Flash Flood and Hail in Wisconsin, April 13, 2026

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
125 PM CDT Mon Apr 13 2026

.KEY MESSAGES...

- Strong to severe storms expected along a warm front this afternoon
through the evening. Hail is the most likely threat, with secondary
threat of tornadoes in southern/southeast Minnesota.

- Areas of dense fog in the morning, followed by clearing skies
tomorrow with continued warm temperatures.

- Multiple chances for rain showers and weak storms throughout
  the rest of the week.

&&

.DISCUSSION...
Issued at 124 PM CDT Mon Apr 13 2026

Eyes are glued to satellite this afternoon as we await convective
initiation within a few hours, with the warm frontal boundary
evident over far southeastern South Dakota through the I-90 corridor
as a secondary boundary has set up farther north associated with the
light showers stretching from central South Dakotas through St.
Cloud. The southern boundary is the warm front associated with an
incoming low pressure system that is expected to be the locus of
severe weather activity later, with the northward extent of the
front one of the key things to watch as this will dictate how far
north the severe weather threat persists. Forecast soundings from
various CAMs showcase extensive low level instability with upwards
of 2500+ J/KG SBCAPE with limited CIN along the warm front but
extensive 100-200 CIN north of it with a lack of low level
winds/shear but extensive 0-6km shear. What this means is elevated
storms capable of producing hail will exist north of the primary
warm frontal boundary, with the warm front the most likely zone for
potential tornadoes as storm interactions and streamwise vorticity
will both be maximized within this zone despite the lackluster low
level shear. The 17z WoFS run has largely favored a southerly
solution for weather potential, keeping the best potential for both
tornadoes and hail confined to the region south of the Twin Cities
metro and favoring an area from roughly Olmsted County in SE MN to
Jackson County in western WI (both covered by NWS La Crosse). The
tornado threat is highly contingent on the dew point depression at
surface level, as the lack of 0-1km shear means we need incredibly
low LCLs below 500ft for the threat to be tangible, which means we
need to be highly saturated below 1000ft otherwise the tornado
threat may not end up being realized. The hail threat is the most
likely overall given the extensive mid level shear and steep lapse
rates, and even with lower level capping elevated storms would be
capable of producing severe hail. The wind threat is largely relying
on precipitation loading/momentum enhancement with limited lower
level flow until the low level jet amplifies, however for our area
this is not realized until later in the evening when the warm front
is already exiting the area to the southeast. Overall, there is
still some higher end hail potential and a tornado threat and we
will have to closely monitor the position of the warm front as well
as overall storm environment over the next few hours. The timing
window looks to be CI from 3-4pm, most intense from 4-9pm across the
area, diminishing quickly as the front moves southeast after 9pm. As
we keep a close eye on the environment over the next few hours, a
Watch seems more likely than not at this point, it is more a
question of if we have the confidence for a Tornado Watch versus a
Severe Thunderstorm Watch given we expect the Tornado threat to be
conditional versus the more likely hail threat.

A few more elevated storms are possible for a few hours after 8-9pm
from cold FROPA with limited potential for severe weather, with
light showers and rumbles of thunder more likely as the environment
quickly shifts towards some patchy dense fog early tomorrow morning
with visibility reductions below 2 miles likely as temperatures drop
back to dew points. This fog persists through the morning commute
before diminishing rapidly after 9-10am, with another day near 70
tomorrow amidst skies clearing out to become mostly sunny by the
afternoon. Another low pressure system developing underneath an
incoming shortwave trough by late Tuesday introduces our next chance
for showers, with the position of the system favoring areas to our
south for severe weather with limited thunderstorm activity north of
the MN/IA border. The low is expected to track from Omaha to
Milwaukee keeping us on the relatively cooler northern side with
showers persisting on and off throughout Wednesday before exiting
early Thursday to the east. There is a non-zero chance for some
isolated severe weather, however the better environment should
remain to our south. Another surface low quickly develops ahead of a
broad trough off the lee side of the Rockies by late Thursday
tracking across the area on Friday bringing further chances for
showers and thunderstorms, with the low becoming broader and
weakening as it approaches. The current favored track would take the
surface low towards northern Lake Superior by early Saturday, which
would wrap in enough cold air from central Canada to introduce snow
or wintry mix chances Friday night into Saturday morning.
Accumulations are uncertain at this point as it will depend heavily
on the track of the system, which is not nailed down just yet as we
have a couple of systems before it arrives to get through. We end
the period into the 2nd half of the weekend with broad high pressure
bringing sunshine and temperatures in the 50s for Sunday.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1203 PM CDT Mon Apr 13 2026

