Warm Season Statistical Verification of the Pennsylvania State University Real Time Mesoscale Model Version 5
Abstract
For this study, warm-season simulations from the real-time Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) mesoscale model, known widely as MM5, are verified against surface METAR and upper-air soundings. Verification statistics are calculated on two model domains. The 36-km coarse-mesh domain encompasses the CONUS and portions of the surrounding regions. The 12-km fine-mesh domain is centered over Pennsylvania and encompasses the surrounding states. Variables that are verified include temperature, dew point, relative humidity, wind direction, wind speed, geopotential height, sea-level pressure, as well as the total totals severe weather index. Verification statistics calculated include bias, mean absolute error, root mean square error, and the decomposition of a skill score based on the mean square error. Coarse-mesh surface results show an early-morning warm and dry bias, a positive wind speed bias, and wind directions that veer clockwise with respect to the observations. A cool bias is present on the coarse mesh at 850 mb for all forecast times, possibly indicating an over-prediction of boundary layer depth. Interestingly, the fine mesh does not perform better than the coarse mesh overall. But, over the 24-hour forecast period, fine-mesh skill markedly improves and nearly matches coarse-mesh skill for many variables, especially the moisture fields. By improving the fine-mesh initialization procedure, the fine-mesh forecasts should prove more skillful than the coarse-mesh forecasts.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1998
- Accession Number
- ADA358701
Entities
People
- Mark P. Fitzgerald
Organizations
- Pennsylvania State University