An Analysis of the Classic Arctic Outbreak Event of Late December 2008-Early January 2009
By Christian M. Cassell
Stratospheric Role |
The 2008-2009 winter was characterized by colder than normal temperatures and above normal snowfall for each month from October through March. While there was no one significant snow event that overshadowed any other this past winter, a bitterly cold Arctic outbreak that persisted for more than two weeks brought the coldest temperatures in a decade to the Anchorage area, and grabbed headlines around the world for extreme cold in interior parts of the state. This analysis will show how the outbreak developed and how it was able to persist for a prolonged period of time.
*-Indicates a record low value for that particular date.
1.    Summary of temperatures and records from the outbreak
The following chart is a breakdown of temperatures and extremes at Anchorage during the two week Arctic outbreak.
**-Indicates tying or setting of the lowest temperature of this decade (2000-2009).
Though it is arbitrary as to when the outbreak began and ended based on the numbers, the temperature at Anchorage dropped below zero degrees during the evening hours of December 29th, and remained below zero until January 8th except for a one-hour period during the afternoon of January 5th when the temperature managed to make it to 0.4 degrees briefly during the mid afternoon hours. This represented the longest streak of sub-zero days since 30 January . 5 February 1999.
Additionally, the eleven-day streak (29 Dec . 8 Jan) with the minimum temperature falling to
-10 degrees or lower from the official reporting station at the National Weather Service office on Sand Lake Road was the longest such streak since 17-29 December 1961. Therefore, while there were no record low minimum temperature values set at the official temperature station in Anchorage, the duration of the cold in terms of minimum temperatures at or below -10 degrees was the longest such stretch in 47 years.
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Stratospheric Role |