diff --git a/prep/ARIA_prep.ipynb b/prep/ARIA_prep.ipynb
index cc90197..3c625c0 100644
--- a/prep/ARIA_prep.ipynb
+++ b/prep/ARIA_prep.ipynb
@@ -342,9 +342,9 @@
     "    print('Preparing GUNWs for MintPY....')\n",
     "    if sitedata['sites'][site]['maskWater'] != 'False':\n",
     "        mask_file = '../mask/watermask.msk'\n",
-    "        command = 'ariaTSsetup.py -f ' + product_glob + ' -b ' + sitedata['sites'][site]['analysis_region'] + ' --mask Download  --croptounion --verbose' # slow\n",
+    "        command = 'ariaTSsetup.py -f ' + product_glob + ' -b ' + sitedata['sites'][site]['analysis_region'] + ' --mask Download  --croptounion --verbose -nt 16' # slow\n",
     "    else: # skip slow mask download when we don't need to mask water\n",
-    "        command = 'ariaTSsetup.py -f ' + product_glob + ' -b ' + sitedata['sites'][site]['analysis_region'] + ' --croptounion --verbose'\n",
+    "        command = 'ariaTSsetup.py -f ' + product_glob + ' -b ' + sitedata['sites'][site]['analysis_region'] + ' --croptounion --verbose -nt 16'\n",
     "\n",
     "    # Crop and prepare stack\n",
     "    print(command)\n",