Saturday, August 25, 2012

Why So Warm on the North Slope?

Courtesy of NCEP/NCAR Reanalysis
Long time reader Trung asked why it has been so warm on the North Slope this summer. The obvious answer would be that the record low sea ice coverage, but that in fact is probably only a small part of the answer. Ice has actually been more persistent in the Chukchi and far western Beaufort Sea than it has been in a few years, though what's left is rapidly melting now. More important has been the persistent trough aloft centered along about 170W longitude, the same feature responsible for the copious rains over much of western Alaska and the quasi-drought in the Interior. This can be seen in graphic to the right, which shows the mean wind direction (arrows) and speeds (color) at 700 mb (about 3000 meters above the ground) for July 1 through August 20 (speed units are meters per second). South winds blowing across the Brooks Range warm and dry as they descend onto the northern plain in a classic "chinook" effect. Barrow has had 15 days with a daily high temperature above 60F, which ties with 1989 and 1936 for the most such days. It is possible that  a new record could be set in the next ten days or so.


  1. Thank you for this very informative post explaining the unusually warm conditions in the North Slope. Looks like things are back to normal now in the interior.

  2. Also is it possible to get rid of the word verification to post comments? It takes forever to get the right words from those jumbled letters and so annoying....