The First AR of Season

NWS Grand Junction is doing a much better job of covering the upcoming storm event than any other NWS office in the Region. Here are some snippets from GJT's coverage: A low pressure system moving out of Siberia into the Bering Sea is the system that will eventually become the winter storm that will impact the region this weekend. The NPJ will pick up this low to strengthen it and carry it southeast over the Pacific Northwest and to eastern Utah and Western Colorado. Where might such moisture be coming from? And, why such an abrupt change in weather pattern, you ask? Well first, guidance from the latest Atmospheric River (AR) outlook by CW3E , identified two plumes of integrated water vapor transport (IVT) making landfall along the PacNW by Thursday, and the second pulse Friday into Saturday. This event is declared the first AR of water year 2023. Even though it`s on the weaker end of the AR scale (AR 1), it`ll bring appreciable rainfall along the PNW, and eventually, ...