Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Jun 29 2026
Valid 291200Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
NORTHERN PLAINS AND UPPER MIDWEST...
...SUMMARY...
Severe thunderstorms are possible from parts of the northern Plains
into the Upper Midwest today. Large hail and severe winds are the
primary concerns, though a couple of tornadoes may also occur.
...Synopsis...
A shortwave trough will advance eastward from the northern Rockies
into the northern Plains today. At the surface, a low will move
northward out of Nebraska into the Dakotas, with a cold front/dry
line extending southward to a secondary low across the central
Plains. Thunderstorm activity is likely to be ongoing at the start
of the period near the northern surface low across portions of the
Dakotas. Additional thunderstorm activity is expected in the wake of
the morning convection near the warm front lifting across North
Dakota into Minnesota and near the cold front back into portions of
the Mid-Missouri Valley and central Plains.
...Dakotas/Mid-Missouri Valley/Upper Midwest...
Elevated supercell activity is likely to be ongoing at the start of
the period across portions of the Dakotas near the surface low and
nose of the low-level jet axis. The environment will be
characterized by moderate to strong instability and strong deep
layer shear. Guidance suggests that this will have the potential to
produce large to very large hail and damaging wind.
As the low develops, a warm front will extend into North
Dakota/Minnesota by the afternoon. Evolution of the morning activity
remains uncertain, but it appears that additional storms will
develop near the warm front and back near the low/cold front into
the afternoon. Near the warm front, filtered heating through broken
low to mid-level cloud cover will allow for moderate instability by
the afternoon. A plume of steep low to mid-level lapse rates will
advect northward through the afternoon. The favorable thermodynamic
profiles and strong deep layer shear around 45-50 kts will support
potential for supercells. If these storms can become surface based,
they will be capable of all hazards.
Back west near the cold front/low, initial supercells are possible
by the afternoon. These will have potential primarily for large hail
and damaging wind. Boundary parallel deep-layer shear will likely
lead to clustering/upscale growth with time. Strong to extreme
instability is expected ahead of the cold front across portions of
the western Dakotas into the Midwest. As the low-level jet increases
into the evening, it is possible that a corridor of more favorable
damaging wind potential (including significant gusts 75+ mph) may
evolve. For now, confidence in convective evolution is low with a
few CAMs suppressing convection towards the evening along the front
amid the strong EML until later in the evening around 06z.
...Kansas/Oklahoma/Texas...
Isolated high-based thunderstorms are possible near the dryline in
Kansas/Oklahoma/Texas. Moderate instability is expected within this
region with generally weak deep layer shear. This will likely keep
more widespread severe potential low. However, a few stronger storms
may be capable of strong winds given deeply mixed profiles. For now,
this potential remains too isolated to include probabilities.
..Thornton/Chalmers.. 06/29/2026
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