October in the West
Strong high pressure was present over the West for much of the month, contributing to the above normal temperatures observed across the region. Several warm and moist storms moved into the Pacific Northwest, resulting in significantly above normal precipitation for that area. Further south, October was generally drier than normal. Light precipitation was observed in central and southern California, the Sierra Nevada, and the Great Basin. A low-pressure system interacting with hurricane remnants brought above normal precipitation to areas of southern Arizona, western New Mexico, and southern Colorado.
Several locations in the West experienced their warmest October on record this month. The month began with very high temperatures along the coast of California. On the 3rd, Monterey hit 94 F (34.4 C), the highest October temperature since records began in 1968. This was also the warmest October on record at Monterey with an average 63.3 F (17.4 C), 4.7 F (2.6 C) above normal. Elsewhere in the Bay Area, Downtown San Francisco observed a high of 92 F (33.3 C) on the 3rd, a rare occurrence but not unheard of; temperatures 92 F (33.3 C) and above have been observed in 26 other times in October in this station’s history. San Francisco recorded an average 65.4 F (18.6 C) for the month, the third warmest October in a 140-year record. In southern California, Santa Ana recorded an average 73.6 F (23.1 C) for the month, 4.9 F (2.7 C) above normal and the warmest October since records began in 1916. In the Pacific Northwest, both Seattle, Washington, and Portland, Oregon, saw their warmest Octobers on record at 58.0 F (14.4 C) and 60.1 F (15.6 C), respectively. Records for Seattle began in 1948 and Portland in 1938. In eastern Washington, Walla Walla also recorded its warmest October on record at 59.9 F (15.5 C), 6.6 F (3.7 C) above normal. Records at Walla Walla began in 1949. Minimum temperatures 6-8 F (3-4 C) above normal were observed in much of Washington, parts of Oregon, and scattered areas of Montana. These above normal minimum temperatures (warm overnight lows) made a strong contribution to the record monthly temperatures seen in the Northwest. Further south, Reno, Nevada, ended its longest streak of above-freezing temperatures this month. Airport temperatures remained above freezing from April 6 through October 26, 204 days. The previous record was 193 days from April 4 through November 2, set in 1992. Records for Reno began in 1937.
The Pacific Northwest saw steady precipitation throughout October as well as an atmospheric river event mid-month that brought copious precipitation to western Oregon, western Washington, and northwestern California. Seattle, Washington, reported 6.75 in (171 mm) of rainfall for the month, 210% of normal and the 4th wettest October on record. In south-central Oregon near the California border, the drought-stricken Klamath River Basin received above normal precipitation this month. Klamath Falls, Oregon, recorded 2.21 in (56 mm), 210% of normal and the 4th wettest October in a 67-year record. In northern California, Arcata logged 5.74 in (146 mm) this month, 200% of normal and the wettest October on record. Records for Arcata began in 1945. This month’s precipitation in northern California and Oregon, though beneficial, was not sufficient to break the persistent drought affecting these regions and they remain categorized as extreme to exceptional drought. Elsewhere in the West, remnants of Hurricane Simon interacted with a cold front to bring precipitation to southern Arizona, western New Mexico, and southern Colorado on the 9th and 10th. Colorado Springs received 2.96 in (75 mm) precipitation for the month over these two days, 2.14 in (54 mm) above normal and the second wettest October in a 66-year record.
Along Alaska’s North Slope, Barrow reported an average temperature of 21.3 F (-5.9 C) this month. This is 4.1 F (2.3 C) above normal and the 13th consecutive October that Barrow has observed October temperatures significantly above the long-term average. The persistence of open water through the end of October due to reduced sea ice in the Beaufort and Chukchi Seas is the main factor keeping October North Slope temperatures above normal. Elsewhere in the state, temperatures were generally slightly warmer than normal in the Southeast and slightly cooler than normal in the Interior, Southcentral, and Southwest regions. Precipitation totals in the state, excepting the Southeast region, were generally under 2.5 inches (64 mm) and highly variable in percentages of normal. In the Southeast, Annette, received 14.39 in (366 mm) of rainfall, 103% of normal. Along the North Slope, Barrow received 1.12 in (28 mm) of precipitation, which was 273% of normal. Further south, much of Hawaii observed above normal precipitation this month due to Hurricane Ana passing to the southwest of the island chain. The highest precipitation totals associated with Ana were generally in the range of 4-7 in (101-178 mm) on Big Island and Oahu, with stations on each of these islands reporting 10+ in (254+ mm). Honolulu, Oahu, recorded 5.51 in (140 mm) for the month, 300% of normal and the 4th wettest October since records began in 1949. Most of this rain fell over the 18th-19th in association with Ana.
Significant Events for October 2014
October 25: Wind storm in Pacific Northwest: Strong winds ahead of a frontal system downed trees and left tens of thousands without power in western Oregon and Washington. Sea-Tac reported a maximum gust of 49 mph (78 kph); Portland International Airport reported a maximum gust of 41 mph (66 kph). Gusts of 70+ mph (112 kph) were reported along the coast. Strong winds like these are typical ahead of a winter-like storm, though tend to be more damaging in autumn when trees still have relatively full foliage.