SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 AM CDT Thu Apr 21 2022
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY INTO
SATURDAY EVENING ACROSS MUCH OF MINNESOTA...ADJACENT WESTERN
WISCONSIN...MUCH OF IOWA...NORTHWESTERN MISSOURI...EASTERN KANSAS
AND NORTHEASTERN THROUGH CENTRAL OKLAHOMA...
...SUMMARY...
Severe thunderstorms are possible Saturday through Saturday night in
a corridor from parts of the Upper Midwest into the southeastern
Great Plains. This may include a risk for tornadoes, in addition to
hail and strong wind gusts.
...Synopsis...
A deep cyclone initially over parts of central/eastern South Dakota
is forecast to begin to occlude by late Saturday or Saturday night,
while slowly migrating toward the Minnesota/Ontario international
border area. It appears that one significant short wave
perturbation may pivot around the southeastern through eastern
periphery of the associated mid-level low during the day. To the
south-southwest of this low, positively tilted larger-scale
mid-level troughing is forecast to linger across the Great Plains
into the northern Rockies. This troughing may tend to largely lag
to the west of a southeastward advancing cold front trailing from
the surface low.
Downstream, the axis of amplified mid-level ridging is forecast to
only slowly shift to the east of the Great Lakes region.
Lower/mid-tropospheric ridging centered near the south Atlantic
coast likely will remain prominent, with the surface ridge axis
being maintained westward through much of the Gulf Coast region.
...Great Plains into Upper Midwest...
Forcing for ascent, and strong low-level and deep-layer shear within
the warm sector of the deep cyclone, will contribute to at least
considerable conditional severe weather potential Saturday through
Saturday night. This includes the risk for organized convective
clusters and supercells capable of producing tornadoes, particularly
in close proximity to the cyclone, across parts of the eastern
Dakotas into Minnesota, and perhaps ahead of the cold front/dryline
arcing south/southwestward to the east of the mid Missouri Valley
into the southern Great Plains.
However, most model output remains strongly suggestive that rather
weak warm sector destabilization will probably be a considerable
limiting factor to severe thunderstorm development. It appears that
this will be due to some combination of stabilizing mid-level lapse
rates, the advection of dry air from the Southeastern low-level
ridging, and, at least initially, a warm and capping layer in
between.
..Kerr.. 04/21/2022
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