- Day Three
acus03 kwns 240717
Storm Prediction Center ac 240716
Day 3 convective outlook
National Weather Service Storm Prediction Center Norman OK
0216 am CDT Friday Oct 24 2014
Valid 261200z - 271200z
..no severe thunderstorm areas forecast...
isolated to scattered thunderstorms are anticipated on Sunday night
over the upper Midwest. Small hail may occur but confidence is too
low to identify a marginal severe-hail area.
Broad middle-level trough will shift east from the northwest to the northern
Great Plains through early Monday...with a downstream ridge moving from
the upper Midwest to the Great Lakes. Primary surface cyclone should
track from the Lee of the southern Canadian rockies across the southern
prairie provinces with a cold front sweeping east and reaching the
upper Midwest to central Great Plains. A warm front will advance NE
over the upper MS valley and Midwest.
Strengthening low-level warm air advection should yield isolated to scattered
elevated convective clusters Sun night. Guidance differs with the
degree of elevated buoyancy as the NAM and WRF-based sref members
appear more aggressive with 850-700 mb moisture return compared to
the GFS and non-NCEP models. Leaning with the less aggressive
guidance...the predominant southwesterly flow regime should effectively cap
thunderstorm development to along the eastern periphery of the moisture plume
where buoyancy should be weak. Given close proximity to the
departing middle-level ridge...effective shear should remain moderate.
In conjunction with a probable cluster Mode...it appears premature
to highlight what may only be a narrow corridor of marginal severe