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Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
0104 PM CDT Sun Jun 12 2022

Valid 131200Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...AND ACROSS THE MIDWEST AND VICINITY...

...SUMMARY...
Scattered severe thunderstorms should develop Monday across parts of
the northern Plains, and from portions of the Midwest into the Great
Lakes and Ohio Valley. Large hail, damaging winds, and a few
tornadoes all appear possible. Some of the winds could be
significantly severe (75+ mph) across parts of the Midwest/Ohio
Valley Monday afternoon/evening.

...Northern Plains...
Large-scale upper ridging will prevail across the Plains states
during the period, ahead of a slowly advancing upper trough crossing
the Intermountain West.  This ridging/subsidence should maintain
capping well into the afternoon within the warm sector of a
developing low over the northern High Plains region.

However, as the upper trough advances and ascent -- implied by
falling mid-level heights -- co*mences by late afternoon/early
evening, isolated to scattered storm development is expected from
northeastern Wyoming/southeastern Montana into the western Dakotas.

With strengthening mid-level southwesterlies atop low-level
easterlies north of the developing surface low, shear quite
favorable for supercells will support updrafts that rapidly acquire
rotation.  As a result, and given the amply unstable environment,
very large hail will be possible, along with risk for locally
damaging winds and a couple of tornadoes.  Storms will spread
northeastward through the evening and into the overnight hours
across western and northern South Dakota and much of North Dakota,
with hints in some models of upscale growth into bowing clusters
(which could locally focus greater wind damage potential).

...Upper Midwest east-southeastward to the central Appalachians...
Substantial uncertainty exists with respect to evolution of
convection, and associated severe potential from the Upper Midwest
east-southeastward Monday, as a mid-level disturbance/vort max
crests the rather stout upper ridge and slides east-southeastward
across the Upper -- and eventually the Lower -- Great Lakes region.

Uncertainty exists even at the start of the period, in terms of
location and coverage of ongoing convection over the Minnesota/Iowa
vicinity.  Some severe threat will likely be ongoing, with a sharp
northern boundary to the risk expected to be maintained through the
day with an east-northeast to west-southwest warm front progged to
lie across southern portions of the Upper Great Lakes.

As the airmass near and south of the front destabilizes through the
day near and south of the front, gradual convective intensification
is expected, with whatever lull in severe risk may exist early on
diminishing as storms redevelop/intensify through mid to late
afternoon.  Eventually, most model guidance at least loosely agrees
that a fast-moving, co*pact, well-organized MCS will evolve.  Given
the moist/unstable airmass along and south of the frontal zone, and
very strong/weakly veering westerly/west-northwesterly flow with
height, damaging winds appear likely, along with hail and even a
tornado or two.  Given the strength of the flow aloft, and potential
that a very well-organized bow evolves, potential for significant
gusts is evident locally.  A narrow corridor of widespread coverage
of severe gusts is expected, though highlighting this corridor
remains difficult -- as highlighted by varying CAM output.  Upgrade
to ENH risk may be required in later outlooks, should the primary
corridor of risk beco*e more clear with time.  Storms should persist
into the overnight hours, and possibly through the end of the
period, with the eastern extent of the risk potentially reaching the
east slopes of the central Appalachians by 14/12z.

..Goss.. 06/12/2022