950
FXUS63 KMKX 271959
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
259 PM CDT Thu Mar 27 2025

.KEY MESSAGES...

- Chances (50-60%) for thunderstorms overnight tonight. Some
  could contain hail, possibly .

- A warm front is expected to move north through the area Friday
  and stall over central Wisconsin Friday night into Saturday.
  Highs may reach the upper 60s to middle 70s Friday, and lower
  to middle 60s Saturday.

- Showers and few thunderstorms are possible at times Friday
  night into Saturday morning, with rain showers & a few
  thunderstorms forecast Saturday afternoon through Sunday
  morning.

- Precip continues into Sunday evening, with colder air allowing
  for a changeover to snow. Sleet & freezing drizzle may mix in
  with the snow, particularly across the north.

- Dry & cool conditions prevail through the first half of next
  week, with the next chances for rain and snow arriving
  Wednesday into Thursday.

&&

.SHORT TERM...
Issued 300 AM CDT Thu Mar 27 2025

Tonight through Friday night:

Into this evening an increasing LLJ over the central US will
nudge into the higher low level moisture to the north and looks
likely (70%) to be enough forcing to bring developing storms to
southwest Wisconsin by around or just after midnight. This will
be ahead of the warm front, and forecast soundings suggest
enough omega in the 850-700mb range to bring elevated storm
potential (60%). The strong midlevel WAA will prevent anything
surface based. 700-500mb lapse rates are very good later this
evening (7-8 C/km) and thus there is plenty of MUCAPE from
500-1200 J/kg moving in with this system. In addition,
effective shear will be in the 30-35kt range. Thus, we could
easily see a few storms produce some hail with potential for a
few storms to produce severe hail, especially with much of the
instability column expected to be above the freezing level. We
will certainly be watching this potential into this evening as
we get a better idea of exactly how things will play out.

Shower/storm chances will push out to the north and east by mid
morning with the warm front pushing north in behind it. Clouds
will clear out as the warm front slides through and pushes any
low level moisture north. This should allow for clearing skies
and given the conditions increased mixing as we start to warm
up. With the LLJ sliding north we should expect to mix down some
very breezy winds with gusts to 35 mph possible, highest gusts
expected further south. We cannot rule out the need for a Wind
Advisory but winds would have to overperform a bit and in a WAA
regime that tends to be less likely. Precip chances Friday seem
fairly limited (20-30%) with most of the potential for showers
storms having shifted further north and west in the latest model
data.

Into Friday evening and overnight period there will be slightly
increased chances for showers/storms as a surface low pulls
through central WI and brings a weak cold front through. This
cold front will bring our chances for precip (30-40%) with the
best chances not expected until Saturday morning. A rumble of
thunder is possible with this but CAMs show this to be fairly
unlikely.

Kuroski

&&

.LONG TERM...
Issued 300 AM CDT Thu Mar 27 2025

Saturday through Thursday:

Synopsis: Surface low pressure will progress toward Lake Huron
during the day on Saturday, concurrently dragging a cold front into
southern Wisconsin during the afternoon hours. Global forecast
guidance suggests that the boundary will stall somewhere across the
area, resulting in considerable north-south spread in high
temperatures Saturday afternoon. An upper disturbance will eject
into the central CONUS Saturday afternoon, ultimately progressing
across the western Great Lakes during the day on Sunday. Increasing
lift ahead of the disturbance will support increasing chances for
showers & a few thunderstorms Saturday afternoon, with periods of
precipitation continuing into Sunday night. A second area of surface
low pressure will accompany the passing disturbance, progressing
from the Upper Mississippi Valley toward Lake Huron Sunday through
Monday morning. Winds will turn northerly in the wake of the
departing surface low Sunday evening, funneling colder air into
southern Wisconsin. The arrival of said colder air will allow for a
rain/snow transition Sunday evening & night. Some sleet & freezing
drizzle could mix in with the snow, particularly across the north.
Conditions will dry out Monday through Tuesday. The next disturbance
will approach from the Plains by mid-week, bringing additional
chances for rain and snow to southern Wisconsin.

Saturday Afternoon Through Sunday Afternoon: Increasing low-level
WAA & mid-level DPVA will support increasing rain chances across
southern Wisconsin. Forecast soundings show some weak (~500 J/kg or
less) MUCAPE Saturday afternoon, which justifies continued thunder
mentions in this forecast. Rain & thunder chances will continue
Saturday night into Sunday afternoon with the approach & passage of
the surface low. The north-south extent of thunder potential will be
driven by the track of the surface low, which ranges anywhere from
central Wisconsin to the WI-IL state line in global ensembles.
Locations that do end up in the warm sector will see chances for
storms, with the aforementioned forecast uncertainties making it too
difficult to speculate on any stronger storm potential at this time.
Will monitor trends over the coming updates.

Sunday Evening Through Monday Morning: Precipitation will continue,
with the arrival of colder air allowing for a transition to snow
from northwest to southeast. Some sleet & freezing drizzle could mix
in with the snow, particularly across the north. Ensemble p-type
probabilities continue to suggest that the changeover will hold off
until Sunday evening, though the potential for a more
southerly/colder surface low track Sunday afternoon (previous
paragraph) leaves some room for an earlier changeover time across
our northern counties. Will be closely monitoring trends in low
track in the coming forecasts. Probabilistic snowfall forecasts
suggest medium potential for minor accumulations (~40-60% chances
of 0.1"+), with 1.0"+ probs coming in considerably lower.

Quigley

&&

.AVIATION...
Issued 300 AM CDT Thu Mar 27 2025

Mid level CIGS will continue through much of this evening. Into
the late evening there looks to be increased potential for
MVFR/IFR CIGS to increase from the southwest as low level
moisture increases. In addition, we may start to see increased
chances for showers and storms. Models take storms chances
through the late night hours, keeping them largely restricted to
southern WI. However, in southwest WI models indicate some risk
for a severe storm or two with the only risk really being large
hail, though small hail should be expected for areas hit with a
stronger storm. Winds will shift more southeasterly overnight
before shifting back toward south to southwesterly as the warm
front lifts north into Friday morning. A bit of uncertainty on
how far north the warm front makes it as it is expected to stall
somewhere over central WI, with a fairly sharp wind shift north
of the boundary with more easterly flow. Southwest winds will
be quite breezy during the day. Otherwise Friday is expected to
remain largely dry and likely seeing some clearing skies behind
the front.

Kuroski

&&

.MARINE...
Issued 300 AM CDT Thu Mar 27 2025

High pressure will continue to shift east as a low pressure
system will swing through the central US tonight with a warm
front lifting north into Friday morning. Modest south to
southeast winds tonight will swing to the southwest behind the
warm front. Southwest winds will persist through the day with
the front stalling somewhere over central Lake Michigan with
more easterly flow to the north. A cold front will sag southeast
across the lake as a low pressure system pulls through, with
north to northeast winds becoming dominant Saturday behind the
front. This front will dissolve tonight and winds will be come
southeast to easterly everywhere over the lake.

Some thunderstorms will be possible tonight, Friday night and
again possibly Saturday. Gales are not expected at this time.

Kuroski

&&

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

&&

$$

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