143
FXUS63 KMKX 052115
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
315 PM CST Wed Feb 5 2025

.KEY MESSAGES...

- A wintry mix of light freezing drizzle and light snow is
  expected tonight. Less than an inch of snowfall accumulation,
  along with a glaze to 0.05 inches of ice are expected. Slick
  roads are possible for the early Thursday morning commute.

- Gusty west winds are expected Thursday, turning northwest
  Thursday night. A Gale Warning is in effect for Lake Michigan
  and a Wind Advisory is in effect for portions of central and
  east-central Wisconsin.

- Confidence in accumulating snowfall continues to increase on
  Saturday, particularly along & north of I-94/US-18. High
  spread remains in model snowfall forecasts, making it too
  difficult to message precise accumulations at this time.

- Given remaining uncertainties regarding Saturday snowfall,
  those with travel plans---particularly along & north of the
  I-94 & US-18 Corridors---should closely monitor the forecast
  over the next 24-48 hours.

- Well-below normal temperatures settle in for the second half
  of the weekend, lasting into the beginning of next week.

&&

.SHORT TERM...
Issued 315 PM CST Wed Feb 5 2025

Tonight through Thursday night:

Seeing an arc of agitated clouds on GOES Day Cloud Phase in
family with the FGEN band mentioned on the prior update. But, as
evidenced by the little to no radar returns, afternoon flurry
chances have diminished.

Within a few hours after dark this evening, expecting light snow
and freezing drizzle to overtake the entire region from south to
north. Though widespread 50-80% chances for precip are featured,
accumulations of only a few hundredths of an inch of ice and /
or snow less than 1 inch (likely less than half an inch) is
expected. Expecting light freezing drizzle to be the dominant
precip type south of a Wisconsin Dells to Port Washington line,
with snow mixing in at times. Further north, expecting
dominantly snow. Even if dominant precip type were to change as
this event unfolds, the lack of forcing for ascent limits our
expected precip amounts (only a few hundredths of an inch
liquid-equivalent to work with, whether it be snow or freezing
drizzle). From 5 AM CST Thursday onwards, expecting dry weather
all areas, but the early Thursday AM commute may see a few slick
spots, particularly on untreated surfaces.

For Thursday, dry weather and decreasing clouds. West winds
gusting upwards of 40 MPH. A wind advisory has been issued for Fond
du Lac, Sheboygan, Green Lake, Ozaukee, and Washington Counties,
where we expect to see 45 MPH gusts, with a few gusts to 50 MPH
possible. Winds turn northwest and gradually decelerate into
Thursday night.


Sheppard

&&

.LONG TERM...
Issued 315 PM CST Wed Feb 5 2025

Friday through Wednesday:

Synopsis: High pressure will be entrenched over the Upper
Mississippi Valley on Friday, supporting weakening west winds by the
afternoon hours. An upper trough will eject into the north-central
Great Plains Friday night, with attendant forcing encouraging lee
cyclogenesis over the Kansas-Nebraska border vicinity. The newly-
developed surface low will progress northeast into the middle
Missisppi Valley by Saturday afternoon, ultimately reaching the Ohio
River Valley Saturday night. Frontogenesis and warm advection will
thus increase in the 1000-700 mb layer over southern and central
Wisconsin to the north of the surface low during the day on
Saturday, supporting areas of widespread snowfall over southern and
central Wisconsin. Confidence in accumulating snowfall continues to
increase in this forecast package, though high spread remains in the
modeled placement of any band(s) of maximized totals. Placement
trends will continue to be monitored over the coming cycles, with
accumulation forecasts materializing as snow band location(s)
clarify. Those with Saturday travel plans---particularly along/north
of the I-94 & US-18 Corridors---should monitor the forecast closely
over the next 24-48 hours. High pressure will settle into the
Northern Plains behind the departing low from Sunday into the
beginning of next week, allowing well-below normal temperatures to
become established over southern Wisconsin through the beginning of
next week.

