The largest active wildfire in the U.S. is nearing 50% containment, according to New Mexico fire authorities. 

More than 3,000 personnel are working to battle the 312,057-acre blaze which has been burning for seven weeks. 

The effort to fight the Calf Canyon and Hermits Peak Fires has been aided by cooler weather and rain over the last few days. 

The U.S. Forest Service warned that critical fire weather would return Friday and continue through the weekend. 

NEW MEXICO FIRE SLOWED DUE TO RAIN, MOUNTAIN SNOW

It said residents of San Miguel, Mora, Taos, Colfax and Santa Fe Counties should remain on high alert for changes to evacuation statuses and road closures.

The agency said to expect higher temperatures, gusty winds and continued dry air.

New Mexico

A helicopter launches on its way to deliver supplies to hotshot crews on New Mexico's Calf Canyon and Hermits Peak Fires. (Credit: U.S. Forest Service)

The National Interagency Fire Center's Predictive Services noted Thursday that areas of moderate to severe drought have worsened to severe to exceptional status across the Southwest.

"Drought impacts are worsening and contributing directly to the increasing fire danger values. Conditions like this have not been seen since the mid-1950s," its advisory noted. 

ABOVE-AVERAGE HURRICANE SEASON FORECAST BY NOAA

The National Weather Service issued fire weather watches for the region on Saturday.

The Forest Service also noted that some residents of evacuated communities are repopulating – some using recreational drones nears the fires. 

"If you fly, we can’t – If any drones are launched in the Temporary Flight Restriction zone, all firefighting aircraft will be grounded immediately," they explained. 

The most recent incidents took place earlier this month on the Cerro Pelado Fire. 

There are more than 6,100 wildland firefighters and support personnel assigned to fires across the U.S. 

Western wildfires have become a year-round threat.

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Scientists and fire experts say they are moving faster and burning hotter than ever due to climate change.

The Associated Press contributed to this report.