Much cooler weather is in store Friday as onshore winds increase and clouds begin filling in from the west. Highs will be mainly in the 60s and 70s across the Bay Area with a few lower 80s for areas south of San Jose. A chance for some showers will increase for areas north of San Francisco by evening before spreading southward over the rest of the Bay Area for Saturday. As cooler air aloft rotates through during the day Saturday, we ll see at least a chance for brief isolated thunder in the North Bay hills, while off/on showers continue into the afternoon. Most of the showers should be done overnight Saturday with drier conditions expected by Sunday. Highs will rebound slightly for Sunday, but things will still feel cool with brisk NW winds at times into early next week. Rob Mayeda reports.