729
ACUS02 KWNS 080548
SWODY2
SPC AC 080546

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1246 AM CDT Mon Jun 08 2026

Valid 091200Z - 101200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL
AND EASTERN NORTH DAKOTA...NORTH-CENTRAL AND NORTHEAST SOUTH
DAKOTA...AND NORTHWEST MINNESOTA...

...SUMMARY...
Numerous severe thunderstorms are likely to develop across parts of
the northern Plains and Upper Mississippi Valley Tuesday afternoon
into night. Very large hail, tornadoes, a few of which could be
strong, and damaging winds with significant gusts appear likely.
Farther south, widely scattered severe storms capable of very large
hail and damaging winds with significant gusts will be possible
across portions of the central Plains Tuesday afternoon into night.
Additional, more isolated storms capable of large hail and damaging
winds are possible from parts of the Midwest into lower Ohio Valley
Tuesday afternoon and evening.

...Synopsis...

A short-wave trough initially over the northern Rockies Tuesday
morning will accelerate northeast into the north Plains, ahead of a
more significant vorticity maximum and associated mid/upper-level
jet streaks moving into the northern and central Plains Tuesday
night.

At the surface, low pressure is expected develop from southeast MT
into northwest ND during the day, along a Pacific front or
dryline-like boundary shifting east through the northern High
Plains. Meanwhile, a boundary initially across northern SD into
northwest MN will retreat north to the International Border as a
warm front. Elsewhere, a diffuse warm or quasi-stationary front will
reside across portions of the mid MO Valley into mid MS Valley.


...Northern Plains into upper Mississippi Valley...

A 30-40 kt low-level jet will enhance moisture return south of warm
front and beneath a plume of steep mid-level lapse rates, with
MLCAPE increasing to 2500-3500+ J/kg by afternoon within the
poleward expanding warm sector. Height falls attendant to lead
short-wave trough coupled with convergence in the vicinity of the
surface low and Pacific front/dryline are expected to foster
scattered thunderstorm development by mid/late afternoon over the
western Dakotas.

Strengthening deep-layer shear to 40-50 kt at a substantial angle to
the surface front will support rapid evolution into supercells,
which could initially be a bit higher based, given initiation on the
western edge of richer, boundary-layer moisture. Large to very large
hail will be the primary hazard initially. Tornado potential is
expected to increase through the evening as storms move east into an
increasingly moist and more strongly sheared low-level environment.
Model forecast soundings indicate large, clockwise-curved hodographs
with substantial SRH. However, there is some uncertainty as to what
the predominant storm mode will be during the time of the low-level
shear amplification. As such, this forecast will include a 10%
unconditional tornado probability with a conditional intensity group
one. Higher values may be required in subsequent forecasts if
confidence increases in a sustained discrete or semi-discrete storm
mode.

At some point, storms are expected to grow upscale into an MCS along
coalescing storm-scale cool pools, signaling an increasing damaging
wind risk across the Red River Valley Tuesday night.


...Central Plains...

Recent model runs have trended toward an earlier arrival of the
upstream short-wave trough mentioned in the synopsis, which results
in meaningful height falls overspreading the dryline during the
latter half of the diurnal heating cycle. Various models indicate
the development of isolated to widely scattered thunderstorm
development by mid/late afternoon across western parts of NE and KS,
perhaps as far southwest as northeast NM. Initial storms will form
in a hot, deeply mixed boundary layer with steep low/mid-level lapse
rates contributing to moderate instability. Initially marginal
deep-layer shear is forecast to strengthen by late afternoon into
Tuesday evening, with the environment becoming supportive of
high-based supercells capable of severe wind gusts and large hail.

There is some model suggestion that the initial high-based storms
may evolve into an MCS that progresses from central NE and northern
KS through the mid MO Valley Tuesday night. Given the strongly
unstable air mass forecast along the path of the MCS, the potential
would exist for a substantial damaging wind event, including the
possibility of intense wind gusts. Confidence in that scenario is
low, which precludes the addition of higher unconditional
probabilities. However, a conditional intensity group one has been
added to acknowledge the potential magnitude of such an event.


...Midwest into the lower Ohio Valley...

A moderate to strongly unstable air mass is expected to develop
Tuesday afternoon in the vicinity of a diffuse warm front or
quasi-stationary boundary oriented northwest-to-southeast across the
region. Storm coverage remains uncertain, which precludes higher
unconditional severe probabilities. Nonetheless, the potential for
large hail and damaging wind gusts will exists with any storms that
can become sustained in that thermodynamic environment.

..Mead.. 06/08/2026

$$