SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Wed Dec 31 2025 Valid 312000Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms may occur across parts of southern California late tonight into early Thursday morning. ...20Z Update Discussion... No changes are made to the outlook for this issuance. ..Broyles.. 12/31/2025 .PREV DISCUSSION... /ISSUED 1010 AM CST Wed Dec 31 2025/ ...Synopsis and Discussion... With upper ridging remaining prominent over the western CONUS and upper troughing centered across the eastern states, thunderstorm potential should remain minimal though tonight for a large majority of the CONUS. One exception will be across parts of southern CA late tonight into early Thursday morning, as an upper trough/low over the eastern Pacific gradually approaches the CA Coast by the end of the period. While low-level moisture and related instability are both expected to remain limited, increasing large-scale ascent and gradually cooling mid-level temperatures preceding the upper trough/low may still support isolated convection capable of producing occasional lightning flashes, mainly after 01/06Z. Both MUCAPE and deep-layer shear appear too weak to support a meaningful threat for organized severe thunderstorms through the end of the period (12Z Thursday morning).
