Western Regional Climate Center

PROVIDING CLIMATE SERVICES SINCE 1986

November in the West

November 2015

Several low-pressure systems crossed the West this month bringing scattered areas of above normal precipitation and cooler than normal temperatures to the region. The first significant snowfalls of the season were observed in the Sierra Nevada, Cascades, and Rocky Mountains, allowing winter snowpack to begin accumulating.

Following widespread above normal temperatures in October, November was cooler than normal for most of the West. In southeastern Oregon, Burns reported an average 27.4 F (-2.5 C), 5.9 F (3.2 C) below normal, the 4th coolest November since records began in 1973. To the northeast in Montana, average November temperature in Butte was 21.5 F (-5.8 C), 6.2 F (3.4 C) below normal and 8th coolest in a 122-year record. Both Burns and Butte saw average temperatures more than 20 F (11 C) below normal during a sharp cold spell over the West. To the south, Pahrump, Nevada, was cooler than normal with an average 46.8 F (8.2 C), 5 F (2.7 C) below normal and 8th coldest November since records began in 1914. Reno, Nevada observed its latest freeze on record, with temperatures remaining above 32 F (0 C) until November 4. The previous record for latest freeze was November 3, 1992. Further south, coastal areas of southern California saw above normal temperatures. In San Diego, average November temperature was 63.6 F (17.5 C), 2.3 F (1.2 C) above normal. Temperatures east of the Rockies were near to above normal.

Precipitation was variable across the West, with scattered areas receiving well above normal precipitation. A storm Nov 1-3 brought heavy precipitation to central California. Monterey recorded 1.7 in (43 mm) on the 2nd and a monthly total of 3.92 in (100 mm), 209% of normal and the 3rd wettest November since records began in 1968. Precipitation was able to spill over into the western Great Basin. Reno, Nevada, observed 1.04 in (26 mm) of rain on November 2. Reno airport totaled 2.1 in (53 mm) for the month, 256% of normal, the 3rd wettest since records began in 1937. Both latter cities noted their 3rd wettest November day on the 2nd. Snow water equivalent (SWE) was variable along the length of the Sierra Nevada, though generally above 75% of normal. Precipitation totals were near to slightly below normal throughout the range. In the Pacific Northwest, Seattle recorded 8.37 in (213 mm) this month, 127% of normal. November facilitated removal of drought conditions throughout western Washington. Values of SWE over 90% of normal only occurred in the far northern Cascades and the Olympic Mountains. SWE in the central and southern Cascades was generally were near or below 60% of normal SWE along with below normal precipitation. In the Great Basin, nearly all ranges reported SWE values above 200% of normal. Further east, western Montana and the northern Rockies observed above normal precipitation. Dillon, Montana recorded its 3rd wettest November on record at 1.04 in (26 mm), 280% of normal. Denver observed 2.13 in (54 mm), 349% of normal precipitation. Despite areas of above normal precipitation, SWE was generally below 75% of normal in the northern and central Rockies. Towards the southern extent of the Rockies, SWE values transitioned into the above normal range. Note that in most cases climatological values are low, so large percentages are common.

Some areas were quite dry this month. Much of southwestern Oregon and northern California observed less than 75% of normal November precipitation. In far northern California, Montague received only 0.38 in (10 mm), 13% of normal, the second driest November since records began in 1948. Southern California and western Arizona also saw below normal precipitation; Los Angeles recorded only 0.01 in (<1 mm) for the month, 1.03 in (26 mm) below normal. Little or no November rainfall is not uncommon for this area; 23 other years in Los Angeles’ 139-year record saw 0.01 in (<1 mm) or less.

The above normal temperatures observed in Hawaii over the past four months continued into November. Most locations saw departures of more than 2.4 F (1.3 C) above normal for the month. Lihue, Kauai (78.6 F/25.8 C), as well as Hilo (76.9 F/24.9 C) and Kona (80.4/26.8 C) on the Big Island all observed their warmest Novembers in 65+ year records. Conditions were also wetter than normal across much of the state. Kahului, Maui recorded 4.42 in (112 mm) of rainfall, 200% of normal and Hilo reported 22.81 in (579 mm), 147% of normal. To the north, conditions were also wetter and warmer than normal for much of Alaska. Some of the greatest departures from normal temperature were observed in the interior part of the state, where McGrath recorded an average temperature of 16 F (-8.8 C), 10.4 F (5.7 C) above normal and the 6th warmest November since records began in 1941. The greatest precipitation anomalies were also seen in the Interior; Fairbanks recorded 1.78 in (45 mm) precipitation for the month, 266% of normal and the 5th wettest November since records began in 1929.

Significant Events for November 2015

November 17th: Powerful windstorm in Pacific Northwest: Areas east of the Cascades in the Pacific Northwest experienced very high winds ahead of a cold front. Spokane, Washington reported a gust of 71 mph (114 kph) and mountain passes in the region observed gusts over 100 mph (160 kph). At least two deaths were reported due to falling trees and hundreds of thousands were without power, some for several days.

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