Tuesday, November 5, 2013

Climatology of First Snowfall in Autumn

Headline:November 5, 2013:
The first snowfall of the season is occurring today across central and northeastern Nebraska.

How does this timing compare with the normal date of the first occurrence of measurable snowfall in the Fall?

The following map produced by the Midwest Regional Climate Center shows the median date of the first measurable snowfall.  The "median" is the mid point date between the earliest and the latest observed first measurable snowfall..

The median date ranges from late November in southeastern Nebraska to mid October in the Nebraska Panhandle.

The next map, also from the Midwest Regional Climate Center,  shows the latest observed first measurable snowfall across our region.  Most of southeastern Nebraska including Omaha and Lincoln have waited as long as late December for their first snowfall.

 The following map produced by NOAA shows the median date of the first measurable snowfall for the conterminous United States.

The following graph shows the date of the first measurable snowfall for Lincoln, NE for the time period 1948-2012.  There is a considerable amount of variability from year to year in the timing of our first measurable snowfall, however an upward trend toward later first snowfalls is clearly evident in the graph (note the red line on the graph)..

Lincoln's snowfall climatology: 113 years of data (1900-2012)
Average date first measurable snowfall:  Day 321 or November 17
Last time Lincoln had a November measurable snowfall, year 2007, 0.4 inches
Novembers with measurable snowfall: 82 years (73% of the Novembers)
Novembers without measurable snowfall: 31 years (27% of the Novembers)
Most November Snowfall: 12.6 inches, 1957.
Least November Snowfall (1900-2012): (0.0 and T) 29 years
0 inches: 9 years since 1900; a trace (T): 22 years since 1900.
A trace of snowfall means it was observed but not enough to be measured.

LINK to ALL of the Snowfall  data for Lincoln, NE

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