Saturday: Expect areas of snow to gradually overspread the region
from late morning through the afternoon hours. Precise onset times
of snow will depend on antecedent high pressure that will be exiting
the region, with lingering subsidence & dry low level air acting as
negating factors to an earlier snow arrival. Negating factors aside,
an abundance of synoptic ascent from low-mid FGEN/WAA & mid-upper
DPVA/divergence will overcome an initially unfavorable low level
thermal profile by Saturday afternoon at the latest. Once this
occurs, a steady period of snow is expected into Saturday evening.
Should the aforementioned forcing mechanisms align in time/space,
there would be some potential for moderate to heavy hourly rates
during this timeframe. Guidance currently depicts the best stacking
of synoptic forcing & attendant moderate/heavy hourly snowfall rates
over central and east-central Wisconsin, though it`s worth noting
that a high amount of spread remains regarding their ultimate
placement. Thus have moderate to high (60-90%) confidence in
accumulating snow areawide on Saturday, with progressively greater
amounts moving north of US-18 and I-94. Given the low passage to the
south of the area & prevailing east-northeast winds, will also need
to watch for possible lake enhancement. Will refrain from offering
any specific accumulation ranges, given the noted spread that
remains in snow placement at this time. Trends will be closely
monitored in the coming forecasts, with specific accumulation
ranges clarifying as model solutions converge. Those with
Saturday travel plans--- particularly those along/north of the
US-18 & I-94 Corridors--- should closely monitor the forecast
over the coming 24-48 hours.

Sunday Through Wednesday: High pressure will settle into the
Northern Plains in the wake of the Saturday low pressure system,
allowing Canadian air to work into the region. Thus expect well-
below normal temperatures during most/all of this time period. The
current forecast shows highs mostly in the upper 10s/low 20s with
overnight lows in the single digits away from Lake Michigan. Low
temps may approach/fall below zero Tuesday night over central
Wisconsin.

Quigley

&&

.AVIATION...
Issued 315 PM CST Wed Feb 5 2025

Lake Effect MVFR clouds (SCT around 2,000 ft) expected to
continue lifting / scattering to 3,000 ft into this evening. A
wintry mix of light snow and freezing drizzle expected after
sunset tonight, with winds turning southerly. Rates will be
very light, and totals are still expected to be a fraction of an
inch (snow) and/or a glaze of ice (a few hundredths of an inch)
at best. Visibilities of 2 to 5 SM may occur tonight with the
precip, along with ceilings lowering to below 1,000 ft (IFR
looking likely early Thursday morning).

Ceilings scatter out west to east Thursday morning, leaving VFR
likely through Thursday afternoon with dry weather. Very gusty
west winds expected, particularly in the afternoon and early
evening (30-42 kt gusts).

Sheppard

&&

.MARINE...
Issued 315 PM CST Wed Feb 5 2025

Low pressure around 29.6 inches over southeast Manitoba tonight
will shift into east central Ontario Thursday, strengthening to
29.3 inches. The low will push further to the east Thursday night,
as high pressure around 30.4 inches moves into the northern
Plains.

The combination of these features will allow for strong west to
northwest winds (gales to 45 kt) to develop Thursday into
Thursday night across Lake Michigan. A Gale Warning is in effect
for most of this period, and a few gusts to storm force may occur,
particularly over central Lake Michigan. High waves are expected
across eastern portions of the lake during this period. Freezing
spray is also expected Thursday night into Friday.

High pressure around 30.3 inches will move into the region Friday
and to the east Friday night. This will result in westerly winds
gradually subsiding during this period.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Wind Advisory...WIZ047-WIZ051-WIZ052-WIZ059-WIZ060...9 AM
     Thursday to 9 PM Thursday.

LM...Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
     LMZ565-LMZ567-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669-LMZ671-
     LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
     LMZ876-LMZ878...9 AM Thursday to 3 AM Friday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...6 PM
     Wednesday to 9 AM Thursday.

&&

$$

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