spc ac 210550
day 2 convective outlook
nws storm prediction center norman ok
1250 am cdt thu may 21 2026
valid 221200z - 231200z
...there is a slight risk of severe thunderstorms portions of the
southern plains...
...summary...
scattered strong to severe storms will be possible across portions
of the southern plains with potential for large hail and damaging
wind.
...synopsis...
two weak shortwaves, with one wave in central plains and a secondary
wave into the tennessee/ohio valleys, are forecast within the
broader northern rockies trough through afternoon on d2/friday. a
surface low will be located across eastern new mexico/southeastern
colorado with a front lifting northward into kansas and a dryline
extending southward into southwestern texas. another surface low
will develop across the mississippi and ohio valleys with a warm
front lifting northward across kentucky. these features will be the
focus for scattered thunderstorm development in both regions by the
afternoon/evening.
...southern and central plains...
scattered thunderstorm development is expected across the cap rock
near the dryline in texas and back into eastern new mexico along the
high terrain friday afternoon and evening. steep low to mid-level
lapse rates will be in place across much of the region from eastern
new mexico into western texas. dew points in the mid 50s to low 60s
and daytime heating will yield moderate instability amid deep layer
shear around 30-40 kts. this will promote initial supercells across
the high terrain with potential for additional multi-cell clusters
through time. these may grow upscale into an mcs into western
oklahoma by the evening. the primary risk will be for large hail
before the damaging wind risk increases into the evening.
a few additional strong thunderstorms may extend into portions of
southern kansas. the thermodynamic environment becomes less
favorable with northern extent due to widespread cloud cover and
morning precipitation. however, increasing mid-level flow and shear
may allow for a few organized cells with potential for large hail
and strong to severe wind further north.
...tennessee and ohio valleys...
a warm front will lift across northern tennessee into kentucky
through the afternoon on friday, with 60-70s dew points streaming
northward ahead of the approaching mid-level wave. modest height
falls are expected across western kentucky into the ohio valley,
with an increase in 850-700 mb flow. widely scattered thunderstorms
are expected overnight into friday morning. an increase in this
activity can be expected as a vorticity maxima and increasing large
scale ascent into the afternoon occurs. though instability will be
marginal, guidance does suggest a plume of higher theta-e air may
advect into western/central kentucky by the afternoon. in addition,
guidance suggests a few transient supercells will be possible with
potential for damaging winds and perhaps a tornado.
..thornton.. 05/21/2026
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note: the next day 2 outlook is scheduled by 1730z