Kaufman Bros. analyst Shaw Wu told clients today that a check of the distribution channel suggests that MacBook Pro supplies are tight and that a refresh of the laptop line is due soon.

He expects the next rev of MacBook Pros to use that Intel's next-generation mobile processor, Arrandale, which is shipping in large volumes. Wu sys the processor will deliver some new features that will help Apple engineers differentiate their laptops from other portables on the market.

"Benefits of the new mobile architecture, helped in part by its new 32 nanometer process (vs. previous 45 nanometer), include much better performance through hyper-threading and turbo mode, battery life, and weight characteristics, which we believe give AAPL engineers more room to further differentiate the MacBook Pro," the analyst said."We believe new Mac models could ship in the March quarter, or at the latest the June quarter. It is not clear to us whether AAPL will introduce these new Macs through special event or 'quietly' through a press release."

Wu also thinks the next MacBook Pros will add automatic switching of dual graphics modes. This would allow switching between integrated and discrete graphics processors automatically.