Dust storm rolls through Phoenix overnight, excessive heat continues

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PHOENIX – Mother Nature took another swipe at the Valley, delivering the fourth major dust storm of the monsoon early Wednesday morning, which was also one of the warmest mornings we've seen in some.

The storm slowly rolled across the Valley between 1 a.m. and 3 a.m., leaving dust hanging in the air hours later. Some early morning commuters thought the dusty haze was fog.

While many people might have heard the wind, they didn’t realize another dust storm had hit until they saw the layer of dust on their cars.

The National Weather Service issued a dust storm warning just before 1 a.m. The storm pushed up from the Tucson area through Pinal County and into Phoenix metro area, bringing high winds and lots of dust.

It was mostly over by the time “Good Morning! Arizona” went on the air at 4:30 a.m., but there still was some thunderstorm activity in Pima County, as well as some light shower in Pinal County. That storm activity was dying down as the sun came up.

Because it happened in the middle of the night, it’s difficult to compare the severity of Wednesday morning’s dust storm with the previous three storms.

Such storms typically form to the south of the Valley during the afternoon hours, which means we see the wall of dust in the evening commute. Still, nighttime dust storms are not rare. According to research by the 3TV Forecasters, about 30 percent of them happen between the hours 10 p.m. and 6 a.m.

In addition to the dust left in the air, heat also is going to be an issue Wednesday. For the second day in a row, we are under an excessive heat warning.

After a high of 113 on Tuesday, the overnight low from Tuesday into Wednesday was an extremely warm 91 degrees. Assuming the mercury does not drop below that before midnight Wednesday, that will be record -- the hottest low temperature for this date.

Plan on a high between 112 and 114 degrees on Wednesday. That excessive heat warning will remain in place through Thursday night.

An ozone health watch also has been issued by the Arizona Department of Environmental Quality for Wednesday.

People who are particularly sensitive or who suffer from respiratory conditions are advised to limit their outdoor activity.