Wednesday, 1 August 2001: 9:00 AM
Verification of 20-km RUC surface and precipitation forecasts
The Rapid Update Cycle (RUC) model running operationally at the National Centers for Environmental Prediction (NCEP) provides high-frequency mesoscale analyses and short-range numerical prediction guidance for aviation, severe weather, and general weather forecasting. In the spring of 2001, a new 20-km version of the RUC will replace the operational 40-km version running at NCEP. In addition to higher horizontal resolution, this new version will feature three-dimentional variational(3DVAR)analysis and cloud analysis schemes. In addition, the 20-km RUC will include improvements to the microphysics and convective parameterization formulations, topography, and land and soil use fields. These enhancements are expected to lead to improvements in surface temperature, humidity,wind, and precipitation forecasts.
In this presentation, we will show verification, as performed against surface METAR data for the new 20-km version of the RUC. The scores will be compared with the 40-km RUC currently operational at NCEP. Results will be shown for forecasts out to 12h in advance for each 3-h cycle (0000, 0300,.....2100 UTC) starting with the implementation that is expected by mid-2001. In addition, summary skill scores for 20-km RUC precipitation forecasts will be presented.