The layoffs at Northwest Airlines are about to get serious. An airline spokeswoman says, by the end of the day, Northwest will let go 162 dispatchers and 15 meteorologists. The spokeswoman, speaking to a Minneapolis radio station, said the layoffs came as the pilot strike is in its fourth day, grounding the airline. Northwest will revisit the issue of layoffs of flight attendants tomorrow. A Teamsters spokesman said earlier that Northwest has put off plans to furlough flight attendants. Meanwhile, Transportation Secretary Rodney Slater called a meeting in Washington this afternoon between Northwest and the pilots’ union to get the negotiations back on track.