The Hydrometeorological Design Studies Center (HDSC) of NOAA's National
Weather Service has published updated precipitation frequency estimates
for the semiarid southwestern United States (Nevada, Utah, New Mexico,
Arizona, and Southeast California). The new estimates cover the full
range of durations from 5 minutes to 60 days and return periods from 2
to 1000 years. For the first time, confidence limits will be included.

The new estimates replace those from Technical Paper No. 49 "Two- to
ten-day precipitation for return periods of 2 to 100 years in the
contiguous United States" (Miller et al 1964), NOAA Atlas 2
"Precipitation-Frequency Atlas of the Western United States" (Miller et
al 1973), "Short Duration Rainfall Frequency Relations for California"
(Frederick and Miller, 1979) and "Short Duration Rainfall Relations for
the Western United States" (Arkell and Richards, 1986).

The estimates are available through the new Precipitation Frequency Data
Server as a link ("PF Data Server" on the left sidebar) on the HDSC's
home page at "http://www.nws.noaa.gov/ohd/hdsc". Documentation of the
estimates will be added in the near future.

For states not included in the semiarid update, links are provided to
current precipitation frequency (PF) documents on-line. Also, states in
the Ohio River Basin (and surrounding states) are password protected for
an up-coming peer-review.

Fur further information please contact HDSC at

Geoff Bonnin
Chief, Hydrologic Data Systems Branch
Office of Hydrologic Development
NOAA's National Weather Service