For more fascinating facts about regional weather, visit Columbian weather blog.A series of wet weather systems are expected to wrap up an uncharacteristically dry December in Clark County, according to the National Weather Service.Rain was forecast to begin late Monday. said Rodger Nelson, a meteorologist with the weather service in Portland. It will continue for the next six days, along with warmer temperatures, Nelson said.“We’ll have rain pretty much through New Year’s Day, with short dry periods in between,” Nelson said.About an inch of rain is expected to fall during the course of the seven days, he said. Temperatures are anticipated to climb to the lower 40s at night and daytime highs will be in the mid- to high 40s, he said.“We are finally getting into our winter weather pattern,” he said.Tuesday has a 100 percent chance of rain, a projected low of 44 degrees and high of 45 degrees, according to the weather service.A ridge of high pressure in the skies above the region has pushed wet weather to the north and south during the month. That high pressure has now moved to the east, enabling rainy systems to migrate in, Nelson said.Despite the rainy conclusion to 2011, December could still attain the distinction of the driest on record in the Portland metro area, Nelson said.“We’ll have to wait and see,” he said.As of early Monday, Vancouver’s Pearson Field has had a third of an inch of rain this month, 5.16 inches less than the December average, he said. The average rainfall for December is 5.46 inches.