title: MetPy suface_based_cape_cin returning error with units
body: <p>At my site, we're having an issue with MetPy returning a units error when trying to call surface_based_cape_cin</p>
  <p>I am seeing the following error:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;Advanced_Sounding_3Dnetcdf2.py&quot;, line 202, in &lt;module&gt;
      sbcape, sbcin = mpcalc.surface_based_cape_cin(p1, T1, Td1)
    File &quot;/gpfs/group/kal6112/default/sw/anaconda3/lib/python3.6/site-packages/metpy/xarray.py&quot;, line 677, in wrapper
      return func(*args, **kwargs)
    File &quot;/gpfs/group/kal6112/default/sw/anaconda3/lib/python3.6/site-packages/metpy/units.py&quot;, line 320, in wrapper
      return func(*args, **kwargs)
    File &quot;/gpfs/group/kal6112/default/sw/anaconda3/lib/python3.6/site-packages/metpy/calc/thermo.py&quot;, line 1851, in surface_based_cape_cin
      return cape_cin(p, t, td, profile)
    File &quot;/gpfs/group/kal6112/default/sw/anaconda3/lib/python3.6/site-packages/metpy/xarray.py&quot;, line 677, in wrapper
      return func(*args, **kwargs)
    File &quot;/gpfs/group/kal6112/default/sw/anaconda3/lib/python3.6/site-packages/metpy/units.py&quot;, line 319, in wrapper
      raise ValueError(msg)
  ValueError: `cape_cin` given arguments with incorrect units: `temperature` requires &quot;[temperature]&quot; but given &quot;none&quot;, `dewpt` requires &quot;[temperature]&quot; but given &quot;none&quot;.
  </code></pre>
  <p>When I check the incoming values p1, T1, and Td1 they all have the correct units (hectopascal, degree_Celcius).</p>
  <p>Just to be sure I added the following and checked the results prior to the call to surface_based_cape_cin:</p>
  <pre><code>p1 = units.hPa * phPa
  T1 =  units.degC * TdegC
  Td1 = units.degC * TddegC
  </code></pre>
  <p>I'm running the following version of MetPy</p>
  <pre><code># Name                    Version                   Build  Channel
  metpy                     0.12.2                     py_0    conda-forge
  </code></pre>
  <p>I don't recall having this prior to updating to this version but I can't be certain the problem I'm seeing arose after the update or not.</p>
  <p>Thanks for any help you can provide.</p>