What is BestForecast? BestForecast is Weather Underground’s proprietary forecasting system that uses multiple weather forecasting models, combined with our predictive algorithm, to create the most accurate forecast.
Evolution/Verification We started verifying our old forecasting system back in 2005, which was directly from the Global Forecast System (GFS) and model output statistics (MOS) designed by Dr. Masters. We looked at two variables--highs and lows--for every airport around the globe, since airport weather stations are considered the most accurate. By evaluating our forecasts and the predictions from the GFS, we were able to create an algorithm that better predicted daily highs and lows. This was the first generation of BestForecast.
From there, we implemented several numerical models such as MOS, GFS, ECMWF, GEM, NAM, SREF and NAFES into our verification and forecast system. You can find more information about all these models from NOAA. Other important weather variables such as hourly temperature, wind, pressure, cloud cover, and humidity were added into our system. Then, we took it further by producing a forecast for each hour of the day, which enables us to bring you more accurate and detailed forecasts.
Weather Underground now integrates about 140+ possible forecasts with 8 to 10 weather variables into our system. We now deliver forecasts for temperature, dew point, humidity, pressure, wind, weather conditions, probability of precipitation, and cloud cover out to 10 days.
Personal Weather Station(PWS) Weather Underground has the largest network of weather observations in the world. In addition to more than 34,000 stations which are owned and operated by government organizations, we have a network of 24,000 personal weather stations across the globe.
Location is an important consideration in BestForecast. Was this forecast made for my neighborhood or the nearby airport, which could be up to 60 miles (100 km) away? Most weather sites can only estimate your neighborhood weather conditions and provide you the closest airport weather observations and forecast . However, Weather Underground gives you options to select any neighborhood you’d like, not just the closet airport, and the forecast is tailored-made to each individual station. Adding personal weather stations into the system brought BestForecast into another generation.
As per our founder and Director of Meteorology, Dr. Jeff Masters: “We gather several years of weather data from a site and optimize the forecast to suit the unique microclimate of a particular station. Thus, "backyard meteorologists" that own and maintain one of the more than 24,000 personal weather stations that record and send live weather conditions to Weather Underground will now have a forecast specifically generated for their own backyard. BestForecast also gives the expected precipitation amounts (in inches), and provides ten days of forecast information, instead of the seven days provided by the National Weather Service.”
We’re constantly improving the BestForecast system, and our goal is to minimize short-term forecast errors to zero.
As our PWS network continues to grow, we not only need to constantly maintain our computer workload but also optimize its performance. We’d like to deliver the most updated forecast as often as possible and as soon as it becomes available.