zczc spcswod48 all
acus48 kwns 180851
spc ac 180851
day 4-8 convective outlook
nws storm prediction center norman ok
0351 am cdt tue jun 18 2019
valid 211200z - 261200z
...discussion...
southwesterly flow aloft is expected to advect very steep mid-level
lapse rates (i.e. over 9 deg c per km between 700 and 500 mb) into
the central plains/middle mo valley on d4/friday. a very moist air
mass will likely be in place over the same region, resulting in
extreme instability with mlcape over 4500 j/kg. some capping is
anticipated and large-scale forcing for ascent is negligible but
convergence along a surface trough is still expected to result in
convective initiation. resulting thunderstorms would likely be
severe. some potential exists for upscale growth into an organized
mcs.
the warm, moist, and strongly unstable air mass will likely remain
over the southern/central plains and lower mo/middle ms valleys on
d5/saturday and d6/sunday. however, the most probable location for
severe thunderstorms each day will be influenced strongly by
convective evolution on the day before. severe probabilities will
likely be needed in subsequent outlooks but uncertainty remains too
high to outlook any areas on these days with this forecast.
current guidance also suggests a post-frontal threat may materialize
across the central high plains on d5/saturday. a bit more
consistency is needed regarding the location of the surface low and
strength of upslope flow before introducing any threat areas.
trend towards more zonal flow across the central conus after
d6/sunday currently limits predictability.
..mosier.. 06/18/2019
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