Meteorologists said an upper-level system moving in from the west was expected to collide with a cold front moving down through the heart of New Mexico.
"This is kind of a unique setup in that we've got monsoon moisture in place for these storms to work with," said David Craft, a Weather Service forecaster in Albuquerque. "We are expecting the potential for anywhere from half an inch to an inch and a half of rain across much of northern New Mexico and central New Mexico."
The rain isn't expected to fall all at once, so forecasters have opted not to call for any flood warnings.
It was a different picture in the Northwest, where fire officials said it could be several weeks before any significant rain or snow dampens the numerous wildfires burning in Washington state.
"While we know we will get a season-ending event in the foreseeable future, it still looks like it's a little ways down the road," fire spokeswoman Connie Mehmel said.
In Seattle, a rain shower Sunday night dropped the first measurable moisture since July 23 at Sea-Tac Airport, ending a 48-day dry stretch — the second longest on record.
Mehmel said firefighters are stretched thin by the number of large fires in the state, but they're putting their best efforts into blazes that could threaten people and property.
Some residents just west of Wenatchee were allowed to return home Wednesday, but about 125 homes were still evacuated by a fire that had grown to more than 1,000 acres. Residents of dozens of other homes were told to be ready to flee if the fire grows.
Near Grand Coulee Dam, three homes and nine outbuildings were confirmed lost to two fires that have burned a combined 78,165 acres. That fire was 20 percent contained Wednesday.
Meteorologist Brent Bower said August and the first half of September are the driest part of the year for the Pacific Northwest.
This year, though, it's a bit drier than usual.
"If you're looking for good summer weather, and if that's defined by dry and sunny, August and September is what you're looking for."
He said wet systems are staying away from Seattle, but he expects rain to come back as September progresses. But for now, the sun will keep shining over often soggy Seattle.
"There really is no rain in the forecast," he said.
Billeaud reported from Phoenix. Associated Press writers Manuel Valdes in Seattle and Susan Montoya in Albuquerque, N.M., contributed to this report.
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