spc ac 191730
day 2 convective outlook
nws storm prediction center norman ok
1230 pm cdt thu mar 19 2026
valid 201200z - 211200z
...there is a marginal risk of severe thunderstorms centered on the
upper ohio valley...
...summary...
strong to locally severe thunderstorms are possible across parts of
the upper ohio valley, mainly late friday afternoon into friday
evening.
...synopsis...
an upper ridge will remain in place over the southwest on friday,
while a large-scale upper trough will cover much of the eastern
conus. within the large-scale trough, an embedded shortwave will
move from the upper great lakes towards the northern mid atlantic
and new england. a surface low will move from parts of lower mi
toward new england through the period, as trailing cold front moves
across the ohio valley and mid atlantic.
...parts of the mid/upper ohio valley...
modest low-level moisture will return through the day along/ahead of
the approaching cold front across parts of the ohio valley/allegheny
plateau region. regarding prefrontal dewpoints, guidance generally
ranges from the low 50s f (hrrr/wrf-arw) to mid/upper 50s f (nam and
other href members). in the presence of strong deep-layer
flow/shear, the magnitude of moisture return will determine the
level and areal extent of any organized severe potential.
if moisture return becomes sufficient to support mlcape of around
500 j/kg or greater, then a few stronger updrafts and perhaps
marginal supercell structures could develop by late afternoon or
early evening, as convective temperatures are approached or breached
and glancing large-scale ascent impinges upon the region. despite
the generally weak instability, any robust storms could pose a
threat of marginally severe hail and perhaps locally gusty/damaging
winds, given the presence of favorable shear and rather cold
temperatures aloft. a brief tornado also cannot be ruled out, though
this will be more conditional on richer low-level moisture return
and maintenance of surface-based convection.
with generally low-quality moisture noted in thursday morning
observations, sufficient moisture return for an organized severe
threat on friday remains quite uncertain. however, given the
presence of very favorable wind profiles and at least some signal
for near-surface-based storm development during the late afternoon
and evening, a conditional marginal risk has been added for friday
across parts of the upper ohio valley. a conditionally favorable
environment will extend outside of the marginal risk into parts of
the mid/lower ohio valley, but the signal for storm development
currently decreases substantially with southwestward extent.
..dean.. 03/19/2026
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