spc ac 220734
day 3 convective outlook
nws storm prediction center norman ok
0234 am cdt wed mar 22 2023
valid 241200z - 251200z
...there is an enhanced risk of severe thunderstorms across eastern
louisiana...southwest arkansas...and western mississippi...
...summary...
supercell thunderstorms capable of all severe hazards, including
strong tornadoes, are possible across the lower mississippi valley
on friday.
...synopsis...
the upper pattern early friday morning will likely be characterized
by broad troughing across the western conus and subtropical ridging
centered over the straits of florida. enhanced mid-level flow will
extend throughout western and southern periphery of the upper trough
and then throughout the northwestern periphery of the subtropical
ridge. a low-amplitude shortwave trough is forecast to move from the
base of the upper trough quickly eastward across the southern plains
throughout the day, and then more northeastward across the mid-south
overnight. strong mid-level flow (i.e. 100 kt at 500-mb) will
accompany this shortwave, spreading across tx into the mid-south.
the surface pattern preceding this shortwave trough is expected to
feature a low over north tx early friday, with a cold front
extending southward from this low into the tx hill country and a
stationary front extending northeastward into the middle oh valley.
this low is forecast to move northeastward throughout the day, while
deepening significantly.
...lower ms valley...
expectation is for a broad area of upper 60s dewpoints to be in
place from east tx across the lower ms valley, ahead of the surface
low and associated front. cloud cover may temper daytime heating,
but afternoon temperatures will likely still reach the 80s,
contributing to moderate buoyancy across much of the region. in
addition to this buoyancy, moderate mid-level flow atop
strengthening low-level flow (supported by the maturing cyclone
ahead of the approaching shortwave trough) will contribute to long
hodographs with substantial low-level magnitude and veering. as a
result, the environment will be very favorable for supercells.
current expectation is for storms to develop during the afternoon
over southwest ar and western la (perhaps as far west as east tx).
this development should occur ahead of the cold front within the
open warm sector, maturing as it moves eastward across the lower ms
valley. a discrete supercell mode is anticipated initially, with all
severe hazards possible, including strong tornadoes. upscale growth
into a convective line is anticipated after this initially discrete
mode, with the line pushing eastward across ms and al overnight.
...mid ms valley...
despite less buoyancy that areas farther south, augmented forcing
for ascent close to the surface low could result in bowing line
segments capable of damaging wind gusts and embedded tornadoes
friday afternoon through friday evening.
..mosier.. 03/22/2023
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note: the next day 3 outlook is scheduled by 0730z