The break-up of low-level cloudiness over Fairbanks yesterday allowed lower-atmosphere temperatures to drop smartly from mid-morning on, with the result that the surface-based inversion was pronounced by early this morning (see below).
This morning's low temperature of -31 °F, which may yet be broken before midnight tonight, is slightly unusual for this early in the season; the -30° mark is reached by this date in only about one quarter of years - and less often since the 1970s. More unusual is today's high temperature of only -22 °F; cold of this degree has occurred this early in the season in only six years since 1930. Interestingly, some years (six of them since 1930) never produce a day this cold throughout the entire winter.
Across the border in Dawson, upriver from Eagle, today's high temperature of -41 °F was within one degree of the coldest on record for so early in the season, with historical records back to 1900 or so.
The typical winter wind driven Tanana Jet commeth. See the dark IR signature of relative E-W flow and warm air in the Tanana River Valley north of the Alaska Range:
ReplyDeletehttp://pafg.arh.noaa.gov/arhdata/sat/hrpt/13325143034/4f1f.jpg
Gary