Comparison of Five Weather Forecast Methods at Four California Locations

In this project we compare five methods of forecasting maximum and minimum temperature and probability of precipitation at four California locations: California Academy of Sciences in San Francisco, Oakland Museum, Sacramento Executive Airport, and Truckee Airport. The five methods are applied to make 24-hour forecasts twice weekly during the period from August 18 to December 2, 2003. The five forecast methods include: (1) Persistence. A persistence forecast assumes that tomorrow's weather will be the same as today's. (2) Climatology. Our climatology-based forecasts use weather conditions for the day at or very near each of the four locations, averaged over the 30-year period from 1971 to 2000. (3) Official National Weather Service (NWS) forecasts. We use the official NWS forecasts for Oakland Museum, Sacramento Executive Airport, and Truckee Airport. For The California Academy of Sciences (CAS) we use the NWS's new Prototype Digital Forecast for the CAS's latitude and longitude. (4) Individual student forecasts, made by four 10th grade students from San Francisco's Burton High School. They consulted the most recent meteograms, satellite images, soundings, synoptic analyses, and computer model forecasts, as well as climatology, persistence, and NWS forecasts. (5) A consensus of student forecasts, comprising the average of the four student forecasts. We calculate forecast error by squaring the difference between a forecast and the verifying observation, and compare the forecast methods based on these errors.