Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0718 AM CDT Mon Apr 20 2026 Valid 201300Z - 211200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe storms are not expected today. ...Synopsis... Water-vapor imagery this morning shows a weak upper trough centered over AZ and Sonora moving east undercutting a ridge over the Rockies. This upper feature will move into the southern High Plains by late tonight. Farther west, a mid- to upper-level low will move slowly east from the eastern Pacific toward the CA/OR coast. Scattered showers and weak elevated storms will be possible across a large portion of TX today. Farther west, isolated to scattered thunderstorms are possible in association with the weak upper trough over parts of the Desert Southwest. Primarily diurnal storm activity over the southern FL Peninsula is expected, as well as isolated late day thunderstorms over portions of the Cascades. Elsewhere, surface high pressure will lead to tranquil conditions across much of the CONUS precluding storm development. ..Smith/Thompson.. 04/20/2026Read more