read_narr_var: Read a specific variable from a NARR NetCDF file
In FoRTExperiment/ed4forte: FoRTE-specific utilities for working with ED2

Read a specific variable from a NARR NetCDF file

1	read_narr_var(nc, xy, variable, unit, datatype, pb = NULL)

`nc`	`ncdf4` connection object
`xy`	Vector length 2 containing NARR coordinates
`variable`	NARR name of variable to retrieve
`unit`	Output unit of variable to retrieve
`datatype`	Type of NARR file – either `flx` or `sfc`
`pb`	Progress bar R6 object (default = `NULL`)