2016 Monsoon Brought Patchwork Precipitation To Arizona

Published: Wednesday, October 5, 2016 - 1:11pm
Updated: Wednesday, October 5, 2016 - 1:59pm

(Map courtesy National Weather Service in Flagstaff)
Total rainfall (in inches) during the 2016 monsoon.
(Map courtesy National Weather Service in Flagstaff)
Amount of 2016 monsoon rainfall, expressed as a percentage of normal.

Nature resists simple summaries, as Arizona’s patchwork precipitation proved once again this monsoon.

“It was not uniformly distributed, but then it typically isn’t,” said state climatologist Nancy Selover.

By and large, folks “riding the high country” around the Mogollon Rim, Alpine, the North Rim of the Grand Canyon and the Flagstaff area saw more than their share of showers. So did the cowboys, winemakers and birdwatchers in the southeastern portion of the state.

Westward to Yuma, though, those dusty border towns stayed dusty.

“Tucson was a little bit wetter than normal — Flagstaff was wetter than normal as well — and then Yuma, as I say, Yuma was really, really dry, about 69 percent of normal,” said Selover.

In the northwest, parts of the Navajo Nation around Kayenta did well, but the Hopi Nation saw drier conditions.

RELATED: See How Much Rain Monsoons Have Dumped On 4 Arizona Cities Since 1899

“The good news, at least for Arizona, is that we’re always highly variable with our temperature as well as our precipitation, so we actually handle it very well, because we always assume that we aren’t going to get any precipitation and, if we get any, then we’re happy,” said Selover.

As for whether Phoenix reached its normal rainfall this monsoon season, it depends on whether you count the .20 inches that fell the weekend after the season officially ended.

According to the definition adopted by the National Weather Service in 2008, which brackets the monsoon season between the calendar dates of June 15 and Sept. 30, the city fell short by .22 inches. But under the old system, which was based on consecutive days of 55-degree-or-higher dew points, we might have made it.

“Yeah, from the seasonal standpoint, they didn’t quite reach it,” said Selover. “But if we include what we had over the weekend, which was into October, then we’re pretty much right on the button.”

Pinning down the monsoon season’s end was often tricky under the old system. By the time the rain-bringing southerly winds shifted to drier westerlies, the Eastern Pacific hurricane season was revving up and dominant pressure patterns were shifting toward winter norms. The result: some pretty fuzzy boundaries.

“We never really know if it’s totally gone for a couple of weeks after it’s gone," Selover said.

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