spc ac 270531
day 2 convective outlook
nws storm prediction center norman ok
1231 am cdt mon apr 27 2026
valid 281200z - 291200z
...there is a slight risk of severe thunderstorms tuesday afternoon
and evening in a corridor across the southeastern great plains
through lower mississippi and tennessee valleys...
...summary...
scattered strong to severe thunderstorm development is probable
across parts of the southeastern great plains through the lower
mississippi and tennessee valleys tuesday afternoon and evening.
the evolution of a long-lived organized cluster accompanied by
potentially damaging wind gusts appears possible.
...discussion...
latest model output still indicates that the center of a fairly
broad surface cyclone may undergo further deepening while migrating
northeast of the upper great lakes region during this period,
particularly as it reaches the southeastern hudson bay vicinity,
near the southeastern periphery of an evolving mid-level low.
surrounding this low, it appears that larger-scale mid-level
troughing, encompassing much of interior north america to the east
of the northern rockies, may make slow further progress toward the
northern/mid atlantic seaboard, while perhaps undergoing some
amplification along an axis southward through the upper and middle
mississippi valley by late tuesday night. this may support modest
surface wave development along a stalling cold front across the
southeastern great plains through lower ohio valley, and contribute
to suppression of mid-level ridging across northern portions of the
eastern gulf coast states.
otherwise, mid-level ridging to the north of a prominent subtropical
high, still centered over southern mexico, is likely to build across
the southern rockies and adjacent great plains, downstream of a low
over the southern mid- to subtropical latitudes of the eastern
pacific. only a slow eastward progression of this low is forecast,
to the south of mid/upper ridging building northeastward into
british columbia and the pacific northwest.
...southeastern great plains into tennessee valley...
there is continuing spread within the latest model output, but a
consensus of guidance suggests that pre-cold frontal outflow,
generated by convection today through tonight, will remain a notable
feature into and through this period. it appears that the leading
edge of this air mass may curve from parts of the southern
appalachians/tennessee valley toward the ark-la-tex at 12z tuesday.
the extent to which this advances southward through the eastern gulf
coast states on its eastern flank, while retreating northeastward
through the lower mississippi valley on its western flank, remains
unclear. however, it seems probable that it will become a focus for
intensifying thunderstorm development by late tuesday afternoon in
response to boundary-layer destabilization along and to its south,
and forcing for ascent aided by low-level warm advection.
at the same time, a corridor of stronger pre-frontal surface heating
across parts of northeastern texas through north central arkansas
may become the focus for stronger convective development, in the
presence of larger cape supported by steeper mid-level lapse rates.
more strongly capping elevated mixed-layer air may continue to
inhibit more than isolated thunderstorm initiation farther to
southwest, along the dryline across central texas into areas
near/south of del rio tx.
strengthening shear with the approach of digging mid-level troughing
on the southern fringe of the westerlies is likely provide support
for a few supercells across the southeastern great plains, and
upscale growing and organizing clusters propagating into the lower
mississippi valley. there appears a consensus within the model
output that the intersection of this activity with the preceding
outflow boundary may ultimately provide the focus for the most
prominent evolving cluster, which may pose a risk for widespread
strong to severe gusts across parts of arkansas through the lower
mississippi valley by late tuesday evening.
too many uncertainties exist to upgrade the categorical severe
threat at this time, but this remains possible in later outlooks for
this period.
..kerr.. 04/27/2026
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note: the next day 2 outlook is scheduled by 1730z