529
FXUS63 KMKX 060941
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
441 AM CDT Sun Apr 6 2025

.KEY MESSAGES...

- A band of wet/slushy snow will quickly move across southern Wisconsin
  Monday morning, with additional scattered snow showers
  possible Monday afternoon. Minor travel impacts are possible.

- Below normal temps expected early next week, with highs
  rebounding to near & just above normal by mid-week.

- The next disturbance approaches Wednesday through Thursday, bringing
  additional chances for mostly rain to southern Wisconsin.
  Precip could begin as a brief rain/snow mix Wednesday morning.

- Temperatures continue to climb through the late week period.

&&

.SHORT TERM...
Issued 443 AM CDT Sun Apr 6 2025

Today through Monday:

Synopsis/Mesoanalysis: A surface pressure ridge is positioned across
west-central Wisconsin this morning, resulting in light northwest
surface winds and clear skies across the area. Evident in GOES water
vapor imagery, a shortwave trough has been analyzed along the
Manitoba-Ontario border. Said shortwave will progress southeast
across Lake Superior today, promoting weak surface cyclogenesis in
the Upper Peninsula of Michigan. The development of the surface low
will allow winds to turn out of the west-southwest across southern
Wisconsin this afternoon, bringing a modestly milder air mass in
from the Northern Plains. The aforementioned shortwave will drive
southeast into the region tonight as its attendant surface low moves
into Lower Michigan. The low will concurrently drag a fast-moving
cold front across southern Wisconsin during the predawn hours. Lift
affiliated with the encroaching upper wave & elevated FGEN lagging
behind the surface front will pull a quick-moving band of steady
snow across the region from late tonight through the first half of
Monday morning. Additional, more scattered snow shower potential
will continue into Monday afternoon areawide. Minor/slushy
accumulations will be possible on grassy surfaces, particularly
across east-central Wisconsin. Combined with increasingly gusty
north winds in the wake of the departing cold front, Monday`s snow
may result in minor travel impacts across southern Wisconsin. Be
sure to allow for extra time if driving Monday morning and
afternoon.

Tonight Through Monday Morning: A quick-moving band of snow will
progress across the area. Initial rain/snow mix can`t be entirely
ruled out along the leading edge of the band, though changeover to
snow will occur rapidly. Snow potential will peak between ~1-5 AM
north of I-94 & US-18, and between ~5-9 AM along/south of I-94 & US-
18. An overlap of pronounced 850-700 mb FGEN & weak CSI within a
post-cold frontal/CAA regime will support the potential for elevated
(0.5"+/hr) hourly snowfall rates within the snow band. While snow
will be wet & slushy in character, said enhanced rates &
increasingly gusty north winds could lead to reduced visibilities &
minor travel impacts before & during the Monday morning commute.
Budget a few minutes of extra time if planning to be on the roads.
Given the potential for elevated hourly rates, anticipate that
most/if not all minor snow accumulation from this event will occur
during the morning snow band. Accumulations should be confined to
grassy surfaces given mild pavement temps across the area. Best
potential for slushy accumulations will be across east-central
Wisconsin, where up to an inch may occur.

Monday Afternoon: Confidence is increasing for additional, more
scattered snow showers across all of southern Wisconsin. Thanks to a
very cold air mass in the 925-700 mb layer, forecast soundings
depict deeply-mixed boundary layers extending to near the 700 mb
level. Given DGZ`s residing between ~850-750 mb & LCL`s rooted
at/just below 850 mb, the aforementioned deep mixing/overturning
would result in efficient ice nucleation within developing cumulus
clouds, and thus the potential for hit/miss snow showers. Have
accounted for this in the Monday afternoon PoP grids. Afternoon snow
showers would be considerably drier & more powdery relative to the
morning snow band, with still gusty north winds would make it easier
for blowing snow & abrupt visibility drops to occur. Thus can`t rule
out continued minor/nuisance travel impacts into the Monday evening
commute across southern Wisconsin. Will continue to monitor trends
in the coming forecasts.

Quigley

&&

.LONG TERM...
Issued 443 AM CDT Sun Apr 6 2025

Monday night through Saturday:

Synopsis: Below-normal temps will persist through Tuesday as high
pressure moves across the western Great Lakes. Winds will turn
southerly and eventually southwesterly Wednesday-Thursday, allowing
temps to climb back to or just above normal. The next upper
disturbance & surface front will approach late Wednesday through
Thursday, bringing the next chances for rainfall to southern
Wisconsin. Temperatures will continue to trend upward through the
late week period.

Wednesday Through Thursday: The next chances for appreciable precip
arrive with the next disturbance. Continue to see signals for
mostly/if not all rain with this system given mild forecast
temperatures. Will nevertheless be monitoring trends regarding the
arrival of precip Wednesday, as a brief period of rain/snow mix
could occur along the leading edge of precipitation. Could also see
a few embedded thunderstorms given weak MUCAPE in global guidance,
though strong/severe storms appear unlikely at the current time.

Quigley

&&

.AVIATION...
Issued 443 AM CDT Sun Apr 6 2025

VFR conditions prevail through the majority of the period at all
terminals. Current northwest winds will briefly shift out of the
west-southwest this afternoon as an area of low pressure develops
over the Upper Peninsula of Michigan. Said low will migrate into
Lower Michigan tonight, concurrently pulling a cold front across
southern Wisconsin. The frontal passage will bring a gusty northerly
wind shift to all terminals, in addition to areas of snow showers.
Snow is expected to hold off until just beyond the current 24 hour
period, though is likely to approach KMKE nearing the end of the 30
hour period. Have accounted for these expectations in the 06/09Z
updates, and will be inserting -SN mentions at all 24 hour sites in
the 12Z forecast.

Quigley

&&

.MARINE...
Issued 443 AM CDT Sun Apr 6 2025

Winds will briefly shift out of the west-southwest this morning and
afternoon, when low pressure of 1012 mb is forecast to develop over
the Upper Peninsula of Michigan. The low will progress across the
northern open waters this evening as it deepens to near 1006 mb,
moving into the Lower Peninsula of Michigan by daybreak Monday.
Winds will shift out of the north to northwest behind the passing
surface low late tonight through Monday, becoming gusty by late
Monday morning. Widespread gusts between 25-30 knots are forecast
through Monday afternoon, with periods of gale force gusts possible.
Confidence in gales is highest across the southern half of the open
waters, where a Gale Watch has been issued between 10 AM and 7 PM
CDT Monday. Periods of snow will accompany the passing low,
particularly tonight through the first half of Monday morning. A few
areas of light freezing spray are possible late Monday afternoon
into Monday evening, particularly across the northern half of Lake
Michigan. Gusts will taper Monday night as 1022 mb high pressure
moves into the western Great Lakes.

In nearshore zones, north-northwest wind gusts and elevated wave
heights will exceed Small Craft Advisory thresholds from late
tonight through Monday night. Small Craft Advisories have been
issued between 3 AM CDT Monday and 1 AM CDT Tuesday from North Point
Light to Sheboygan, and between 5 AM CDT Monday and 7 AM CDT Tuesday
from North Point Light to Winthrop Harbor. Winds and waves will
taper comfortably below advisory levels Tuesday morning as high
pressure builds into the Upper Midwest. Additional periods of Small
Craft Advisory conditions are possible during the day on Wednesday,
when low pressure will approach from the Great Plains.

Quigley

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644...3 AM Monday to 1 AM
     Tuesday.

     Small Craft Advisory...LMZ645-LMZ646...5 AM Monday to 7 AM
     Tuesday.

     Gale Watch...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
     LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 AM
     Monday to 7 PM Monday.

&&

$$

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