- Day Three
acus02 kwns 181714
Storm Prediction Center ac 181713
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1213 PM CDT Tue Sep 18 2018
Valid 191200z - 201200z
..there is a marginal risk of severe thunderstorms from the High
Plains of Wyoming and Colorado into southern Minnesota and western
A few severe storms are possible across parts of the northern plains
and upper Mississippi Valley on Wednesday, mainly during the
..synopsis and discussion...
An upper high will shift east from the lower Mississippi Valley
toward Kentucky and Tennessee, providing very warm temperatures
aloft, while an upper trough develops across The Rockies. Increasing
southwesterly winds aloft will develop across the northern plains
into the Great Lakes ahead of the upper trough, with increasing lift
during the evening. At the surface, a stationary front will extend
from a Lee trough over eastern Colorado northeastward into central
Wisconsin, with a moist air mass along and south of the boundary.
..northern plains into the upper Mississippi Valley...
Scattered thunderstorms may be ongoing across the upper Mississippi
Valley Wednesday morning on the nose of a weak southwesterly
low-level jet. These storms are not likely to be severe, but may
contain small hail and heavy rain. More vigorous and widespread
thunderstorms will occur after 00z mainly from northeast Colorado
into Wisconsin as warm advection increases during the evening, near
or just after peak destabilization. Hail will be the primary threat
as most of the storms will be north of the surface front.
..maximum risk by hazard...
Tornado: <2% - none
wind: 5% - marginal
hail: 5% - marginal