Models are locking onto a high amplitude ridge to build over the North Pacific into the Aleutians. Thsi commonly starts with a cold pattern for the West, warm Southeast but it can also be the 1st step towards a cold CONUS pattern if the North Pacific ridge builds into the N Pole pic.twitter.com/dHvxEQC7RS

— Mike Ventrice (@MJVentrice) December 29, 2019