While doing WRF runs over CONUS with single-layer urban canopy model and outputting temperature variables within the single-layer urban canopy model like TC_URB, it shows patchy patterns in certain places within the domain. For example, below is a quick simulation over Boston and the temperature shown is TC_URB. One can clearly see that in certain regions TC_URB looks 'weird'.

The problem arises from the fact that the default geo data now provided by WRF has NUDAPT data, which will be processed by geogrid.exe if GEOGRID.TBL is not modified (specifically the URB_PARAM entry, see below). For reference, please read https://ral.ucar.edu/sites/default/files/public/product-tool/NUDAPT_44_Documentation.pdf. As a result, in certain places where NUDAPT data are available, WRF will use the morphological data provided by NUDAPT. However, in other places where NUDAPT data are not available, WRF will use the default morphological data provided by URBPARM.TBL. The 'patchy' places in the previous figure are those places where NUDAPT data are available.

If one prefers not to use NUDAPT data, one option is to modify GEOGRID.TBL so that URB_PARAM in GEOGRID.TBL is NOT processed. For example, in the following you can see that I removed the content in real_path for URB_PARAM so that geogrid.exe can't find it.

===============================
name=URB_PARAM
        priority=1
        optional=yes
        dest_type=continuous
        fill_missing = 0.
        z_dim_name=num_urb_params
        interp_option=default:nearest_neighbor
        rel_path=default:
        flag_in_output=FLAG_URB_PARAM
===============================

With this change, the TC_URB looks like the following, which no longer shows any patchiness.