With fewer forecasts verifying in the в’ categories and more correct forecasts than would be expected randomly, these results confirm the usefulness of these forecasts. The forecast was only in the opposite direction as the observations (в’ categories) an average of 14% of the time at each location, which is lower than the 22% from the random tercile forecasting. The majority of remaining 60% incorrect forecasts was in the same direction as the observations, i.e., forecasts of median when below or above median occurred and forecasts of below or above median when median occurred). The results from the accuracy analysis show that the forecast has been correct about 40% of the time at each location, which is higher than the expected 33% correct from a random tercile forecasting. Using this scale we calculated the accuracy of the 6-10 day precipitation forecasts at the 50 stations in the United States and evaluated the improvement of the accuracy in the past 6 years. Specifically, we assigned an error value: error=0, if the forecast matched with the observation at the location error=+1 or +2, if the predicted precipitation was one or two terciles above the observed and error=-1 or -2, if the predicted precipitation was one or two terciles below the observed. The observed precipitation category was compared to the predicted, and the difference was used to define the accuracy of the forecasts. Meanwhile, observed daily precipitation from these locations was used to calculate the actual 6-10 day precipitation and then categorized it by the climatological terciles at the location. These forecasts were made in three terciles: вЂњmedianвЂќ (вЂњNвЂќ in Fig. 2007 were digitized from the forecast maps (whose electronic archives began in Dec. Actual forecasts made every day for 50 locations in the U.S. This forecast is identified by farmers and extension agents as the most useful forecast for nearly all farming decisions during the growing season. We examined the accuracy of the 6-10 day (accumulated) precipitation forecasts issued by the NOAA CPC for the contiguous United States (see an example in Fig. Thus, for the interest of users and for improving use of the forecasts it is necessary to provide the accuracy that measures how the forecasts have been compared to the observations for different seasons and for various locations. This skill may be a good mathematical measure of the forecast accuracy but it is no longer a direct measure of the accuracy and, thus, could confuse the forecast users whose sole concern is вЂњhow the forecasts for my location have been compared to the observations in the past,вЂќ i.e., the plain accuracy of the forecasts.

The second comparison in this procedure gives a measure of the вЂњskillвЂќ of the forecasts. The current method that CPC is using, the Heidke Skill Score, compares the forecast to the observation and then takes a step further to compare how this accuracy is compared to that of a random forecast, the climatology. It is thus important to inform users the accuracy along with weather and climate predictions so users can start building skills, experience, and confidence to use the forecasts in decision-making.Дifferent methods of measuring the accuracy of weather and climate predictions convey slightly different information about the accuracy to the users. The lack of this information prevents potential users of the predictions from developing their personal knowledge and self efficacy of using the forecasts effectively in decision-making, resulting in the overall low attitude toward use of the forecasts. Although some medium- and long-range predictions are provided with probability, there is no information of how the probability may have been validated for specific areas and regions of the usersвЂ™ interest. Science and Technology Infusion Climate BulletinД§th NOAA Annual Climate Prediction Application Science WorkshopДЄ major factor weakening peopleвЂ™s intention to use weather and climate predictions in decision-making is the lack of knowledge of the accuracy of the predictions. Accuracy of 6-10 Day Precipitation Forecasts and Its Improvement in the Past Six Years

Accurate 5 day weather forecast