DENVER — Haze over the Denver metro area on Thursday was being caused by smoke coming from fires in southern Colorado, New Mexico and Arizona, the National Weather Service said.

A 500-acre fire is burning near Fort Carson’s training grounds near Colorado Springs, and southwest winds are bringing the smoke north into the metro area.

Smoke haze and odor effecting SMFR's area now. This is from out of area wildland fires. No active fires in Parker, Castle Pines or DTC.

— South Metro Fire Rescue (@SouthMetroPIO) June 16, 2016

The Colorado Department of Public Health and Environment issued an alert for the smoke.

“Smoke and haze are also likely across large sections of south-central and southeastern Colorado due to several wildfires currently burning in Arizona and New Mexico,” the alert said. “Smoke will be most apparent during the morning hours, then dissipate during the afternoon as atmospheric mixing increases. Smoke will decrease at a slower rate for locations along the Arkansas River Valley.”

Besides the Fort Carson fire, the Dog Head Fire near Albuquerque has more than doubled in size to more than 12,000 acres. And the Cedar Creek Fire in east-central Arizona has charred about 8,000 acres.