diff --git a/modules/icing/util.py b/modules/icing/util.py
index 91147ad49914f67f003818f4bc1d36d57df6434b..cac9e3b8be4196fa8c3e5348cb67d4ce9c8208ff 100644
--- a/modules/icing/util.py
+++ b/modules/icing/util.py
@@ -832,6 +832,8 @@ def run_icing_predict(clvrx_dir='/Users/tomrink/data/clavrx/RadC/', output_dir=h
         num_tiles = len(all_idxs)
         num_day_tiles = len(day_idxs)
         num_nght_tiles = len(nght_idxs)
+        day_cth_max = np.array(day_cth_max)
+        nght_cth_max = np.array(nght_cth_max)
 
         # initialize output arrays
         probs_2d_dct = {flvl: None for flvl in flight_levels}