Monsoon moisture not as widespread as it could be
PRESCOTT - The 2011 monsoon has been better for some than others in the Southwest.
Prescott precipitation has been below average, although New Mexico and the southeast corner of Arizona and New Mexico are faring much worse.
Prescott's official Sundog measuring site preliminarily recorded 1.8 inches of rain in July, only 62.5 percent of the 113-year average of 2.88 inches. It also was warmer than average, with the average minimum temperature 3.1 degrees warmer than normal and the average maximum temperature 1.2 degrees above normal.
Other preliminary July rainfall totals for sites in Yavapai County are Bagdad 1.15 inches, Castle Hot Springs 0.74, Chino Valley 1.96, Cordes 1.36, Jerome 2.61, Clarkdale 2.60, Seligman 2.50, Walnut Creek 1.71 and Walnut Grove 0.52 inches.
The highest July rainfall totals for northern Arizona have been in the White Mountains, with 6.47 inches in Alpine, 4.45 in Heber, 4.18 in McNary, 5.07 in Springerville and 4.20 on Sunrise Mountain.
July traditionally is the second-wettest month of the year here, with August the wettest. The annual average precipitation in Prescott is 18.9 inches.
After a bone-dry June, the monsoon started off a bit early and strong here with the help of Tropical Storm Arlene, which pushed moisture up the Gulf of California. The rains arrived in Prescott on July 2.
But an overabundance of West Coast troughs have pushed in several series of dry air masses, including this weekend, said Justin Johndrow, a meteorologist with the National Weather Service office in Flagstaff.
Some parts of the Prescott region have experienced heavy rainfall events, but they have missed Prescott's Sundog measuring site. The most rain that fell on a single day at Sundog during this monsoon so far was 0.37 inches.
The Prescott airport on the northern edge of the city recorded 2.61 inches of rain in July, much better than the Sundog site several miles to the south. That's 0.54 percent over the airport's 30-year average, Johndrow said.
The Sundog site has registered 0.40 inches of rain so far in August. The long-term average is 3.22 inches.
The Weather Service reported heavy rain Thursday afternoon about 10 miles northeast of Prescott, prompting it to issue a small stream flood advisory. Heavy rain in the Verde Valley also prompted an urban and small stream flood advisory.
After the weekend break, the Weather Service is seeing signs of the return of monsoon moisture this week with a 20-percent chance of rain Sunday and Monday and a 30-percent chance Tuesday.
The U.S. Climate Prediction Center is forecasting above-average temperatures for the Southwest through the rest of the year.
The center is not so sure about precipitation in the long-term forecast because of conflicting computer forecast models.
Extreme southeast Arizona, along with most of New Mexico and Texas, remained in the grips of an exceptional drought as of the most recent report from the federal government on Aug. 2.
The monsoon arrived late in New Mexico July 14-21, and rains have been below average. The eastern half of the monsoon region in Mexico has been drier than average, limiting the moisture available to flow into New Mexico, according to the High Plains Regional Climate Center and the Climate Assessment for the Southwest. And the position of the high-pressure monsoon ridge aloft has been slightly to the east, preventing water vapor from the south from moving into The Land of Enchantment.
At the end of July, the U.S. Department of Agriculture rated 88 percent of New Mexico's rangeland and pastures in very poor to poor condition, along with 64 percent in Arizona.
The San Carlos Reservoir in the Upper Gila River Basin in southeast Arizona was at only 2 percent of its average capacity at the end of July, and 5 percent of last year's level.
The Verde River Basin reservoirs were at 60 percent of their average capacity at the end of July, and only 46 percent as full as they were at the end of July in 2010.