NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 191209
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
609 AM CST Thu Feb 19 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Quiet weather today with a little sunshine for east-central
  Wisconsin.

- Confidence in location of snow and impacts from Thursday night
  into Friday morning as decreased, as guidance has shifted a few
  times over the past model runs. An area of impactful snow is
  likely, but where this occurs is highly uncertain.

&&

.DISCUSSION...
Issued at 448 AM CST Thu Feb 19 2026

Overnight precipitation has mostly ended, with just a few sites in
far north-central WI reporting some light mixed precip. Expect
most of the day to remain dry, with some clearing/sunshine peaking
through in the Fox Valley and east-central WI through mid-
afternoon, helping to give temperatures a boost. Highs today will
range from the mid to upper 30s in the Northwoods, to the middle
40s in the Fox Valley.

Forecast details for the Thursday night to Friday system are less
clear today than they were 24 hours ago. Colorado low looks to
generally move through southeast WI early Friday morning, then
northeast across Lake Michigan to northern Lower Michigan.
However, a small shift in this track will have large impacts to
precip/snow amounts across central and northeast WI. While there
was a large spread in amounts, the general location (central to
north-central WI) was favored. Then, the 18/18Z and 19/00Z
deterministic runs started trending farther east, bringing snow
into the Fox Valley, and leaving much of north-central WI dry or
with very light snow amounts. Now, at least the 19/06Z NAM has
trended back to the west, and concerned other models may do the
same. As mentioned, the spread in snowfall amounts has always been
high with this event (0-10" in some parts of north- central WI),
and the probabilistic guidance is still favoring a western
solution and does not jive with any of the eastern solutions,
leading to massive differences in probabilistic vs. deterministic
output. So, confidence in how this system will play out is low.

Timing is more certain, with precip arriving in the south around
03Z and spreading northward. The heaviest of the precip will
likely occur between 06Z-16Z, and then end during the late
morning and early afternoon.

Temperatures will initially be warm enough for all rain,
especially in the southern forecast area where precip begins. As
precip expands north a change to snow (mixed with a little
freezing rain in spots) is expected. As temperatures cool, expect
the rain to change to snow across the south as well, but exactly
when this occurs is uncertain. It does appear there will be at
least a swath of snowfall totals around 1 to 3 inches, with a
narrow band within that of higher amounts, which could be up to
6"+. But this narrow area may only be 1 to 2 counties wide, making
it very difficult to pin down and creating such high spread,
especially when the larger swath keeps shifting east and west as
well.

Uncertainty in this axis of heaviest precipitation, snow amounts
within the axis of heaviest precipitation, and precip types
depending on where the axis is located, have all resulted in
holding off on issuing any winter weather headlines this morning.
Wherever wintry precip occurs tonight will likely need an
advisory for hazardous road conditions, especially given a couple
hundredths of ice accumulation is also possible. But did not want
to issue an advisory that had a high likelihood of needing
adjustments and shifting around, would like to see more consensus.
Per coordination with surrounding offices, did not expand the
advisory in southwest WI any farther at this time and waiting to
see how the next model runs pan out.

Beyond Friday, lingering low in eastern Michigan with trough
extending back west will keep light snow chances in the forecast
through most of the weekend, but amounts and impacts should be
minimal. Dry weather follows early next week, followed by a
midweek clipper system.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 609 AM CST Thu Feb 19 2026

Mostly MVFR flight conditions area wide early this morning due to
low clouds with bases between 1-2kft. Some clearing right along
the Fox River and eastward resulting in VFR conditions. With the
leading edge of the low clouds right near KGRB and KATW at 12Z a
couple hours of sky conditions fluctuating between SCT/BKN and
therefore VFR/MVFR are possible, with these clouds then retreating
northward.

For today, MVFR with occasional IFR conditions will persist
across most of central and north-central WI due to low clouds.
Some clearing across the Fox Valley into far northeast WI will
result in VFR conditions.

Lower clouds arrive tonight with an approaching low pressure
system, expect MVFR/IFR conditions area wide, along with snow
across central and north-central WI, and rain transitioning to
snow across the east.

Winds will be light through most of the TAF period. LLWS develops
late tonight.

&&

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

&&

$$

DISCUSSION.....KLJ
AVIATION.......KLJ