spc ac 300607
day 2 convective outlook
nws storm prediction center norman ok
0107 am cdt tue jun 30 2026
valid 011200z - 021200z
...there is a slight risk of severe thunderstorms from the
mid-missouri valley into central wisconsin...
...summary...
isolated to scattered 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.
...mid-missouri valley into central wisconsin...
models are in general agreement that a cluster/mcs will be ongoing
in the eastern south dakota/southern minnesota vicinity early
wednesday morning. there is at least some potential for damaging
surface gusts with this activity. further intensification could also
occur as the airmass destabilizes in parts of wisconsin into the
afternoon. however the early day activity evolves, an outflow
boundary from this activity will serve as a focus for additional
afternoon thunderstorms. 70+ f dewpoints to the south of the
boundary will again promote strong to locally extreme buoyancy.
moderate to strong mid-level winds on the southern flank of the
upper trough in canada will allow for 40-55 kt of effective shear
near the surface boundary. initial supercells will be capable of
large to isolated very large (around 2-2.5 in.) hail and perhaps a
tornado or two. given the instability, strong downdrafts will likely
lead to upscale growth relatively quickly. the risk for
severe/damaging winds will become the primary hazard with time,
particularly if an mcs can develop. a slight risk has been added to
cover both potential scenarios.
...northeast...
the forecast continues to be uncertain given the nebulous forcing
for ascent. nonetheless, substantial buoyancy will be in place
across the region (3000-5000 j/kg mlcape). effective shear of 35-40
kt will promote some storm organization. model guidance shows
variable solutions from more isolated cellular activity to a cluster
moving southeastward out of canada. given the low confidence in
placing more organized activity, a marginal risk will be maintained
for now. damaging winds and isolated large hail will be possible.
...central high plains...
thunderstorm development is expected within the lee trough during
the afternoon. a deeply-mixed boundary layer will promote potential
for severe winds especially if any clustering can occur. shear will
be modest and severe coverage is expected to be isolated.
...southeast...
strong buoyancy will be in place during the afternoon given rich
moisture (70+ f dewpoints). shear will be quite weak with some minor
enhancement in the lower mississippi valley. models do show some
potential for clustering, but the location is quite variable. lack
of even subtle features to focus convection keeps confidence in a
more organized damaging wind threat low.
..wendt.. 06/30/2026
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note: the next day 2 outlook is scheduled by 1730z