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Oregon's climate,
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FOR THE
FOREST INDUSTRY
SEPTEMBER I960
CLIMATOLOGICAL NOTE NUMBER 32
FREQUENCIES OF AMOUNTS OF DAILY PRECIPITATION IN CENTRAL OREGON
(CHEMULT, CRATER LAKE, FREMONT, REDMOND)
Question: "During a given 10-day period in Central Oregon, what is the likelihood that
precipitation during a day will be light, medium, or heavy?"
Table:
As an example of how to read the Table, look at the top row of numbers for the
period 1-10 January. The values tabulated are based on actual observations
made at the stations indicated during the years 1949-58, and are presented on
the basis of "days in 100 days". The numbers 0, 1, 2, and 3 above the columns
stand for amount of precipitation as follows:
0 no precipitation
1 light precipitation
Trace through 0.09 inch
2 medium precipitation 0.1 through 0.49 inch
3 heavy precipitation
more than 0.49 inch
That is, during the first third of January at Chemult, rainless days have
occurred at the rate of 43 days in 100 days, and light precipitation has fallen
at the rate of 17 days in 100 days. Combining these two statements, precipi
tation at Chemult during the period has been either absent or light on 43+17,
or 60 days in 100 days. This last value for Crater Lake is 32+16, or 48 days
in 100 days, and at Fremont, it is 66+21, or 87 days in 100 days. Conversely,
at Fremont precipitation rate has been medium or heavy on 100 - 87, or 13 days
in 100 days during the first third of January. Similar combinations of data may
be made with respect to various intensities of precipitation at other times of
the year.
The data: Because of the nature of precipitation, tabulations here cannot be considered
any more than a suggestion of patterns in time and space of precipitation
occurring on a given day in Central Oregon. Note that "precipitation" includes
rain, snow, hail, and sleet expressed in terms of water equivalent. Similar
data for Klamath Falls and Medford are available in detail as Climatological
Notes 10 and 16 of this series.
•
William P. Lowry,
In Charge, Forest Meteorology
OREGON
FOREST
LANDS
RESEARCH
FOREST
RESEARCH
CENTER
CORVALLIS
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