spc ac 111929
day 3 convective outlook
nws storm prediction center norman ok
0229 pm cdt sat apr 11 2026
valid 131200z - 141200z
...there is a slight risk of severe thunderstorms across portions of
the upper mississippi valley...and across parts of the southern
plains...
...summary...
severe thunderstorms are possible across the upper mississippi
valley and great lakes region, and across portions of the southern
plains on monday.
...synopsis...
the pattern on d3/monday will be characterized by continued
mid-level troughing across the western us, shifting east into the
great basin. strong west to southwesterly flow will continue across
the rockies into the central plains and upper midwest. a surface low
will shift across sd/ne into the upper midwest, with attendant
northward lifting warm front and eventual southward moving cold
front. these features will be the focus of thunderstorm activity
late monday afternoon across mn/ia/wi will additional development
likely into upper mi through the late evening.
across the southern/central plains, a surface dryline will extend
from central ks into western ok/southwest tx. strong daytime heating
will occur along and ahead of the dryline with an increase in the
low-level jet by the late afternoon/evening and potential for
isolated to scattered thunderstorm development.
...upper midwest...
across the upper midwest, southerly flow will usher low to mid 60s
dew points northwards into portions of ia/wi/mn as a surface low
shifts eastward. the exact northern extent of this moisture remains
uncertain, however it does appear that thunderstorms will develop
near the low and along or north of the effective warm front across
some portion of ia/mn border, perhaps as far west as southeastern
sd/northern ne. steep midlevel lapse rates and elongated hodographs
suggest large to very large hail (some 2-2.5+ inch in diameter) will
be possible both within the warm sector and with any elevated storms
on the cool side of the boundary. some consideration was given to
introduction a 30% area, primarily concerning the hail risk, across
the ia/mn border. there still remains uncertainty in guidance of the
coverage of storms in the open warm sector. through time, storms may
consolidate with a shift to damaging wind potential. for now, opted
to expand the marginal and slight risks further west into the
dakotas but maintain 15% probabilities.
...central/southern plains...
a more conditional threat for thunderstorms will be possible across
the dryline in the central/southern plains. through the day, the
environment looks to remain largely capped. beneath this, strong
daytime heating will yield moderate to strong cape within a plume of
steep low to mid-level lapse rates. into the late afternoon/evening,
the low-level jet will increase and this may support development of
isolated thunderstorm activity along and ahead of the dryline.
should this occur, the environment will favor supercells capable of
large to very large hail, damaging wind, and a couple of tornadoes.
..thornton.. 04/11/2026
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note: the next day 3 outlook is scheduled by 0730z