MONTHLY WEATHER SUMMARY
By Bill Mork
California Department of Water Resources
August 2004

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A mean upper level trough of low pressure near the West Coast was deep and dominant enough to produce a fairly comfortable August in the Golden State. Preliminary data show the statewide average temperature in August to be 72.0 degrees, 0.4 degree above normal, and 0.4 degree cooler than July in California. Drainage area average temperatures ranged from 1.2 degrees above normal in the Sacramento basin to 1.1 degrees below normal on the South Coast.

Cities with the greatest average temperature departures from normal include plus 3.2 degrees at Burney, plus 2.9 degrees at San Francisco Airport, plus 2.7 degrees at Eureka, and plus 2.5 degrees at Quincy. Cities with average temperatures well below normal include minus 4.1 degrees at Santa Barbara Airport, minus 3.5 degrees at Twentynine Palms, minus 3.1 degrees at Long Beach, and minus 2.7 degrees at downtown Los Angeles. A strong upper level ridge of high pressure brought the warmest temperatures of the month to most of the State August 8 - 13. Some peak high temperatures in that period include 125 at Death Valley, 117 at Needles, 116 at Palm Springs, 114 at Blythe and Imperial, 107 at Paso Robles and Redding, and 106 at Bakersfield, Fresno, Red Bluff, and Sacramento. June Gloom conditions continued in the Southland with below normal temperatures on 30 days in Santa Barbara and a peak temperature of only 78.

Summer monsoonal activity was somewhat below normal except for one active period August 13 - 16. One of the lucky recipients was Big Bear Lake with 1.58 inches of rain August 13 - 14. Locally heavy rainfall produced extensive flash flooding in Death Valley National Park on August 15. Rainfall began along the eastern portions of the park, over the Black and Funeral Mountains, 7:30 - 7:45 PM. Flooding began about 8:00 PM with intense flooding at 8:30 PM. Radar rainfall estimates were 1 - 2 inches, but the cooperative station only received 0.33 inch. The worst flooding occurred along SR190 which runs along Furnace Creek Wash. Entire sections of the roadway were washed out, cars were pushed off the highway and flipped over, power lines were knocked down, and water pipelines were segmented. Two people were killed. This event is being compared to the floods of 1939, 1941, and 1985. A tornado was also reported at Victorville on August 15.

Monsoonal moisture worked northward up the Sierra with afternoon and evening showers and thunderstorms common along the crest and east of the mountains August 16 - 23. Some rainfall totals during this period include 0.57 inch at Bridgeport, 0.52 inch at Markleeville, and 0.30 inch at Bodie. Several strong Pacific weather systems brought heavy rain to the Pacific Northwest with leftovers into northwest California August 22 - 25. Some rainfall totals that period include 0.68 inch at Fort Dick, 0.63 at Crescent City, 0.48 at Gasquet, 0.42 at Arcata, 0.40 at Eureka, 0.29 at Hoopa, and 0.20 inch at Orleans. Additional nice totals for August include 0.80 inch at Alturas, 0.67 inch at Idyllwild, and 0.44 inch at Mount Shasta. As is the case in most summer months, the majority of California cities had no precipitation in August.

Page last updated 9/10/04.