Brookfield, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

715
FXUS63 KMKX 220948
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
348 AM CST Mon Dec 22 2025

.KEY MESSAGES...

- Light wintry mix expected during the morning commute to the
  north of I-94 & US-18. Slick spots are possible, particularly
  on untreated surfaces.

- Additional light drizzle, flurries, and freezing drizzle
  possible (~10-20% chances) east of I-39 this afternoon.

- Temperatures trending well above normal through the end of the week.

- Chances (~20-40%) for rain in southeast Wisconsin late
  Christmas Eve, with additional rain (~30-50% chances) possible
  areawide Christmas night.

&&

.SHORT TERM...
Issued 352 AM CST Mon Dec 22 2025

Today through Tuesday:

Synopsis/Mesoanalysis: Low pressure is pulling into South Dakota
this morning, with an attendant warm front extending southeast into
central Nebraska. A pronounced area of warm advection has blossomed
in the 850-700 mb layer to the northeast of the warm front, with
sharpening frontogenesis supporting the ongoing band of wintry
precipitation arcing from central Minnesota into west-central
Wisconsin. The aforementioned 850-700 mb frontal zone is forecast to
sharpen with east-southeastward extent through daybreak, allowing
wintry precipitation to fill into areas north of I-94 & US-18. A mix
of light snow, sleet, and freezing rain will be possible within this
area of wintry precip. Accumulation will be minor (no more than a
dusting of snow or light glaze of ice) as precipitation moves
through, though conditions could become slippery through the morning
commute. Budget extra time if planning to be on the roads. Precip
should push northeast of the area following 9 AM. Broad 925-700 mb
warm advection will continue through the afternoon hours today, with
additional light flurries, drizzle, and freezing drizzle possible to
the east of I-39 through the first half of the evening hours. Any
lingering light precip will end after midnight tonight, with mild
temperatures in the upper 30s and low 40s expected on Tuesday.

Early This Morning: Light wintry precip is expected to move into
areas north of I-94 & US-18 through daybreak. A mix of p-types is
expected, with predominant p-type at a given location being a
balancing act between warm advection influences in the 850-700 mb
layer & dynamic cooling from accompanying frontogenesis. Thus
anticipate that any/all of light snow, sleet, and freezing rain will
be possible in any given spot as precip moves through. Light rates
will keep any accumulations minor (dusting of snow/sleet or light
glaze of ice), though any untreated surfaces could quickly become
slippery. Given overlap of conditions with the morning commute, have
issued a Special Weather Statement through 9 AM for all counties to
the north of I-94 and US-18. Allow for extra travel time if
planning to be on the roads across the north through mid-
morning.

This Afternoon & Evening: Broad warm advection will continue within
the 925-700 mb layer, which could result in additional periods of
light drizzle, flurries, or freezing drizzle to the east of I-39
from the lunch hour through the first half of the evening.
Accumulation isn`t expected given even lighter precip rates relative
to this morning. Nevertheless, be sure to slow down if encountering
light wintry precip on the roads later today.

Quigley

&&

.LONG TERM...
Issued 352 AM CST Mon Dec 22 2025

Tuesday night through Sunday:

Synopsis: Winds will turn out of the south to southwest during the
middle to late week period. Said winds will advect a mild air mass
into the western Great Lakes, with temperatures expected to climb
well above normal by Friday. Light rain is possible (~20-45%
chances) later Christmas Eve as an upper disturbance passes just
south of the region. Best rainfall potential will be in southeast
Wisconsin. Another batch of rain is possible (~30-50% chances)
areawide Christmas night into Friday as a wing of warm advection
crosses the western Great Lakes.

Tuesday through Friday: Temperatures will steadily climb upward
through Christmas Day thanks to persistent south to southwest
surface flow. Currently expect Christmas Day & Friday to be the
warmest days of the period, with probabilistic temperature guidance
indicating medium (~40-60%) potential for highs at/above 45 each
day. Can`t rule out a few highs around 50 near the WI-IL state line
on Christmas, and across all of the region Friday, where
probabilistic temp guidance indicates low (~10-30%) potential for
highs at/above 50. Some light rain is possible later Christmas Eve
as the next disturbance moves near the WI-IL state line, with the
best chances being closest to the system`s track in southeast
Wisconsin. Additional rain is possible areawide Christmas night into
Friday morning.

Quigley

&&

.AVIATION...
Issued 352 AM CST Mon Dec 22 2025

VFR flight categories prevail early this morning across southern
Wisconsin, and are expected to continue through the majority of the
period at all fields. Light wintry precip remains possible this
morning, particularly across the northern half of the area. A mix of
-SN, -RASN, -UP, and -FZRA are all possible in this precip. Have
 accounted for this potential where forecast confidence is
 greatest in the 06 & 09Z forecasts, and will continue to
 monitor trends for additional amendments. South to southwest
 winds will become gusty this afternoon as low pressure builds
 into the Northern Plains. With warm advection ongoing above the
 surface, LLWS is possible through the late morning hours. Have
 accounted for this potential in the 06 and 09Z updates, and
 will make additional forecast modifications should model trends
 warrant. Additional -DZ or -SN is possible later this afternoon
 and evening to the east of I-39, the forecast confidence
 remains too low for mentions at this time. Winds will turn
 west-northwest late tonight as low pressure moves east of the
 area.

Quigley

&&

.MARINE...
Issued 352 AM CST Mon Dec 22 2025

High pressure of 1026 mb around the Ohio River Valley will continue
southeast through the rest of the overnight, as broad low pressure
around 1010 mb moves into the northern Great Plains. This will
result in increasing southwest winds across the waters. Light snow
should move into northern and central portions of the lake this
morning. Winds will shift south and continue to increase today, as
the low slowly moves east. Gusts to 30 knots are possible over
southern Lake Michigan, with gales not expected at this time.

Southwest winds will turn west tonight into Tuesday, as low pressure
around 1010 mb moves into Ontario. Winds will shift out of the
northwest by Tuesday afternoon, as high pressure around 1030 mb
moves into the northern Great Plains. Winds will subside Tuesday
night, as the high crosses Lake Michigan. These winds will shift out
of the southeast Wednesday, as the high moves east of the region.

Increasing southerly winds will result in increasing wave heights in
nearshore zones this afternoon. Waves are expected to exceed 4 ft
from Port Washington and points north. A Small Craft Advisory has
thus been issued between 12 PM and 10 PM CST given this potential.
Waves will subside as winds turn out of the west-northwest
tonight.

Quigley

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643...noon Monday to 9 PM Monday.

&&

$$

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