Day 1 Severe Weather Outlook

Valid 170100Z – 171200Z


Scattered severe storms are expected to continue into tonight from
the central Plains into the Lower Missouri Valley with very large
hail and damaging winds as the primary threats.

…Central High Plains…

Widely scattered storms that developed within the upslope flow
regime over the higher terrain intensified as they moved into the
moderately unstable environment across eastern CO through western NE
and where effective shear from 40-50 kt is sufficient for
supercells. It remains possible that a cluster of storms might
organize and continue east through western KS and or southwest NE.
However, there has been a trend for some storms to diminish over
northeast CO as they move toward lower elevations where a very warm
EML (16C at 700 mb) will result in strong surface based convective
inhibition as the boundary layer begins to cool. This lowers
confidence in future evolution of the storms moving off the higher
terrain and into western KS but will maintain a SLGT risk for this

…Central Plains into the Lower Missouri Valley…

A quasi-stationary front extends from northern MO through central
and southwest KS and into southeast CO. The atmosphere is strongly
unstable (3000-4000) J/kg MUCAPE) in vicinity of and south of this
boundary where a plume of very steep (8-8.5 C/km) mid-level lapse
rates have overspread the moist sector. However, the warm air at the
base of an elevated mixed layer has also resulted in a substantial
cap over much of this region, except in southwest KS and northwest
OK where deep mixing has eroded the inversion, resulting in a few
high-based severe storms. A substantial increase in storm coverage
is expected later this evening into tonight from northern KS,
southern NE into northern MO and possibly southern IA. This will be
supported by increasing forcing for ascent along and north of the
stationary front on nose of a strengthening southwesterly low-level
jet. Most of these storms will probably be slightly elevated, but
the thermodynamic environment and 30-40 kt effective bulk shear will
support some supercell structures capable of large to very large
hail and isolated damaging wind as the primary threats. Storms may
eventually grow upscale with damaging wind becoming the main threat.

..Dial.. 08/17/2019


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