spc ac 171927
day 3 convective outlook
nws storm prediction center norman ok
0127 pm cst tue feb 17 2026
valid 191200z - 201200z
...there is a slight risk of severe thunderstorms for parts of the
lower/middle ohio valley...
...summary...
severe thunderstorms with potential to produce a few tornadoes and
damaging wind gusts are possible across parts of the middle
mississippi into lower ohio valleys thursday afternoon into early
evening.
...synopsis...
two shortwave troughs are expected to quickly lift
north-northeastward through the central plains and into the ohio
valley region on thursday. the initial perturbation will reach
illinois/indiana by early afternoon. the intensity of this feature
will remain modest with perhaps some gradual weakening in time. the
second trough will evolve in the lower missouri valley during the
evening and intensify as it approaches the lower ohio valley by
friday morning. at the surface, a cyclone will deepen as it lifts
northeastward from eastern kansas into the great lakes region. at
least partially modified gulf moisture will advect northward ahead
of the surface cold front from the upper midwest into the southern
plains.
...lower/middle ohio valley...
ahead of the cold front, a prefrontal trough/pseudo dryline is
expected to be the focus for convective development during the
afternoon. the degree/quality of moisture return ahead of this
feature will be key in terms of the overall magnitude of the severe
threat. current observations (tuesday) from soundings depict a very
modest moist layer along the gulf coast. a modest shortwave trough
on tuesday night into wednesday will lift northward too quickly for
more substantial moisture return. the surface pattern on thursday
will be more robust, but deeper moisture may still not reach far
enough north given that mid 60s f dewpoints are only as far north as
the central gulf currently. guidance suggests mid to upper 50s f
dewpoints are most probable, which does seem reasonable. that said,
temperatures aloft will not be overly cold and lapse rates will not
be overly steep. this will lead to convection that may remain
somewhat low topped in nature. despite limiting factors within the
environment, 40-50 kts of effective shear roughly perpendicular to
the boundary will favor discrete storms. low-level flow will be
increasing with time as well. supercells capable of few tornadoes,
damaging winds, and isolated large hail are possible during the
afternoon/evening.
..wendt.. 02/17/2026
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