SPC AC 080600
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Jun 08 2026
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL PLAINS...
...SUMMARY...
Scattered thunderstorms with large to very large hail, severe wind
gusts potentially above 70 mph, and a few tornadoes will be possible
today from the Front Range east-southeastward into the central
Plains. Isolated severe gusts and hail will also be possible in
parts of the southern High Plains, northern Plains and mid
Mississippi Valley. An isolated hail threat may develop toward the
end of the period in the northern High Plains.
...Front Range Into Central High Plains...
Southwesterly mid-level flow will be in place today from the
Intermountain West into the Great Plains. At the surface, a cold
front will advance southward across the central High Plains as a low
deepens ahead of the front. During the afternoon, an axis of
maximized low-level convergence will become focused along the Front
Range of east-central Colorado, along which thunderstorms are
expected in the afternoon. These storms will move eastward out of
the higher terrain into northeast Colorado during the mid to late
afternoon. A line of severe storms is expected to organize by early
evening.
RAP forecast soundings in northeastern Colorado late this afternoon
have MLCAPE peaking around 2000 J/kg with 0-6 km shear near 55
knots. 700-500 mb lapse rates are forecast to be around 8.5 C/km.
This will support supercells with large hail, and hailstones greater
than 2 inches in diameter will be possible with any rotating storms
that can become intense. In addition, 0-3 km storm-relative helicity
is forecast to peak around 200 m2/s2 over parts of northeastern
Colorado during the late afternoon, which will support a tornado
threat. As a cluster moves eastward into the central High Plains,
organization into a line is expected. This will increase the
potential for severe wind gusts, and a few gusts above 70 mph will
be possible.
...Great Plains...
A very moist and unstable airmass will be in place across the
southern and central Plains today, with surface dewpoints mostly
from the upper 60s F into the mid 70s F. This will enable a pocket
of strong instability to develop by afternoon across central Kansas.
From near the instability max westward, model forecasts suggest that
low-level convergence will become maximized during the afternoon
over parts of western and central Kansas. This should result in
isolated to scattered convective initiation. A cell or two is
expected to develop and move southeastward into the strong
instability during the mid to late afternoon.
RAP forecast soundings near the instability max at 21Z have MLCAPE
near 4000 J/kg with 0-6 km shear around 40 knots, and 700-500 mb
lapse rates near 8.5 C/km. This will be favorable for supercells
with large hail and severe wind gusts. Low-level shear may also
support a conditional and isolated tornado threat. In addition, the
strong instability will contribute to a potential for hailstones
greater than 2 inches in diameter and wind gusts above 70 mph with
the more intense rotating cells.
...Mid Mississippi Valley...
A mid-level trough will move northeastward today across the mid
Mississippi Valley. Ahead of the trough, an axis of moderate
instability is forecast from far western Kentucky into southern
Illinois. Along this axis, deep-layer shear is forecast to be
sufficient for an isolated severe threat. As low-level lapse rates
steepen in the late afternoon, a few severe wind gusts will be
possible.
...Northern High Plains...
An upper-level trough will move eastward into the western U.S.
today, as mid-level heights fall over the northern High Plains.
Ahead of the trough, a surface low will form in eastern Montana
tonight, as upslope flow develops to the east of the low. Near the
surface low, low-level convergence is forecast to become maximized
late in the period, which will support isolated thunderstorm
development from northeast Montana into far northwestern North
Dakota. Instability, deep-layer shear and steep lapse rates may be
sufficient for an isolated hail threat, mainly between 09Z and 12Z
Tuesday morning.
..Broyles/Supinie.. 06/08/2026
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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
WUUS02 PTSDY2
SPC AC 080722
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0222 AM CDT Mon Jun 08 2026
Valid 101200Z - 111200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF EASTERN MINNESOTA...MUCH OF WISCONSIN...CENTRAL AND EASTERN
IOWA...AND NORTHWEST ILLINOIS...
...SUMMARY...
Scattered to numerous severe thunderstorms capable of large to very
large hail, tornadoes, and damaging winds with significant gusts
appear likely across portions of the upper Mississippi Valley and
Midwest Wednesday afternoon into night. More sporadic occurrences of
large hail and damaging winds are possible into the central Plains.
...Synopsis...
The 00z models have trended toward a similarly timed, but slightly
more amplified short-wave trough, which will move through the
northern Plains into upper MS Valley, in tandem with a 50-60+ kt jet
streak. Meanwhile, a stronger upstream system is forecast to amplify
across the northern and central Plains late Wednesday night into
Thursday morning.
At the surface, a cold front initially from the eastern Dakotas into
central High Plains will push east into the upper Great Lakes. A
frontal wave is forecast to develop from eastern SD into central MN
by afternoon, where it may link with an outflow boundary extending
into central WI. The trailing extension of the front is expected to
stall across the mid or lower MO Valley in response to the deepening
of a surface low over the central or southern High Plains.
...Upper Mississippi Valley into upper Great Lakes and mid/lower
Missouri Valley...
A very moist boundary layer, characterized by boundary-layer
dewpoints in the upper 60s to mid 70s is forecast ahead of the
front, which coupled with steep lapse rates, will contribute to
moderate to strong instability by afternoon. Thunderstorms are
expected to develop by early afternoon along the surface front and
any outflow boundaries across the upper MS Valley, with subsequent,
south/southwestward storm development into IA and the lower MO
Valley by mid to late afternoon. The strongest deep-layer shear is
forecast across the upper MS Valley into upper Midwest, with
decreasing bulk-shear magnitudes with southward extent being offset
by stronger instability. The CAPE/shear parameter space will favor
organized storm modes including supercells and bowing structures.
Large to very large hail will likely be the initial hazard, with the
threat for damaging winds and tornadoes increasing as storms move
into WI, eastern IA, and northwest IL, where stronger low-level
shear is forecast.
Additional, isolated to widely scattered storms are anticipated by
late afternoon into evening across portions of the lower MO Valley
into at least eastern KS. While vertical shear will be somewhat
marginal, the strong instability will support strong up/downdrafts
capable of isolated occurrences of large hail and damaging winds.
A separate, elevated thunderstorm regime may materialize Wednesday
night into Thursday morning across portions central/eastern NE and
northern KS as low-level warm advection increases ahead of the next
mid-level trough moving into the northern and central Plains. The
strongest storms will be capable of a large-hail threat.
..Mead.. 06/08/2026
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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