Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0229 AM CDT Thu May 21 2026

Valid 231200Z - 241200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Widely scattered thunderstorms are expected from the
central/southern Plains into the lower Mississippi Valley and
southeastern US. A few stronger storms may be possible across the
southern Plains, particularly near the Texas and Oklahoma
Panhandles.

...Synopsis...
A weak impulse will rotate across the central Plains on D3/Saturday
as a surface low moves northward across the Ohio Valley. A trailing
cold front will extend from the surface low back into the southern
Plains.  Widely scattered thunderstorm activity will be possible
from the central/southern Plains into the lower Mississippi Valley
and across the Southeast. A few stronger storms may be possible
across the Texas/Oklahoma Panhandles.

...TX/OK Panhandles...
Weak forcing for ascent and easterly upslope flow across the Caprock
will produce scattered thunderstorm activity Saturday afternoon.
Forecast soundings suggest a plume of steep to low mid-level lapse
rates will still reside across the OK/TX Panhandles with mid 50s to
60s dew points and moderate instability by the afternoon. Shear
profiles will be fairly weak, with deep layer shear around 25 kts. A
few stronger storms may produce gusty winds and hail. Overall, weak
deep layer shear for organization may limit the severe threat.

..Thornton.. 05/21/2026

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0347 AM CDT Thu May 21 2026

Valid 241200Z - 291200Z

...DISCUSSION...
Severe potential will remain low through the beginning of the
extended period. Weak troughing will continue across the central
Plains D4/Sunday before height rises begin across the central US
with a high amplitude ridge settling in from the west D5/Monday.
This pattern will remain in place through early next week. Slow
moisture return will be ongoing across much of the Plains into the
Midwest with occasional rounds of widespread rainfall and
thunderstorms, but generally weak flow and subsidence will keep
organized storm potential low.

By the midweek, a trough is progged to begin deepening across the
Pacific Northwest. As the upper low slowly shifts eastward, stronger
flow will overspread the Intermountain West into the Northern
Rockies, resulting in strengthening lee troughing across the
central/northern Plains D6/Tuesday and D7/Wednesday. Moisture
advection will spread northward amid strengthening southerly flow
across the central/northern Plains. While there are some differences
in the placement of upper-level and surface features, it is possible
that severe chances will return across portions of northern High
Plains. For now, confidence in exact corridors remains low given
model guidance differences.