Janesville, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

179
FXUS63 KMKX 020357
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
957 PM CST Sun Feb 1 2026

.KEY MESSAGES...

- A band of light snow will progress west to east through
  southern Wisconsin through tonight, with a brief period of
  freezing drizzle also expected after the snow ends. Expect a
  dusting to approximately 0.5 inch of snow and up to a light
  glaze of icing. Snow and freezing drizzle end early Monday
  morning (by 5 AM CST).

- A weak clipper system may (approximately 20 percent chance)
  bring light snow to areas southwest of Madison Monday night
  into early Tuesday morning.

- Milder this week, with highs in the low to mid 20s through
  Wednesday, then 30s for Thursday and most of the area on
  Friday.

- Chances for light snow (25 to 45 percent) returns Thursday
  afternoon into Friday.

&&

.UPDATE...
Issued 958 PM CST Sun Feb 1 2026

A band of light snow progressing west to east across southern
Wisconsin is still expected to produce minimal accumulations
(less than 0.5 inch in the majority of locations). Although the
majority of lift has remained focused along this main band,
convergence ahead of an effective weak warm front moving
southeastward is leading to a broad area of light radar
reflectivity returns that are likely associated with an area of
freezing drizzle. Upstream observations are at minimum showing
drops in visibility and low ceilings, with previous manual
observations taken in eastern Iowa and Minnesota indicating
freezing drizzle as a likely precipitation type. Therefore,
confidence has increased in a period of freezing drizzle between
snow ending and the frontal passage drying things out early
Monday morning (between 1 AM and 5 AM CST). Still, only a light
glaze of icing is expected.

MH

&&

.SHORT TERM...
Issued 239 PM CST Sun Feb 1 2026

Tonight through Monday night:

Snow largely underperformed early this afternoon as lingering
dry air from the high pressure that moved through last night
held firm. Looking at upstream obs near Minneapolis, snow along
the sfc trough should perform better and spread east through
southern WI during the evening into tonight. Snow totals will
generally be a few tenths less than previous forecasts and stay
at or below a half inch. There have been some reports of
freezing drizzle immediately following the band of snow across
MN. Confidence remains low that freezing drizzle will be
realized here, but some freezing drizzle following the snow
tonight can`t completely be ruled out given RAP soundings over
southern WI just barely lose ice crystals aloft while remaining
saturated near the surface Monday morning before dawn.

Once snow moves out, the rest of the daytime on Monday looks
dry. A weak clipper system is expected to move through the
eastern Corn Belt Monday night and may offer a glancing blow of
light snow to the area southwest of Madison. For now 15 to 20%
PoPs have been introduced to Iowa, Lafayette, Green, and Rock
Counties from 06Z to 12Z Tuesday.

CMiller

&&

.LONG TERM...
Issued 222 PM CST Sun Feb 1 2026

Tuesday through Sunday:

Not many changes to the extended forecast today. Northwest flow
over the Upper Midwest and troughing over the Eastern US will
promote relatively dry conditions and highs in the upper teens
to low 20s. High pressure sinking southeast into the state will
keep skies mostly clear Tuesday and Wednesday.

Thursday, Global forecast models have generally shifted the
position of the surface low that`s expected to bring us our next
snowfall chances further north. Its positioning will still promote
southerlies and some modest WAA over the area however.
Temperatures will rise to near freezing. Snow chances look to
have decreased slightly as more of the optimal forcing for
ascent from the WAA will be displaced further into northern WI
and Upper Michigan. Snow chances now sit between 25 to 45% for
Thursday afternoon into Friday.

Models continue to agree that another push of arctic air will
briefly occur behind a cold front in association with this low
to the north, and temperatures may briefly dip into the teens
and low 20s on Saturday, before moderating into the mid to upper
20s on Sunday.

CMiller

&&

.AVIATION...
Issued 958 PM CST Sun Feb 1 2026

A band of light snow will continue to progress eastward,
reaching Lake Michigan terminals within the next hour. Expect
reductions in visibility as low as 3 SM, with accumulations
generally less than 0.5 inch. As snow exits, a 2 to 3 hour
period of freezing drizzle is expected to develop across all of
southern Wisconsin. A glaze of icing is possible with this
activity. All precipitation is expected to end across southern
Wisconsin by 5 AM CST as a front pushes through west to east.
Ceilings will remain around 1000 ft into the early morning hours
before gradually improving.

Southwesterly breezes continue through late tonight, becoming
light and gradually shifting to become northwesterly and
increasing back to around 10 kt into Monday morning.
Northwesterly winds will persist into Monday evening, but will
become light again Monday night.

MH

&&

.MARINE...
Issued 246 PM CST Sun Feb 1 2026

Breezy southwest winds to 20 knots continue through tonight ahead
of an approaching cold front. Winds will then ease in strength
Monday morning and come around to northwesterly following the
front. Light to moderate northwest winds are then expected to
continue until late in the work week when a low pressure trough
approaches the lake. Southwest winds will return for Thursday,
before north northwest winds return on Friday behind a cold
front. Gales and moderate freezing spray may occur behind the
cold front.

CMiller

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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