SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0209 AM CST Sun Dec 21 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States on Tuesday or Tuesday night. ...Synopsis... A dominant mid- to upper-level ridge will remain steadfast across central portion of the Lower 48 states. An upper trough will encroach on the West Coast, and a lead mid-level trough will move quickly northeast from the eastern Pacific into the northern CA coastal area late Tuesday night. Scant to weak buoyancy will gradually develop Tuesday night in the vicinity of the CA coast and coastal range from near Point Conception to near the OR border. Scattered showers and isolated thunderstorms will gradually spread inland concurrent with increasing large-scale forcing and instability. Some forecast soundings depict a deep, lower-tropospheric moist layer co-located with intense low-level shear, which could imply storm organization being possible with the strongest low-topped storms. Uncertainty is high at this time for such a scenario given appreciable model variability. Farther east, a weak upper trough near the lower Rio Grande Valley will undercut a mid- to upper-level ridge over the central US. Weak convection is possible in association with this upper feature, but confidence in attaining 10-percent thunderstorm probabilities is low at this time. ..Smith.. 12/21/2025
