Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Jun 29 2025
Valid 292000Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY...AND OVER PARTS
OF THE UPPER MIDWEST...
...SUMMARY...
Isolated to scattered strong to severe thunderstorms are possible
from the upper Great Lakes into the central High Plains. Wind is the
primary risk, though hail is expected across portions of the High
Plains.
...20Z Update...
The Slight risk was expanded southeastward from parts of the central
Plains into the Middle MS Valley, where a cluster of thunderstorms
is intensifying as it impinges on a strongly unstable air mass. The
primary concern with this activity is damaging wind gusts. For
information on the severe risk here, reference Severe Thunderstorm
Watch 478. Additionally, 2-percent tornado probabilities were added
along this corridor and westward into southeast/south-central KS and
far northeast/north-central OK. Here, antecedent outflow is
diurnally destabilizing amid rich boundary-layer moisture.
Clockwise-curved low-level hodographs will support a localized
tornado risk with any cells that can develop in this corridor.
Farther west, significant-wind probabilities were added over
northwest KS, southwest NE, and far eastern CO. Any thunderstorm
clusters that evolve out of CO and move through this area will have
the potential of producing gusts upward of 75 mph -- aided by steep
deep-layer lapse rates and sufficiently elongated hodographs.
Additionally, visible satellite imagery shows a shallow
boundary-layer cumulus field along a surface wind shift in this
general area. As storms move into this area of enhanced moisture and
steep lapse rates, a brief tornado will be possible.
Reference Severe Thunderstorm Watch 477 and MCD 1508 for the severe
risk in the Upper Midwest, and MCDs 1509 and 1510 for the High
Plains severe risk.
..Weinman.. 06/29/2025
.PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Jun 29 2025/
...Eastern KS/Western MO...
An overnight MCS is slowly weakening over central MO, with an
associated outflow boundary extending from eastern KS into
south-central MO. Strong heating will occur along and south of the
boundary, where several 12z CAM solutions indicate development of
afternoon thunderstorms. Given this scenario, have extended the
SLGT risk farther south into this region. Locally damaging wind
gusts would be the main concern. Refer to MCD #1506 for further
short-term details.
...WY/CO/SD/NE...
A low-amplitude shortwave trough is digging into WY. As forcing
associated with this system overspreads the High Plains of WY,
high-based convection is expected. Thunderstorms will intensify as
they track into a moderately unstable air mass and weak but backed
low-level flow. Severe storms capable of large hail and damaging
winds may affect the Black Hills region and southward into the NE
Panhandle.
Storms will also develop southward into the foothills of CO this
afternoon and spread eastward. Winds and temperatures aloft are
less favorable for organized/severe storms that far south, but at
least isolated instances of large hail and damaging winds are
possible.
...IA/WI...
Strong heating is occurring across much of WI today, where a moist
air mass will lead to moderate CAPE values. Thunderstorms will
develop by mid-afternoon along a remnant weak boundary across
central WI/northeast IA and spread northeastward through the day.
Vertical shear is not particularly strong, and overall convective
organization is expected to be low. Nevertheless, steep low-level
lapse rates and ample instability will promote strong downdrafts and
some hail in the strongest cells.
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