December was an extraordinary month weather- and climate-wise in Alaska. Cold weather from November persisted into the first week of the month, but by mid-December, massive high-pressure aloft over the north Pacific brought a sustained flow of subtropical moisture from near Hawaii north into western Alaska before turning east into southwest and then Interior Alaska. Over a large portion of western and northern Alaska, December precipitation totals were 2-5 times average and were the highest on record at most of the locations with a century or more of climate observations. However, the same pattern kept moisture away from the Gulf of Alaska coast and Southeast, resulting in unusually low precipitation for the month. Except for parts of Southwest Alaska and all of Southeast, the wide variation in temperatures in many areas resulted in December average temperatures not too far normal. At Bethel, the turnaround from November was remarkable, with the December average temperature of 18.6°F an unprecedented 18°F higher than the November average temperature. Persistent low clouds, fog, rain, and icy runways and ramps stranded hundreds of people in Bethel for days who trying to get home for the holidays. Open water and breakup-like conditions were reported during the last days of the month on Tuluksak River upriver from Bethel. In the eastern Aleutians, Unalaska Airport reported a remarkable 11 days during December with a high temperature of 50°F or higher in the nearly continuous southerly flow of air.
展开▼
