Forecasters for the National Weather Service and other official agencies have been criticized this week for imprecision in their prediction of a winter storm – ice, snow, sleet and freezing rain – that was given a strong chance of slamming Northeast Mississippi with crippling amounts of frozen precipitation.
It happened in a few places, but in others the impacts were minimal compared to what had been forecast
Some people expressed anger at having been bypassed by the kind of storm that leaves thousands without electricity for days, sometimes weeks, and convenient life is almost fully disrupted – just because the forecast wasn’t right.
At worst, the lack of a huge winter storm in Mississippi, Alabama and Tennessee generally made preparations a safe precaution if a storm had hit, and schools canceled, businesses closed temporarily and extra safety urgency made almost everyone ready.
The weather service, not surprisingly, began as part of the War Department, under President U.S. Grant. It has evolved into a worldwide service producing complexity of weather forecasting using billions data bits every day.
That’s the equivalent of the entire printed collection of the Library of Congress about three times per second, the NWS reports.
But if prediction is the truest way to put our information to the test, The New York Times surmised, we have not scored well. In November 2007, economists in the Survey of Professional Forecasters – examining some 45,000 economic-data series – foresaw less than a 1 in 500 chance of an economic meltdown as severe as the one that would begin one month later.
Progress is remarkable. In 1940, the chance of an American being killed by lightning was about 1 in 400,000. Today it’s 1 in 11 million. This is partly because better weather forecasts have helped us prepare.
The “holy grail” of meteorology, cited by the Times, was when scientists realized dynamic weather prediction – programs that simulate the physical systems that produce clouds and cold fronts, windy days in Chicago and the morning fog over San Francisco as they occur.
The National Weather Service, as a matter of practice, recognizes the importance of communicating the uncertainty in its forecasts as completely as possible. “Uncertainty is the fundamental component of weather prediction,” said Max Mayfield, an Air Force veteran who ran the National Hurricane Center when Katrina hit. “No forecast is complete without some description of that uncertainty.”