Shown here are an AMSU TPW composite valid between 03 and 06 Z, and a matching 6-hour Eta TPW forecast from the 00-Z run. Compare AMSU and Eta model TPW values over the nose of the moisture plume just west of the Washington coast.

Looking west along the moisture axis to near 35N and 135W, the Eta depiction compared with that of the AMSU is farther north and may be slower than the AMSU indicates.