It’s personal.

The teachers union launched a million-dollar TV ad blitz yesterday attacking Mayor Bloomberg for pushing to repeal the “Last In/First Out” state law that requires teachers be laid off based on seniority rather than merit during a budget crisis.

The spot argues that Bloomberg should support extending a state-tax surcharge on the wealthy to prevent teacher layoffs.

Rubbing road salt in the wound, the ad refers to the infamous December blizzard that crippled the city because the government was unprepared.

“Instead of making his number one priority to attack teachers, the mayor should join our effort to extend the millionaire’s tax,” said United Federation of Teachers president Mike Mulgrew.

A Bloomberg spokesman said, “While the UFT fights for its self-interest, the mayor will continue to fight for our children’s future.”