Bugfix: Enable MPAS UGRID support to parse forecast lead time from diag files

[DanielAdriaansen]

Describe the Problem

When using ugrid_dataset=mpas;, the forecast lead time is not correctly parsed from the input file. To work around this, set_attr_lead can be configured to use the forecast lead time in METplus wrappers for each forecast variable. However, support for reading this directly from the MPAS files should be added.

In the ugrid_metadata_map, one option is to add a new item for forecast_lead_time_varname (or some other key name, I don't think this is the correct/best option), so the user can set the name of the variable that contains the forecast lead time. We can set the default to be the name we see in the diag files we have used or others have used, but this would allow the user to configure it themselves if it deviated from the default.

Expected Behavior

Grid-Stat and Point-Stat will correctly parse the forecast lead time from MPAS files so it can be used in the output filenames and the FCST_LEAD column in the output files.

Environment

I was working on Seneca preparing for the 2026 MPAS user's workshop mini-tutorial.

To Reproduce

On Seneca, you can find a sample file:
/home/dadriaan/projects/mpas/data/fcst/mpas/ugrid/OK_1km_ugrid/2025051800/ens_1/diag.2025-05-18_01.00.00.nc

There are three variables related to time:

inital_time
xtime
Time

I think that initial_time = forecast initialization time, xtime = forecast valid time, and Time = forecast lead time.

I've created an easy-to-run environment for testing at:
seneca:/home/dadriaan/projects/mpas/bugfix_3410_mpas_ugrid_lead_time

You can issue the command:

./grid_stat fcst_file obs_file GridStatConfig_bugfix -outdir /path/to/your/output

And replacing /path/to/your/output to an area that's writeable.

Running that command as-is, produces these three output files:

-rw-r--r-- 1 dadriaan rap  626 Jul  6 17:53 grid_stat_000000L_20250518_010000V_ctc.txt
-rw-r--r-- 1 dadriaan rap  11M Jul  6 17:53 grid_stat_000000L_20250518_010000V_pairs.nc
-rw-r--r-- 1 dadriaan rap  580 Jul  6 17:53 grid_stat_000000L_20250518_010000V.stat

However note that the 000000L in all of the files, should be 010000L for a "1-hr" lead time as that is the lead time being processed with the sample command.

Additionally, inside the file:
grid_stat_000000L_20250518_010000V.stat

The FCST_LEAD column shows 000000, which once fixed, should say 010000.

Relevant Deadlines

NONE

Funding Source

NCAR base 2702701

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