Narrative Summary - July 1998

July 1998 was much warmer than normal, averaging 82.0ºF, 5.8º above normal (76.2ºF),
and was the second warmest July (and also the second warmest month) on record. The
warmest month ever was July 1985 which averaged 82.2ºF. The coolest July was 70.5ºF
in 1993. July 1998 was the 12th consecutive month that averaged above normal. There
were 26 days in July with maximum temperatures >= 90ºF (normal for July is 19 days), and
there were 14 days with maximum temperatures >= 100ºF (normal is 6). The maximum
temperature of 112ºF on July 27 was the highest temperature ever recorded in the month
of July (the previous highest was 111ºF on July 22, 1994 and July 31, 1971). This was
also the hottest temperature at the HMS since 112ºF was recorded on August 9, 1971.
The minimum temperature of 81ºF on July 28 was the second highest minimum
temperature ever recorded, the highest was 82ºF on July 23, 1994. For the year (through
July) there have been 37 days with maximum temperatures >= 90ºF (normal is 30 days),
and 14 days >= 100ºF (normal is 8 days). The following daily temperature records were
established in July:

                         New       Old
Date     Category       Record    Record     Year

 26    High Maximum       108       108      1996   Tie
 27    High Maximum       112*      108      1975
 27    High Minimum        74        74      1973   Tie
 28    High Maximum       108       108      1968   Tie
 28    High Minimum        81        76      1968

 *Highest temperature ever recorded in July, previous record 111ºF on July 22, 
  1994 and July 31, 1971.

Precipitation for July 1998 totaled 0.34 inch, 189% of normal (0.18 inch). While the HMS
received only 0.16 inch of rain on Friday, July 31, a monitoring station on the north slope
of Rattlesnake Mountain reported 1.03 inches, and the monitoring station in the 300 Area
received 0.65 inch. The wettest July, in 1993, received 1.76 inches; while the driest, in
1980 and earlier years, received only a trace. There were 8 thunderstorms recorded at the
Hanford Meteorology Station in July 1998, tying 1983 for the most thunderstorms in July.
Total precipitation since January 1, 1998 totals 4.30 inches, 128% of normal (3.36
inches).

July 1998's average wind speed was 8.1 miles per hour (mph), compared to a July normal
of 8.8 mph. The peak wind gust for the month was 47 mph recorded on July 27. The
record wind gust for July was 69 mph in 1979. The windiest July averaged 10.7 mph
(1983); while the July with the lightest winds (1955) averaged 6.8 mph. During the
thunderstorm of Friday evening, July 10, meteorological monitoring stations at Pasco and
Vista Field in Kennewick recorded peak wind gusts of 68 and 66 mph respectively.

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.