(UPDATED, 3:51 p.m., with details on West Ada’s reopening plan, and Boise’s timetable.)

Local health officials say the state’s two largest school districts can open their doors — at least part-time.

And West Ada School District students could be back in school in less than a week.

On Tuesday, the Central District Health department moved Ada County schools from the “red” Category 3 for coronavirus transmission to the “yellow” Category 2. That means coronavirus rates have dropped enough that CDH recommends a mix of online and face-to-face instruction.

The CDH recommendation is nonbinding. In Idaho, school districts — and not health districts — decide whether to open buildings for in-person learning. But the West Ada and Boise school districts have both tied their revised reopening plans to the CDH guidelines.

West Ada’s reopening is slated for Monday. The district will allow pre-kindergarten and kindergarten students into school full-time, while first- through 12th-grade students will attend school every other day, on an alternating schedule. All of West Ada’s 40,000 students will take online classes through this week.

In Boise, the transition might take more time. Under its proposed plan, Boise could allow pre-K through second-grade students back in school as early as Sept. 21, on a part-time basis. Boise has said it hopes to open its doors to third- through sixth-graders on Oct. 5, and reopen junior high schools and high schools on Oct. 19 — again on a part-time basis. The district will take public comments on the plan through noon Wednesday and make a final decision Thursday.

But on Tuesday, Superintendent Coby Dennis said he was just to see Boise’s reopening plan move one step closer to reality. “Of course, we are hopeful everyone will continue to implement the basic precautions that have helped so far,” he said in a news release.

CDH’s announcement Tuesday was not a surprise. New coronavirus case numbers have been tapering off in Ada County for a couple of weeks, and last week, CDH officials hinted that they might roll back the county’s designation after the Labor Day holiday. On Thursday, the CDH board linked a plan to reopen bars to the school reopening plan.

Since Aug. 3, CDH has recommended online-only instruction in Ada County schools — drawing a mixed response from districts.

Boise opened for the year on Aug. 17, with online-only learning for its 25,000 students. West Ada delayed the start of the school year. Tuesday was opening day — with a rocky online-only launch for its 40,000 students.

Kuna, however, opened its doors on Aug. 31 with a hybrid schedule, with students attending two days of in-person classes each week. On Friday, the district reported two confirmed coronavirus cases and a third, probable case. The district has an enrollment of about 5,500.

CDH has four counties in its jurisdiction: Ada, Boise, Elmore and Valley counties. The department Tuesday moved Valley County schools into the “green” Category 1 for coronavirus transmission — recommending that McCall-Donnelly and Cascade schools can open full-time.

That in itself is a departure. Earlier this summer, CDH suggested it was unlikely it would move any county into Category 1 for the entire 2020-21 school year.