SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sat Apr 23 2022
Valid 232000Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EXTENDING FROM
PARTS OF THE SOUTHERN PLAINS TO THE UPPER MIDWEST...
...SUMMARY...
Scattered severe thunderstorms remain possible this afternoon and
evening from the Upper Midwest to Oklahoma. This includes a risk for
a few tornadoes, damaging winds, and large hail.
...20Z Update...
Main change with this update was to trim severe probabilities behind
a line of convection over eastern ND into far western MN. Additional
robust thunderstorms behind the cold frontal passage appears
unlikely. Still, plentiful low-level shear remains present
along/near the warm front across this region, and a few tornadoes
will remain possible in addition to hail and damaging wind gusts.
Farther south, additional thunderstorms are starting to form over
parts of eastern KS/NE into western IA. For more information on the
near-term severe threat across this region, see Mesoscale Discussion
545. Finally, isolated to widely scattered supercells are still
expected to develop later this afternoon/evening over
central/eastern OK, posing a threat for all severe hazards.
..Gleason.. 04/23/2022
.PREV DISCUSSION... /ISSUED 1132 AM CDT Sat Apr 23 2022/
...Eastern Dakotas and west-central/northwest Minnesota...
Upper jet exit region/ample diffluence will overspread the region
ahead of the northeastward-moving upper low over the Dakotas. A
relatively narrow warm/moist sector will precede the eastern
Dakotas/northern Minnesota low, which will undergo some additional
deepening before beginning to weaken/fill later tonight.
Pronounced mid-level height falls/DCVA will aid in substantial
mid-level cooling and support a broken arc of low-topped convection
from southeast North Dakota/northeast South Dakota into
west-central/northwest Minnesota beginning around midday or early
afternoon. A few supercells can be expected with a risk for
short-lived tornadoes, large hail, and locally damaging winds.
Updrafts should quickly become elevated after they cross a sharp
surface warm front in northeast North Dakota/northern Minnesota but
may still pose a threat for isolated severe hail.
...Iowa/eastern Kansas into northern/western Missouri...
Although a few semi-discrete supercells could initially occur,
clusters of storms should be prevalent across the region later this
afternoon and evening. This will include the potential for severe
hail, damaging winds, and possibly a couple of tornadoes even with a
mixed/quasi-linear mode of storms.
...Oklahoma/western North Texas/southeast Kansas...
Relatively mild mid-level temperatures /-9 to -12C at 500mb and 11+
C at 700mb/ exist atop the warm sector at these latitudes, which
relates to tempered mid-level lapse rates that exist. Regardless,
the potential for hail-producing supercells will be compensated by
long/semi-straight mid/high-level portions /50+ at 500 mb/ of the
hodograph, with deep-layer shear vectors largely orthogonal to the
initiating boundary favorable for some discrete supercells. There
will also be some increase in low-level moisture (lower 60s F
surface dewpoints), which will contribute to upwards of 1500+ J/kg
MLCAPE by peak heating. At least isolated/widely scattered storms
are expected to develop by late afternoon/early evening in vicinity
of the dryline/Pacific front. Large hail is possible along with the
potential for a couple of tornadoes and damaging winds.
...West-central Texas...
At least isolated severe storms may develop late this evening and/or
overnight with the potential for isolated severe hail and locally
damaging winds.
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