WSP09524

• File Number: 8056
• Description: Drought Preparedness
• State: CO
• Basin: Statewide
• Date: 8/1/1996
• Author: Colo Climate Center
• Title: Colorado Climate - August 1996 through June 1999 - Volume 19 Number 6
• Water Supply Pro - Doc Type: Publication

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adults was initiated in 1998 as a means of collecting
detailed local data on rain and hail patterns to help us
study Colorado stonns and to provide useful information
to scientists, engineers, water managers and many more.
After a very successful start in the Fort Collins area,
spear-headed by three high school student interns, the
project was expanded to Adams and Weld Counties in
1999 with the help of grants from the Colorado Water
Conservation Board and the U.S. Department of Agricul-
ture. This project will be expanding in Colorado in 2000
so we'll be telling you more about that later. Check out
the COCO RaHS website at httD:/Iccc.atmos.colostate.edul
-haiU for more information. Maps showing the detailed
rainfall patterns for every day this year are shown. We
hope your community will get involved soon. If you
would like to become a volunteer rain and hail observer
for COCO RaHS, please contact us. Tell your friends.

1998-2000 The National Oceanic and Atmospheric
Administration, NOAA, is concerned about the quality
and consistency of climate data being collected in our
country now and in the past. The Colorado Climate
Center is currently being funded to study and document
the impacts of rooftop weather station exposures on the
accuracy and representativeness of climate data. Tom
McKee is leading this study. We will begin to have
results to report next year. As we've pointed out before in
"Colorado Climate," it's easy to measure the temperature
of a thermometer, but it's a lot harder to take accurate and
representative measurements of the temperature of the air
- and even harder to do this consistently year in and year
out.

1998-2000 It has long been noted that the time of
day selected for taking snowfall observations and the
interval of time between snowfall observations has a direct
bearing on the observed snowfall totals. In most circum-
stance, the more often snowfall measurements are taken,
the greater the observed snowfall totals. Since not all
stations take observations with the same frequency or at
the same time, we may be introducing artificial differ-
ences in snowfall totals across the country. The Colorado
Climate Center is currently supported conducting a
national evaluation of the impact of the choice of time of
observation and frequency of observation on measured
snowfall totals, using data provided by cooperators in
Colorado, Ohio, North Carolina, Virginia, New Jersey and
New York. Results will be available in 2000.

1996-2000 NOAA Climate Data Continuity Study.
Tom McKee and several graduate students in the CSU
Department of Atmospheric Science have been actively
involved for several years in an evaluation of changes to
national climate data resulting from the deployment by the
National Weather Service during the 1990s of the Auto-
mated Surface Observing System (ASOS) at airports
across the country. Many reports have been written and
presentations delivered at conferences and workshops
across the country. Results to date show that the deploy-

ment of ASOS has resulted in systematically cooler
temperatures at most airport locations across the country
(approximately one degree F cooler, but with considerable
variations among sites). ASOS does not measure snow, so
urban locations have had to turn to local volunteer observ-
ers to provide snowfall data. The ASOS precipitation
gauge initially deployed had serious problems and under-
reported precipitation at most locations. Subsequent
changes have produced much better results with most
stations now showing differences from the previous gauge
ofless than 10%. Unfortunately, the heated tipping
bucket rain gauge used at all ASOS installations does not
perform well in measuring the water content of snow at
temperatures below the freezing point. A newall-weather
gauge is under development, but in the meantime, there
are now several years of questionable winter precipitation
data in the national database for major weather stations
across the country. Copies of these reports are available
on request.

Automated surface observing system

1996-1999 "Historical Dry and Wet Periods in
Colorado" by Thomas B. McKee, Nolan 1. Doesken and
John Kleist. This nearly 400 page report was completed
during the summer of 1999 and is the culmination of
years of research and deVelopment work using new types
of drought indexes for monitoring precipitation. snowpack
and streamflow. Results suggest that Colorado is cur-
rently enjoying a long period free of widespread multi-
year droughts. From the 1930s through the 19705, Colo-
rado experienced several severe and widespread droughts
separated by significant wet periods.

We will be providing a summary of the results of this
research in the near future here in "Colorado Climate."
For those of you with a good memory, this will be the long
awaited "Drought in Colorado, Part IIr') that will finally
complete the series of reports on drought that we began
back in 1994.

1996-2000 CoAgMet - the Colorado Agricultural
Meteorology Network, is a collaborative project of several
departments at Colorado State University, the Agricultural
Experiment Station, CSU Cooperative Extension, the U.S.
Department of Agriculture, and other sponsors. Data are

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