Western Regional Climate Center


August in the West

August 2016

Temperatures were within a few degrees of normal across the West, with slightly warmer than normal temperatures observed in the coastal states and slightly cooler than normal temperatures for the inland states. Many locations in the Southwest and Rocky Mountain states observed above normal precipitation, while dry conditions dominated throughout California, the Great Basin, and the Pacific Northwest.

Temperatures were above normal in a broad swath from western Nevada across interior northern California to western Oregon and Washington. Temperatures at Mt. Shasta, California, averaged to 70.8 F (21.6 C) for August, 4.2 F (2.3 C) above normal and the 2nd warmest since records began in 1948. Further north, Astoria, Oregon, recorded an average temperature of 64.3 F (17.9 C), 3.4 F (1.9 C) above normal and the warmest August in a 64-year record. Along the central and northern California coast, foggy conditions kept temperatures slightly cooler than normal. Temperatures 0-4 F (0-2 C) cooler than normal were also observed in most of the Southwest and areas within and east of the Rocky Mountains, generally resulting from cloudy conditions and precipitation associated with thunderstorm activity. In northern New Mexico, Santa Fe reported and average temperature of 68.5 F (20.3 C) for the month, 2.5 C (1.4 C) below normal and tie for the 3rd coolest August. Records for Santa Fe began in 1941. In southwestern Montana, Bozeman observed an average 64.2 F (17.9 C), 4.0 F (2.2 C) below normal.

Dry conditions dominated much of the western half of the region, which for many locations was not abnormal. Los Angeles received no precipitation, consistent with August in over 100 other years in the station’s 140-year record. Los Angeles’ August normal is 0.04 in (1 mm). Medford, Oregon, also received no precipitation, as in 35 other years in the station’s 106-year record. Normal August precipitation for Medford is 0.4 in (10 mm). Further north, the lack of precipitation was more anomalous. Seattle, Washington received only 0.17 in (4 mm), 19% of normal and the 10th driest August since records began in 1945. Dillon, Montana recorded 0.12 in (3 mm) for August, 11% of normal and the 5th driest August in a 77-year record. In northeastern Idaho, Dubois reported 0.12 in (3 mm) 7% of normal and the 8th driest August since records began in 1925. Drier than normal conditions in western Montana, eastern Idaho, and northwestern Wyoming prompted the introduction of abnormally dry conditions or increased severity of drought conditions in the US Drought Monitor this month. Drought conditions also worsened in a large area of northeastern Oregon, and abnormally dry conditions were noted along the Utah-Wyoming-Colorado border area.

After a break for much of July, the Southwest Monsoon was active in August, bringing above normal precipitation to many areas of the Southwest. Northern Arizona was especially wet; Flagstaff reported 6.34 in (161 mm), 204% of normal and the second wettest August since records began in 1893. In eastern New Mexico, Roswell reported 5.05 in (128 mm), 256% of normal and the second wettest August in a 71-year record. This month’s precipitation helped to ease drought conditions in the Four Corners area and along New Mexico’s southern border. Further north, southern Montana and eastern Wyoming saw several days of thunderstorms that resulted in areas of above normal precipitation. Billings, Montana, observed 1.67 in (42 mm) precipitation, 223% of normal and the 12th wettest August since records began in 1934. In Wyoming, Casper recorded 1.3 in (33 mm), 153% of normal and the 10th wettest August in a 69-year record.

August was a uniformly warm month across Alaska, with most stations reporting one of their top-three warmest Augusts on record. Annette Island (63.6 F/17.6 C), Cold Bay (56.5 F/13.6 C), King Salmon (59.5 F/15.3 C), Kodiak (58.9 F/14.9 C), and Yakutat (57.7 F/14.3 C) all saw their warmest average August temperatures on record. Precipitation was generally near normal across mainland Alaska; however, Anchorage observed several days of locally heavy rain and precipitation totaled 5.45 in (138 mm), 168% of normal and the 4th wettest August since records began in 1952. Further south, an upper level disturbance passing over the Hawaiian Islands on the 22-24th brought abundant precipitation to windward locations; Hilo, on Big Island, reported 7.15 in (182 mm) on the 23rd. Tropical Storm Madeline brushed the southern part of the state over the last few days of the month, bringing heavy rainfall to the southeast side of Big Island and light rain to other parts of the state. August rainfall totaled 24.68 in (627 mm) in Hilo, 250% of normal and the 4th wettest since records began in 1949. Honolulu, Oahu, also observed above normal precipitation at 1.58 in (40 mm), 282% of normal and the 8th wettest August since records began in 1940.

Significant Events for August 2016

August (all month): Large, destructive Fires in the West: Several large fires impacted the West this month, most notably in California. The Soberanes Fire in central California that began in late July more than doubled in size during August, reaching over 94,000 (38,000 hectares) acres and only 60% containment by month’s end. Near San Luis Obispo, California, the Chimney Fire began on the 13th and has burned over 46,000 acres (19,000 hectares) and destroyed 49 residences. In southern California, the Blue Cut fire began on the 16th and burned over 36,000 acres (15,000 hectares) near Cajon Pass. The fire destroyed over 100 homes and caused temporary closure of major roads. In western Montana, the Roaring Lion Fire began July 31 and, during August, grew to over 8,600 acres (3,500 hectares), destroyed 16 homes, and was 70% contained at month’s end.

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