spc ac 070530
day 2 convective outlook
nws storm prediction center norman ok
1230 am cdt tue jul 07 2026
valid 081200z - 091200z
...there is a slight risk of severe thunderstorms wednesday
afternoon into wednesday night across parts of the central great
plains and upper midwest...
...summary...
clusters of strong thunderstorms with potential to produce severe
hail and wind may evolve across parts of the upper midwest into
central great plains wednesday through wednesday night.
...discussion...
while a blocking, but perhaps weakening, mid-level high lingers in
the north central canadian arctic latitudes, it appears that one
still fairly vigorous short wave trough and embedded low will begin
to dig southeast of the hudson bay vicinity wednesday through
wednesday night, while an upstream short wave trough pivots across
the canadian rockies, then northward toward the northwest
territories. in association with these developments, within a belt
of modest westerlies closer to and south of the international
border, subtle mid-level ridging may overspread the northern
rockies, with similar amplitude downstream troughing digging across
the northern great plains, upper midwest and great lakes region.
beneath this regime, a weak cold front, perhaps reinforced by
convective outflow in some locations, is forecast to overspread much
of the remainder of the upper midwest/adjacent great lakes and
middle missouri valley vicinity by late wednesday night. this may
be preceded across parts of the central great plains by conglomerate
convective outflow emanating from considerable thunderstorm
development spreading off the laramie range/front range vicinity,
within weak west-northwesterly steering flow.
in the southern mid- to subtropical latitudes, modest mid-level
ridging is forecast to generally prevail, but weak remnant troughing
may slowly migrate from the mid south toward the southern
appalachians, along its northern periphery.
...upper midwest...
steeper mid-level lapse rates associated with a remnant plume of
elevated mixed-layer air may become increasingly confined to the
higher plains during this period. however, seasonably high moisture
content along/ahead of the southward advancing cold front may still
become supportive of mixed-layer cape of 1500-2000+ j/kg with
daytime heating.
based on latest guidance, it is appearing less probable that a
cluster of strong continuing thunderstorm development, with a
possible mcv, will be substantively maintained into this period
across parts of the upper midwest into adjacent great lakes region.
but, this remains uncertain.
there appears a stronger signal for renewed thunderstorm development
within the corridor of pre-frontal destabilization trailing to the
southwest, across central into southern wisconsin, southeastern
minnesota and northeastern iowa by late wednesday afternoon, aided
by forcing for ascent with the digging mid-level troughing.
it is possible that a belt of convectively augmented westerly
mid-level flow, including 30+ kt around 700 mb, contributes to
sufficient shear for evolving supercell structures. these may pose
a risk for severe hail, and perhaps some potential for a tornado or
two, before damaging wind gusts become more prominent prior to storm
weakening wednesday evening.
...central great plains...
by late wednesday afternoon or early evening, it appears that
boundary-layer destabilization associated with moistening easterly
low-level flow may support intensification of initially scattered
thunderstorm development off the laramie mountains through colorado
front range. pronounced veering of wind fields with height may
yield sufficient shear for supercells posing a risk for severe hail
and wind.
there remains a fairly notable signal that forcing associated with a
nocturnally strengthening low-level jet, and perhaps a subtle
digging mid-level perturbation, may contribute to an upscale growing
and organizing cluster with potential to produce more widespread
strong to severe wind gusts wednesday evening into wednesday night.
...parts of the southern mid atlantic...
thermodynamic profiles may again become conducive to locally strong
downbursts in convection likely to develop off the blue ridge
mountains, and within surface troughing to the north and northeast
of a weak developing lee surface low. aided by forcing for ascent
associated with weak low-level warm advection and convergence, an
upscale growing cluster, with potential to produce potentially
damaging wind gusts along the leading edge of consolidating outflow,
could overspread the north carolina piedmont by wednesday evening.
..kerr.. 07/07/2026
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note: the next day 2 outlook is scheduled by 1730z