883
FXUS63 KMKX 310910
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
410 AM CDT Mon Mar 31 2025

.KEY MESSAGES...

- Light wet snow early this morning is slowly ending across
  southern Wisconsin. Less than an inch of snowfall
  accumulation is forecast, mainly north of Madison and
  Milwaukee.

- Dry and cool conditions prevail from mid morning through
  Tuesday.

- More showers and thunderstorms for Tuesday night and
  Wednesday. A few stronger storms may be possible Wednesday.

&&

.SHORT TERM...
Issued 409 AM CDT Mon Mar 31 2025

Today through Tuesday:

Temperatures will continue to drop to 28 to 32 across southern
Wisconsin this morning. The light wet snow is slowly ending as
the low pressure system in eastern Michigan continues northeast
into Ontario and Quebec. Accumulations will and have remain low
to near zero this morning. Warm grounds and road temperatures
(around 34 to 37 degrees) should keep snow from sticking and
also prevent any potential refreeze this morning.
Bridges/Overpasses and other elevated surfaces have the best
potential for any refreezing as the air temperatures around 28
to 32 can more affectively  cool theses surfaces. Shortly after
sunrise temperatures will begin to climb again across the state
to above freezing. CAA will keep temperatures cooler across the
board however with highs in the lower to upper 40s.

High pressure will build in from the Plains today, passing
overhead Tuesday. Dry and cool conditions are expected.

Patterson

&&

.LONG TERM...
Issued 409 AM CDT Mon Mar 31 2025

Tuesday night through Sunday:

Low pressure will develop out of the Rocky Mountain west Tuesday
and begin its approach toward the Great Lakes Region.Tuesday
night through Wednesday, rain and storms are expected to return
as this low passes through the state. Uncertainty on the track
of this low remains with the spread putting the low in either
northern Wisconsin or southern Wisconsin. This large shift in
track will play a big roll the potently for severe/strong
storms to develop. A more northern track solidly puts Wisconsin
in the warm sector and a more southern track will limit the
potential for the warm sector to move into the state and will
push the severe/strong storm potential south and east.

Now this system will be a strong one regardless, but the
question comes down to how much of an impact will this have on
the state. The upper level trough will be negatively tilted,
moisture advection is expected to start Tuesday night, Effective
shear is strong with values of 60-80 kts and hodographs don`t
look bad either. Some guidance has run away with these values a
bit, giving very high totals for southern Wisconsin. For
example when looking at the 0-6 km shear some guidance is
suggesting 100 to 110 kts. This is likely way to high for
Wisconsin and is very localized across southeastern Wisconsin.
When looking at this over time (from model run to model run)
most are showing an increasing shift to the south and east
overtime. So with models overdoing it a bit and some rather
large uncertainties this will be a time period to keep an eye
on. As things stand now, rain and storms are likely regardless
of track and intensity. Precipitation is likely to start Tuesday
night prior to the wind shift and warm air advection kicking
in. So its likely precip could start as snow and then
transition into rain by the early morning hours Wednesday. With
the impressive winds and shear its possible that rain/storms
will overrun the warm front bringing additional chances for rain
in the morning. The environment would need a chance to recover
and then in the afternoon we will have the potential for more
rain/storms.

Wednesday afternoon/evening will be the time frame for any
stronger storms. If the warm front stays south, storms will
remain elevated and hail will be our largest concern. If the
warm front moves into the state we can expect some surface based
convection which will bring damaging winds into the equation.
Given the strong winds/shear it wont be hard to mix down some of
those stronger winds. There is less confidence when in comes to
the potential for any tornadic activity. Model hodographs do
look decent, however there are so many caveats with just far
better conditions to our south that this threat is lower than
the other two. Shear can make up a lot for any lacking
instability/lift, but if guidance is correct with those higher
values its just as likely we could shear out as well. So much
more of a conditional tor threat here in comparison to hail and
damaging winds. Will need to keep an eye on the track of the
low.

Beyond Wednesday, high pressure returns to the Great Lakes
Region. Quiet weather with temperatures near normal for this
time of year are expected. This area of high pressure will
advect in form the Northern Plains and move overhead Friday
before quickly exiting to the east. Guidance suggests another
potential for rain Saturday. There is still a lot of uncertainty
here, but this system looks to largely pass by to our south
which will clip the state. Did keep some POPs due to the
potential (15-25%), for light rain even if the uncertainty is
high.

Patterson

&&

.AVIATION...
Issued 409 AM CDT Mon Mar 31 2025

VFR to MVFR conditions are expected to continue through the
period. A few to scattered clouds could potentially be around
1000 feet this morning, but the ceilings are expected to remain
around 2-6 kft through this morning. Skies will gradually clear
from west to east which will bring VFR conditions to all of
southern Wisconsin. The last of the light snow this morning is
exiting to the east. Any areas that did see light accumulations
can expect that to begin melting at the temperatures increase
after sunrise. Dry conditions are expected through Tuesday.
Tuesday late afternoon/evening mid to high clouds will return
and are expected to build in from the west.

Breezy north winds this early morning will diminish/decrease
through the remainder of the morning. Moderate winds this
afternoon will become light winds tonight and shift to the
northeast. Wind will continue to shift to easterly and remain
light heading into Tuesday morning.

Patterson

&&

.MARINE...
Issued 409 AM CDT Mon Mar 31 2025

Low pressure around 29.5 inches will continue northeast into
Ontario and Quebec early this morning. As the low moves out, brief
periods of dense fog are possible and gusty north winds are
expected. An occasional gust to gale force is possible across
the open waters through this morning. A small craft advisory is
in effect for the nearshore waters through this afternoon. North
winds will then gradually subside in the afternoon and evening.
Light winds are then expected tonight into Tuesday morning as
high pressure moves across the lake.

Wednesday, a low pressure system around 29.1 inches will move
into the Great Lakes Region from the Central Plains. Rain and
thunderstorms will be possible as the low moves through bringing a
cold front across the lake. Gusty east winds are expected ahead of
this system with gales possible. Additional small craft
advisories may be needed Wednesday.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 1 PM
     Monday.

&&

$$

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