snapshot...

modules/util/util.py

@@ -231,7 +231,7 @@ def pressure_to_altitude(pres, temp, prof_pres, prof_temp, sfc_pres=None, sfc_te
 
     if sfc_pres is not None:
         if pres > sfc_pres:  # incoming pressure below surface
-            return -1
+            return -999.0
 
         prof_pres = np.array(pres_s)
         prof_temp = np.array(temp_s)