518
ACUS03 KWNS 210627
SWODY3
SPC AC 210626

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0126 AM CDT Tue Jul 21 2026

Valid 231200Z - 241200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorm potential appears low on Thursday. However,
locally gusty winds could occur with thunderstorms across the
central High Plains into the northern Rockies.

...Central High Plains...

Scattered thunderstorms are expected to develop over higher terrain
in the central Rockies during the afternoon. Easterly low-level flow
across the adjacent High Plains will transport modest boundary layer
moisture westward across western KS and eastern CO. Meanwhile, a
weak surface boundary may develop south across the central High
Plains as convection moves off higher terrain into the High Plains.
Forecast soundings indicate generally weak midlevel lapse rates, but
steep low-level lapse rates within modest instability (MLCAPE up to
1000 J/kg). This could support gusty outflow winds with storms
across the Plains. However, effective shear values in the 20-25 kt
range and very weak flow below 500 mb suggests organized severe
convection is unlikely amid the weakly unstable airmass.

...Northern Rockies...

Some enhancement to upper flow is forecast as a shortwave upper
trough moves across Alberta and Saskatchewan, and an upper low
persists off the Pacific Northwest coast. Forecast soundings show a
deeply-mixed boundary layer with steep 0-3 km lapse rates. Steep
midlevel lapse rates will be sufficient for weak destabilization,
and isolated thunderstorms are expected during the
afternoon/evening. Given weak vertical shear and limited
instability, organized severe potential is low, though gusty outflow
winds could occur.

..Leitman.. 07/21/2026

$$