Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Aug 08 2025
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE EASTERN
DAKOTAS INTO MUCH OF MN AND NORTHWEST WI...
...SUMMARY...
Scattered severe thunderstorms are possible later today and tonight
across parts of the Upper Midwest. Scattered damaging winds, large
hail, and couple tornadoes are possible.
...Synopsis...
A seasonably deep upper-level trough will move eastward into the
northern Great Plains later today into tonight. In conjunction with
this trough, a cold front will move across parts of the
northern/central Plains into parts of MN/IA. The stronger
mid/upper-level flow associated with the trough will generally lag
the cold front, though there is some potential for increasing
deep-layer flow/shear to impinge on a strongly unstable environment
during the afternoon and evening.
...Dakotas into MN and northern WI...
Elevated convection and possibly a remnant MCS will likely be
ongoing at the start of the period somewhere from the eastern
Dakotas into northern MN. These storms could pose a threat of
isolated damaging wind and hail.
The influence of the early-day convection results in considerable
uncertainty regarding storm evolution later in the day. Convection
may persist through much of the day behind the front, and also
potentially along/north of an outflow boundary that will likely be
in place somewhere across northern MN. Warm-sector development along
the cold front will be possible by late afternoon, though stronger
large-scale ascent attendant to the approaching trough will not
overspread the region until evening, when widespread storm
development will become possible.
Steep lapse rates atop rich low-level moisture will support strong
to extreme buoyancy along/ahead of the cold front, and to the warm
side of any outflows. Deep-layer shear will become sufficient for
supercells, though deep-layer shear generally parallel to the cold
front could result in a quick transition to cluster or linear mode.
Any sustained warm-sector supercells could pose a threat of large
hail and a tornado. Damaging winds may become the primary threat as
storms increase and spread eastward through the evening into late
tonight.
Greater severe probabilities may eventually be needed for part of
the region, if uncertainties regarding the influence of early-day
convection and potentially late timing of redevelopment are
resolved.
...Black Hills into northeast CO and the NE Panhandle...
Guidance varies regarding the potential for post-frontal storm
development from the Black Hills into northeast CO and the NE
Panhandle. Steep lapse rates and moderate deep-layer shear would
conditionally support supercells within this regime, with a threat
of hail and strong to severe gusts. However, some guidance is rather
aggressive with drying behind the front, resulting in limited storm
coverage. This area will be monitored for greater hail
probabilities, if trends support development of multiple sustained
cells.
...Southern High Plains...
High-based convection is expected to develop this afternoon within a
hot and well-mixed environment across the southern High Plains.
Deep-layer flow will generally remain weak, but may be sufficient
for development of small outflow-driven clusters capable of
localized severe gusts.
...Northern Lower MI...
Similar to Thursday, a few strong storms may develop this afternoon
and evening across parts of northern lower MI, along the northeast
periphery of the substantial buoyancy reservoir centered over the
central Plains and Midwest. Modest northwesterly flow aloft will
provide sufficient shear for some storm organization, with a threat
for isolated hail and damaging winds.
..Dean/Moore.. 08/08/2025
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