480
ACUS02 KWNS 110600
SWODY2
SPC AC 110558

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Tue Jun 11 2024

Valid 121200Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE UPPER MIDWEST...

...SUMMARY...
Thunderstorms associated with large hail and severe wind gusts, and
perhaps a tornado or two are expected on Wednesday in parts of the
Upper Midwest.

...Upper Midwest...
A belt of strong mid-level flow will be in place on Wednesday across
the far northern U.S. Within the flow, a 60 to 80 knot mid-level jet
is forecast to move eastward across far southern Saskatchewan. The
exit region of this feature will overspread the upper Mississippi
Valley during the day, strengthening large-scale ascent and
deep-layer shear. At the surface, a cold front will advance eastward
through the eastern Dakotas. Ahead of the front, surface dewpoints
will likely reach the lower to mid 60s F from the mid Missouri
Valley northeastward into the upper Mississippi Valley. During the
afternoon, surface-based thunderstorms are expected to form along
the western edge of the moist airmass, from eastern South Dakota
into western Minnesota. These storms are expected to gradually
increase in coverage, moving eastward into the upper Mississippi
Valley during the late afternoon and early evening.

NAM forecast soundings near the instability axis at 00Z/Thursday
from central Minnesota into far northwest Iowa have MLCAPE in the
1500 to 2500 J/kg range, 0-6 km shear around 45 knots, and 700-500
mb lapse rates near 7.5 C/km. This environment will favorable for
severe storms. The stronger cells could become supercellular and
have a large hail threat. Hailstones greater than 2 inches in
diameter will be possible with supercells that form in areas that
destabilize the most. Some model solutions suggest that cells could
be separated enough to favor discrete modes. By early evening,
forecast soundings increase 0-3 km storm-relative into the 200 to
250 m2/s2 range. These factors would support an isolated tornado
threat with the more intense supercells. A wind-damage threat will
also be possible with supercells, and with organized short line
segments. The severe threat should continue into the mid to late
evening as storms move eastward into the far western Great Lakes
region.

..Broyles.. 06/11/2024

$$