Jun 21, 2017

Hourly storm characteristics along the U.S. West Coast: Role of atmospheric rivers in extreme precipitation

M. A. Lamjiri, M. D. Dettinger, F. M. Ralph, Bin Guan
Geophysical Research Letters
  • Analyzes gridded hourly precipitation observations over the conterminous U.S. from 1948 to 2002 to determine climatological characteristics of storm precipitation totals
  • Finds that:
    • Despite generally lower hourly intensities, precipitation totals along the U.S. West Coast (USWC) are comparable to those in southeast U.S.
    • Storm durations, more so than hourly intensities, strongly modulate precipitation‐total variability over the USWC
    • Atmospheric rivers (ARs) contribute 30–50% of annual precipitation on the USWC
    • 60–100% of the most extreme storms, i.e., storms with precipitation‐total return intervals longer than 2 years, are associated with ARs
    • These extreme storm totals are more strongly tied to storm durations than to storm hourly or average intensities, emphasizing the importance of AR persistence to extreme storms on the USWC