MORE ON BAROMETRIC PRESSURE: I recently posted two articles on the effects of barometric pressure on fishing. Stefan forwarded me this page from Humminbird that attempts to further explain what happens when the pressure drops.
One nugget: "An incoming weather system and falling barometric pressure rapidly cools the lake’s surface water and the action of the raindrops pelting the water increase oxygen levels. This sudden mix of cooler water and increased oxygen triggers most fish and game to become quite active, which generally enhances their feeding instincts."