Valley storm brings cool-down, rain and hail

The Valley under gray skies as a steady drizzle falls. Memorial Day vacationers heading to the Rim Country for some fun in the snow. A remarkably strong storm, perhaps historic, made for some wildly unseasonable weather across the state on Thursday.

Record-breaking rainfall, hail-dropping thunderstorms and temperatures about 30 degrees cooler than normal were reported in the Valley. In northern Arizona, snow fell in late May for only the ninth time in the last 110 years.

Areas that saw the most rain were in the southeast Valley, where totals ranged from an inch to almost two inches. Rainfall totals in Mesa were less than an inch and parts of Scottsdale saw only sprinkles.

And this was only the beginning, meteorologists predicted. The forecast peak time for thunderstorms was 11 p.m. Wednesday through 11 a.m. today.

By the time this low-pressure system exits on Saturday, much of the Valley will have received about a half-inch of rain. In the high country, snow accumulations could reach 6 inches.

And all this just three days after Valley thermometers reached 110 degrees.

A storm of this magnitude would be notable if it arrived in January, weather experts said. But its presence in midspring is almost unheard of.

The National Weather Service’s office in Phoenix said this could be the most intense storm to strike Arizona during May.

Even if it isn’t historic, this weather is highly unusual; any rain falling today will be only the second time that May 23 has seen precipitation in Phoenix’s recorded history, which goes back to the 1880s.

Also, the meteorologists noted the Valley’s 30-year average for precipitation for the month is 0.16 inches. But this storm could dump in excess of an inch in parts of the Phoenix area.

A rain gauge in Queen Creek took in 0.71 inches by midafternoon Thursday.

At Phoenix Sky Harbor International Airport, the Valley’s official station, 0.03 inches were recorded by 4 p.m. The record was 0.06 inches, set in 1919, but the weather service expected that to fall. Also, hail measuring a half-inch across was reported in south Chandler.

Meanwhile, the Valley’s official high temperature was 78 degrees — and that was recorded shortly after noon, right before the storm rolled in. At 2 p.m., the “high” was 64 degrees; the daily normal is 96.

Responsible for the weird weather is a large low-pressure system parked over the Southwest. This is the same storm that sparked damaging tornadoes in northern Colorado on Thursday morning.

It also brought gusts of 50 mph to west Texas, dropped 2 feet of snow on the mountains of Montana and created flash floods outside San Diego.