spc ac 190727
day 3 convective outlook
nws storm prediction center norman ok
0227 am cdt sun apr 19 2026
valid 211200z - 221200z
...no severe thunderstorm areas forecast...
...summary...
thunderstorms will be possible across the western conus, the
south-central conus, and the southern great lakes. no severe weather
is anticipated.
... synopsis ...
a large-scale midlevel trough will move push inland across the
western conus into the great basin on wednesday, with downstream
ridging building across the central conus in response. across the
northeast, northwest flow aloft will prevail downstream of the
central conus ridge. an embedded jet streak and associated vorticity
maximum within the northwest flow will aid driving a weak surface
low and attendant frontal boundary southeast across the great lakes
through the forecast period. meanwhile, the surface ridge across the
southeast will move east, just offshore of the southeast atlantic
coast, promoting return flow across the plains. the return flow will
be aided by the development of lee troughing across much of the high
plains.
... western us ...
scattered showers are expected across portions of the west in
association with the inland-moving large-scale trough. seasonably
cool midlevel temperatures will support enough instability for a few
thunderstorms, although severe potential is very low.
... south-central us ...
showers and thunderstorms will be possible across the region within
the return flow regime. here, weak warm-air advection combined with
between 500-1000 j/kg of mucape will support convective development.
weak vertical shear and the lack of strong forcing for ascent should
limit any severe potential.
... southern great lakes ...
scattered showers a few thunderstorms will be possible within the
surface frontal zone as it pushes south/southeast during the day.
instability around 500 j/kg mucape and weak effective layer shear
should preclude a more robust severe weather event, but a strong
wind gust or two may be possible.
..marsh.. 04/19/2026
click to get wuus03 ptsdy3 product
note: the next day 3 outlook is scheduled by 1930z