spc ac 280709
day 3 convective outlook
nws storm prediction center norman ok
0209 am cdt tue jul 28 2026
valid 301200z - 311200z
...there is a marginal risk of severe thunderstorms over the
northern and central plains into the upper mississippi valley...
...summary...
sporadic occurrences of mainly damaging wind appear possible
thursday afternoon into night across the northern and central plains
into the upper mississippi valley thursday afternoon into night.
...synopsis...
a series of vorticity maxima is forecast to pivot through the
northern plains and upper midwest, within the northeast periphery of
an upper high centered over the southern rockies. at the surface, an
area of low pressure initially over the western dakotas will develop
east-southeast to eastern sd or southern mn by thursday night.
meanwhile, a trailing cold front will advance through the northern
into central plains.
...northern and central plains into the upper mississippi valley...
latest model guidance indicates the potential for multiple areas of
showers and thunderstorms to be ongoing at 12z thursday, aided by
forcing for ascent attendant to a lead disturbance aloft and
low-level warm advection along a waning, nocturnal low-level jet.
the extent and duration of the early-day convection will have
implications for the degree of air mass destabilization by afternoon
ahead of the cold front. where stronger heating can occur, the
presence of dewpoints in the 60s to low/mid 70s will yield a
moderately to potentially strongly unstable air mass. however,
vertical shear will tend to be limited by generally less than 30 kt
of mid-level flow across the warm sector.
thunderstorms are expected to increase in coverage and intensity
through the afternoon along the cold front as well as any residual
outflow boundaries from the morning convection. the models suggest
the potential for upscale growth into one or multiple
cold-pool-driven mcss with the primary hazard being damaging wind
gusts. only 5% total severe probabilities will be included in this
forecast due to uncertainty in the preferred corridor(s) of greater
air mass destabilization and resultant severe weather threat. an
upgrade to a level 2/slight risk may become necessary once those
details become more clear.
..mead.. 07/28/2026
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note: the next day 3 outlook is scheduled by 1930z