July in the West
July average temperatures were slightly cooler than normal across the northern tier of the West this month, and slightly above normal across much of the Southwest. Scattered areas of above normal precipitation were recorded across Northwest. In the Southwest, a break in monsoon activity was observed in the first half of the month, with a return to monsoon conditions in the latter half of the month.
A trough passing over the Northwest July 8-11 brought precipitation to many locations across the northern tier of the region, resulting in above normal monthly totals. Thunderstorms and a smaller disturbance in the latter half of the month also contributed to precipitation totals for some inland locations, though generally to a lesser extent. In northern California, Crescent City observed 1.03 in (26 mm) rainfall, 251% of normal and the wettest July in a 68-year record. On the Washington-Idaho border, Lewistown logged 1.57 in (40 mm) precipitation, 238% of normal and the 7th wettest July in a 69-year record. Further east, Missoula, Montana recorded 2.06 in (52 mm) for the month, the 5th wettest July since 1948. In the Southwest, precipitation at Tucson, Arizona, totaled 3.32 in (84 mm), 148% of normal for the month. Southern and central Utah also observed some areas of above normal precipitation; Ferron logged 1.2 in (30 mm) precipitation, 151% of normal.
Several Southwest locations saw below normal precipitation. Salt Lake City, Utah, recorded no measurable July precipitation for only the second time since records began in 1928. Normal July precipitation for Salt Lake City is 0.61 in (15 mm). Monsoon activity favored Arizona this month, leaving most of New Mexico drier than normal. In eastern New Mexico, Roswell saw only one day of precipitation totaling 0.45 in (11 mm), 22% of normal. This was the 16th driest July in a 124-year record. In southwestern New Mexico, Hachita reported only 33% of normal precipitation. Further north, Lander, Wyoming, reported no measurable July precipitation for the first time since its record began in 1946. Normal July precipitation for Lander is 0.78 in (20 mm). Most of California received little to no precipitation this month, typical for July. Drier than normal conditions allowed for drought to develop or increase in severity along the Oregon coast, western Montana, and eastern New Mexico. Along the eastern Wyoming-Montana border, extreme drought conditions are now present. Only very small areas of improvement were seen this month in the New Mexico panhandle and eastern Idaho.
Average temperatures across the West were generally within 2-4 F (1-2 C) of normal, with the exception of New Mexico. A notable but not unprecedented heat wave impacted much of the West July 26-29, with average temperatures of 5-10 F (3-5 C) above normal. Las Vegas, Nevada, reported a high temperature of 115 F (46.1 C) on July 27 and 28, 2 F (1 C) below their all-time record of 117 F (47.2 C). Their July tied with 18 others for 11th warmest July temperature on record. Temperatures at Las Vegas averaged 95.4 F (35.2 C), 2.9 F (1.6 C) above normal and the second warmest July since records began in 1948. Further east, Roswell, New Mexico, had its warmest July on record with an average 86.5 F (30.3 C), 6.2 F (3.4 C) above normal. In the Northwest, temperatures trended cooler than normal. In the Idaho Panhandle, Moscow recorded an average 81 F (27.2 C) for the month, 2.6 F (1.4 C) below normal.
Temperatures in coastal regions of Alaska were generally above normal this month, reflecting strong positive sea-surface temperature anomalies; inland areas saw more moderate temperatures. Anchorage recorded an average July temperature of 62.7 F (17.1 C), 3.9 F (2.2 C) above normal and the warmest July since records began in 1952. Much of Alaska’s Interior observed above normal precipitation; Fairbanks recorded 4.97 in (126 mm) for the month, 230% of normal and the 3rd wettest July since records began in 1929. To the south, above normal precipitation was reported at many locations in Hawaii, much of it resulting from Tropical Storm Darby. Kaneohe, Oahu, recorded 10.75 in (273 mm) for the month, of which 7.65 in (194 mm) fell on the 25th. This was 400% of normal and the wettest July since records began in 1905.
Significant Events for July 2016
July (all month): Large Fires in the West: Several large fires impacted the West this month, notably in California and Nevada. By month’s end, the Soberanes Fire in coastal central California grew to 40,600 acres (16,400 hectares), destroyed 57 homes, and was only 18% contained. In southern California, the Sand Fire burned over 41,000 acres (16,600 hectares) and destroyed 18 homes. In northern Nevada, the Hot Pot Fire, fueled by brush, burned over 122,000 acres (49,000 hectares) in a week. The fire grew at a rate of 10,000 acres (4,000 hectares) per hour during a period of strong winds on July 2-3.
July 24-25: Tropical Storm Darby impacts Hawaiian Islands: TS Darby produced minor to moderate flooding, high surf, power outages, and road closures on Oahu, Maui, and Big Island. Some areas of eastern Oahu received 5-7 in (127-178 mm) or more of rain in a single day. Peak wind gusts of 50-60 mph (80-97 kph) were reported on Big Island.