cpc winter weather prediction u climate prediction center winter outlook climate prediction center unit national oceanic atmospheric administration discusses outlook winter agency expect el nino la nina affect global weather next nine months two weather patterns occur changes ocean temperatures pacific ocean directly influence us rain patterns land temperatures cpc says winter first year three us strong influence particular climate driving force mean whole lot difference terms winter start something temperatures la nina el nino tended make temperatures moderate winter cpc expects winter nationwide average still slightly warmer normal warm last three northern part nation particularly northeast however could exception colder weather warmer pattern confined west south east mississippi exception florida cooler winter california northern half rockies dakotas fall winter expect southwest mild dry