fix fcst time offset in get_bounding_gfs_files

modules/deeplearning/amv_raob.py

@@ -519,7 +519,7 @@ def get_bounding_goes16_files(timestamp, ch_str):
 
 def get_bounding_gfs_files(timestamp):
     dt_obj, time_tup = get_time_tuple_utc(timestamp)
-    dt_obj = dt_obj + datetime.timedelta(hours=12)
+    dt_obj = dt_obj - datetime.timedelta(hours=12)
     date_str = dt_obj.strftime(gfs_date_format)
     dt_obj0 = datetime.datetime.strptime(date_str, gfs_date_format).replace(tzinfo=timezone.utc)
     dt_obj1 = dt_obj0 + datetime.timedelta(days=1)
@@ -527,9 +527,11 @@ def get_bounding_gfs_files(timestamp):
 
     flist_0 = glob.glob(gfs_directory+'gfs.'+date_str+'??_F012.hdf')
     flist_1 = glob.glob(gfs_directory+'gfs.'+date_str_1+'00_F012.hdf')
-    if (len(flist_0) == 0) or (len(flist_1) == 0):
+    if len(flist_0) == 0:
         return None, None, None, None
-    filelist = flist_0 + flist_1
+    filelist = flist_0
+    if len(flist_1) > 0:
+        filelist = flist_0 + flist_1
 
     ftimes = []
     for pname in filelist:  # TODO: make better with regular expressions (someday)