Another analysis of the temperature forecast errors was performed to illustrate the
models' performance for the critical task of properly forecasting the diurnal temperature
wave. In Fig 11.31, a time series was constructed from all the forecast models initialized
at 06 UTC, or 1 AM CST. The red line is the corresponding observations. Note that the
amplitude of the WRF wave is smaller than reality, resulting in a warm bias at night and a
cool bias during the day. The MM5 model is remarkably close to reality until sunrise,
and then a significant warm bias during the daytime hours becomes evident.
Fig. 11.31. Time series of temperature forecast errors from the 06 UTC (1 AM CST)
model runs and verifying observations.