SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1026 AM CST Fri Dec 26 2025 Valid 261630Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis and Discussion... An upper trough will continue to progress eastward over the western CONUS today. With cool temperatures at mid levels supporting weak MUCAPE, isolated thunderstorms may occur across parts of CA into the Great Basin and northern Rockies through the period as large-scale ascent associated with the upper trough spreads inland. Mid-level flow and related deep-layer shear should remain strong enough to support some updraft organization across these areas, but limited low-level moisture, cool surface temperatures, and overall weak instability will likely hinder a meaningful severe threat from materializing today. Elsewhere, isolated lightning flashes may occur with elevated convection in a strong low-level warm advection regime over portions of the Great Lakes into the Mid-Atlantic and southern NY as a mid-level shortwave trough advances east-southeastward across these areas. ..Gleason/Wendt.. 12/26/2025
