Today’s Forecasts Are Better Than Ever

Uccellini points out that there has been a steady improvement in weather forecasts over the last two decades. He says there was a 20-30 percent improvement in the last 7 years alone.

"There have been two fundamental changes since the late 1980s," he states. "(1) We have extended our predictions to the 7-day range with an accuracy that is really remarkable. Today, our accuracy in the 5-day range is as accurate as it was in the 3-day range 20 years ago."
 

 
 
Top: Weather forecast models have steadily improved over the last 20 years. This graph shows how well model forecasts scored when compared to a grid of actual meteorological measurements from 1977 to 1990. "Anomaly correlation score" refers to the statistical relationship between a geographical grid of measurements and a corresponding grid of numbers generated by models. Notice that by 1990, 5-day forecast models were as accurate as 3-day forecast models were in 1977. (Graph by Robert Simmon, courtesy of Louis Uccellini, NCEP)

Bottom:As model forecasts improve over time, they help improve "manual" forecasts made by humans that incorporate the models into forecasts that also use the larger suite of meteorological tools at their disposal (e.g., satellites, radar, aircraft, and ground-based instruments). The bottom line shows the improvement in the accuracy of model forecasts, from 1977 to 1990, and the top line shows the relative improvement in the accuracy of manual forecasts. (Graph by Robert Simmon, courtesy of Louis Uccellini, NCEP)

He continues, "(2) We are now able to predict major weather events farther in advance than light to moderate events."

Remember the winter bomb that hit the U.S. East Coast in March 1993? The National Weather Service predicted that event 5 days in advance. Later, in January 1996, we had another major snowstorm that produced more snow than any other storm in the 20th century; again, this was forecast 5 days in advance. Uccellini asserts that no one could have made those predictions 20 years ago.

"But Mother Nature has a way of exacting revenge," he laughs, "like last Monday, when we only got a warning out 8 hours in advance. While that didn’t meet our current standards, it really is a testament to how far we’ve come."

Okay, so meteorologists missed the snowstorm of Y2K. They nailed with astonishing accuracy the next winter storm that arrived almost a week later. Forecasters predicted time of day the precipitation would begin, and precisely maps the boundaries of where there would be snowfall, where there would be sleet, and where there would be rain. They even accurately described snow accumulation totals.

Jones not only agrees with Uccellini, he believes the best is yet to come...and soon. He says as meteorologists fine-tune their models and computers get more powerful, in 10-15 years forecasters will be able to accurately predict the weather 10 days, perhaps even 14 days, ahead of time.

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