SPC Jun 4, 2026 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Thu Jun 04 2026

Valid 041630Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PORTIONS OF THE NORTHERN PLAINS...

...SUMMARY...
Severe thunderstorms capable of large to very large hail and
damaging winds are possible today from parts of the northern High
Plains across northern Nebraska and much of South Dakota. More
isolated occurrences of large hail and damaging winds appear
possible farther south across portions of the central Plains.

...Southeast MT through the Dakotas into southern MN...
Morning surface analysis places a weakening cold front from
northwest MN through south-central SD to a weak low near the
WY/SD/NE border intersection. Western portion of this boundary (from
central SD westward) is forecast to stall, with perhaps some retreat
northward during the late afternoon, while the eastern portion over
MN progresses slowly eastward. Dewpoints will likely stay in the 60s
along this boundary, with moderate to strong buoyancy developing by
late afternoon. Moisture convergence, augmented by modest
large-scale ascent attendant to a shortwave moving across MT, will
likely result in scattered convective initiation by the late
afternoon. Additional storms are expected farther west across
eastern MT ahead of the aforementioned shortwave. Moderate
deep-layer shear will support occasional supercells, with large to
isolated very large hail as the primary risk. Storms will spread
into the central Dakotas through the evening with a continued severe
threat.

Farther east, late afternoon thunderstorm development is expected
along the cold front. Deep-layer shear will be weaker than areas
farther west, and a more outflow-dominant storm mode appears likely.
Isolated hail is still possible early in the convective cycle,
particularly into central SD where steeper mid-level lapse are
expected.

...Central/Eastern KS into southeast NE/northwest MO/western IA...
Morning satellite imagery shows a well-defined MCV over western KS,
with widespread cloud cover throughout its eastern periphery from
central KS across south-central and eastern NE. Surface observations
show dewpoints in the mid 60s beneath this cloud cover, with
temperatures ranging from the upper 60s across central KS to the mid
70s across southwest IA. Southerly flow is anticipated throughout
the day today, maintaining low-level moisture advection within this
corridor. This increasing moisture coupled with sheltered/cloudy
conditions will likely result in dewpoints climbing into the upper
60s (perhaps even some low 70s) across this region by the late
afternoon. Modest heating is anticipated as well, with temperatures
likely in the mid 70s to low 80s. Mid-level lapse rates are poor
(generally less than 6 deg C per km from 700 to 500 mb), but the
ample low-level moisture will still support afternoon/late afternoon
MLCAPE around 1500 to 2000 J/kg and little, if any, convective
inhibition.

Ascent attendant to the MCV and low-level convergence throughout its
eastern periphery will support widespread thunderstorm development
within this unstable and uncapped environment. Deep-layer shear will
be weak (less than 25 kt from 0-6 km) across much of the region,
with a largely multicellular mode anticipated. That being said, an
increase in low-level southerly flow is expected throughout the
eastern periphery of the MCV, contributing to some moderate
lengthening of the low-level hodograph. This stronger low-level
southerly flow combined with the ample moisture in place (i.e. PW
values approaching 1.8" by the late afternoon, which is above the
90th percentile at TOP) results in a unique environment supportive
of brief tornadoes. Even so, the lack of stronger deep-layer shear
still suggests a predominantly disorganized storm mode, which should
keep any tornado threat isolated enough to keep probabilities at 2%.
A few water-loaded downbursts are possible as well.

..Mosier/Chalmers.. 06/04/2026


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SPC Jun 4, 2026 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0658 AM CDT Thu Jun 04 2026

Valid 041300Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING OVER PORTIONS OF THE NORTHERN PLAINS....

...SUMMARY...
Severe thunderstorms capable of large to very large hail and
damaging winds are possible today from parts of the northern High
Plains across northern Nebraska and much of South Dakota. More
isolated occurrences of large hail and damaging winds appear
possible farther south across portions of the central Plains.

...MT/Dakotas/MN...
Fast zonal flow is present today over the northern U.S, with a
shortwave trough now over western MT approaching the northern High
Plains. Easterly low-level winds have transported 50s dewpoints
westward into southeast MT/northeast WY, where daytime heating and
increasing large-scale ascent will lead to scattered afternoon
thunderstorms. Coverage of storms is not expected to be very high,
but those cells that can develop will likely be supercells capable
of large hail and damaging wind gusts. Storms will spread into the
central Dakotas through the evening with a continued severe threat.

Farther east, a surface boundary is forecast to extend from
south-central SD into central MN. Strong heating in this corridor
will promote scattered thunderstorms after 20z. Forecast soundings
suggest an environment favorable for hail and damaging winds in the
strongest cells.

