Effect of Using Probabilistic Contingency Tables to Modify Forecast Predictions
Abstract
The 45th Weather Squadron (45 WS) records daily rain and lightning probabilistic forecasts and the associated binary event outcomes. Subsequently, they evaluate forecast performance and determine necessary adjustments with an implemented verification process. For deterministic outcomes, weather forecast analysis typically utilizes a Tradition Contingency Table (TCT) for verification, however the 45 WS uses an alternative tool, the Probabilistic Contingency Table (PCT). Using the TCT for verification requires a threshold, typically at 50 percent, to dichotomize probabilistic forecasts. The PCT maintains the valuable information in probabilities and verifies the true forecasts being reported. Simulated forecasts and outcomes as well as 2015-2018 45 WS data were utilized to compare forecast performance metrics produced from the TCT and PCT to determine which verification tool better supports producing the greatest quality forecasts. Comparisons of frequency bias, reliability, and Brier Score (BS) computed from both dichotomized and continuous forecasts revealed misrepresentative performance metrics from the TCT as well as a loss of information necessary for verification. Exploration of the 45 WS data with a probabilistic verification process revealed a need to verify seasonally as well as slightly unreliable warm season lightning event forecasts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2019
- Accession Number
- AD1077388
Entities
People
- Sarah A. Gold
Organizations
- Air Force Institute of Technology