As westerners start to enjoy moderating temperatures after record snowfalls and intensely cold conditions, another round of bitterly cold arctic air may be on the horizon by late next week.
Latest forecast models continue to suggest a repeat performance, with a similar pattern of cold air aloft diving south on a powerful jet stream with frigid temperatures once again likely as far south as southern California shaping up just before next weekend.
Unusually strong surface high pressure prevailing over western North America and along and off the U.S. west coast continues to support development of cold upper air disturbances which drop rapidly south, and strengthen. While available moisture tends to be somewhat limited, significant snowfall and blizzard conditions are once again a possibility over a multi-state area stretching from Montana southward across Wyoming, Utah and Colorado beginning Thursday morning, December 19.
These conditions may spread south and east into the mountains of Arizona and New Mexico over the first weekend of official winter, Dec. 21 – 22.
It is still to early for accurate estimates. But this does appear to be a significant developing situation.
Strong northerly winds and below normal temperatures in California typically occur with this pattern. In Los Angeles, Santa Ana winds can reach peak velocities of 50 to 60 mph across mountain passes and canyons, prompting wind advisories and warnings.
Present precipitation models suggest California should remain dry with this event, being to the west and south of projected areas of rain and snow.