Sunday, August 11, 2013

Canadian Ridge

**Update 6 pm AKDT Aug 12** Eagle airport is reporting 90 °F at this hour - the hottest ever recorded in Eagle so late in the season.  So we have a significant record after all.

**Update 6 am AKDT Aug 12**  Eagle dropped to 54 °F by midnight, so the 24-hour minimum was 54, not 60.  No records broken.  Also, there appears to be little doubt that the September 1995 temperatures were correct.  The Eagle RAWS data show hourly temperatures of 60 or above, with a southeasterly breeze, from 6 am on the 20th to 7 pm on the 22nd.  The Eagle COOP observations were taken at 7 am, so the numbers match very well; in fact the midnight-to-midnight lowest hourly reading at the RAWS was 67 for the 21st.  Also, numerous other interior Alaska sites reported minimum temperatures of 60 or above on the 20th and 21st, including 63 at North Pole on both days, and 65 at Fairbanks airport and Eielson AFB on the 20th.  Clearly the 1995 event was an extreme outlier for the time of year; it probably deserves its own write-up. **End of Update**

Extremely warm air continues to reside over northwestern Canada under a persistent upper-level ridge.  Close to the border, Eagle airport recorded an overnight minimum temperature of 60 °F last night, which is the highest recorded so late in the season except for a remarkable pair of readings in late September 1995.  The all-time highest minimum temperature at any of the Eagle stations (as far as I can tell) is 64 °F in that 1995 event, which admittedly looks somewhat suspect and deserves further investigation.  Minimum temperatures of 60 °F or above are quite rare in Eagle, as I'll show in a subsequent post that I'm working on about the climatology of high minimum temperatures.

Elsewhere in northern Alaska, there was a hint of autumn in Bettles this morning, with fog and 37 °F.  The median date for Bettles to first reach 37 °F or lower in the late summer is August 10, so this is right on schedule.


  1. The September 30- October 2nd chinook of 2003 was quite amazing also. I remember mid 70's. (although the temporary valley inversion would pop up during the night and it would drop off into the high 40's)

  2. Mike,

    Yes - that event brought the only 70+ temps ever recorded in October in Fairbanks. The previous monthly record (post-1929) was 65. According to Rick, the event also produced the October state record high at Dry Creek (76 F).