diff --git a/modules/util/viirs_l1b_l2.py b/modules/util/viirs_l1b_l2.py
index 166b26012feb5d2b7a6a06ccee56536f83244278..1f83e0b11a6245bd40f4493844e63e59c94fb4e4 100644
--- a/modules/util/viirs_l1b_l2.py
+++ b/modules/util/viirs_l1b_l2.py
@@ -226,7 +226,7 @@ def run(data_h5f, param_s, train_tiles, valid_tiles, num_keep_x_tiles=8, tile_wi
                 continue
             train_tiles.append(nda)
 
-    j_start = num_y_train * tile_width + 1
+    j_start = num_y_train * tile_width + 1*tile_width
     for j in range(num_y_valid):
         j_a = j_start + j * j_skip
         j_b = j_a + tile_width