spc ac 290734
day 3 convective outlook
nws storm prediction center norman ok
0234 am cdt mon jun 29 2026
valid 011200z - 021200z
...there is a marginal risk of severe thunderstorms within parts of
the central plains into the upper midwest...and parts of the
northeast...
...summary...
isolated strong to severe storms will again be possible from the
central plains into the upper midwest as well the northeast on
wednesday. severe wind gusts and large hail are the main concerns.
...synopsis...
the upper-level pattern across the conus will not significantly
change from tuesday into wednesday. a broad trough in the west will
maintain modest to moderate mid-level flow across the plains into
the upper midwest. some stronger mid-level flow is possible in the
upper great lakes vicinity due to the main synoptic trough displaced
to the north in canada. moderate northwesterly winds aloft will
persist in the northeast as well. strong to extreme buoyancy will
develop during the afternoon from the upper midwest into the
northeast with a very moist airmass beneath the upper ridge.
...central plains into the upper midwest...
a stalled surface boundary will may eventually make modest northward
progress as a weak surface trough develops in the central/northern
plains. models suggest convection will be ongoing early in the
morning in the nebraska/south dakota vicinity. given the strong
low-level jet expected, it is not clear if this convection will
weaken during the morning or continue eastward into an increasingly
unstable airmass. depending on how that early activity evolves,
there is potential for another round of convection to develop along
the boundary in the upper mississippi valley. this may be aided by a
subtle shortwave trough moving northeast. in either case, mcs
development is possible with time. damaging winds and isolated large
hail are possible, though there may end up being a corridor of
greater wind damage potential should an mcs develop. greater severe
probabilities may be needed as confidence increases.
...northeast...
forcing for ascent will be more nebulous on wednesday. even so, the
very unstable environment will promote a risk of strong/damaging
downburst winds as well as isolated large hail. given the
uncertainty in storm coverage, only low severe probabilities have
been added.
..wendt.. 06/29/2026
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note: the next day 3 outlook is scheduled by 1930z