spc ac 220600
day 2 convective outlook
nws storm prediction center norman ok
0100 am cdt wed apr 22 2026
valid 231200z - 241200z
...there is a slight risk of severe thunderstorms from southern
kansas into southern minnesota...
...summary...
severe thunderstorms will be possible from southern kansas into
southern minnesota on thursday. large hail to very large hail,
damaging winds, and a few tornadoes are possible.
... synopsis ...
a shortwave trough will move northeast along the eastern periphery
of a western us longwave trough. this shortwave will help maintain a
surface cyclone in southern canada, while a secondary surface low
may develop across southern minnesota late in the period. a
secondary shortwave will approach the southern plains late in the
forecast period.
as the shortwave trough lifts northeast, a cold front will
accelerate east across the central and northern plains. ahead of the
surface front southerly winds will support mid 50f dewpoints as far
north as northern minnesota and pockets of 60f dewpoints perhaps as
far north as southern-to-central minnesota.
... central and northern plains ...
diurnal heating of the moist airmass ahead of the advancing surface
front will yield an increasingly unstable atmosphere during the
afternoon with the 20260422/00z href showing ensemble mean sbcape
values approaching 2000 j/kg as far north as the greater omaha, ne,
vicinity by 20z. interrogation of forecast soundings ahead of the
frontal boundary shows a strong cap stretching from oklahoma
northward into nebraska and iowa. this cap does lift during the day
in response to increasing large-scale ascent from the approaching
trough, but thunderstorm initiation will likely require convergence
along the surface front.
this should occur by mid-afternoon anywhere from northeast kansas
into southern minnesota. initially, deep-layer shear is not
particularly strong across the warm sector, but would still support
a combination of multi-cells and supercells. given the degree of
instability and steep midlevel lapse rates, large-to-very-large hail
would be possible with any of these initial storms. a tornado or two
would also be possible given some low-level curvature in the
forecast hodographs associated with at least a modest low-level jet.
as the cold front continues to move east into the moist and unstable
airmass, additional thunderstorms should develop along the front,
eventually growing upscale into one or more linear systems and a
transition to a damaging wind threat. vertical shear should improve
during the late afternoon and evening as the mid-to-upper-level
winds respond to the approach trough, yielding a continued tornado
threat with any persistent discrete cell.
... oklahoma and northwest texas ...
a very unstable airmass will develop across the region to the east
of a dryline across western oklahoma during the afternoon. forecast
soundings show varying degrees of a cap across oklahoma and
northwest texas. with the strongest large-scale ascent remaining
largely to the north of the area, forcing for ascent will likely
require strong dryline circulations. given afternoon temperatures in
the 90fs to the west of the dryline, there is at least some
potential for dryline circulations to break the cap and initiate at
least a couple of storms. vertical shear profiles will support
supercells capable of very large hail. a highly conditional tornado
threat could develop with any discrete storm that is able to move
off the dryline and into the increasingly moist and unstable
environment to the east.
..marsh.. 04/22/2026
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note: the next day 2 outlook is scheduled by 1730z