Southern California’s trend of rainy weather is expected to resume this week after several dry and unusually warm days. The National Weather Service says a few disturbances will move through Friday and Saturday, bringing rain and mountain snow. The second system arriving Saturday will be very cold and snow levels may affect travel through mountain passes. Just as the recent strong El Nino ocean-warming phenomenon failed to bring rain to Southern California, the ocean-cooling known as La Nina hasn’t lived up to expectations of drier than normal weather.