DETECT_GRASS not working in an operational setting

In an operational setting, when meteorological forcing data from the future is not available, the DETECT_GRASS algorithm doesn't work. The following problems were found:

• First of all, the DETECT_GRASS algorithm doesn't check for nodata values in the helper variables TSS_A24H, TSS_A12H and HS_A3H. Regardless of any other issue, this needs to be fixed. Proper handling for cases when these variables are nodata needs to be developed.
• If data from the future is not available, the helper variables become nodata in recent time steps. This is a bit unexpected, since the AGGREGATE filters are defined with LEFT windows and it shouldn't be bothered my missing data in the future.