I have been plotting boundary layer height times series from the ruc2 and noticed some interesting features in some of the plots that I am not sure how to interpret.

Anyone interested can view said plots at:
http://metosrv2.umd.edu/~forecaster/Ruc_Pbl_Times_series/pbl_time_series_06aug01_bwi.gif
http://metosrv2.umd.edu/~forecaster/Ruc_Pbl_Times_series/pbl_time_series_09aug01_bwi.gif
http://metosrv2.umd.edu/~forecaster/Ruc_Pbl_Times_series/pbl_time_series_09aug01_fdk.gif

Any comments on how robust ruc2's calculation of pbl height and what might lead to the results in these plot (which seem unrealistic) is would be appreciated.

I did find the definition of PBL height:
PBL height - Find level aloft at which theta-v again exceeds theta-v at surface. Distance above surface.

thanks,

Charles