SPC AC 231716
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1216 PM CDT Wed May 23 2018
Valid 241200Z - 251200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE EASTERN DAKOTAS INTO MINNESOTA...AND INTO CENTRAL NEBRASKA AND
Isolated to scattered severe thunderstorms are expected across
portions of the northern Plains and upper Mississippi Valley on
A low-amplitude shortwave trough will move slowly across the
northern Plains into the upper MS Valley, with a surface trough
across the central Dakotas into Nebraska by late afternoon. A large
area of mid to locally upper 60s F dewpoints will stretch from east
of the surface trough southward to the Gulf Coast as southerly
low-level winds persist. Stronger flow will exist across the central
Plains into the upper MS Valley in association with the shortwave
trough, with an evening increase in a southwesterly low-level jet
across the central and southern Plains as well. Scattered severe
storms are expected near the surface trough from parts of the
central Plains northward, with the main threat area from the eastern
Dakotas and NE into MN where instability and lift will be strongest.
Elsewhere, a moist and unstable air mass will remain over much of
the Gulf Coast states, with clusters of daytime storms likely within
a low-shear environment, capable of strong wind gusts. A few strong
storms may also occur across far southwest TX as southeasterly
surface winds back moisture westward toward the higher terrain.
...Northern Plains into the Upper Mississippi Valley...
A few ongoing showers and storms may be ongoing across NE and
southeast SD early in the day, but these are expected to dissipate.
Strong destabilization will occur thereafter, with MUCAPE around
2000-3000 J/kg developing. While shear profiles will not be strong,
some enhanced winds aloft with the upper trough will support
clusters of severe storms from northern NE across the eastern
Dakotas, moving into MN during the evening. In addition, daytime
storms may also form across part of northern MN where the air mass
will become uncapped and aided by a broad zone of warm advection.
Damaging wind will be possible in all areas, with hail most likely
across western portions of the risk area.
...Central High Plains...
Strong heating will lead to a deeply-mixed boundary layer and steep
overall lapse rate profiles. The presence of cold profiles aloft and
50s F dewpoints will lead to moderate instability, and a few severe
storms are expected to form by late afternoon near the low pressure
trough, continuing a few hours into the evening and moving in an
east/southeastward direction. Both severe hail and wind will be
...MAXIMUM RISK BY HAZARD...
Tornado: <2% - None
Wind: 15% - Slight
Hail: 15% - Slight
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