SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1142 PM CDT Fri Jun 10 2022
Valid 111200Z - 121200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
EASTERN KANSAS...SOUTHEAST NEBRASKA...SOUTHWEST IOWA...AND NORTHWEST
MISSOURI...
...SUMMARY...
A few clusters of strong to severe thunderstorms may develop from
the northern Rockies into the middle and lower Missouri Valley
Saturday into Saturday night. Damaging winds and hail will be most
likely. An isolated tornado is possible over the middle Missouri
Valley and vicinity.
...Synopsis...
A weakening upper trough will remain over the Great Lakes and
Northeast, with a surface high over the Mid Atlantic providing
stable conditions. To the west, upper ridging will occur over the
Plains, with gradual height falls occurring over the Pacific
Northwest. A weak feature may round the upper ridge into the
northern High Plains late in the day, aiding lift from MT into SD.
Lift may also be focused over the mid MO Valley during the late
afternoon/evening in a low-level warm advection regime. Here, 850 mb
winds around 30 kt will aid theta-e advection.
At the surface, ample low-level moisture will exist from the central
Plains to the Gulf of Mexico and Southeast, with the greatest
instability forecast from the central Plains to the ArkLaTex. A weak
cold front will drop south across MN and WI, with another boundary
moving across NE and into northern KS. The combination of strong
instability and sufficient lift is expected to result in a small
area of severe thunderstorm potential over the mid MO Valley late in
the day into the evening.
...Eastern NE and KS...northern MO...southwest IA...
Dewpoints are expected to rise through the 70s by late afternoon
from both advection and evapotranspiration, resulting in strong
instability profiles. MLCAPE may exceed 4000-5000 J/kg by 00Z over
eastern KS.
A few early day storms may occur from southeast SD into IA, in a
zone of strong theta-e advection at 850 mb. Some of this activity
could pose a marginal hail or wind threat early. By late afternoon,
the front will push across NE, and enhance convergence. In addition,
there could be outflow reinforcement and/or ongoing storms from IA
into eastern NE. The greatest severe risk is expected from near 00Z
into the 06-09Z time frame, from far southeast NE into eastern KS
and parts of far western MO. Moderate west/northwest flow aloft will
favor a south/southeastward-moving cell and/or cluster of storms,
capable of damaging hail and wind. Depending on actual
boundary-layer moisture quality, isolated significant hail reports
or wind gusts could occur. A tornado may occur during the first few
hours prior to storms growing upscale. If an MCS forms, the severe
risk may persist a bit farther south toward the OK/MO border.
...Southeast MT into SD...
A gradual flattening of the upper ridge will occur over the region,
beneath 50+ kt midlevel westerlies. Surface convergence will
increase during the day across southern MT as a weak lee trough
develops toward the Black Hills. Strong heating will lead to an
uncapped air mass but instability will be weak as dewpoints struggle
to reach the 50s F. Strong deep-layer shear should allow for
hail/wind threat across southeast MT and into western SD during the
evening. Several CAMs indicate at least one bowing structure,
suggesting severe gusts may be the primary risk. Given the narrow
corridor of potential and questions regarding instability, will
defer potential Slight Risk to later outlook updates.
..Jewell/Jirak.. 06/11/2022
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