The downturn in SAT scores by last year's seniors may soon reverse as the Washington area saw an increase in National Merit semifinalists, students recognized for top scores on the PSAT exam.

It was a record year for Fairfax County Public Schools, whose 234 semifinalists toppled the county's 2009 record of 219, as well as last year's 189.

When it comes to National Merit, Fairfax tends to rise and fall with Thomas Jefferson High School for Science and Technology, a magnet in Alexandria consistently ranked as the nation's best public school.

Two-thirds, or 156, of the semifinalists attend "TJ." The remaining third were spread among 18 high schools.

Montgomery County Public Schools also enjoyed 170 semifinalists, an increase of 13 over the previous year.

"We are very proud that so many MCPS students have been selected as National Merit semifinalists for 2012," Superintendent Joshua Starr said. "Their outstanding academic performance is a testament not only to their hard work, but also to the dedication of MCPS staff to the mission of preparing all of our students for success in college and careers."

Montgomery Blair High School, which offers several magnet programs in Silver Spring, topped the district with 44 semifinalists, followed by Richard Montgomery High School in Rockville with 39. Students in 12 other county high schools also claimed honors.

Ten students in Arlington County Public Schools were named semifinalists, there were five semifinalists at Alexandria's T.C. Williams High School, and D.C. Public Schools' semifinalists doubled -- from one, to two. School Without Walls Senior High School in Foggy Bottom celebrated a semifinalist for yet another year, and a student at Woodrow Wilson Senior High School in Tenleytown was recognized.

The top 1 percent of juniors on the PSAT are qualified to win scholarships from the National Merit corporation.

The National Merit corporation estimates that 90 percent of semifinalists will become finalists eligible for 8,300 scholarships worth more than $34 million, some open to all students, some available only to black or Hispanic students, and others given through colleges or corporations.

Finalists will be announced in the spring. - Lisa Gartner