WASHINGTON - And the heat goes on. Forecasters predict toasty temperatures will stretch through the summer in the U.S. And that's a bad sign for wildfires in the West.

The forecast for June through August calls for warmer-than-normal weather for about three-quarters of the nation, the National Oceanic Atmospheric Administration said Thursday.

The warmth is expected south of a line stretching from middle New Jersey to southern Idaho. Only tiny portions of the northwestern U.S. and Alaska are predicted to be cooler than average and that's only for June, not the rest of the summer.

Last May until April was the hottest 12-month period on record for the nation with records going back to 1895. This year so far has seen the hottest March, the third warmest April and the fourth warmest January and February in U.S. weather history. And it was one of the least snowy years on record in the Lower 48.

Some people called it the year without winter.

And the outlook for summer is "more of the same," said Jon Gottschalck, head of forecast operations at NOAA's Climate Prediction Center in Camp Springs, Md. "There's definitely a tilt toward being above normal through the summer."

For some areas of the Southwest that could mean temperatures 1 or even 2 degrees warmer than normal on average, and maybe close to half a degree warmer than normal in the East, he said.

One of the reasons is that much of the country's soil is already unusually dry. So the sun doesn't use as much energy evaporating water in the soil and instead heats up the air near the ground even more, Gottschalck said.

Forecasters say the combination of the heat and dryness will only make western wildfires worse. The fire season has already gotten off to a dramatic start. Wildfires in northern Arizona and northern Colorado forced residents to flee their homes on Thursday.

Fires in those areas could be even worse today, said Greg Carbin, the meteorologist who coordinates warnings at the Storm Prediction Center in Norman, Okla.

"To see fires to the extent that they are this early isn't a good sign," he said. And the summer forecast is for "a pretty significant wildfire season developing across the western United States."