- Day Three
acus02 kwns 170544
Storm Prediction Center ac 170544
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1244 am CDT Tue Jul 17 2018
Valid 181200z - 191200z
..there is a marginal risk of severe thunderstorms across parts of
the central and northern plains into the middle Missouri Valley...
A marginal severe threat will be possible on Wednesday in parts of
the central and northern plains into the mid Missouri Valley.
..central and northern plains/mid Missouri Valley...
A shortwave trough will move across the northern plains on Wednesday
as a cold front moves across the northern High Plains. A broad
corridor of maximized low-level moisture should be in place from
eastern portions of the Central Plains into the northern plains with
surface dewpoints in the mid to upper 60s f. This should enable
moderate instability to develop by afternoon in areas that are not
affected by morning convection. Model forecasts suggest that
thunderstorms will form near the shortwave trough during the early
to mid afternoon with a cluster moving southeastward across
south-central South Dakota and into east-central Nebraska. GFS
forecast soundings along this corridor during the late afternoon
show MLCAPE values in the 1500 to 2500 j/kg range with 0-6 km shear
in the 35 to 50 kt range. This should be a favorable environment for
at least an isolated severe threat. However, the model spread for
instability is considerable which introduces substantial
uncertainty. For this reason, a marginal risk in the central and
northern plains will be maintained for this outlook and adjusted
spatially for the new data.
..maximum risk by hazard...
Tornado: 2% - marginal
wind: 5% - marginal
hail: 5% - marginal