Past Snowfall Norm: A Glimpse at Tomorrow?

[donsutherland1]

It has been noted in various places that the long-term patterns may have shifted back to what was more common several decades ago e.g., due to the return of the cold PDO, among other things.

If this is the case, this might mean greater snowfall on average for the Mid-Atlantic to New England (particularly the Mid-Atlantic to southern New England) and less in the Ohio Valley, Midwest, and Plains States (Southern Plains would fare the worst). With colder winters and the Great Lakes being frozen to a greater extent and longer duration than the recent past, seasonal snowfall in cities affected by LES could fall significantly.

Here are seasonal norms for ten cities based on those published in the 1924 U.S. Statistical Abstract, 1964 U.S. Statistical Abstract (base: 1932-1961), and the most recent base norms (1971-2000):

City: 1924 Abs. 1964 Abs. Latest
-----------------------------------------
Boston: 44.2" 40.2" 45.3"
Buffalo: 74.4" 106.8" 96.9"
Chicago: 33.7" 36.1" 38.0"
Detroit: 42.4" 31.6" 44.0"
Indianapolis: 23.2" 18.6" 27.0"
Louisville: 15.2" 15.7" 18.1"
New York City: 34.9" 30.0" 22.4"
Omaha: 19.9" 32.2" 30.2"
St. Louis: 20.1" 17.3" 22.2"
Washington, DC: 23.6" 15.9" 15.2"

1924 Figures as a Percentage of Latest Figures (for an idea where things might be trending until the PDO switches)--<b>1890-1924</b> saw a cool cycle:

Boston: 97.6%
Buffalo: 76.8%
Chicago: 88.7%
Detroit: 96.4%
Indianapolis: 85.9%
Louisville: 84.0%
New York City: 155.8%
Omaha: 65.9%
St. Louis: 90.5%
Washington, DC: 155.3%

At this point, this is merely a hypothesis. However, given the recent lack of snowfall in some of the above-mentioned cities, while others such as NYC are approaching the most 30" or more seasons in the 2000s since the 1960s (4 in the 1960s; 1 in the 1970s; 0 in the 1980s; 2 in the 1990s; within 3.2" of 3 in the 2000s), a look back was in order.

Right now, it is too soon to say more on this. Other factors e.g., the frequency of ENSO phases, solar cycles, etc., may well be skewing the figures.

[JCT777]

Very interesting, Don. Thanks for the info!

[donsutherland1]

Thanks, John.

The following is temperature data (December-February period) to go along with the snowfall data:

The mean temperature data for December-February for 1924 and the latest base normals is below:

City: 1924 Abs. Latest
-----------------------------------------
Boston: 29.7 31.9
Buffalo: 26.2 26.7
Chicago: 27.5 25.5
Detroit: 26.3 30.3
Indianapolis: 30.6 29.8
Louisville: 36.4 36.1
New York City: 32.4 34.7
Omaha: 24.6 25.1
St. Louis: 33.4 33.0
Washington, DC: 35.1 37.5

If one is looking for a trend back toward the older figures for a cold PDO period, the change from the 1971-2000 base normals to 1924 would be:

Boston: -2.2 degrees
Buffalo: -0.5 degrees
Chicago: +2.0 degrees
Detroit: -4.0 degrees
Indianapolis: +0.8 degrees
Louisville: +0.3 degrees
New York City: -2.3 degrees
Omaha: -0.5 degrees
St. Louis: +0.4 degrees
Washington, DC: -2.4 degrees

As a quick note, given the greater urbanization (heat island effect), one could probably expect the increase in temperatures to be greater than what is depicted, while the decline would be less than shown.