NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 142013
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
313 PM CDT Tue Apr 14 2026

.KEY MESSAGES...

- Significant severe weather event remains forecast this
  afternoon & evening (peak intensity 3-10 PM). All severe
  weather hazards, including very large hail greater than golf
  ball size and tornadoes, are possible. Seek immediate shelter
  if a warning is issued for your area later today.

- Additional severe storms possible Wednesday afternoon if a
  front remains stalled across the area. If the front sets up
  south of the area, severe potential will greatly decrease but
  flash flooding will remain possible due to training
  convection.

- Heavy rainfall could lead to additional periods of flooding
  this afternoon into Wednesday. Additional Flood Watches are
  possible especially tomorrow.

- Additional windows for heavy rainfall, flooding, and severe
  thunderstorms Friday into Saturday. All severe hazards will
  be possible later Tuesday afternoon into the evening.

&&

.SHORT TERM...
Issued 309 PM CDT Tue Apr 14 2026

Tonight through Wednesday night:

Storms have begun to fire this afternoon over central to NW
Iowa. This corroborates a westward shift in initiation trends in
recent runs of the HRRR model. Current runs of the WoFS support
two main areas of storms this afternoon with a cluster of
storms over central WI through Sauk, Columbia, Green Lake, and
Marquette Counties that will then track east to the lakeshore
and a cluster that will move through southwest Wisconsin and
east to the lake. These storms are projected to be supercells
when they enter our area but may cluster into a line with
eastward extent

An 18z sounding from Davenport supports a very unstable
environment supportive of 4000 J/kg held by a cap at 800mb. With
the cap eroding to our west, explosive supercell development is
expected, leading to the corridors of storms in southern WI
mentioned in the previous paragraph. All hazards will be
possible during the supercell mode, as mid level lapse rates ~8
C/km and hodograph curvature will support large hail, and
curvature in the low levels of the hodographs and 3CAPE >150J/kg
will support 0-1 km SRH >200 m2/s2 and low level stretching for
tornado formation. As we head into the evening, there may be
some potential for these storms to become linear, leading to a
damaging wind and QLCS tornado threat, especially as the LLJ
increases near sunset and lengthens the low level hodographs.
Todays severe weather hazards are expected to be high end and
should not be taken lightly. Have multiple ways to receive
warnings.

Storms are largely expected to be out of the area after 10PM,
and may push a surface boundary through our area. If this
happens, storms tomorrow will be less severe though flash
flooding will still be a threat. Runs of the CAMs depict a west
to east oriented line of storms that may set up along the WI/IL
border during the late afternoon into the evening, capable of
heavy rain. The wind, hail, and tornado threat with the storms
tomorrow will be far less than today.

CMiller

&&

.LONG TERM...
Issued 245 PM CDT Tue Apr 14 2026

Thursday through Tuesday:

A shortwave trough will track across southern WI Thursday morning.
Scattered showers and a few thunderstorms are expected with this
feature, especially in the morning with deeper moisture still in
place over the region. The chance for showers and thunderstorms
will linger into the afternoon. As the deeper moisture departs
during this time and we heat up, the low level lapse rates will
increase to allow for instability (up to 1000 j/kg) to develop. A
lake breeze should push inland and help to trigger some of the
showers/storms. Look for the precip chances to exit by sunset.

High pressure will pass through Thursday night and lows will dip
into the 40s wherever the lake breeze hit, so bisecting southern
WI from east to west. Friday morning and early afternoon look
quiet, but we will be getting primed for the next system to arrive
Friday late afternoon and night.

Low pressure tracking across the northern Plains on Friday, in
response to a high-amplitude upper trough, will cross Lake
Superior Friday night. A strong cold front will slide across WI
from west to east late Friday night through Saturday morning.
Showers are thunderstorms are expected within the warm sector
Friday afternoon/evening and also along the cold front. Scattered
showers are possible behind the front during the day Saturday.
Strong cold air advection will follow, so low temps should dip
down to around or below freezing Saturday night on brisk westerly
winds. The models dry out the atmosphere quickly, but if there
happens to be any lingering moisture, the precip type would chance
to flurries/snow.

Brisk westerly winds will persist through Sunday. Finally, high
pressure will dominate and give us dry weather through Monday or
Tuesday. The weather pattern has a large degree of uncertainty
beyond Monday between the models.

Cronce

&&

.AVIATION...
Issued 236 PM CDT Tue Apr 14 2026

Severe storms are expected this evening across all of southern
Wisconsin. These storms will be capable of all severe weather
hazards. The storms should track from west to east across the
area between 21Z and 03Z tonight. Higher surface moisture has
supported low VFR to high MVFR BKN to SCT conditions and those
cigs should largely continue into tonight. Ambient, background
flow should be southerly to southwesterly with breezes from 15
to 20 knots. After storms move through tonight, winds should
briefly become light and variable for a time before southerly
winds return. Fog may also form over south central WI.

CMiller

&&

.MARINE...
Issued 245 PM CDT Tue Apr 14 2026

A stationary front will remain parked over the middle third of
the lake into tomorrow, slowly sinking south to the southern end
of the lake by Thursday morning. Winds will remain southerly
south of the front and modestly breezy, while winds north of the
front will remain light and variable to northerly during this
time. Today, severe storms are expected over the southern half
to southern two thirds of the lake. Hail and gusty winds will be
possible and waterspouts may occur with any tornadic storms from
land that move over the waters. This will be most likely near
the shoreline of Wisconsin and Illinois.

The front will clear the lake as a cold front Friday, before
low pressure of 29.6 inches approaches from the west.

CMiller

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Dense Fog Advisory...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ643-LMZ644-LMZ669-LMZ671-LMZ868-LMZ870-LMZ872
     until 7 AM Wednesday.

&&

$$

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