NWS-Milwaukee/Sullivan Forecast Discussion
FXUS63 KMKX 311011
AFDMKX
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
411 AM CST Wed Dec 31 2025
.KEY MESSAGES...
- Another round of light snow is expected late this morning and
afternoon, with amounts ranging from a dusting to an 1 inch.
The best chances (20-40%) for snow amounts around/exceeding an
inch will be for areas from Sauk county through Rock and
Walworth counties.
- Cannot rule out a brief window of freezing drizzle ahead of
the onset of the snow as well on the back edge, bringing minor
impacts.
- Single digit temps and wind chills of 5 below to 15 below
zero are expected overnight New Years Eve into New Years Day.
&&
.SHORT TERM...
Issued 405 AM CST Wed Dec 31 2025
Today through Thursday:
Another round of light snow is expected today across portions
of southern WI as a mid-level shortwave trough to digs down
across the Upper Great Lakes region through the day while a cold
front pushes down from the nort-northwest to southeast. May be
a brief window on the leading edge of the snow transition to see
some light freezing drizzle before the DGZ saturates this
morning. However confidence remains on lower side as uncertainty
remains on how quickly it takes to saturate along with
warmer/above freezing temps creeping from the southwest this
morning.
Otherwise, expecting this snow activity to begin late morning
across the Wisconsin River Valley and spread southeastward
through the afternoon and into the early evening. Snowfall
amounts will once again be on the low side given QPF less than a
tenth of an inch and SLR of 12:1-16:1. The better slug of
Pacific moisture is progged across areas along and southwest
line from WI Dells to Kenosha where another 0.5-1.0 inch of snow
is likely given the better alignment of a small swath of low-
level WAA and the bands of 925-850mb frontogenesis pairing with
the edge of the higher PWATS (around 0.5 inch). Would not be
surprised to see locally higher swath of 1-2 inches within this
area from Sauk County through Rock/Walworth county given the
tendency for banded precip to over achieve. Meanwhile, while
some models do have this snow activity spreading into east-
central WI, overall trend limits this activity up that way with
a dusting to under an additional half an inch. On the back side
of the snow this evening could be another brief window for
freezing drizzle as things dry out aloft, but less certain as
models hint at a narrow/brief window. Lastly, timing of this
activity will coincide with the afternoon/evening commute this
New Year's Eve, so some impacts tor travel will be possible.
Behind the cold front expecting temps to fall as we ring in the
New Year with temps around the teens after sunset and falling
into the single digit as 2026 rolls on into southern WI. Breezy
northwest winds will accompany this colder airmass and will
result in even colder wind chills bottoming out between -5F to
-15F into New Year morning. Otherwise, New Year Day will be
drier, but on the chilly side with high temps ranging from
around 20F to the mid teens.
Wagner
&&
.LONG TERM...
Issued 405 AM CST Wed Dec 31 2025
Thursday night through Tuesday:
The colder trend is expected to continue through the end of the
week with below normal temps as high pressure builds from the
Dakotas and into the Great Lakes. While it is looking drier with
the high pressure, there are a few models that hint a small
ripple of mid- level vorticity working across the area with
another slug of Pacific moisture and a weak cold front on
Friday. So cannot completely rule out a quick burst of light
snow.
Temps remain on the cool side Saturday as the high pressure
weakens and as model continue to delay the ridge from moving
into our neck of the woods. Temps then gradually warm Sunday
into the start of next week as the upper-level ridge builds in
and kicks the surface high east. However the pattern does
continue to hint at becoming more active Sunday night with a
series of mid-level disturbances traversing the Upper Midwest
into the start of next week with a more prominent wave Later
Tuesday.
Wagner
&&
.AVIATION...
Issued 405 AM CST Wed Dec 31 2025
Clouds are here to stay today as MVFR (1-2kft) and occasional
IFR (<1KFT) ceilings persist through the day. Will see
prevailing northwesterly winds increasing into the afternoon
with gusts of 20- 25kt expected. Will see a another round of
light snow and accompanying drops of visibility and ceilings
today spread in from the northwest late this morning and
continue southeast through the afternoon and ending early
evening. Overall expecting 0.5-1.0 inch for most area terminals
with the exception of SBM where lighting snow from a dusting to
under half an inch is only expected. Additionally may see a
brief window for some light freezing drizzle develop both on the
front end and back edge of the snow. This activity will
gradually taper off after 00z with ceilings and flight
conditions improving overnight into New Years Day.
Wagner
&&
.MARINE...
Issued 405 AM CST Wed Dec 31 2025
Northwesterly winds prevail across the Lake today as strong low
pressure meanders back into the Hudson Bay region. Extending off of
this low is a secondary cold front that is expected to slide down
across the Lake through the day with increasing northwesterly gusts
behind it into this evening. Cannot rule out seeing a few gales
across the far northern portions of Lake Michigan this evening, but
this window looks brief. Thus have held off on any gale headlines at
this time. However, with the colder airmass and gusty winds behind
the cold front, moderate freezing spray will be a concern overnight
into New Years Day. Then winds slowly lessen through Thursday as
high pressure builds down across the Upper Midwest Thursday through
the weekend.
Wagner
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...9 AM
Wednesday to 3 AM Thursday.
&&
$$
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