Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Tue Jun 09 2026
Valid 091200Z - 101200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL AND NORTHERN PLAINS...
...SUMMARY...
Numerous severe thunderstorms with a potential for 60 to 80 mph
winds with locally higher gusts, along with tornadoes (some
potentially strong), and large to very large hail are expected to
develop in parts of the central and northern Plains from this
afternoon into tonight. Severe wind gusts and hail will also be
possible from north-central and west-central Kansas southwestward
into the Texas Panhandle.
...Central and Northern Plains...
An upper-level trough will move eastward across the western U.S.
today. Ahead of the system, mid-level heights will fall over the
central and northern Plains. At the surface, a moist airmass will be
in place over the Great Plains, with a dryline located from far
western North Dakota southward into western Nebraska. To the east of
the dryline, surface dewpoints will be in the upper 60s and lower
70s F. As surface temperatures warm today, an axis of moderate
instability is expected to develop over the central Dakotas.
Thunderstorms will form near and to the east of the dryline in the
mid afternoon. Strong low-level convergence near the instability
axis will result in a relatively rapid transition to linear mode
with a large MCS expected to develop during the late afternoon and
early evening. The severe MCS will move eastward across the central
and eastern Dakotas, with the southern part of the line located in
central Nebraska.
Late afternoon RAP forecast soundings in the central Dakotas near
the instability axis have MLCAPE in the 4000 to 5000 J/kg range with
0-6 km shear between 30 to 40 knots. Low to mid-level lapse rates
are forecast to be in the 7 to 8 C/km range. This will be very
favorable for large hail and severe wind gusts. Hailstones greater
than 2 inches in diameter and wind gusts above 80 mph will be
possible with supercells early, and along the more intense parts of
the line as it develops.
Concerning the tornado threat, a mid-level jet will become
juxtaposed with a low-level jet in the late afternoon across central
and northern North Dakota. Storms that can remain discrete for a few
hours after initiation will have potential to become supercells and
produce tornadoes. The strongest low-level shear is forecast in
northeastern North Dakota, where RAP forecast soundings increase 0-3
km storm-relative helicity into the 250 to 300 m2/s2 range by early
evening. This will be favorable for a few strong tornadoes. Further
south from central South Dakota into Nebraska, there will be
potential for supercells with tornadoes near gaps in the line. The
threat for strong tornadoes may be greatest in the early to mid
evening as the line interacts with a 45 to 55 knot low-level jet
from far southeastern South Dakota southward into eastern Nebraska.
From late evening into the early overnight period, the severe threat
associated with the severe MCS is expected to gradually downtrend as
it moves into the upper Mississippi Valley.
...North-central and Western Kansas/Texas and Oklahoma Panhandles...
At mid-levels today, heights will fall within southwesterly flow
over the southern and central High Plains. At the surface, a moist
and unstable airmass will be located over much of the region. By
afternoon, a focused zone of maximized low-level convergence is
forecast to develop. This axis will move eastward toward the western
edge of the stronger instability, with thunderstorms forming in the
mid to late afternoon. Near the axis, MLCAPE is forecast to be
around 2000 J/kg with 0-3 km lapse rates near 8 C/km. In addition,
surface temperature-dewpoint spreads will be large, which will be
favorable for severe wind gusts in the late afternoon and early
evening.
...Upper Mississippi and Lower Ohio Valleys...
A mid-level ridge will move eastward toward the upper Mississippi
and lower Ohio Valleys today. Ahead of the ridge, moderate
instability will be in place by afternoon. Scattered thunderstorms
that form within this moist and unstable airmass will have potential
for isolated severe gusts, mainly as low-level lapse rates become
steep in the afternoon.
..Broyles/Thornton.. 06/09/2026
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