LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 PM CDT Wed Apr 22 2026
Valid 222000Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE HIGH PLAINS INTO THE NORTHERN PLAINS AND EASTERN PARTS OF THE
OHIO VALLEY...
...SUMMARY...
Isolated strong-severe thunderstorms with strong gusts and hail will
be possible across parts of the High Plains this afternoon and
evening, as well as from northeast Indiana into northern Ohio.
...20Z Update...
The previous forecast (see below) remains on track, with mainly
minor adjustments made to the general thunder and severe
probabilities to reflect the latest observations and guidance
consensus.
..Squitieri/Mosier.. 04/22/2026
.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Apr 22 2026/
...Synopsis...
Recent surface analysis shows an airmass modifying under low-level
moisture advection across the southern and central Plains, with mid
50s dewpoints reaching through central KS and into eastern
NE/western IA. This moderate low-level moisture also extends
eastward from IA into northern IL and IN, just south of a stationary
boundary that demarcates a drier, more stable airmass across much of
the Great Lakes from the modifying airmass farther south/southwest.
This analysis also reveals a pair of surface lows, one over
north-central MT and the other over far northeast WY/far southeast
MT, linked by modest surface troughing. A wavy surface trough also
extends southward to another low over southeast CO. Thunderstorm
development is anticipated today/tonight near these lows and their
related surface boundaries. In particular, strong to isolated severe
thunderstorms appear possible near the northeast WY/far southeast MT
low as it moves eastward across SD, as well as in the vicinity of
the stationary boundary across northern IN and OH.
...IN/OH...
Weak surface low over southern Lower MI has already contributed to
thunderstorm development. The airmass downstream of this low, and
south of the stationary boundary that extends east-to-west near the
MI and IN/OH border vicinity, will likely destabilize throughout the
day amid continued low-level moisture advection and strong diurnal
heating. This destabilization coupled with low-level convergence
near the low and boundary will support increasing thunderstorm
coverage. Deep-layer wind profiles will be modest, but cool
mid-level temperatures and weak-moderate buoyancy could support
isolated severe hail and gusty outflow winds with the strongest
storms.
...High Plains...
Primary surface low over central MT is forecast to deepen today as a
closed upper low currently over the Great Basin ejects northeastward
while evolving towards a more open wave. At the same time, a
secondary surface low (currently over far northeast WY/far southeast
MT) is forecast to move eastward across SD, interacting with the
modifying airmass across the northern/central Plains. Expectation is
for this airmass to be deeply mixed, with perhaps some minimal
buoyancy atop the well-mixed boundary layer. Development of a few
high-based thunderstorms is possible this afternoon/evening from NE
into SD, as well as northeast MT, along the trough where deep mixing
and inverted-v profiles will favor strong outflow gusts.
Farther south, an even more conditional risk is anticipated along a
sharpening dryline from southwest NE and western KS into west TX.
Given the limited large-scale forcing and only weak low-level
convergence, warm mid-level temperatures and related capping
associated with a notable elevated mixed layer will likely suppress
thunderstorm development. Here, deep-layer vertical shear will be
sufficient for supercells, and a conditional risk for large hail and
strong gusts exists with any updrafts that are able to persist and
mature.
...Western/Central NE into the Dakotas...
Additional thunderstorms are possible tonight from western/central
NE into the Dakotas as an eastward-progressing cold front interacts
with low-level moisture continuing to advect northward across the
Plains and a strengthening low-level jet. These storms will likely
be elevated behind the front, with some isolated hail possible early
in the convective cycle. Additionally, mid-level dry air will likely
remain across the region, supporting the potential for strong
outflow gusts despite the storms elevated character.
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