The biggest storm so far this winter is headed for the Sierra Nevada, with up to 2 feet (0.6 meters) of snow possible in the mountains by early Friday and winds potentially gusting in excess of 100 mph (161 kph) over the ridgetops. On Wednesday, the National Weather Service upgraded a winter storm watch to a winter storm warning in effect from 4 p.m. Thursday to 4 p.m. Friday for the greater Lake Tahoe area stretching north of Reno to Susanville, California.