Western Regional Climate Center

PROVIDING CLIMATE SERVICES SINCE 1986

August in the West

August 2015

Near to above normal temperatures were observed throughout the West this month. Though the magnitude of departures was not extremely large, generally 1-4 F (0.5-2 C) above normal, several locations in the Southwest and Pacific Northwest reported one of their top-10 warmest Augusts. Areas of above normal precipitation were scattered across the West resulting from different atmospheric features.

August marked the fourth consecutive month of widespread above normal temperatures in the Pacific Northwest. Rome, in the southeastern Oregon high desert, and Crescent City, along the coast in far northwest California, both experienced their warmest August on record at and average 73.9 F (23.3 C) and 61.0 F (16.1 C), respectively, which was 4 F (2 C) above normal at both locations. Records for both stations began in 1949. Portland, Oregon recorded its 3rd warmest August with an average of 72.4 F (22.4 C) and its warmest summer (June-July-August) on record at 72.2 F (22.3 C). Above normal temperatures were prevalent along the southern border of the West as well. Temperatures at Tucson averaged to 89.0 F (31.7 C), 3.7 F (2 C) above normal and the 3rd warmest August since records began in 1946. Average summer temperatures in Tucson tied 2013 for second warmest on record at 88.3 F (31.3 C).

Two low-pressure systems, one in the middle and another at the end of the month, brought much-needed precipitation to western Washington and scattered areas of coastal Oregon northern California. Rainfall totaled 3.28 in (83 mm) in Seattle for the month, the 4th wettest August in a 71-year record. Eastern Washington and Oregon and much of California remained drier than normal, though these areas typically receive little summertime precipitation. Scattered areas of above normal precipitation were observed in the Intermountain West associated with thunderstorm activity. Dyer, in west-central Nevada, recorded 3.55 in (90 mm) for the month, nearly all of it falling on the 2nd. This August set the record for wettest month of any month in Dyer’s 113-year record. In eastern Nevada, Elko observed 0.63 in (16 mm), 170% of normal August rainfall. Further east, Malad City in southeastern Idaho observed nearly 3 times its normal August precipitation at 2.27 in (58 mm) during the first week of the month. In the Southwest, areas of well above normal precipitation were observed in the elevated areas of northern Arizona. Pipe Springs, along the Utah-Arizona border, recorded 3.45 in (88 mm) for the month, 165% of normal. Winslow, Arizona logged 3.26 in (83 mm), 272% of normal and its 3rd wettest August in a 123-year record. Precipitation was generally below normal in New Mexico. Albuquerque reported only 0.32 in (8 mm) for August, 20% of normal and the 10th driest August since records began in 1897.

The Southeast, Interior, and Northern regions Alaska observed above normal precipitation this month while the Southcentral and Southwest regions were drier than normal. In the Southeast, Juneau recorded 8.92 in (227 mm) for the month, 156% of normal and the 8th wettest August in an 80-year record. Year to date, 2015 is Juneau’s wettest on record. Anchorage observed only 0.97 in (25 mm) of rain, 30% of normal for August. Further south, above normal rainfall was observed throughout Hawaii in association with Hurricanes Hilda, Kilo, and Ignacio passing near the state. Honolulu recorded 7.63 in (194 mm) of rain for August, more than twice the previous August record set in 2004. Warm, moist, tropical air associated with these storms, anomalously warm ocean temperatures, and persistent high pressure over the state kept temperatures well above normal. Many locations experienced their warmest month on record of any month of the year, including Hilo, Big Island at 79.7 F (26.5 C) and Kahului, Maui at 82.9 F (28.2 C).

Significant Events for August 2015

August 9: Flash flooding near Marble Canyon, northern Arizona: Heavy precipitation from thunderstorms produced flash flooding in the Marble Canyon area on the afternoon of August 9. A 25+ mile (40+ km) stretch of highway was closed due to the large boulders and mud deposited on the roadway.

August (all month): Fires in Pacific Northwest, northern California: Large fires burned throughout the Northwest this month, concentrated in Idaho, western Montana, Oregon, Washington, and northern California. Lightning on August 14 ignited the Okanogan Complex Fire and it grew to be Washington’s largest fire on record at over 300,000 acres (121,000 hectares) before being broken into two smaller fires for management reasons. The Soda Fire in southwest Idaho began August 10 and has consumed over 279,000 acres (113,000 hectares), displaced wildlife, and damaged locations of historic significance. The Rocky Fire in Lake County, northern California began July 29 and spread rapidly with high winds over the first couple days of August. The Rocky fire has burned over 69,000 acres (28,000 hectares) and destroyed 43 residences. The Rough Fire in southern Sierra Nevada was ignited by lightning July 31 and grew to over 77,000 acres (31,000 hectares) by the end of August. The fire threatens many natural and cultural resources and has disrupted recreation in the region.

Hurricanes in central/eastern Pacific: Over the last days of August, Category 4 Hurricanes Kilo, Ignacio, and Jimena were all present in the central and eastern Pacific basins. This was the first occurrence on record of 3 major hurricanes (category 3 or better) in these basins at the same time.

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