11. Without arctic air , Chicago clouds flourished within the moist confines of Pacific air. 12. Arctic air will surge into New England on brisk winds from the northwest.13. Sunday, daytime readings will edge above zero degrees as Arctic air slowly erodes. 14. It also blocks frigid arctic air that otherwise would spill southward. 15. At Portland, Arctic air arrived after draining west through the Columbia River Valley. 16. The stronger jet stream is also shouldering frigid Arctic air to the north. 17. Meanwhile, Arctic air will slowly retreat from the upper Middle West. 18. The Arctic air has settled in a wide section of the nation's heartland. 19. That's when the idea of a dome of arctic air seems most useful. 20. The blast of arctic air responsible for the white-out conditions will continue Saturday.
