spc ac 180554
day 2 convective outlook
nws storm prediction center norman ok
1254 am cdt mon may 18 2026
valid 191200z - 201200z
...there is a slight risk of severe thunderstorms from the great
lakes to the southern plains...
...summary...
widely scattered severe thunderstorms will be possible along a cold
front extending from the great lakes into the ohio valley and the
southern plains on tuesday. damaging winds and large hail will be
the primary threats.
...synopsis...
a mid-level trough will lift across the great lakes region on
d2/tuesday with a surface low moving east across southern ontario
and quebec. a trailing cold front will be located from the great
lakes south into the ohio and mid mississippi valleys into the
southern plains. convection will likely be ongoing across this
boundary at the beginning of the d2/tuesday period.
...great lakes vicinity to the lower ohio valley...
some convection may be ongoing across the cold front towards the
beginning of the d2 period, with additional development likely by
the afternoon along the eastward shifting cold front. enhanced
mid-level flow aloft and weak to moderate instability will support
organized storms with potential for damaging winds and isolated
large hail. additional afternoon thunderstorm development may extend
into the northeast with potential for large hail and damaging wind.
...mid mississippi valley to southern plains...
convection will be ongoing at the start of the period from the mid
mississippi valley driven by the cold front and potential cold pool
propagation. these boundaries will be the focus of
re-intensification of convection in the afternoon. mid-level flow
aloft will be weaker across the region but sufficient shear for
organization should remain in place. a plume of more favorable
moderate to strong instability will be available across
central/northern texas into southern oklahoma. with afternoon
development, steep low to mid level lapse rates and moderate
instability will support potential for a few large hail reports.
with time, upscale growth will support a downstream damaging wind
risk.
..thornton.. 05/18/2026
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note: the next day 2 outlook is scheduled by 1730z