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WW 412 SEVERE TSTM SD 290300Z - 291100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 412
NWS Storm Prediction Center Norman OK
1000 PM CDT Sun Jun 28 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Southwest and central South Dakota
* Effective this Sunday night and Monday morning from 1000 PM
until 600 AM CDT.
* Primary threats include...
Scattered damaging winds and isolated significant gusts to 90
mph likely
Scattered large hail and isolated very large hail events to 3
inches in diameter likely
A tornado or two possible
SUMMARY...A cluster of severe storms, including embedded supercells,
is expected to form and move northeastward into central South Dakota
through daybreak. The storms will be capable of producing very
large hail up to 3 inches in diameter, significant severe gusts of
up to 90 mph, and possibly a tornado or two.
The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 35 miles north northeast
of Pierre SD to 75 miles south of Philip SD. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU2).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
3 inches. Extreme turbulence and surface wind gusts to 80 knots. A
few cumulonimbi with maximum tops to 600. Mean storm motion vector
23035.
...Thompson
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WW 0412 Status Updates
STATUS FOR WATCH 0412 HAS NOT BEEN ISSUED YET
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MD 1371 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF NORTH CENTRAL NORTH DAKOTA
Mesoscale Discussion 1371
NWS Storm Prediction Center Norman OK
1021 PM CDT Sun Jun 28 2026
Areas affected...parts of north central North Dakota
Concerning...Severe potential...Watch unlikely
Valid 290321Z - 290515Z
Probability of Watch Issuance...5 percent
SUMMARY...Isolated strong thunderstorm activity may continue to pose
a risk for severe hail, and perhaps a strong downburst before
weakening, while overspreading the region through Midnight-2 AM CDT.
DISCUSSION...While the warmest elevated mixed-layer air has been
suppressed a bit farther southeastward through the middle Missouri
Valley, Rapid Refresh output suggests that temperatures around the
700 mb level remain as warm as 10+ C along a corridor northeast of
the Black Hills through northeastern North Dakota. Associated
inhibition, coupled with the onset of boundary-layer cooling, has
contributed to rapid dissipation of earlier isolated storms within
this regime.
However, isolated strong thunderstorm development has persisted, and
even increased and intensified a bit, within the mid-level thermal
gradient to the northwest of the stronger capping. This appears
aided by forcing associated with weak warm advection accompanying a
subtle wave, which is forecast to continue slowly migrating toward
the international border area to the northwest of Devils Lake
through 05-07Z. As it does, the risk for severe hail may persist at
least a couple more hours. Thermodynamic dynamic profiles
characterized by steep mid-level lapse rates may also support a
strong downburst, before activity weakens and/or spreads across the
international border.
..Kerr/Thompson.. 06/29/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FGF...BIS...
LAT...LON 48860017 48649914 47660040 47440095 47600142 48860017
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0755 PM CDT Sun Jun 28 2026
Valid 290100Z - 291200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NORTHERN PLAINS...
...SUMMARY...
Severe thunderstorms are possible tonight across the Dakotas. Large
to very large hail and severe winds are the primary hazards. More
isolated severe storms capable of large will be possible in northern
Wisconsin late tonight into early tomorrow morning.
...Discussion...
Water vapor imagery this evening shows a mid-level trough located
across northern Montana into Alberta/Saskatchewan. At the surface, a
low is occluding to the north across southern Alberta, with a
secondary low developing across eastern Colorado. A surface cold
front extends across portions of the western Dakotas north to the
occluding front in Canada. As the surface low in Colorado deepens
and moves northeastward late this evening, thunderstorm activity is
expected to increase in coverage near the low/cold front and along a
warm front lifting into the Upper Midwest.
...Northern Plains...
Initial thunderstorm development has occurred this evening within a
zone of weak low-level convergence in central/western North Dakota
as enhanced mid-level westerly flow overspreads the region from the
trough to the west. Daytime heating and dew points in the upper 60s
F have led to strong buoyancy across the region. Low-level flow is
rather weak but deep layer shear around 50-55 kts will likely
support a few isolated supercells capable of large to very large
hail. See MCD#1369 for more information.
Additional thunderstorm activity is progged to develop overnight as
the surface low moves northward and forcing for ascent continues to
increase. Aforementioned strong instability and deep layer shear
profiles will support supercells capable of large to very large
hail. The Slight Risk was maintained with this update to account for
this potential overnight. See MCD#1370 for more information.
...Upper Midwest...
Thunderstorm development is expected along and north of a warm front
lifting into northern Wisconsin late tonight into early Monday
morning. As the warm front lifts northward, moisture and instability
will increase from the south. Moderate to strong instability
overlapping increasing deep layer shear from the trough to the west
will support a mix of supercells and multi-cell clusters with
potential for large hail. A Marginal Risk was maintained across
central/northern Wisconsin and extended into the northern Lower
Michigan Peninsula to account for this potential.
...West Texas...
A few stronger storms may continue across portions of western Texas
near dryline and south to the Trans Pecos with a few instances of
marginally severe hail and gusty winds. Loss of daytime heating
should limit the duration of this risk past sunset with storms
decreasing in coverage and intensity.
..Thornton.. 06/29/2026
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