Students exit Howard High School on Monday. Howard's first day enrollment count was down by about 200 students, but Principal Zac Brown expects it to return to normal within the next week.

Hamilton County's school buses ran a little lighter Thursday, as fewer kids showed up for classes on the first day of school.

The system's first-day enrollment count came up 320 students lower than last year's first-day count. Collectively, high schools were down 367 students, with one campus -- Howard -- accounting for more than half of that. Elementary enrollment fell by 47 students. Middle school enrollment, however, was up by 94 more students this year.

That left a systemwide enrollment of 40,035 on Thursday, down from 2012's first-day count of 40,355.

"I was disappointed in our high school numbers. We want our kids to show up on the first day. And we've still got kids showing up today," Superintendent Rick Smith said Monday.

But with more kids trickling back into schools, administrators expect the next official head count on Wednesday to be much higher. It usually takes several days or even weeks for all kids to come back to school in Hamilton County. And this year's relatively early start might have played a role in fewer kids making it back to school on time.

"We're going to be excited to see the fifth-day report," said Assistant Superintendent Lee McDade.

The district doesn't expect to see another year of huge growth, though he said officials are estimating a net gain of 100 to 300 students overall. Last year's 20th-day enrollment count of 42,705 was the highest in recent history and a total increase of about 500 students over 2011.

Enrollment counts matter because school officials set schedules and staffing levels based on how many kids show up to each school. While it's a good barometer of attendance, the first-day count isn't all that important. The 10th-day count determines staffing levels at each school, grade level and subject area, the superintendent said. And the 20th-day count is what sets funding levels for the school district.

High schools were down the most students on Thursday, though about four schools were mostly responsible for the big dip. Central High was 68 students lighter than last year. Soddy-Daisy was down 99 students. Brainerd High was 108 students short. And The Howard School's first-day enrollment of 323 was down by 200 students from last year's count of 523.

Howard Principal Zac Brown said the low number wasn't much of a concern. He suspects starting school in early August is partly to blame. And each day, more and more students are coming to school.

"We've definitely been seeing an increase since Thursday," Brown said. "I think it's just a first-day thing."

Contact staff writer Kevin Hardy at khardy@timesfree press.com or 423-757-6249.