How accurate are 12-hour and 48-hour weather forecasts?

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Weather forecasting Doppler radars, such as this one operated by the U.S. National Weather Service at New Underwood, South Dakota, extract the Doppler frequency shift of the echo produced by a moving target by noting how much the frequency of the received signal differs from the frequency of the signal that was transmitted.

In the field of weather forecasting, predictive skill is generally highest for short-range intervals and tends to decrease as the forecast period extends further into the future.1

12-hour forecasts: Predictive skill is at its greatest for periods of approximately 12 hours.1
48-hour forecasts: Accuracy remains quite substantial for 48-hour predictions.1

While modern meteorology utilizes sophisticated numerical weather prediction models and high-speed supercomputers to process atmospheric data, forecasting is inherently complex due to the interaction of numerous variables across vast areas. Consequently, while current tools are highly effective, they are not perfect, and accuracy naturally diminishes as forecasters attempt to look further ahead in time.231