spc ac 180530
day 2 convective outlook
nws storm prediction center norman ok
1230 am cdt tue jun 18 2019
valid 191200z - 201200z
...there is a slight risk of severe thunderstorms from north tx
through the middle ms valley into the lower oh valley...
organized severe thunderstorms may occur wednesday from parts of the
southern plains into the middle mississippi valley and lower ohio
...southern plains into the mid ms valley and midwest...
convectively strengthened vorticity maximum will likely exist in the
vicinity of central/southern mo wednesday morning, although there is
still location uncertainty given the mesoscale nature of this
feature. this shortwave trough is then expected to gradually drift
eastward, with the seasonally strong mid-level flow (i.e. 50-60 kt
at 500 mb) extending through its base from eastern ok through the
lower oh valley. thunderstorms will likely develop ahead of this
shortwave trough across the lower oh valley wednesday afternoon.
dewpoints in the upper 60s/low 70s will contribute to
moderate/strong instability with the strong upper flow resulting in
effective bulk shear around 40 kt. these conditions support
organized thunderstorms, including bowing line segments and isolated
supercells. primary threat would be damaging wind gusts, but
isolated tornadoes are also possible, particularly in areas near the
surface low where winds remain backed.
farther southwest (from ar into north tx), composite outflow
boundary/cold front is expected to push southeastward into the warm
and moist air mass extending from north tx into the middle ms
valley. combination of temperatures in the low 90s and dewpoints in
the low to mid 70s will result in a strongly unstable air mass with
thunderstorms development likely along the front during the late
afternoon. given the strong instability, intense updrafts are
anticipated. vertical shear will be weaker in this area than areas
farther north with some storm organization possible but most storms
will likely be outflow dominant. as a result, primary severe threat
will be water-loaded downbursts but some hail is also possible.
lee troughing along the length of the high plains is expected to
contribute to thunderstorm development wednesday afternoon. a few of
the stronger storms may be capable of damaging wind gusts. somewhat
higher storm coverage is anticipated along the mt/wy border where a
surface low will develop ahead of an approaching shortwave trough
and associated strong mid-level flow. instability will be modest but
the strong forcing for ascent and robust vertical shear will likely
still result in a few organized thunderstorms capable of hail and
damaging wind gusts.
...maximum risk by hazard...
tornado: 5% - slight
wind: 15% - slight
hail: 15% - slight
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note: the next day 2 outlook is scheduled by 1730z