...KS/NE/IA...
A weak upper trough has emerged from the central/southern High
Plains overnight and is now moving across western KS. Radar loops
show an MCV near Hays KS that will track into southeast NE and
western IA later today. A combination of low-level convergence,
daytime heating, and the affects of the MCV will lead to scattered
afternoon thunderstorms from northeast KS into IA. CAPE values of
2000-3000 J/kg are expected, along with sufficient deep-layer shear
for multicell or perhaps supercell storm structures. The potential
exists for hail and damaging wind gusts in the stronger cells this
evening. An upgrade to SLGT was considered, but the shield of
clouds/precip in vicinity of the MCV limits confidence in heating
and the area of greatest concern at this time.

..Hart/Kerr.. 06/04/2026


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SPC Jun 4, 2026 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Thu Jun 04 2026

Valid 041200Z - 051200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...

...SUMMARY...
Severe thunderstorms capable of large to very large hail and
damaging winds are possible today from parts of the northern High
Plains across northern Nebraska and much of South Dakota. More
isolated occurrences of large hail and damaging winds appear
possible farther south across portions of the central Plains.

...Synopsis...

Broadly zonal mid-level flow across the northern CONUS will persist
on Thursday, with a subtropical ridge located across the northern
Gulf. Additionally, a weak mid-level vorticity maximum/short-wave
trough across the southern/central Plains will continue to
weaken/open and begin merging into the main belt of westerlies
across the north-central US.

At the surface, a weak surface low will develop during the day
across the central High Plains. This low will move south and east
into north-central Kansas/south-central Nebraska overnight.

... Portions of the Northern Plains ...

Embedded within the broadly zonal flow are several subtle short-wave
troughs. One of these troughs will move from the northern Rockies
across the northern Plains. Ahead of this feature, moderate
instability will develop, with surface-based CAPE between 1500-2000
J/kg likely. As weak height falls overspread the region, a surface
low across eastern Wyoming will move south and east into northeast
Colorado and eventually into the central Plains. To the north of
this low, easterly/southeasterly upslope flow and increasing
large-scale ascent will combine for thunderstorms to develop during
the afternoon. Supercells will be possible as the southeasterly
surface winds and westerly mid-level flow results in 40-50 knots of
vertical shear. Steep mid-level lapse rates will support large to
very large hail and the potential for damaging thunderstorm winds. A
tornado or two will be possible with any storm that can interact
with the synoptic front.

Another area for storms will likely occur farther east, across
eastern South Dakota along a residual/slow-moving cold front.
Moderate instability and weak-to-moderate shear will support some
thunderstorm organization. Large hail will be possible with initial
development, with a tendency for storms to grow upscale and
transition to a damaging wind threat.

... Central Kansas northeast into Central Iowa...

A remnant MCV/sub-synoptic low/mid-level trough located across the
Southern Plains this morning will slowly lift north/northeast across
the Central Plains during the day. Ahead of this feature, surface
dewpoints will rise into the upper-60Fs to low-70Fs, resulting.
Diurnal heating should result in increasing instability during the
day, as suggested by the HREF mean surface-based CAPE reaching
between 1000-1500 J/kg and localized areas approaching 2000-2500
J/kg.

With several days of convection upstream of northeast Kansas into
southwest Iowa in the elevated mixed layer source region, forecast
soundings across the region reflect a largely uncapped environment
during the afternoon. The result should be multiple areas/rounds of
convective development during the afternoon and evening hours. The
moist environment and potential for moderate instability will result
in a potential for strong thunderstorm winds and marginally severe
hail. Additionally, forecast guidance shows an increasing low-level
mass field response during the evening hours, resulting in
increasing low-level curvature/shear. Thus, a tornado threat may
materialize during the late afternoon/evening hours, especially with
any thunderstorms that can remain discrete.

..Marsh/Moore.. 06/04/2026


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SPC Jun 4, 2026 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0800 PM CDT Wed Jun 03 2026

Valid 040100Z - 041200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
EASTERN NORTH AND SOUTH DAKOTA AND WESTERN MINNESOTA...

...SUMMARY...
Thunderstorms with large hail, severe wind gusts, and a couple of of
tornadoes will be possible this evening in parts of the northern
Plains. A few marginally severe wind gusts may occur across parts of
Kansas and northern Oklahoma.

... Eastern North and South Dakota and Western Minnesota ...

Severe thunderstorms continue this evening across portions of
eastern South Dakota, particularly across Tornado Watch #271. The
environment across the watch remains unstable with MLCAPE values
ranging from 2000 J/kg across southern South Dakota to around 1000
J/kg across northern South Dakota. Deep-layer shear will remain
sufficient for thunderstorm organization, including supercells into
the overnight hours. Low-level wind fields are expected to improve
over the next 2-3 hours, which may yield an increased potential for
tornadoes during this period.

The severe threat should continue slowly eastward into portion of
far western Minnesota during the overnight hours.

..Marsh.. 06/04/2026


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