From: witt@nsslsun.nssl.uoknor.edu (Arthur Witt)
Subject: Weather forecasting (was: Re: Dateline : NBC)
Organization: National Severe Storms Laboratory
Date: Tue, 14 Apr 1992 00:15:12 GMT

In article <1992Apr11.194124.19912@cs.yale.edu> korins-russ@CS.YALE.EDU (Russ Korins) writes:
>
>Yesterday, the New York City NWS forecast was predicting a high for today of
>72 in Central Park.  Right now it's 40, and even if the warm front does make
>it through NYC, temps probably won't get much past 55.
>
>Now, on the face of it, to the general public, the NWS was 32 degrees off
>for today.  To the general public, a prediction of "highs in the low 70's"
>means that afternoon temps will be in the low 70's.  So now it's mid-after-
>noon, and it's 40.
>
>Of course, we know that the situation, or explanation, is more complex.  We
>know that it is more accurate to say, NOT that the NWS was 20 or 30 degrees
>off, but that the NWS was about a hundred miles off with its prediction
>of the warm front position.  We know that especially in the spring time,
>warm fronts are very obnoxious to forecasters by being extremely fickle.
>Who would have predicted that, on March 13, 1990, the temperature at White
>Plains NY would rise from 37 to 80 in 4.5 hours?
>
>Who would have predicted that on April 26, 1990, at 3pm, it would be
>50 at Bridgeport CT but 90 at Trenton NJ?  
>
>The NYC forecaster in that case is in a tough situation.  What is he or
>she supposed to do, say "highs from the low 50's to the low 90's?"  In
>the eyes of the general public, he or she would lose all credibility.  It
>most likely is a no-win situation.
>
>With their prediction of "low 70's" for today, the NWS NYC office was not
>so much predicting low 70's per se as banking on the passage of the warm
>front.  Unfortunately, in the eyes of millions of New Yorkers today, it will
>be just another reason for them to believe -- UNFAIRLY -- that forecasters
>are "always wrong."


The problem with most people is that they always remember the bad
forecasts and usually forget about the good forecasts.  As an 
example, the following letter appeared in the "Your Views" section
of the April 9, 1992 edition of the Daily Oklahoman newspaper:

Headline - "Weather Forecasting Is Terrible

To the editor:
     Is it just me or has weather forecasting gone to hell in a
handbasket?  Maybe I'm missing something or not reading the local
weather report just right, but has there been an accurate weather
forecast that anyone can remember?
     It seems rather ironic that we now have technology such as
Doppler 9000, NEXRAD, First-Alert and Satellite Imagery, yet the
Farmer's Almanac seems to do a better job of forecasting our weather.
     And for your local TV weatherman, is it possible to make the
little state map showing severe weather just a little larger.  Since
it takes up one-fourth of the screen let's go for broke and use half
the screen.
     While I may sound cantankerous and cynical, I guess I just long
for the days of Bob Thomas, Jim Williams and Fred Norman.  At least
they weren't pursuing an Oscar nomination for their weather broadcast."


The letter does make one valid point, pertaining to the wildly 
sensationalizing nature of TV weather in the Oklahoma City area,
which, unfortunately, only adds to the public's negative view 
about weather forecasting (e.g., one TV station recently claimed to 
be measuring winds of 115 mph with their Doppler radar on a storm 
100 miles away!).


Arthur Witt
Forecasting Applications Research Group