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Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1244 AM CDT Mon May 30 2022

Valid 301200Z - 311200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EASTERN SOUTH DAKOTA...FAR SOUTHEAST NORTH DAKOTA AND WESTERN
MINNESOTA...

...SUMMARY...
Numerous severe thunderstorms are forecast across parts of the
Northern Plains and Upper Mississippi Valley southward into the
central Plains today into tonight. Large to giant hail, 60-80 mph
gusts, and tornadoes are probable, including the possibility for a
couple of intense long-track tornadoes.

...Outbreak of Severe Storms and Tornadoes Likely Today Across Parts
of Northeast South Dakota, Far Southeast North Dakota and Western
and Northern Minnesota...

...Northern Plains/Upper Mississippi Valley...
An upper-level low, and an associated powerful 90 to 100 knot
mid-level jet, will eject quickly north-northeastward across the
central and northern Plains today. At the surface, a low will move
northward across the eastern Dakotas. To the east of the surface low
track, a moist and unstable airmass will be in place, with MLCAPE
forecast to increase into the 2000 to 3000 J/kg range by late
morning. As the exit region of the mid-level jet moves into the
central Plains this morning, scattered convection is forecast to
initiate in central Nebraska. These storms are expected to increase
in coverage, moving north-northeastward into eastern South Dakota by
early afternoon. A co*plex of storms is expected to quickly
organize, moving north-northeastward across northeastern South
Dakota, far southeast North Dakota into western and northern
Minnesota. Severe storms and tornadoes appear likely with this
convective system from this afternoon into the early evening.

Several factors are co*ing together for an outbreak of severe storms
today across parts of the northern Plains and upper Mississippi
Valley. The first is that the system will be particularly organized,
as the upper-level low rapidly deepens and the trough takes on a
negative tilt. The second is that the exit region of the mid-level
jet will be associated with a strong and focused band of large-scale
ascent. The mid-level jet is forecast to move out of the base of the
trough at nearly 50 knots, which will provide support for an
outbreak. The third factor is that the mid-level and low-level jets
will beco*e coupled. This will strengthen lift and create strong
deep-layer shear very favorable for severe storms. Intense
supercells will be likely within a large convective cluster by
afternoon. 

As the low-level jet consolidates in west-central Minnesota to the
east of the upper-level low, shear in the boundary layer will beco*e
favorable for tornadoes. Tornadoes will be most likely from
northeast South Dakota north-northeastward across western Minnesota.
Forecast soundings along this corridor, to the west of the low-level
jet, have 0-3 km storm-relative helicities in the 350 to 450 m2/s2
range. This, along with curved hodographs, will contribute to a
potential for a few strong tornadoes. One or two long-track
tornadoes will be possible as well. Both strong deep-layer shear and
steep mid-level lapse rates in the 7.5 to 8.0 C/km range, will be
favorable for large hail. The more intense supercells will produce
hailstones greater than 2 inches in diameter. The cluster of storms
is expected to gradually organize into a bowing line segment by late
afternoon, moving across northwest and north-central Minnesota,
where a swath of wind gusts in the 60 to 70 knot range appears
likely.

...Central Plains/Mid Missouri Valley...
Mid-level flow will be southwesterly across the central Plains and
Mid Missouri Valley today, in the wake of a strong upper-level
system. At the surface, a dryline will sharpen during the day from
far eastern Nebraska southward into central Kansas. To the east of
the dryline, a moist and unstable airmass will be in place by
afternoon, with surface dewpoints in the mid to upper 60s F. This
will contribute to moderate instability. Thunderstorms are forecast
to develop along or near the instability axis by late afternoon,
with a rapid expansion of convective coverage taking place in the
early to mid evening. 

Forecast soundings during the early evening from Wichita, Kansas
northward to just east of Omaha have MLCAPE in the 2500 to 3000 J/kg
range. This co*bined with 60 to 80 knots of 0-6 km shear will be
favorable for supercells with large hail. Hailstones of greater than
2 inches in diameter will be possible with the more intense
supercells. Storms are expected to remain discrete for a few hours
this evening. This co*bined with 0-3 km storm-relative helicities in
the 200 to 250 m2/s2 range, will support a tornado threat. As a line
emerges during the evening, a wind-damage threat will likely be
maintained with the more intense cells or line segments. The severe
threat should continue into tonight, as the line of strong to severe
storms moves eastward across Iowa, northwestern Missouri and
east-central Kansas.

..Broyles/Lyons.. 05/30/2022