(UPDATED 6 p.m.) The Sawmill Fire burning north of Sonoita is now estimated to be 18,000 acres in size and is expected to grow as strong winds grounded air tankers on Tuesday afternoon.

Meanwhile, residents in the J-6 Ranch area south of Interstate 10 are being notified by law enforcement personnel this afternoon that there may be a need to evacuate because of the fire. Officials said residents there should be preparing in case an evacuation order is given.

The fire, which started Sunday south of Green Valley near Madera Canyon, blew northeastward across the northern foothills of the Santa Rita Mountains. The fire was estimated earlier today at about 17,000 to 20,000 acres, but the size was changed later in the day after an aerial survey, according to officials.

It crossed Arizona 83 in two locations Monday night, said Heidi Schewel, spokeswoman for Coronado National Forest.

That highway, which connects Interstate 10 to Sonoita remains closed. Forest roads and trails in the area are also closed temporarily.