SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0237 AM CDT Tue Jun 21 2022
Valid 231200Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE NORTHERN HIGH PLAINS...CENTRAL PLAINS...AND UPPER MIDWEST...
...SUMMARY...
Isolated severe thunderstorms are possible across northern High
Plains, the central Plains, and Upper Midwest on Thursday.
...Central Plains...
Upper ridging is forecast to be centered over the southern Plains
early Thursday morning. This upper ridge, which will extend across
much of the southern third of the CONUS, is expected to remain
largely in place throughout the period. A subtle shortwave trough
will likely traverse the northern periphery of this upper ridge,
moving from the central Rockies eastward across the central Plains
throughout the period. An associated surface low should move
eastward just ahead of this shortwave. Ascent attendant to the
shortwave combined low-level convergence in the vicinity of this
surface low and strong buoyancy will likely result thunderstorm
development. Upper flow will be modest, but veering wind profiles
should still result in enough vertical shear for storm organization
and a few strong to severe storms. Subtle character of the shortwave
and timing difference within the guidance introduce some uncertainty
regarding storm coverage and the most probable location for
development. This uncertainty merits keeping severe probabilities at
5% for this outlook.
...Northern High Plains...
Given the presence of the expansive upper ridging over the southern
CONUS, any stronger westerly flow aloft will be displaced north to
the international border vicinity. A shortwave trough embedded
within this stronger flow is forecast to move from British Columbia
into Saskatchewan. Enhanced southwesterly flow throughout the base
of this shortwave should expand across the northern Rockies. Modest
large-scale ascent and increasing mid-level moisture coincident with
this increasing mid-level flow could support a few strong
thunderstorms capable of damaging wind gusts.
...Eastern Dakotas/Upper Midwest...
Strong buoyancy is expected to develop Thursday afternoon as a
result of ample low-level moisture, strong daytime heating, and
relatively cool temperatures aloft. A weak surface boundary may be
exist over the region, with convergence along the boundary just
enough to produce isolated thunderstorms. Given the robust buoyancy,
a few strong updrafts capable of damaging wind gust and/or hail are
possible.
..Mosier.. 06/21/2022
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