August heat creeps into September in Phoenix
High-pressure system is to blame, forecasters say
You’ve got to feel for football players around here at this time of year.
In most parts of the country, once the games start, you can hope for cooler weather. Here, there is plenty of football being played, but players are sweating through a weather pattern that seems stuck in the dog days of August.
Toward the end of last month, a strong area of high pressure parked itself over the Southwest and brought higher-than-normal temperatures. That system doesn’t seem interested in moving on — not for a while, at least.
“Normally at this time, our subtropical high-pressure system starts to break down,” Arizona State University meteorology professor Randy Cerveny said. “We usually start to see some drier westerly air coming into the state. But so far that’s not been the case. It’s been pretty humid and hot for pretty
much the last few weeks.”
The September outlook from the Climate Prediction Center calls for a 50 percent probability of above-normal temperatures for the month. Meanwhile, the CPC is pretty ambivalent about the state’s chances for rain, with an equal probability of above average, below average or normal rainfall for September.
In addition to being a little hotter than normal, Phoenix saw significantly more rain than usual in August. The National Weather Service’s official rain gauge at Phoenix Sky Harbor International Airport recorded 1.43 inches of rain for the month, 0.43 inches above normal.
Most of that rain (0.92 inches) fell during an Aug. 3 monsoon storm.
The August total puts Phoenix on track for an above-normal monsoon if September delivers its usual precipitation. Since June 15, the city has recorded 2.32 inches of rain, while the normal total for the Arizona monsoon season (June 15 to Sept. 30) is 2.71 inches.
Normal rainfall for September in Phoenix is 0.64 inches.
The month was a little hotter than normal, but it didn’t come close to the record heat of August 2011. In fact, August 2017 didn’t register among the 10 hottest months in any major statistical category.
The average high temperature for the month was 105.4 degrees. That’s 1 degree higher than normal but short of the 2011 record for that statistic: 109 degrees.
The average temperature (taking the average high and low and dividing by two) was 94 degrees, four-tenths of a degree above normal. The record average temperature for the month is 98.3, also set in 2011.
The average minimum temperature for the month was 82.6 degrees. That’s one-tenth of a degree below normal and 5 degrees below the record set in 2011.
The only high-temperature record set during the month was a tie for the warmest low temperature (90 degrees) on Aug. 28. The 0.33 inches of rain Aug. 13 set a record for that date.
“It’s been pretty humid and hot for pretty much the last few weeks.” RANDY CERVENY ARIZONA STATE UNIVERSITY METEOROLOGY PROFESSOR