Western Regional Climate Center


July in the West

The North American Monsoon was very active this month, bringing much needed precipitation to the Southwest. As is typical for July, dry conditions dominated in the Pacific Northwest. The Great Basin and Intermountain West saw record high July temperatures, while temperatures in coastal regions were moderated by persistent marine stratus and temperatures in the Southwest curbed by frequent thunderstorms.

Persistent ridging produced record monthly temperatures in the northern Great Basin. In Nevada, Reno and Elko logged their warmest month in their 126-year records, at 80.2 F (26.8 C) and 76.8 F (24.9 C), respectively. In Utah, Salt Lake City averaged 84.1 F (28.9 C), its warmest month in a 140-year record. Boise, Idaho saw its 3rd warmest July in a 136-year record, with 30 days reaching 90 F (32.2 C), tying 2007 for the most such days in July there. In Oregon, Medford saw its hottest month in an 86-year record, averaging 78.9 F (26.1 C), surpassing the previous record of July 2009 by 1.0 F (0.6 C). In Washington, Yakima recorded its hottest month on record as well, at an average 77.5 F (25.3 C), exceeding the July 1998 record by 1.4 F (0.8 C). In the Southwest, Tucson, Arizona ended a 39-day streak (June 1-July 10) of temperature reaching 100 F (37.8 C), the longest such streak in a 119-year record. Monsoon clouds lowered temperatures from the warmest Tucson June on record to the 19th warmest July.

Monsoon precipitation brought spotty and minor drought relief to Arizona and New Mexico, with many locations recording above normal precipitation. After consecutive below normal monsoon seasons, the Albuquerque, New Mexico airport recorded 2.77 in (70 mm) this month, the 9th wettest July in a 117-year record. This rainfall came in deluges, with nearly half (1.36 in/35mm) on the 26th, resulting in some flooding. In Arizona, Flagstaff tied 1919 for the wettest July on record at 7.58 in (193 mm). Phoenix, Yuma, and Tucson all saw an excellent start to the monsoon season as well, receiving above normal precipitation for the month. Cedar City, Utah logged 5.25 in (133 mm) of monsoon rain, 625% of normal and easily surpassing the previous July record of 4.37 in (111 mm) set in 1975. Los Angeles, California typically receives no precipitation in July, so that a mere 0.09 in (2.3 mm) led to the 3rd wettest July in a 108-year record.

In contrast, the Northwest experienced its typical dry July weather. Seattle, Washington received a trace of precipitation this month, tying 1958 and 1960 for driest July. Normal there is 0.7 in (18 mm). Quillayute, Washington averages 1.98 in (50 mm) for July, but saw only 0.01 in (0.25 mm) on the last day of the month, beating out 2010 (0.35 in/9 mm) for driest July in its 48-year record. Locations throughout Northern California, such as San Francisco and Sacramento stayed dry this month. July 6 brought the first rainfall to Las Vegas since April 16. This 80-day dry stretch is the 4th longest on record.

Quiescent conditions prevailed in Hawaii for most of July until the remnants of Tropical Storm Flossie brought high winds and locally heavy precipitation near the close of the month. Storm totals were highest around Maui County, helping stations in that area surpass their July normals. Kahului recorded 0.86 in (22 mm) for the month, 238% of normal. Of this, 0.79 in (20 mm) fell on the 29th associated with Flossie. Further north, warm temperatures continued in Alaska this month. Anchorage set a record of 14 consecutive days above 70 F (21.1 C) July 17th-30th. This beats the previous record of 13 days set in August of 2004 and helped to make this the 4th warmest July on record in Anchorage. On July 31, Fairbanks tied its all-time record for number of 80 F or greater (26.7 C) days in a summer at 30 days. So far, this is the second warmest summer on record at Fairbanks behind the summer of 2004.

Significant Events for July 2013

July (all month): Wildfires in the West: Though many large fires burned throughout the West this month, year-to-date the nationwide number of fires is 58% of the 10-year normal and acres burned is 55% of the 10-year normal. Some of the fires include: Douglas Complex Fire, Southwest Oregon: This group of fires ignited by lightning on the 26th had burned approximately 28,000 acres (11,300 hectares) and was 9% contained at month’s end. Smoke from these fires has produced hazardous air quality in many southwest Oregon cities such as Medford, Grants Pass and Glendale. Bison Fire, Northwest Nevada: This lightning-caused fire burned from July 4th through July14th, charring over 24,000 acres (9,700 hectares), one of the largest fires in western Nevada history. High winds helped the fire spread quickly, and smoke from the fire caused poor air quality in Carson City and Reno, Nevada. Aspen Fire, Southeast California: This lightning-caused fire began July 22 and was 45 % contained on July 31. The fire had burned nearly 18,000 acres (7,300 hectares) and caused hazardous air quality in Mammoth Lakes and northern Inyo County.

July (throughout month): Flooding in the Southwest: Heavy precipitation caused several instances of flooding in Arizona and New Mexico. On July 28, a tour bus was swept off the road while trying to cross a wash near Kingman, Arizona. In Albuquerque, high winds and lightning caused power outages. Flooding and winds damaged homes and businesses as well as city’s zoo.

July 2013 Departure from Normal Temperature and Percent of Normal Precipitation for Western United States

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