Probability distributions of apparent temperature from ensemble MOS
The EKDMOS technique has now been used to generate forecast PDFs/CDFs of heat index (HI) and wind chill (WC). Model estimates of HI and WC were important predictors for these weather elements, and the development sample for each had to be limited to cases where the element was well-defined and useful. In geographic areas where HI and WC occurred infrequently, regions were selected and data were combined to develop regional equations.
HI attempts to reflect the combined effects of heat and humidity on the human body. Similarly, WC attempts to reflect the combined effects of cold and wind on the human body. Both HI and WC are used extensively by the National Weather Service (NWS) to inform public health officials and the general public about forecast weather hazards. For convenience, forecasts of HI, WC, and T are frequently combined into a single weather element named apparent temperature (AppT).
EKDMOS forecast CDFs of HI, WC, and T are combined to form AppT. The AppT forecasts have been mapped to the National Digital Forecast Database (NDFD) 2.5-km grid. The resultant grids will be available to NWS customers and parters as part of the National Digital Guidance Database.
Glahn, B., M. Peroutka, J. Wiedenfeld, J. Wagner, G. Zylstra, B. Schuknecht, and B. Jackson, 2009: MOS uncertainty estimates in an ensemble framework. Mon. Wea. Rev., 137, 246–268.