diff --git a/modules/icing/util.py b/modules/icing/util.py
index 818c147781946cff333454dcf6265af68b9810e5..d267255167ef281b79e860303014f8420deae661 100644
--- a/modules/icing/util.py
+++ b/modules/icing/util.py
@@ -909,13 +909,11 @@ def run_icing_predict(clvrx_dir='/Users/tomrink/data/clavrx/RadC/', output_dir=h
                 mode = 'DAY'
                 nght_train_params = train_params_dnb
 
-            nght_data_dct = {name: [] for name in nght_train_params}
-            for name in nght_train_params:
-                for k in all_idxs:
-                    nght_data_dct[name].append(data_dct[name][k])
+            all_idxs = np.array(all_idxs)
             nght_grd_dct = {name: None for name in nght_train_params}
-            for ds_name in nght_train_params:
-                nght_grd_dct[ds_name] = np.stack(nght_data_dct[ds_name])
+            for name in nght_train_params:
+                nght_grd_dct[name] = data_dct[name][all_idxs,]
+
             if use_max_cth_level:
                 nght_grd_dct['cth_high_avg'] = nght_cth_max