Kenneth F. Heideman

Effects of improved information on the components of skill in weather forecasting

Abstract The relation between the amount and quality of information available to meteorologists and the accuracy of their forecasts of a highly uncertain event (severe weather) was investigated. In three studies, meteorologists made forecasts under a total of four different information conditions. Forecast accuracy was low, and as the amount and quality of the information increased substantially, there was a modest increase in the accuracy of forecasts. The results suggest that subjective factors, particularly the reliability of forecasts, deteriorated with additional information.

Forcing Mechanisms and Other Characteristics of Significant Summertime Precipitation

Abstract Satellite, radar, surface, and upper-air data from the June–August periods of 1982–83 are examined to determine the mechanisms, and their relative contributions, for producing warm-season precipitation in the United States. Only areas where rainfall equaled or exceeded 12.7 mm during the 24-h period ending at 1200 UTC were considered. Rainfall associated with extratropical cyclones accounted for about half of the warm-season precipitation. Most of the remaining precipitation was produced by mesoscale forcing mechanisms acting independently from the traveling extratropical cyclones. Nearly all the warm-season precipitation was convective; over 80% of the total was directly or indirectly associated with thunderstorms. Nearly three-fourths of the precipitation that occurred between the Rockies and the Mississippi Valley was nocturnal. Conversely, about three-fourths of the precipitation east of the Mississippi Valley fell during the daylight hours. During the 1983 July-August drought, the area of pr...

The Weather Information and Skill Experiment (WISE): The Effect of Varying Levels of Information on Forecast Skill

Abstract The relationship between the quality and quantity of information available to meteorologists and the skill of their forecasts was investigated. Twelve meteorologists were asked to make probabilistic forecasts of significant and severe weather events under three information conditions. Forecast accuracy was generally low. As the amount and quality of the information increased substantially, there was a modest increase in the accuracy of the forecasts. However, the results suggest that the forecasters were least consistent when they had the most information to work with, partially reducing the benefits of the increased information.

Some characteristics of the limited-area fine-mesh (LFM) model quantitative precipitation forecasts (QPF) during the 1982 and 1983 warm seasons

Abstract The skill of the limited-area fine-mesh (LFM) model in making 24-h areal quantitative precipitation forecasts (QPF) of ⩾ 0.5 in. (12.7 mm) is evaluated and analyzed for two warm seasons; 1982 and 1983. Differences in skill between the eastern and western United States are investigated and the impact of updated initial conditions is explored. The skill in predicting precipitation from cyclonic versus mesoscale systems is also examined. It is found that the model skill changed drastically from the summers of 1982 to 1983. Skill levels for 1982 were about 25% to 35%. In 1983, they dropped to an average value of less than 10% and often to zero on a daily basis. The precipitous drop in skill appears to be the result of changes made in key model threshold parameters. These parameters include grid-resolvable saturation criterion and convective cloud base boost. The introduction of constraints on convective precipitation and the vertical advection of moisture also appear to have reduced model skill. A co...

Faster, Cheaper, and More Nimble: Improvements and Innovations in Publishing AMS Journals

The American Meteorological Society (AMS) is committed to continually improving the total author and reader experience associated with AMS journals. This article discusses improvements to the peer-review process, reduction in publication costs, streamlining of article production, incorporation of cutting-edge technologies, and other imminent improvements in AMS publications.