A somewhat complicated forecast due to potential TSRA from
roughly 20-03z across the area combined with some potential
IFR/LIFR visibility concerns post-FROPA after the TSRA is out of
the area. Winds favor easterly/southeasterly ahead of the
incoming TSRA, becoming light and variable after TSRA heads out
of the area with speeds remaining 8kts or lower throughout. The
confidence to include gusts within the prob30/TEMPO groups with
TSRA was too low, however gusts are certainly a possibility with
any TSRA that moves through, the magnitude is just uncertain.
The key feature to watch will be the position of the warm front
as that will directly relate to the best TSRA potential as well
as the position of potential IFR CIGS during the period of TSRA.
A period of IFR/LIFR is likely after the TSRA ends from roughly
06-15z depending on location due to low level fog/CIGS, which
wraps up quickly after 14-15z.

KMSP...Kept the previous TEMPO from 22-01z intact as this period
is most likely to see TSRA, with a start time perhaps an hour
earlier as far as the first storms to appear. Lingering -SHRA is
less certain and could contain brief thunder, however the post
TSRA period is less certain with guidance handling it in
dramatically different ways. There is solid consensus for a 5-6
hour period of IFR due to fog after 08-09z, ending around 15z.

/OUTLOOK FOR KMSP/
WED...MVFR/SHRA early, then VFR. Wind NE 5kts.
THU...VFR, chc MVFR/-SHRA. Wind N 5-10kts.
FRI...MVFR/SHRA likely, chance -TSRA. Wind SE to SW 10-15G25kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.

&&

DISCUSSION...TDH
AVIATION...TDH

Hazardous Weather Outlook
National Weather Service Twin Cities/Chanhassen MN
108 PM CDT Mon Apr 13 2026

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
140900-
Douglas-Todd-Morrison-Mille Lacs-Kanabec-Stevens-Pope-Stearns-
Benton-Sherburne-Isanti-Chisago-Lac Qui Parle-Swift-Chippewa-
Kandiyohi-Meeker-Wright-Hennepin-Anoka-Ramsey-Washington-
Yellow Medicine-Renville-McLeod-Sibley-Carver-Scott-Dakota-
Redwood-Brown-Nicollet-Le Sueur-Rice-Goodhue-Watonwan-Blue Earth-
Waseca-Steele-Martin-Faribault-Freeborn-Polk-Barron-Rusk-
St. Croix-Pierce-Dunn-Pepin-Eau Claire-
108 PM CDT Mon Apr 13 2026

This Hazardous Weather Outlook is for portions of central and
southern Minnesota, and west central Wisconsin.

.DAY ONE...This Afternoon and Tonight.

Scattered thunderstorms can be expected this afternoon and
evening. Some storms may be strong to severe, capable of
producing very large hail in excess of 2 inches in diameter, wind
gusts in excess of 70 mph or a few tornadoes across southern
Minnesota through western Wisconsin. Some storms may also produce
heavy rain.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

SKYWARN spotter activation will likely be needed this afternoon
and evening.

Preliminary Local Storm Report
National Weather Service Twin Cities/Chanhassen MN
349 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0348 PM     Hail             4 NE Faribault          44.34N 93.20W
04/13/2026  M2.00 Inch       Rice               MN   Trained Spotter

&&

mpg

Preliminary Local Storm Report
National Weather Service Twin Cities/Chanhassen MN
353 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0353 PM     Hail             4 NNE Faribault         44.34N 93.23W
04/13/2026  M3.00 Inch       Rice               MN   Emergency Mngr

&&

mpg

Preliminary Local Storm Report
National Weather Service Twin Cities/Chanhassen MN
357 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0355 PM     Hail             5 NW Hader              44.42N 92.87W
04/13/2026  M1.50 Inch       Goodhue            MN   Public

            Report from mPING: Ping Pong Ball (1.50
            in.).

&&

Preliminary Local Storm Report
National Weather Service Twin Cities/Chanhassen MN
400 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0356 PM     Hail             6 S Cannon Falls        44.43N 92.88W
04/13/2026  E1.50 Inch       Goodhue            MN   Public

            Report from mPING: Ping Pong Ball (1.50
            in.).

&&

JMS

Preliminary Local Storm Report
National Weather Service Twin Cities/Chanhassen MN
405 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0400 PM     Hail             2 W Dennison            44.41N 93.08W
04/13/2026  M1.75 Inch       Rice               MN   Trained Spotter

            Reported relayed via Slack.

&&

JMS

Preliminary Local Storm Report
National Weather Service Twin Cities/Chanhassen MN
435 PM CDT Mon Apr 13 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0425 PM     Hail             2 NE Dennison           44.44N 93.01W
04/13/2026  E1.50 Inch       Goodhue            MN   Public

&&

JMS