Correlation between the TPW plume, short wave #1, and precipitation development
becomes evident during this period as short wave #1 moves across the CWA. Despite
the steady increase in TPW from west to east, precipitation across western Washington
gradually diminishes for a time in response to downward forcing behind short wave
#1. Over the eastern CWA, interaction between upward forcing out ahead of short
wave #1 and the increase in TPW results in a brief period of light orographic
snows. The more significant precipitation expected with the stronger short wave
#2 has yet to impact the region. Short wave #2, however, is poised just off the
northwest Washington coast by the end of the period.