spc ac 201903
day 3 convective outlook
nws storm prediction center norman ok
0203 pm cdt fri mar 20 2026
valid 221200z - 231200z
...there is a slight risk of severe thunderstorms across portions of
the ohio valley...
...summary...
severe thunderstorms are expected on sunday afternoon and evening
across parts of the ohio valley.
...ohio valley vicinity...
westerly mid/upper flow will amplify on sunday as a shortwave trough
deepens across the great lakes to the central appalachians. as this
occurs, a 60-80 kt southwesterly jet max will overspread the ohio
valley by late afternoon. around midday, a cold front will extend
southwest from lakes ontario and erie into northern in/central
il/mo. this front will progress southeast through the period,
becoming oriented from the mid-atlantic coast to the lower ms valley
by monday morning. boundary-layer moisture is forecast to remain
somewhat modest across the warm sector ahead of the front (mid 50s
to near 60 f). however, steep midlevel lapse rates are noted in
forecast soundings, and model guidance depicts 500 mb temperatures
around -14 to -16 c at 00z. this should support mlcape from 500-2000
j/kg.
while forecast wind profiles are generally unidirectional, rapidly
increasing wind speeds with height will result in modestly
enlarged/curved low-level hodographs becoming elongated above 2-3
km, with effective shear magnitudes 40+ kt. however, the warm sector
is expected to largely remain capped. low-level frontal convergence
will be the main forcing mechanism as large-scale ascent will arrive
with the front or perhaps delayed behind the front during the
evening. while shear profiles could support supercells, it is
unclear if capping and broad ascent will limit supercell potential,
especially with southwest extent into the lower ohio valley and
mid-south vicinity. if supercells can develop and persist, large
hail and damaging winds are possible. once linear convection
develops, severe/damaging wind gust will become the main hazard.
tornado potential is more uncertain given concerns regarding
low-level moisture, capping, and storm mode/evolution, but a tornado
or two cannot be ruled out.
..leitman.. 03/20/2026
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note: the next day 3 outlook is scheduled by 0730z