MNT: Use more Quantity() for creation

This is more robust for masked arrays, etc. with pint master than using
multiplication.

src/metpy/calc/thermo.py

@@ -706,8 +706,8 @@ def _parcel_profile_helper(pressure, temperature, dewpt):
 
     # If the pressure profile doesn't make it to the lcl, we can stop here
     if _greater_or_close(np.nanmin(pressure.m), press_lcl.m):
-        return (press_lower[:-1], press_lcl, np.array([]) * press_lower.units,
-                temp_lower[:-1], temp_lcl, np.array([]) * temp_lower.units)
+        return (press_lower[:-1], press_lcl, units.Quantity(np.array([]), press_lower.units),
+                temp_lower[:-1], temp_lcl, units.Quantity(np.array([]), temp_lower.units))
 
     # Find moist pseudo-adiabatic profile starting at the LCL
     press_upper = concatenate((press_lcl, pressure[pressure < press_lcl]))

src/metpy/calc/tools.py

@@ -482,9 +482,11 @@ def get_layer_heights(heights, depth, *args, bottom=None, interpolate=True, with
     if interpolate:
         # If we don't have the bottom or top requested, append them
         if top not in heights_interp:
-            heights_interp = np.sort(np.append(heights_interp.m, top.m)) * heights.units
+            heights_interp = units.Quantity(np.sort(np.append(heights_interp.m, top.m)),
+                                            heights.units)
         if bottom not in heights_interp:
-            heights_interp = np.sort(np.append(heights_interp.m, bottom.m)) * heights.units
+            heights_interp = units.Quantity(np.sort(np.append(heights_interp.m, bottom.m)),
+                                            heights.units)
 
     ret.append(heights_interp)