As improvements and additions are made to the WRF code, continual questions arise in the user community regarding the improvement and/or degradation of specific WRF configurations with subsequent releases of WRF. With the numerous options available in WRF, the answer to that question may be different for each user. Prior to a release, the WRF code is run through a large number of regression tests to ensure it successfully runs a wide variety of options; however, extensive testing to investigate the skill of the forecast is not widely addressed. To provide information regarding the progression of WRF code with time, the Developmental Testbed Center (DTC) has tested one particular configuration of the Advanced Research WRF (ARW) dynamic core with recent versions of WRF (v3.4, v3.4.1, v3.5, v3.5.1, v3.6). The testing spans over a warm season and a cold season to capture the model performance over a variety of weather regimes. The model was run over a 15-km North American domain and the forecasts were initiated every 36 hours and run out to 48 hours.

*All results presented here have been rerun with the PB2NC bug fix*