235
FXUS63 KMKX 180405
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1005 PM CST Mon Nov 17 2025

.KEY MESSAGES...

- A band of rain is expected across southern WI, with wintry mix
  along and north of I-90/I-94 and mostly snow over central WI
  tonight into Tuesday morning. Snow accumulations of 1 to 2
  inches are anticipated over central WI, with locally higher
  amounts up to 3 inches possible. Areas along and immediately
  north of I-90/I-94 will see a few tenths to 1 inch of slushy
  accumulation. Tuesday morning commute impacts will be most
  likely over central WI.

- Additional precipitation chances for the latter portion of the
  workweek. Rain is favored at this time.

&&

.UPDATE...
Issued 1005 PM CST Mon Nov 17 2025

Forecast remains on track, with the strongest band of
precipitation beginning to nudge its way into southwestern
Wisconsin. Expecting initial burst of rain with a few snowflakes
sprinkled in, transitioning to a mix of rain and snow as
temperatures fall into the mid-30s late tonight. In central
Wisconsin, temperatures will fall to near freezing by the time
precipitation begins, allowing for a quick transition to all
snow late tonight into the early morning hours. Currently still
anticipating a slushy few tenths to an inch of precipitation
generally across the I-90/I-94 corridor and northward. The
highest accumulations of 1-2 inches with local amounts up to 3
inches are expected across Sauk, Columbia, Marquette, and Green
Lake Counties where the heaviest precipitation is collocated
with the coolest expected temperatures. However, trends will be
monitored through tonight.

MH

&&

.SHORT TERM...
Issued 251 PM CST Mon Nov 17 2025

Tonight through Tuesday night:

Tonight, low pressure is anticipated to move from the central
plains toward the Mississippi River. As this happens,
700mb frontogenesis and WAA on the north side of the low is
anticipated to bring banded precipitation to southern WI, with
this precip moving in from southwest to northeast around and
after midnight. With colder and drier air in position over
northern to central WI, wet bulbing is expected to support a
transition to rain/snow mix north of I-94. All snow is more
likely over central WI where temperatures profiles remain colder
than freezing through a larger depth of the atmosphere. With the
anticipated change over to snow, temperatures profiles will
generally support low ratios ranging from 4:1 to 8:1, leading to
slushy wet snow. Rates will also be modest, as HREF guidance
supports 0.25 to 0.5 inch per hour rates through the night.
Given the lower snow ratios and rates, combined with 0.25 to 0.5
inches of QPF, snow totals are expected to be between 1 to 2
inches over central to east central WI, with totals tapering of
to a trace south toward I-94.

With most of the snow occuring overnight, some commute impacts
may occur over central to east central WI Tuesday morning. Warm
advection is then expected to win out Tuesday morning with a
gradually south to north change over to rain into the
afternoon.

One lingering bit of uncertainty has to do with the position of
the heaviest snow. 12Z guidance suggests that the highest snow
totals will remain north of the CWA limiting higher impacts,
which is a shift from previous forecasts. 18Z guidance seems to
suggest a slight shift back south, though models disagree in the
magnitude of this shift. (The HRRR being the most aggressive.)
For now, have stuck with this 12Z guidance, but trends will be
monitored into tonight for any last minute shifts in the snow
band.

CMiller

&&

.LONG TERM...
Issued 242 PM CST Mon Nov 17 2025

Wednesday through Monday:

High pressure over the Great Lakes will begin to shift out of the
area on Wednesday. A weak mid level shortwave should give us mid/high
clouds over the state, but there is also some indication that the
steeper low level lapse rates could cause diurnal cumulus clouds
as well. While sprinkles seem unlikely, they are a possibility
Wednesday afternoon and into the evening hours as low level
warm air advection ramps up. Wednesday highs will be in the mid
40s, Wed nt lows will be in the mid 30s.

Thursday, an upper trough will be swinging across Lake Superior,
so precip chances extend into central WI from that. Meanwhile,
ongoing low level warm air advection will allow for a fairly deep
profile of increasing moisture (from mid levels north and low
levels south) so southern WI has a chance (15 to 23% in the
morning and 25 to 30% in the afternoon-evening) of light rain.
Temperatures will be in the upper 40s to lower 50s during this
time. Cold advection will follow this exiting area of precip and
temps should drop to around 30 Thu nt. The below-freezing temps
would only occur if skies clear, as the cold advection is not
strong.

Clouds (but also small rain chances (18-25%)) will linger across
southern WI Friday. This is due to weakening low pressure tracking
across the mid Mississippi River Valley. The northern edge of the
precip is trending south in the forecast and may be removed at a
later time.

The weekend looks quiet and mild as high pressure drifts across
the region. Highs will be above normal, in the mid-upper 40s, and
lows will be around 30. Winds should be on the lighter side as
well.

Cronce

&&

.AVIATION...
Issued 1005 PM CST Mon Nov 17 2025

Bands of rain with snowflakes mixing in are beginning to push
northeastward through southern Wisconsin. Expectation for
temperatures to fall into the mid-30s by midnight CST, allowing
for a transition to steady rain/snow mix, before transitioning
to all snow for a brief period across MSN and UES terminals
during the early morning hours Tuesday. A few tenths of an inch
of accumulations are expected. Near Lake Michigan, onshore winds
will keep temperatures higher and prevent a transition to only
snow. In addition, terminals near the Illinois border will see
warmer temperatures and also prevent a transition to all snow. Snow
will transition to all rain through Tuesday morning, tapering
off from west to east Tuesday afternoon.

Ceilings will slowly lower to 1000-2000 ft late tonight as the
heaviest precipitation develops across southern Wisconsin.
Ceilings will further lower to IFR going into Tuesday morning.
Ceilings will begin to recover into the 1000-2000 ft range going
into Tuesday afternoon and overnight hours.

MH

&&

.MARINE...
Issued 243 PM CST Mon Nov 17 2025

Low pressure will move from the Central Plains through the
central Mississippi Valley region tonight into tomorrow
afternoon. As this happens, light and variable winds overnight,
will come around to southeasterly and easterly through tomorrow
morning. Winds will become breezy over the southern half of the
lake as the low moves into the Ohio River Valley tomorrow
evening. Winds then ease Wednesday as high pressure moves over
the lake.

CMiller

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644...6 AM Tuesday to 9 PM
     Tuesday.

     Small Craft Advisory...LMZ645-LMZ646...6 AM Tuesday to
     midnight Wednesday.

&&

$$

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