Narrative Summary - December 1998

December 1998 was warmer than normal, averaging 33.0ºF, 1.6º above normal (31.4ºF). The
warmest December occurred in 1957 and averaged 38.5ºF, while the coldest was 21.0ºF in 1985.
The minimum temperature of -1ºF on December 21 was the coldest temperature in nearly two
years. The following daily temperature records were established in December:

			  New        Old
Date      Category        Record     Record     Year
 17	 High Maximum       57         57       1971  Tie
 28	 High Maximum	    59         57       1997
 28	 High Minimum	    46         38	1949
 29	 High Maximum	    60	       60	1949  Tie
 29	 High Minimum	    41	       39	1962

Precipitation for December 1998 totaled 0.44 inch, 43% of normal (1.03 inches). The wettest
December, in 1996, received 3.69 inches, while the driest, in 1976, received 0.11 inch. There
was 0.9 inch of snowfall recorded in December 1998, compared to a December normal of 5.7
inches. The snowiest December received 22.6 inches (1996), while December 1957 and 1963
received only a trace.

The average wind speed for December 1998 was 7.8 miles per hour (mph) compared to a
December normal of 5.9 mph. The peak wind gust for the month (at the HMS) was 55 mph
recorded on December 26. Monitoring stations in Richland recorded gusts of 67 and 70 mph on
December 27. The record wind gust for December was 71 mph in 1955. The windiest December
averaged 8.3 mph (1968); while the December with the lightest winds (1985) averaged 3.3 mph.

Calendar year 1998 tied 1992 as the warmest year on record, averaging 56.4ºF, 3.1? above normal
(53.3ºF). The coldest year (1985) averaged 49.6ºF. The hottest day during 1998 was July 27,
which reached 112ºF, while the coldest was December 21 with a low of -1?F. Precipitation for
1998 totaled 6.45 inches, 103% of normal (6.26 inches). The wettest year was 1995 with 12.31
inches, while the driest was 1976 with 2.99 inches. The peak wind gust for the year was 56 mph
on November 21. A comprehensive climatological summary for 1998 will be issued at a later date.

The monthly climatological data summaries, as well as other information, are available
on the Internet. Address: http://etd.pnl.gov:2080/HMS/. Hanford Site personnel can
access the HMS Intranet site at: http://hms.rl.gov/

For additional information contact:
Ken Burk373-3215
Dana Hoitink372-6414

Note: The information in this summary pertains specifically to
the Hanford Meteorology Station (HMS), which is located
approximately 25 miles northwest of Richland, Washington. No
attempt should be made to infer meteorological conditions at other
locations from these data.