Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 240926
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
426 AM CDT Sun Mar 24 2024

.KEY MESSAGES...

- Periods of snow showers may produce light accumulations through
this afternoon before temperatures warm this evening.

- Rainfall chances continue on Monday and Tuesday.

&&

.SHORT TERM...
Issued 422 AM CDT Sun Mar 24 2024

Today through Tuesday:

Synopsis/Mesoanalysis: Regional radar mosaics depict a broad area of
mostly light radar echoes from the Twin Cities southeast toward the
Chicago metro area early this morning. A scattering of stations over
west-central and southwestern Wisconsin are reporting light/moderate
snow beneath the aforementioned area of radar returns, which has
developed & persisted along the northern periphery of a zone of 925
mb warm air advection. Obs have remained precip-free over south-
central and southeastern Wisconsin, which is likely a testament to a
layer of dry air between the surface and 700 millibars. Said layer
has been well-sampled in the MSN and MKE ACARS soundings, though
steady wet-bulbing has been noted above 850 millibars with precip
continuing to evaporate into the column. Thus expect that light
flurry/snow shower coverage will continue to expand east through
sunrise, with snowfall gradually tapering by mid-morning as WAA
shifts away from the region. Currently positioned over southern CA,
an upper trough will progress into the Four Corners today,
consolidating into a closed upper low & reaching the Front Range of
the Rockies by this evening. Surface cyclogenesis will concurrently
proceed along the KS-CO border beneath the encroaching upper low,
with the newly-formed surface low lingering over the Central Plains
through Monday. The low is expected to reach the Northern
Mississippi Valley by Tuesday morning, tracking toward Lake Superior
on Tuesday afternoon as it drags a cold/occluded front across the
state. Southern Wisconsin will stay positioned downstream of the
aforementioned upper trough through Tuesday afternoon, with rounds
of WAA working in tandem with divergent flow aloft to support
several rounds of precip from this afternoon through Tuesday.

Rest Of Overnight: Expect flurries & light snow showers to continue
to expand east through sunrise. Don`t anticipate any accumulations
beyond a dusting over eastern areas, where flakes will begin to fly
the latest, though areas along/west of the I-39 Corridor could pick
up a quick 0.5". Wouldn`t be surprised if an isolated 1" total comes
out of the Wisconsin River Valley, where light snow has persisted
for the last couple hours. Be sure to slow down and allow for extra
time if taking to the roads early this morning.

Today & Tonight: Early morning flurries/snow showers will pivot away
from the area by mid-morning. Attention will then turn to the west,
where an additional round of precip is expected to develop during
the afternoon hours as WAA ramps up ahead of the ejecting western
trough. Continue to expect western and northern zones to have the
best chances of seeing steady precip given closer proximity to the
WAA driving precip. Expect precip to remain all snow across the far
north, though a transition to rain/snow mix or all rain remains
likely in south-central and southwestern WI as the low levels warm
during the mid-late afternoon hours. This expectation is reflected
in regional snow accumulation forecasts through today. 0.5-1" totals
are forecast in northern/western areas experiencing primarily snow,
with isolated totals in the 1-2" range possible in Sauk and
Marquette Counties. Precip will taper by mid-evening, giving way to
a predominantly dry overnight period.

Monday: Widespread rainfall is forecast areawide as an area of upper
divergence passes over the state. Snowfall isn`t expected given
WAA/mild temperatures ahead of the upper trough & surface low over
the Central Plains. Given the favorable upper forcing, considered
inserting some thunder mentions into the afternoon forecast
along/west of I-39, but ultimately held off given an abundance of
cloud cover and the placement of the coldest mid-level temps & lapse
rates over northern IA.

Tuesday: Gusty winds are anticipated areawide as the surface low
tracks from the MS River toward Lake Superior. Additional precip is
possible given the passage of the parent upper trough & a cold front
at the surface. Temps should be mild enough ahead of the front to
support primarily rain, although a few flakes could mix in during
the afternoon over southwestern Wisconsin. Have inserted some
mentions of thunder over far southeastern Wisconsin given the
afternoon passage of the front, as well as cold temps & steep lapse
rates in the mid-levels. Don`t currently expect strong/severe
storms, though the cold temps in place aloft could support some hail
potential in any storms that materialize. Will monitor trends over
the coming forecast cycles.

Quigley

&&

.LONG TERM...
Issued 422 AM CDT Sun Mar 24 2024

Tuesday night through Saturday:

Cooler temperatures are expected for Wednesday as cold air wraps
into the upper midwest on the heels of the departing low pressure
system. High pressure will then sink into the Middle Mississippi
Valley and give dry conditions through Wednesday and most of
Thursday.

Thursday night into Friday, WAA, frontogenesis, and weak gulf
moisture return should drive light shower precipitation over the
corn belt and into southern WI. Temperature profiles will be warm
enough to make all of this precipitation rain through Friday and
into Friday night.

With climatological highs for Madison and Milwaukee being around
47 for this time of year, Wednesday will be below normal with
highs in the upper 30s, while Thursday will be right around
normal. Temperatures then look to swing toward above normal this
weekend with the expected WAA in the upper midwest.

CMiller

&&

.AVIATION...
Issued 422 AM CDT Sun Mar 24 2024

Expect primarily VFR conditions to prevail through the period at all
terminals. One exception to the overall expectation will be through
sunrise, as periods of light flurries/snow showers will be possible.
Confirmed in recent obs from KUES, VIS and CIG readings could
briefly drop in any snow showers, making brief periods of MVFR and
IFR possible. Have withheld any prevailing mentions at the southern
Wisconsin terminals given the widely scattered nature of -SN, and
will plan to address brief periods of categorical reductions with
TEMPO groups. Conditions will dry out through late morning and early
afternoon, prior to the arrival of additional -SN. Expect the
greatest impacts from the second round of -SN at SBM, where periods
of reduced VIS and CIG readings will be possible through the first
half of Sunday evening. Conditions will dry out through the
remainder of the 24 hour forecast. -RA chances will increase nearing
the conclusion of the 30 hour forecast at MKE, though confidence in
arrival/development time is too low to justify mentions in the TAF
at this time.

Quigley

&&

.MARINE...
Issued 422 AM CDT Sun Mar 24 2024

Breezy southeast winds will prevail today as a 1030 mb high pressure
center pushes east into Quebec and a 980 mb low pressure center
develops over the central Great Plains. Gusts could approach gale
thresholds tonight, particularly over the southern half of the open
waters, though confidence in sustained and widespread gale-force
readings is too low to warrant any headlines at this time. Breezy
southeast winds will continue on Monday as the Great Plains low
pressure center pivots toward the Missouri River. Once more, gusts
could approach gale thresholds at times over central portions of the
lake, with confidence too low to justify any headlines. Trends
pertaining to tonight`s and Monday afternoon`s gusts will be closely
monitored over the coming forecasts. The aforementioned low pressure
center will track into the Upper Mississippi Valley on Tuesday,
resulting in the windiest day of the period. Confidence in gale
force gusts is thus higher on Tuesday, particularly during the
morning and early afternoon hours over the central open waters. Gale
watches/warnings may become necessary should forecast trends hold.
Sustained winds & gusts will slowly start to decrease Tuesday
afternoon and night as a cold front crosses the lake.

Quigley

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...1 PM
     Sunday to 7 AM Tuesday.

&&

$$

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