the evening to early overnight. Still, can`t rule out a few
flurries, especially once leaving traffic patterns and heading to
altitude.

Behind this first wave of snow, an MVFR stratus deck will move in
for the early overnight period, with cloud heights around
2500-3000 feet AGL. Shortly behind this will come another push of
snowfall, which will included visibility impacts for the early
morning period. Expect ceilings to also lower through this period,
with IFR likely for a time in the morning hours. Some improvement
in ceilings will come later in the day on Friday, but intermittent
light snow showers will continue through much of the day and thus
are included in the current TAF.

&&

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

&&

$$

DISCUSSION.....MPC
AVIATION.......Uhlmann

NWS GRB Office Area Forecast Discussion