diff --git a/modules/util/gfs_reader.py b/modules/util/gfs_reader.py
index 0bc0785ce8f42c10373d19e16debda62027fde8c..b4107744f57dc5dc93931ab955e2c3940b53d76c 100644
--- a/modules/util/gfs_reader.py
+++ b/modules/util/gfs_reader.py
@@ -71,6 +71,7 @@ def get_bounding_gfs_files(timestamp):
     farr = np.array(filelist)
     farr = farr[sidxs]
     ftimes = tarr[sidxs]
+    idxs = np.arange(len(filelist))
 
     above = ftimes >= timestamp
     if not above.any():
@@ -82,7 +83,7 @@ def get_bounding_gfs_files(timestamp):
         return None, None, None, None
     tL = ftimes[below].max()
 
-    iL = np.searchsorted(ftimes, tL, 'left')
+    iL = idxs[below].max()
     iR = iL + 1
 
     fList = farr.tolist()