There was a dramatic difference in the temperatures experienced in the valleys and mountains of northern Utah this January. The National Weather Service reports that January 2013 was the coldest month at the Salt Lake City airport since 1949, the 6th coldest January since 1874 (presumably the late 19th and early 20th century observations are from Salt Lake City proper), and the 9th coldest month of any month since 1874.
The NWS has some very nice graphs on their web site showing the departures from the daily averages, but I need to cook something up for comparison with Alta. Thus, the image below shows the temperatures observed at the Salt Lake City International Airport during January (red line) compared to the average (1948–2012) maximum and minimum temperatures for the month (enclosed by green box) as provided by the Western Region Climate Center. Note the prolonged periods of well-below average temperatures in early January and mid January, both of which were associated with inversions.
|Salt Lake data source: MesoWest|
|Alta Guard data source: MesoWest.|
This illustrates one of the paradoxes of northern Utah weather and climate. During winter, when under the influence of a large-scale upper-level ridge, it is possible to have below average temperatures in the valleys and above average temperatures in the mountains. The contrast can become most exaggerated when there is a deep snowpack in the valleys. Consideration of these effects is important for those who utilize long-term climate statistics in Utah and surrounding states that also see strong valley inversions and cold pools.