Experiences with 0–36-h Explicit Convective Forecasts with the WRF-ARW Model

• DOI: 10.1175/2007waf2007005.1
• Publication Date: 2008-06-26T20:46:10Z
• Authors: Morris L. Weisman; Christopher Davis; Wei Wang; Kevin W. Manning; Joseph B. Klemp
• Keywords: Squall line; Forcing (mathematics); Mesoscale convective system

Abstract Herein, a summary of the authors’ experiences with 36-h real-time explicit (4 km) convective forecasts Advanced Research Weather and Forecasting Model (WRF-ARW) during 2003–05 spring summer seasons is presented. These are compared to guidance obtained from 12-km operational Eta Model, which employed parameterization (e.g., Betts–Miller–Janjić). The results suggest significant value added for high-resolution in representing system mode squall lines, bow echoes, mesoscale vortices) as well diurnal cycle. However, no improvement could be documented overall timing location outbreaks. Perhaps most notable result strong correspondence between WRF-ARW guidance, both good bad forecasts, suggesting overriding influence larger scales forcing on development 24–36-h time frame. Sensitivities PBL, land surface, microphysics, resolution failed account more forecast errors completely missing or erroneous systems), that further research needed document source such at these scales. A systematic bias also noted Yonsei University (YSU) PBL scheme, emphasizing continuing need refine improve physics packages application problems.