Fog Predicting Snow?
Name: Phillip Dean C.
Date: Sunday, October 27, 2002
Our local TV weather"scientist" equates the number of
foggy mornings in August to the anticipated number of snow days for the
I have a problem grasping this logic...are the two phenomena not mutually
The TV weatherman may have found some statistical relationship between
the two phenomena over a period of time. However, what we call the
"confidence level" of that relationship has to be very marginal. Do not
put any stock in that relationship. My guess is that if you looked
closely at the data you may find that an average of the number
of foggy mornings over 20 or 30 years is similar to the number of
snow days in the following winter. However, that does not mean (and
I can bet doesn't) that that will be true for any one year, with rare
exceptions. Just like the Old Farmer's Almanac weather predictions,
which are based on climatological means, your TV weatherman's predictor
of snow days is no more valid for a particular year. A professional
meteorologist, like myself, is not likely to make such statements.
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
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Update: June 2012