LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Wed Mar 22 2023
Valid 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
NORTHEASTERN KANSAS EASTWARD TO NORTHERN INDIANA...
...SUMMARY...
Isolated/elevated strong to severe thunderstorms -- capable of large
hail -- are possible from far northeast Kansas eastward to northern
Indiana late tonight.
...Synopsis...
An upper trough across the western U.S. will move gradually eastward
with time, with the broader cyclonic flow field to encompass roughly
the western half of the country through the period. As this trough
advances, downstream ridging centered over the Gulf of Mexico will
amplify a bit, with a trend toward a bit of anticyclonic curvature
within the westerlies across the central and eastern U.S. with time.
At the surface, a low initially over the northern Minnesota vicinity
is forecast to shift quickly northeastward into -- and then across
-- Ontario through the period. Meanwhile, the trailing cold front
will become an increasingly west-to-east quasi-stationary front from
the central Plains into the Midwest. This boundary -- or more
specifically, a zone of warm advection focused to the cool side of
the front -- will focus a zone of elevated convection through the
period.
...Northeastern Kansas to northern Indiana...
Elevated showers and isolated/embedded thunderstorms are forecast to
be ongoing at the start of the forecast period across the northern
Missouri vicinity -- i.e. portions of the MRGL risk area. This
convection is forecast to shift eastward across the Midwest region
through the day.
Meanwhile, as a southwesterly low-level jet redevelops later this
evening, a gradual increase in new, elevated convection is expected,
in tandem with the increase in low-level warm advection atop a
surface-based stable layer.
With continued low-level theta-e advection within the 900 to 700 mb
layer, and some steepening of lapse rates aloft, the elevated
destabilization will likely be sufficient to support locally
strong/vigorous updrafts. This, combined with favorably strong
speed shear through the cloud-bearing layer, will likely support
locally severe storms, capable of producing large hail. With time,
an expanding convective cluster is forecast to spread eastward,
crossing central Illinois and eventually northern Indiana through
the end of the period.
..Goss/Lyons.. 03/22/2023
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