NEW YORK (AP) - Shipments of notebook computers edged passed desktop sales in the third quarter for the first time, according to data from the research firm iSupply.

Preliminary figures for the quarter show notebook PC shipments shot up about 40 percent from the same period a year ago to 38.6 million, according to iSupply. Meanwhile desktop shipments fell about 1.3 percent to 38.5 million.

The numbers underscore a broader shift toward portable computing as more functions like e-mail and Web surfing migrate to mobile phones and the popularity of inexpensive "netbooks" used mainly for Internet access grows.

"The trend has accelerated and will continue going forward," AmTech Research analyst Dinesh Moorjani said.

He expects computer makers to ratchet down production of desktops by 20 percent in the fourth quarter while notebook production should remain flat.

The research firm IDC also predicted this month that sales of laptops would fair better amid a deepening recession. IDC projects portable PC shipments will grow by 15.2 percent in 2009, while expecting a 6.7 percent decline for desktops and servers using PC microprocessors.