Update README.md

Add a description of the patch artifacting

README.md

@@ -64,6 +64,7 @@ Some known weaknesses of HiRO are:
 - May not produce physically consistent precipitation features; different precipitation regimes (convective, stratiform, orographic) have not been rigorously analyzed separately
 - Does not tend to produce the strongest isolated convection over tropical ocean regions of X-SHiELD (e.g., representative of 99.9999th percentile of X-SHiELD outputs)
 - Not trained or tested outside of 66S -- 70N, and cannot run outside of 88S or 88N
+- Downscaling regions larger than the 16x16 1-degree patch size used for training will have discontinuities for patch overlaps of 0 or some blending artifacting from averaging in the overlap region for overlaps > 0
 
 ## License