Clearpost.online It's your post, so post it!

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1254 AM CDT Thu Sep 08 2022

Valid 081200Z - 091200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
NORTHERN WYOMING TO THE BLACK HILLS AREA AND ACROSS PARTS OF
MINNESOTA...WISCONSIN AND UPPER MICHIGAN...

...SUMMARY...
Thunderstorm gusts may beco*e locally severe this afternoon into
early evening over parts of northern Wyoming to the Black Hills
area.  Isolated strong-severe hail and gusts may occur during the
evening and overnight across parts of Minnesota, Wisconsin and Upper
Michigan.

...Synopsis...
A substantial pattern shift has begun over the CONUS. A large
anticyclone initially covering much of the Great Basin and central
Rockies is forecast to erode from the southwest, as eastern Pacific
Hurricane Kay proceeds northwestward near the western Baja coast. 
Even more height falls are expected on the north side of the present
anticyclone from northern-stream processes.  A synoptic cyclone will
pivot slowly around the northern Hudson Bay/eastern Nunavut region,
with troughing extending southwestward to the northern Rockies and
amplifying considerably.  This will occur as a series of shortwave
troughs traverse the strong cyclonic flow across the northern
Rockies, northern High Plains and Canadian Prairie Provinces.  By
the end of the period, this will result in a synoptic trough from
the cyclone across northern AB to eastern MT and central/western WY.

The associated surface cold front -- analyzed at 04Z from a low over
southeastern SK to near the AB/MT line, then across the northern
Rockies -- should reach northwestern MN, central SD, and
northwestern NE by 00Z.  The front should advance across the
remainder of the northern Plains overnight, reaching western Lake
Superior, south-central MN, northeastern/southwestern NE, and
northeastern CO by 12Z tomorrow.  A wavy warm front -- drawn
initially across the eastern Dakotas to the lower Missouri Valley --
should beco*e more diffuse as it shifts northeastward over the Upper
Great Lakes through the period.

...Upper Midwest...
A conditional potential exists overnight for thunderstorms to
develop on either side of the surface cold front, offering large
hail and strong/isolated severe gusts.  The main uncertainties
involve convective coverage and timing.

Lower/middle-level warm advection is expected from a stout upstream
EML regime -- where record to near-record surface temperatures have
been set on the higher terrain of the West. This, in co*bination
with an immature return-flow process and limited boundary-layer
moisture, may keep the front and warm sector capped for development
through daylight hours.  Any convection that can develop along the
front in the late afternoon to early evening may produce strong/
damaging gusts and/or hail near severe limits, but at this time, the
EML appears too strong to support an organized threat until later. 
Progress of the cold front also will outpace the eastern rim of the
large-scale DCVA/ascent associated with the shortwaves pivoting
through the synoptic trough.

During the evening/overnight hours, prefrontal low-level warm
advection, moist advection and moisture transport will moisten and
destabilize the layer near the EML base, reducing MUCINH and
increasing elevated buoyancy.  During the 29/06Z-29/12Z time frame,
forecast soundings depict around 1000-2000 J/kg MUCAPE rooted in the
700-850-mb later across parts of eastern MN and northern WI, with
buoyancy beco*ing more elevated to the northeast and decreasing with
greater capping to the southwest.  With convection likely being
predominantly elevated, effective shear will be modest (generally
less than 30 kt magnitudes), limiting potential organization and
keeping any severe threat rather disorganized.

...Northern WY to Black Hills...
Isolated to widely scattered thunderstorms should develop over
higher terrain of north-central WY during mid/late afternoon, then
move eastward over a post-frontal but still well-heated/mixed
boundary layer.  Moisture will be meager (surface dewpoints
generally in the 30s F), but with cooling conditions aloft
contributing to steep low/middle-level lapse rates and minimal
MLCINH.  Just enough moisture should be present to support MLCAPE up
to about 250 J/kg, supporting high-based, skeletal convection that
may produce strong gusts -- locally augmented by momentum transport
from strengthening midlevel winds.  This threat should diminish
through the evening and with eastward extent, as already small
buoyancy weakens atop a boundary layer undergoing both cold
advection and diabatic surface stabilization.

..Edwards/Lyons.. 09/08/2022