BOISE, Idaho (AP) — Two small but unseasonably early fires burning in California's wine country likely are a harbinger of a nasty summer fire season across the West.

Officials with the National Interagency Fire Center in Boise said Wednesday in their first 2013 summer fire outlook that a dry winter and expected warming trend mean the potential for significant fire activity will be above normal on the West Coast, in the Southwest and portions of Idaho and Montana.

"We're looking at a combination of a low-moisture winter and a warming and drying pattern in the West that will increase the fire potential," said Ed Delgado, predictive services manager.

If that sounds familiar to the region's residents, it should.

In 2012, record-setting fires raged in New Mexico and Oregon, while destructive Colorado blazes torched hundreds of homes amid one of the state's worst seasons in years.

Just like last year, Colorado experienced some of its first 2013 wildfires in March.

Outside the West, however, much of the U.S. is expected to experience normal fire conditions, with below-normal danger in the South where significant, long-duration rains saturated the landscape since Jan. 1, Delgado said.

In California, wine-producing counties Napa and Sonoma experienced early-season blazes Wednesday, as warm temperatures, low humidity and gusting winds through already-dry foothills areas east and north of San Francisco led to warnings of extreme wildfire conditions.

Both were more than half-contained, according to crews.

The culprit behind a California fire season that's a month ahead of schedule? A winter where only 40 percent of normal precipitation fell and scant spring rain that typically greens up hillsides and pushes fires back into summer.

California's "precipitation pretty much shut off at the beginning of the year," NIFC wildland fire analyst Jeremy Sullens said during a telephone conference with reporters. "Since they're not expecting a lot more precipitation for the remainder of the summer, conditions are going to worsen as we go into the hotter part of the year."

In Arizona, a nearly-square mile wildfire near the Chino Valley had state forestry officials busy Tuesday, as the fire rolled through grass and brush. The National Interagency Fire Center says there's likely more to come across the Southwest.

"Above normal significant fire potential will develop across much of the southern halves of New Mexico and Arizona in May," the report concluded.

In Northwestern states, cool temperatures and rain in April mean May will be mostly quiet. That could change quickly.

"Warmer and drier conditions beginning in June will quickly elevate significant wildland fire potential to above normal across southern and eastern Oregon and portions of south central and southeastern Washington," the fire center said.

And in the Northern Rockies including Idaho and Montana, fire danger is forecast at near normal through May and June, before escalating in July and August to above-normal potential.

Idaho is also coming off one of its worst-ever fire seasons in 2012, with 1,151 wildfires tallied and a nation-leading 1.7 million acres, or 2,600 square miles, burned.

Nevada also is in the grip of a drought, but persistent lack of moisture has stunted fuel growth, Sullens said.

The same goes for southeastern Oregon's open ranching country, where massive range fires last year torched great swaths of ground, including the state's biggest blaze in a century, July's Long Draw Fire.

"There's still a potential, but it's less than it was last year," Sullens predicted. "Nevada isn't really included in the above-normal fire potential."