July in the West
The onset of the North American Monsoon brought widespread precipitation to the Southwest this month, while persistent high pressure produced record high temperatures in the Northwest.
The North American Monsoon began during the first week of July, consistent with its climatological average start date. Many stations in the Great Basin and Four Corners states received near to above normal precipitation, though scattered pockets of below normal precipitation were observed. Albuquerque, New Mexico, recorded 3.49 in (89 mm) precipitation for its 4th wettest July in a 118-year record. Drought conditions improved for a large area of New Mexico this month. In Arizona, Phoenix received only 0.06 in (1.5 mm) of rain, 6% of normal and the 4th driest July since records began in 1933 Farther north, Flagstaff recorded 4.32 in (110 mm), 166% of normal. On the Arizona-California border, Needles logged 1.73 in (44 mm), its second wettest July in a 67-year record. Along the Colorado Front Range, Boulder recorded 4.57 in (116 mm) this month for its 5th wettest July in a 121-year record. Several monsoon surges moved moisture into the Great Basin and even beyond to the Sierra Nevada this month. Tonopah, Nevada logged 1.33 in (34 mm) precipitation, 296% of normal and the 9th wettest July since records began in 1954. Near Truckee, California, Boca Reservoir recorded 1.34 in (34 mm), 291% of normal and the 12th wettest July in a 109-year record. Several locations along the typically dry central California coast picked up small amounts of precipitation this month. San Francisco recorded 0.08 in (2 mm), 800% of normal and the 7th wettest July in a 165-year record. Such small amounts are barely enough to be beneficial, and much of California and Nevada remain in persistent extreme to exceptional drought.
Persistent ridging throughout July resulted in below normal precipitation and above normal temperatures for the inland Northwest. Sandpoint, in the Idaho panhandle, reported 0.02 in (0.5 mm) this month, only 1% of normal and tied for 7th driest July in a 104-year record. Missoula, Montana recorded 0.24 in (6 mm) this month, 24% of normal. Drought conditions expanded in northeastern Oregon, slightly in eastern Washington, and in portions of the Idaho panhandle and western Montana as well as a large area of northern California. Many locations in the inland Northwest, northern California, and the northern Great Basin saw one of their top-10 hottest Julys on record. Reno, Nevada, recorded an average temperature of 80.5 F (26.9 C) this month, the warmest July in a 78-year record. In northern California, Mt. Shasta City saw an average temperature of 74 F (23.3 C), 6.1 F (3.4 C) above normal and the hottest July since records began in 1948. In Oregon, Medford observed its hottest July in a 104-year record at 79.9 F (26.6 C). Further north, Yakima, Washington, also recorded its warmest July at an average 77.8 F (25.4 C), 7.2 F (4 C) above normal. Records for Yakima began in 1946. Reno, Medford, and Yakima all previously saw their warmest July on record in 2013. Temperatures in the Southwest were generally within 2 F (1 C) of normal as they were moderated by cloudiness and precipitation associated with the monsoon.
A slightly cooler than normal summer continued for northern and interior Alaska with stations in this region reporting average temperatures 1-4 F (1-2 C) below normal. The Interior also saw wetter than normal conditions. Fairbanks recorded 5.78 in (147 mm) precipitation this month making it the second wettest July since records began in 1929. Further south, most of Hawaii’s windward locations received above normal precipitation. On Big Island, Hilo logged 15.99 in (406 mm) 150% of normal and the 7th wettest July on record. On Oahu, Kaneohe recorded 7.24 in (184 mm) of rain, 447% of normal for July. A majority of this precipitation occurred on the 19th-20th when remnants of Tropical Storm Wali interacted with an upper level trough to produce heavy rainfall over portions of Hawaii.
Significant Events for July 2014
July (all month) Fires in the West: Many fires burned throughout the western states this month. Among the largest were: The Carlton Complex Fire in Washington, ignited by lightning on July 14. It has torched over 300 homes and over 250,000 acres (101,000 hectares) and became the larges fire in Washington history. The north-central Washington fire also killed livestock, destroyed critical infrastructure and along with other fires in the area prompted a disaster declaration for the state. The fire was roughly 70% contained at the end of the month. Lightning also started the Buzzard Complex Fire in eastern Oregon on July 14 and it has since consumed nearly 400,000 acres (162,000 hectares). Oregon has declared several fire emergencies for blazes throughout the state. However, nationwide, 1,651,320 acres (668,000 hectares) have burned year-to-date. This is the lowest acreage in the last 10 years and 39% of the 10-year average.
July (throughout month): Flash flooding in Southwest: Heavy rains beginning July 29th inundated areas near Denver, Colorado and impacted travel on Interstate 25. On July 28th, heavy precipitation occurred northwest of Las Vegas and flash flooding occurred in the community of Rainbow, damaging 20+ homes. Monsoonal moisture moved into northern Nevada and flash flooding was observed July 20 in rural areas near Carson City resulting in damage to driveways, structures, and landscaping. Arizona also experienced heavy precipitation and flash floods during each monsoon surge.