Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1248 AM CDT Mon May 25 2026
Valid 251200Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON INTO TONIGHT ACROSS PARTS OF THE RIO GRANDE
VALLEY...CENTRAL GREAT PLAINS AND UPPER GREAT LAKES REGION...
...SUMMARY...
The risk for organized severe thunderstorm development appears low
across much of the U.S. today through tonight.
...Discussion...
Amplification within the westerlies across the northern mid-latitude
Pacific is ongoing. Near the leading edge of this regime, a
significant short wave trough and embedded mid-level cyclone are now
digging toward the Pacific Northwest coast, and forecast to progress
inland across coastal areas later today through tonight. As this
occurs, the center of broad, weak troughing emerging from the
subtropical eastern Pacific is forecast to sharpen some, along a
negatively tilted axis across the southern Great Basin through
northern Mexican Plateau by daybreak Tuesday.
Downstream, weak troughing across eastern Texas and the western Gulf
Basin will tend to slowly shift north-northeastward toward the lower
Mississippi Valley, as a high remains prominent across the
subtropical western Atlantic. In higher latitudes, mid-level
ridging is forecast to continue to build to the east the Canadian
and northern U.S. Rockies. This will include further mid-level
height rises across the Missouri Valley through Upper Midwest and
adjacent Great Lakes region.
In lower levels, a cold front likely will advance inland across
Washington, Oregon and much of northern California, while surface
troughing deepens across much of the Great Basin and northern
Rockies through northern Great Plains. However, seasonably moist
boundary-layer air appears likely to generally remain confined to
portions of the southern Great Plains and lower Mississippi Valley
through Southeast and Mid Atlantic.
...Minnesota Arrowhead/adjacent Upper Great Lakes...
Mid-level heights are forecast to continue to rise across the region
today, even as a fairly significant short wave trough and associated
forcing for ascent dig across northwestern Ontario, generally well
to the north of the upper Great Lakes region. Even so, convection
allowing and related machine learning guidance continue to suggest
that isolated thunderstorm development is possible as far south as
the Minnesota Arrowhead vicinity, in an environment that could
become supportive of a supercell. As a result, 5 percent severe
weather probabilities will be maintained. However, given the lack
of better available low-level moisture and the spread evident within
guidance concerning potential destabilization, these may be too
high.
...Central Great Plains and adjacent Middle Missouri Valley...
Calibrated thunderstorm probabilities from most ensemble output
suggest that widely scattered thunderstorm development is probable
by late this afternoon, in a corridor of stronger potential
boundary-layer destabilization within the lee surface troughing,
from portions of southwestern Nebraska through southwestern
Minnesota/northwestern Iowa. If inhibition associated with
continuing mid-level height rises and more substantive
lower/mid-tropospheric warming is overcome, thermodynamic profiles
may be conducive to locally strong to severe surface gusts and some
hail, particularly where a narrow corridor of better low-level
moisture is maintained across the northeastern Nebraska through
southern Minnesota vicinity.
...Parts of southwestern Texas into south central New Mexico...
Stronger deep-layer layer shear and forcing for ascent, within the
exit region of a strong subtropical jet nosing into the northern
Mexican Plateau, may support and enhance thunderstorm development
across parts of northeastern Chihuahua into adjacent portions of the
Rio Grande Valley by late this afternoon. This probably will be
rooted within a weakly unstable, but deeply mixed boundary layer
supportive of at least a risk for strong to severe wind gusts.
..Kerr/Chalmers.. 05/25/2026
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