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Day 2 Convective Outlook CORR 1
NWS Storm Prediction Center Norman OK
0227 AM CDT Tue Apr 19 2022

Valid 201200Z - 211200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE WEDNESDAY
AFTERNOON AND EVENING ACROSS PARTS OF SOUTHEASTERN
KANSAS...SOUTHWESTERN MISSOURI AND NORTHEASTERN INTO CENTRAL
OKLAHOMA...

CORRECTED GRAPHIC ISSUE AND TYPO IN TEXT HEADER

...SUMMARY...
A few supercells are possible late Wednesday afternoon and evening,
near or east of the Interstate 35 corridor between Kansas City and
the Dallas-Fort Worth Metroplex.  A few strong storms may also
impact areas west of the Oregon Cascades, acco*panied by at least
some risk for severe weather.

...Synopsis...
Models indicate little change to the general large-scale pattern
impacting much of North America through this period.  Short waves
within a primary belt of westerlies emanating from the mid-latitude
Pacific appear likely to remain progressive, but this regime may
take on more a southwesterly co*ponent inland of the Pacific coast
through the northern Atlantic Seaboard, as a large and still
amplifying trough digs offshore of the Pacific coast.  

Downstream of this feature, mid-level heights may begin to rise
across much of the western through eastern Gulf Coast states by
Wednesday night.  However, the most prominent mid-level height rises
are forecast across and to the lee of the Canadian/U.S. Rockies.  To
the east of the building ridging, a lower amplitude trough is
forecast to dig within an increasingly confluent regime
east-southeast of the central Canadian/U.S. border vicinity toward
the upper Great Lakes.  This will occur fairly close behind a more
prominent trough migrating across and northeast of the Canadian
Maritimes, acco*panied by an initially broad occluded surface
cyclone.

In the wake of the lead impulse, potentially cold/dry surface
ridging is forecast to initially be entrenched across most areas
east of the Mississippi Valley at 12Z Wednesday.  This ridging
likely will build through New England while being maintained across
much of the Atlantic Seaboard into the northeastern and central Gulf
of Mexico through the remainder of the period.  At the same time, an
initial cold front associated with the upstream mid-level trough is
forecast to advance southeast of the northern/central Great Plains,
while another front, trailing the primary lingering surface cyclone
migrating from southern Saskatchewan into Ontario, advances south of
the international border.

Ahead of the lead front, modest low-level moistening appears likely
to continue within southerly return flow around the southwestern
periphery of the Eastern ridging, from near the Mexican Gulf coast
northward through the southeastern Great Plains and middle
Mississippi Valley.  This is expected to mostly occur beneath a
plume of warm and capping elevated mixed-layer air emanating from
the southern Rockies/Mexican Plateau vicinity.  However, models
continue to suggest that this warm mid-level air beco*e suppressed
across parts of the central Great Plains, before returning northward
again in the wake of the mid-level troughing passing to the north
and northeast.

...I-35 corridor from Kansas City to Dallas-Fort Worth...
Precipitation associated with convection and embedded thunderstorms,
driven by elevated moisture return within an eastward spreading
lower/mid tropospheric warm advection regime, may reinforce
cool/stable boundary-layer conditions across much of the Mississippi
Valley, in advance of the lead surface cold front.  However, on the
western periphery of this air mass, beneath the plume of initially
capping elevated mixed-layer air, models continue to indicate that a
corridor of stronger pre-frontal heating may contribute to a narrow
zone of boundary-layer destabilization.  Aided by surface dew point
increases through the lower/mid 60s F, mixed-layer CAPE on the order
of 1000-2000 J/kg appears possible, in the presence of at least
moderately strong deep-layer shear.  Located near/southeast of the
I-35 corridor by peak late afternoon heating, this may provide
support for the development of a few supercells.  

A clustering of storms may eventually evolve near the intersection
of the cold front/dryline and remnant differential heating zone by
Wednesday evening, probably somewhere across northeastern Oklahoma,
before tending to shift north-northeastward as mid-level heights
tend to rise across the southern Great Plains Wednesday night.

...Pacific Northwest...
It still appears that at least a narrow warm sector, of a broad and
deep occluded cyclone centered over the northeastern Pacific, may
spread inland to the west of the Oregon Cascades early Wednesday. 
This is when wind profiles including large clockwise-curved
low-level hodographs and strong deep-layer shear will be most
conducive to low-topped supercells with the potential to produce a
tornado.  However, latest model output appears more unclear
concerning potential for even weak boundary-layer CAPE within this
regime.  It seems more probable that appreciable boundary-layer
destabilization might await the inland advance of the post-frontal
mid-level cold pool later Wednesday.  However, deep-layer shear may
remain strong, and the thermodynamic profiles may still beco*e
conducive to small to marginally severe hail and gusty winds in
widely scattered to scattered thunderstorm activity.

..Kerr.. 04/19/2022