The region’s dry, hot spring resumes this week after a brief pause for below-normal temperatures. That means Southern Arizona’s grasslands and forests will continue to dry out.

Land managers warn that a single spark can start a big blaze. It could reach 100 by the end of the week as April continued this year’s run of record-breaking temperatures — the hottest March on record, followed by the fourth-warmest April and scant rain totals, according to the monthly climate report of the National Weather Service in Tucson.

February rain totaled 0.21 inches. March did not produce a measurable amount. May and June historically produce little rain and a lot of heat. That’s not a good combination for our vast stretches of public lands. Lower-elevation grasslands are thick with explosively dry fuel as we head into the hottest months of the year.

“The Sawmill Fire demonstrated the fire potential out there this year,” said Michelle Fidler, spokeswoman for the interagency team that fought wind-driven flames as the fire raced from just southeast of Green Valley nearly to Benson last week.

By Monday, the 47,000-acre Sawmill Fire was 94 percent contained and was turned over to a small fire-fighting force for monitoring.

“Things are very dry in the grasslands,” said Heidi Schewel, a spokeswoman for the Coronado National Forest. “We’ve been accumulating fuel for several years, which, as we’ve just seen, is ready to burn.”

The forests atop the Coronado’s Sky Island mountain ranges are in better shape after some decent winter rains, but have plenty of time to dry out before monsoon rains arrive in July, she said.

“It’s going to continue warming up throughout the rest of the week with a chance of hitting 100 degrees on Friday,” said meteorologist Aaron Hardin of the National Weather Service in Tucson.

A storm system Saturday will bypass Tucson, with slight rain chances for the eastern edge of Arizona. Hardin said a second system brings a chance of rain to Tucson on Monday.

“For us to see any relief, it would have to be a significant storm,” said Schewel. Meanwhile, land managers are “keeping an eye on everything, especially in high-traffic areas where people can create sparks.”

The national Climate Prediction Center says the Southwest has an enhanced probability of higher-than-normal temperatures. On Monday, the National Interagency Fire Center said Southern Arizona has an above-normal “significant wildland fire potential,” for both May and June.

The effects of the Sawmill Fire are evident in this grassland area near Empire Ranch Road and Arizona 83, north of Sonoita. The dry weather could lead to more fires, land managers say.

Contact: tbeal@tucson.com or 573-4158. Follow him on Facebook or on Twitter: @bealagram