000
FXUS63 KMKX 030343
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
943 PM CST Sat Dec 2 2023

.UPDATE...
(Issued 943 PM CST Sat Dec 2 2023)

Rain and snow associated with an approaching shortwave trough over
ern IA and wrn IL is on track to overspread srn WI during the
early morning hours. The pcpn will reach the Madison area around
07Z, the Milwaukee metro area around 07-08Z, and Fond du Lac and Sheboygan
around 08-09Z. Pcpn type continues to be the challenge given the
relatively mild and moist surface layer. The pcpn will begin as
rain or a rain and snow mix with a best estimate of change over
about a couple hours after the steady pcpn begins. However, all
rain will continue along and east of a line from Sheboygan to
Waukesha to Burlington due to the relatively mild onshore flow
from Lake MI. The pcpn will continue through Sun AM, then
diminishing in the afternoon. The expected snow accum forecast
hasn`t changed with 1-2 inches north of Madison and less than an
inch elsewhere.



Gehring

&&

.SHORT TERM...
(Issued 320 PM CST Sat Dec 2 2023)

Tonight through Sunday night:

Low clouds will linger this evening, with some light drizzle
possible moving onshore from Lake Michigan.

QPF trends with the 12Z suite of models continues to show a steady
increase, with ensembles also showing this trend. There remains
good synoptic upward vertical motion from the negatively tilted
500 mb shortwave trough shifting through the region during this
period, along with some upper divergence from the left front
quadrant of a jet streak overnight. There is some modest
frontogenesis response in the 700 to 500 mb layer overnight as
well. The dendrite growth zone is tapped, but the best upward
vertical motion is above it.

Light snow will move northeast into the area between 04Z and 08Z
Sunday, peaking 08Z to 14Z Sunday before slowly tapering off
Sunday afternoon. Temperature profiles will be warm enough for all
rain in far southeast Wisconsin including Milwaukee and Kenosha,
with a mix between that area and all snow from a Fond du Lac to
Monroe line and west.

Forecast QPF is generally in the 25th to 50th percentile of NBM
away from the lake, and more towards the 75th percentile near it.
Forecast snowfall amounts have increased to around the 50th
percentile of NBM, which generally gives a 1 to 2 inch
accumulation northwest of Madison. Model Certainty continues to
trend upwards as well, and the forecast QPF and snowfall amounts
are around or below the 25th percentile there. This indicates that
the QPF and snowfall amounts could trend upward more with later
forecasts. The snow should cause some slippery roads in south
central Wisconsin.

Low clouds should linger Sunday night, as the low departs the
region. Forecast lows may be too cold given the expected clouds.

Wood

&&

.LONG TERM...
(Issued 320 PM CST Sat Dec 2 2023)

Monday through Saturday:

Models and ensembles are in good agreement with a clipper-type
system shifting southeast through the region Monday night into
early Tuesday morning. The 500 mb shortwave trough is fairly
robust, and there is decent deep layer moisture to work with.
Temperature profiles suggest mainly light snow showers with this
system, and brought PoPs upward to reflect higher confidence (60
percent) in the snow showers occurring. Snow accumulations up to
an inch may occur, which ensembles seem to be indicating.

Cluster analysis of 500 mb heights indicate an anomalous ridge
developing in the Northern Plains by the middle of next week, and
shifting east later in the week over the region. The ridge should
remain relatively amplified, which should lead to milder
temperatures by later in the week, with south to southwest winds
developing.

Wood

&&

.AVIATION...
(Issued 943 PM CST Sat Dec 2 2023)

Cigs will fall well below 1 kft for the early morning hours of
Sunday as rain and snow overspread srn WI. The rain will change
to snow over south central WI with a mixture continuing over se
WI. Areas of fog will also develop with vsbys ranging anywhere
from 1/2-4SM with the precipitation and fog. The very low Cigs
will continue through Sunday into Sunday night while the rain and
snow will gradually end Sunday afternoon.

Gehring

&&

.MARINE...
(Issued 320 PM CST Sat Dec 2 2023)

Low pressure will track toward the far southern portion of Lake
Michigan tonight into Sunday morning. Modest east to northeast
winds during this period will become north to northwest Sunday
afternoon and night, as the low moves east of the region. Low
pressure is then expected to move from North Dakota to southwest
Minnesota Monday, then across southern Lake Michigan Monday night
and southeast of the region on Tuesday. Modest winds Monday into
Monday night should become north to northwest and increase Tuesday
into Tuesday night. Winds may reach Small Craft Advisory levels
later next week, as milder air moves into the region.

Wood

&&

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

$$

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