keep only < 273 for both icing and no-icing regions

modules/icing/pirep_goes.py

@@ -1240,7 +1240,7 @@ def split_data(num_obs, perc=0.2, skip=1):
     np.random.shuffle(test_idxs)
     np.random.shuffle(train_idxs)
 
-    return train_idxs[::skip], test_idxs[::skip]
+    return np.sort(train_idxs[::skip]), np.sort(test_idxs[::skip])
 
 
 def test(filename):