Thursday, September 12, 2013

September 1992…The First Snows

Continuing the saga…snow began in earnest in the Fairbanks area during the afternoon of September 12th and continued with only a few breaks into the early morning hours of the 15th. Below are the NCEP/NCAR reanalysis 500mb heights and anomalies for 10am AKDT Sep 12th (left) and 4pm AKDT Sep 13th (right). The most notable feature of this is the massive high over the southern Bering Sea. The "Death Star" had moved onto the Arctic coast with west-northwest winds aloft into Fairbanks-land.

500mb Heights and Anomalies, 18Z Sep 12 (left) and 00Z Sep 14 (right), courtesy NCEP/NCAR Reanalysis

The corresponding reanalysis for 850mb temperatures and anomalies are below. Note the temperature anomalies under the massive high aloft are not so dramatic except over the central Aleutians:
850mb Temperatures and Anomalies, 18Z Sep 12 (left) and 00Z Sep 14 (right), courtesy NCEP/NCAR Reanalysis
The image below is a scan of a gem I found in a file of miscellaneous stuff related to this event I have kept for the past 21 years. This is a hand plot of surface observations and a analysis sketch made within a few days of the event (as I recall, this was part of a post event analysis and not produced in real-time):

This is a plot of 4pm AKDT Sep 13th data. The area of snow at this time, as warm air had pushed in across the western Tanana Flats and Alaska Range: note the rain at Healy and Cantwell as well as southwest of Nenana. This critical detail is not evident in the relatively coarse-scale reanalysis. Also note that at this time north of the Yukon-Tanana uplands there was no precipitation occurring. On the 14th the cold air would push south to the Alaska Range. Here was the scenery at my house in Two Rivers (off of 22 Mile Chena Hot Springs Road) on the afternoon of September 13th:
This would be a boring photo if it was October 13th, but it wasn't. If you look close you can see the cottonwood trees behind the house are still in full leaf.


  1. I've been following these articles - I wasn't in Fairbanks that Sep but have certainly heard of the noteworthy weather. Very interesting to see what it looked like on the charts. And on the trees!

  2. Well told story. The temperatures were clearly anomalous. How did the precipitation totals look? Who were the winners?