1. Adapting WRF for Solar Forecasts Clear sky conditions - more often, less error, most easily fixed Cloudy conditions – less frequent, more error All errors worse for DNI than GHI

2. Clear sky conditions

3. May clear sky average error by time of day Forecast-Observed Sunrise NoonSunset

4. June average error by time of day clear sky, no smoke Sunrise NoonSunset

5. Cloudy Conditions Significantly more variability Can break up clouds into different cases with different physics Dust algorithm nearly eliminates bias in July, suggesting total cloud mass is proper Error mostly related to time and location of convective clouds Slight underprediction of winter clouds? We will get more data on this later this year.

6. MonthBias(total error)Average error: uncorrected May83.1398138.59 corrected May-4.4894781.2545 uncorrected June91.3892141.603 corrected June-0.065079478.5955 uncorrected July96.5335272.241 corrected July-18.3734221.625