MD 0331 CONCERNING FREEZING RAIN FOR CENTRAL AND NORTHEAST WISCONSIN


Mesoscale Discussion 0331
NWS Storm Prediction Center Norman OK
0727 AM CDT Thu Apr 02 2026

Areas affected...central and northeast Wisconsin

Concerning...Freezing rain 

Valid 021227Z - 021530Z

SUMMARY...Freezing rain will continue this morning across portions
of central and northeast Wisconsin.

DISCUSSION...Moderate to heavy freezing rain continues across
central and northeast Wisconsin this morning. Several ASOS/AWOS
sites have measured around 0.25" of ice accretion in the past 6
hours with 1 hour totals up to 0.1". Strengthening low-level
east-northeasterly flow should maintain below freezing surface
temperatures across this region this morning. Given the upstream
radar mosaic, expect similar ice accretion rates for at least a few
more hours, especially across northeast Wisconsin where temperatures
remain in the upper 20s and the heaviest precipitation should last
longer.

..Bentley.. 04/02/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MQT...GRB...MKX...ARX...

LAT...LON   43768770 43718840 43948930 44359020 44649043 45029017
            45568974 45848945 46008905 45998853 45968817 45878785
            45638771 45418761 45378718 45038705 43768770

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0756 AM CDT Thu Apr 02 2026

Valid 021300Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS EASTERN
IOWA...NORTHERN ILLINOIS...AND FAR SOUTHERN WISCONSIN...

...SUMMARY...
Severe thunderstorms capable of producing a few tornadoes appear
probable across parts of eastern Iowa, northern Illinois, and
southern Wisconsin this afternoon. Additionally, damaging
thunderstorm winds will be possible from eastern Iowa northeast into
Michigan.

...Synopsis...
Early morning satellite and radar imagery show an extensive warm
conveyor, with embedded showers and thunderstorms, extending from
the southern Plains into the Upper Midwest, with some westward
branching noted over the Mid MO Valley. This warm conveyor is
associated with shortwave trough currently progressing through the
central Plains. Recent surface analysis places a surface low just
ahead of this wave over central KS, with a warm front extending
eastward from the low into the middle OH Valley and a dryline
extending south-southwestward from this low through the TX Trans
Pecos. 

Expectation is for this shortwave to eject quickly northeastward
throughout the day, maintaining a negative tilt as it progresses
through the Mid MO Valley and Upper Midwest before ending the period
over northeastern Ontario. The associated surface low will move
quickly northeastward as well, progressing across southern and
eastern IA and southern WI before occluding over upper MI tonight.
Warm front attendant to this low will move northward as well,
bringing low 60s dewpoints into eastern IA, northern IL, and
southern WI before a cold front moves through. Strong to severe
thunderstorms are possible along and ahead of the cold front over
much of the Mid MS and Lower OH Valleys, with the highest potential
for severe thunderstorms from eastern Iowa, northern IL, and far
southern WI.

...Northern MO/Southern IA across southern WI/northern IL into Lower
MI...
Extensive area of showers and thunderstorms is currently ongoing
from central TX into the Upper Midwest, within the warm conveyor
mentioned in the synopsis. Moderate to strong southerly low-level
flow exists within this warm sector. Progression of the negatively
tilted shortwave and associated surface low mentioned in the
synopsis will lead to a strengthening of this low-level flow, with
attendant moisture advection into more of the Mid MS Valley. Some
eastward displacement of the warm conveyor is anticipated, leaving
the potential for airmass destabilization ahead of the surface low
and cold front. This is supported by most of the guidance, which
depicts a corridor of surface-based buoyancy and little to no
convective inhibition from eastern IA/northern IL into central/east
TX by the early afternoon. 

Best forcing for ascent within this corridor will be over the Upper
Midwest and Mid MS Valley, particularly from southern/eastern IA
into northern IL/southern WI, as both the shortwave and surface low
move through the region. The strongest vertical shear will be over
this region as well, supporting the potential for supercells with
the initial, more cellular development. Very strong low-level shear
supports a heightened tornado potential with any supercells,
including the possibility of strong (EF2+) tornadoes. Given the
linear forcing along the approaching cold front, a transition to a
more linear storm mode is anticipated, although there is some
uncertainty to how fast this transition occurs. The strength of the
low-level flow supports a continued risk for tornadoes within any
convective lines, but the primary hazard once any lines develop will
become strong gusts. Kinematic fields are strong enough to support
60 to 80 mph gusts. Additionally, despite weakening buoyancy, strong
ascent and robust kinematic fields support the potential for
damaging gusts across much of Lower MI later tonight.

...Mid MS and Lower OH Valleys into the Mid-South...
As previously mentioned, showers and thunderstorms are currently
ongoing from central TX into the Upper Midwest, within the extensive
warm conveyor mentioned in the synopsis. There is some potential for
reintensification of these showers and thunderstorms late this
afternoon/early evening from central/eastern IL into the northeast
AR/MO Bootheel, supported my modest destabilization and increasing
ascent. Storm structures will likely be somewhat shallow, but strong
flow will still support the potential for damaging gusts within any
bowing line segments. A brief tornado is possible as well.

Airmass destabilization is also anticipated west of this warm
conveyor, but ahead of the cold front, from central IL into
central/southern MO and northern AR. Much of this area will be
displaced south and west of the departing shortwave trough and
surface low, limiting large-scale ascent. However, some modest
ascent is possible along a weak lagging upper trough, which could be
enough to promote additional development. If updrafts can be
maintained, parameters support the potential for strong to severe
storms capable. Large hail is the primary risk, but a
low-probability tornado risk exists as well.

..Mosier/Bentley.. 04/02/2026