Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0207 PM CDT Sun Oct 18 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
No severe thunderstorms are expected on Tuesday.

...Synopsis...
A large upper trough is forecast to amplify just off the CA coast,
with increasing south/southwest winds aloft, as well as cooling
aloft near the coast overnight. To the east, minor height rises will
occur over the Plains, while an upper low meanders off the Mid
Atlantic coast.

At the surface, high pressure over the Upper Great Lakes and Ontario
will shift eastward, though the surface ridge will remain entrenched
into the Southern Plains. This will maintain stable conditions over
the central and eastern states.

General thunderstorm chances will be limited to parts of the
southwestern states in relation to the upper trough. Veering winds
with height and moderate deep-layer shear will develop over AZ and
NM as the upper trough amplified. However, forecast soundings show a
subsidence inversion above 500 mb during the day, which will limit
storm intensity. Overnight, elevated instability may increase as
cooling aloft occurs, with isolated storms still possible. Potential
should generally increase into Wednesday/D4 as the upper trough
strengthens.

..Jewell.. 10/18/2026