Clearpost.online It's your post, so post it!

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1259 AM CDT Tue May 17 2022

Valid 171200Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS
SOUTHEAST NEBRASKA...NORTHEAST KANSAS...FAR SOUTHWEST IOWA AND
NORTHWEST MISSOURI...

...SUMMARY...
Scattered severe storms are expected across parts of the central
Plains and lower to mid Missouri Valley this afternoon through
tonight. Large hail, wind damage and a few tornadoes are expected.

...Central Plains/Lower to Mid Missouri Valley...
A belt of west-northwesterly mid-level flow will be in place today
across the north-central United States. A subtle shortwave trough is
forecast to move east-southeastward across the central and northern
Plains. Ahead of this feature, a moist and unstable airmass will
advect northward across the eastern half of Kansas and into eastern
Nebraska. By afternoon, a corridor of moderate to strong instability
is expected to develop, where MLCAPE is forecast to reach the 2000
to 4000 J/kg range. Surface-based thunderstorms are expected to
first initiate near the northern edge of the instability axis in
southeast South Dakota and northeast Nebraska during the afternoon.
These storms are expected to gradually increase in coverage, moving
southeastward across eastern Nebraska during the late afternoon and
early evening. MCS development appears likely with the co*plex of
storms reaching northeast Kansas and northwest Missouri during the
early to mid evening.

Forecast soundings from the 4 Km NAM along the track of the MCS in
southeast Nebraska at 00Z have MLCAPE approaching 3500 J/kg. 0-6 km
shear near 35 knots, and 700 to 500 mb lapse rates near 8.0 C/km.
This environment should be favorable for supercells with large hail.
Hailstones of greater than 2 inches in diameter may occur with the
strongest of updrafts. As the low-level jet increases during the
late afternoon and early evening, forecast soundings along the track
of the developing MCS, increase 0-3 storm relative helicities into
the 300 to 350 m2/s2 range. This should be favorable for tornadoes,
mainly with supercells. However, uncertainty does exist concerning
the favored storm mode.  The MCS could quickly take a linear form.
This would make the wind damage threat greater than the tornado
threat. This could be especially true as the MCS matures when
discrete storms may beco*e less likely. By mid to late evening, the
MCS should beco*e well-developed, moving southeastward into the area
near Kansas City. Wind damage, large hail and a tornado threat
appears likely. The severe threat could continue into the overnight
period across the Ozarks and into southeast Kansas.

...Central High Plains...
West-northwest mid-level flow will be in place across the central
and northern High Plains today, as a subtle shortwave trough moves
east-southeastward across the region. The western edge of a
relatively moist airmass is forecast to be in western Nebraska and
western Kansas by afternoon, where moderate instability is forecast
to develop. Isolated to scattered thunderstorms are expected to
initiate in parts of southeast Wyoming, western Nebraska,
northeastern Colorado and northwestern Kansas during the mid to late
afternoon. The stronger of these storms may persist into the early
to mid evening. By 00Z, model forecasts have moderate instability
located across much of western Nebraska and northwestern Kansas.
Moderate deep-layer shear is also forecast across this area, mainly
due to speed shear in the mid-levels. This will support isolated
severe storms capable of large hail. Also, steep lapse rates below
700 mb could aid downdraft acceleration, making a wind-damage threat
possible. The greatest severe threat could occur during the early to
mid evening with storms that form further to east in south-central
Nebraska, where instability is forecast to be much stronger.

..Broyles/Bentley.. 05/17/2022