Water flows into the spillway at Agate Lake Reservoir Tuesday.

Warm weather finally arrived this week, and water from snowmelt won’t be far behind.

High temperatures in Medford rose into the 80s and 90s — with the chance of a heat record Saturday — which means the heavy snowpack in the mountains of southwest Oregon will be melting in the days and weeks ahead to help fill reservoirs.

“I think our best chance of actually breaking a record in Medford is (Saturday),” said meteorologist Tim Daldrup of the local National Weather Service office, when the high is expected to hit 90 degrees. It hasn’t been that hot on that day of the year since 1957, when it also was 90 degrees in Medford.

“Right now, we’re looking to match the record,” Daldrup said.

Lots of water is flowing in area creeks and rivers, which bodes well for fish, recreational users, agricultural irrigators, cities and industry. It’s flowing into reservoirs, too, with snowmelt adding to the flow.

Agate Lake, a reservoir near White City, is full, as it is most years. It is managed by the Rogue River Valley Irrigation District, which on Monday began flowing water through the district’s irrigation canals. Stream flow into the system is expected to be strong into early June, according to Brian Hampson, district manager.

“I think we’re going to be in pretty good shape,” he said Tuesday in a brief telephone call from Washington, D.C., where he, as president of the Oregon Water Resources Congress, joined others to lobby for funding.

Fourmile and Fish lakes in the Cascade Mountains feed the water district’s system. Hampson said he doesn’t expect them to fill, but time will tell.

“Snowmelt is important for those, as well,” he said. “We’re waiting. They’re better than past years.”

Most of Jackson County, except for its western edge, is experiencing moderate drought, according to the U.S. Drought Monitor website, which is maintained by the National Drought Mitigation Center at the University of Nebraska. Much of eastern and northern Josephine County is listed as abnormally dry.

Snow depth across Oregon is at 150% or greater than the median, according to the Natural Resources Conservation Service. Snow depth at 6,500 feet elevation at Crater Lake National Park was 146 inches Tuesday, compared with the average 95 inches, according to a Weather Service posting.

Snowmelt is expected to help fill Lost Creek Lake, about 30 miles northeast of Medford, and Applegate Lake, south of Jacksonville and near the Oregon-California border. Dams at those reservoirs are managed by the U.S. Army Corps of Engineers.

“Things are way better in the Rogue than it has been, with some nice snowpack above both projects,” said Salina Hart, reservoir regulation and water quality section chief for the Corps. “We’re looking really good.”

Applegate and Lost Creek reservoirs, built primarily for flood control, provide recreational opportunities on the lakes and cool water for fish downstream, as well as irrigation water for farmers and ranchers, and water for city and industrial users.

Hart, speaking via telephone from her office in the Portland area, said she expects Lost Creek Lake to fill by June 1, a month behind schedule, and Applegate Lake to fill by early May. As of Tuesday, Applegate lake was at 87% full, while Lost Creek Lake was 77% full.

“Applegate is just looking really good,” she said. “At Lost Creek, it’s looking like it’s going to be a late season (to fill). We’re waiting for some of that melt to happen.”

Ideally, Lost Creek Lake would be a bit more full, she said, but there’s flood danger if rain and snowmelt overfill the reservoir.

“You’re constantly balancing,” she said. “You don’t want no storage.”

At the same time, “Being full is great for recreation,” she said.

Fill levels at other lakes as of Tuesday included Fourmile Lake, 33%; Fish Lake, 46%; Emigrant Lake, 59%; Howard Prairie Lake, 30% and Hyatt Lake, 28%, according to the U.S. Bureau of Reclamation.