Fixes to get the atm+aero+snow test running

[aerorahul]

Description

This PR:

• contains fixes to ensure the atm+aero+snow test runs to the end with success.

Type of change

• Bug fix (fixes something broken)

Change characteristics

• Is this a breaking change (a change in existing functionality)? NO
• Does this change require a documentation update? NO

How has this been tested?

C96_atmaerosnowDA was run on Hera with this branch. See:

EXPDIR: /scratch1/NCEPDEV/stmp2/Rahul.Mahajan/RUNTESTS/EXPDIR/aas 
ROTDIR: /scratch1/NCEPDEV/stmp2/Rahul.Mahajan/RUNTESTS/COMROOT/aas

Checklist

• Any dependent changes have been merged and published
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• New and existing tests pass with my changes
• I have made corresponding changes to the documentation if necessary