If Tuesday morning's inversion was lackluster by Interior Alaska standards, Wednesday morning's sounding looks a lot more like what we expect in winter. Temperatures above the valley floor have been rising since early Tuesday evening, and overnight the winds picked up. Nothing extreme, but enough to "mix it up". With clear skies under the big high aloft, the valley floor continues to cool, and the resulting inversion becomes self-reinforcing, isolating the valley surface from winds generated by the moderate pressure gradient. The result of all this are temperatures in the teens below in the usual cool areas on the valley floor (-15F at Goldstream Creek at 8am) to the teens above well up in the hills (+16F at Keystone Ridge at 8am). Fairbanks Airport has been down to 9 below thus far, the lowest of the season to date.
