diff --git a/ush/config.sh_rrfs_a_enkf_c3_retro b/ush/config.sh_rrfs_a_enkf_c3_retro
index 1eb245ad5..cca089dcc 100644
--- a/ush/config.sh_rrfs_a_enkf_c3_retro
+++ b/ush/config.sh_rrfs_a_enkf_c3_retro
@@ -79,6 +79,8 @@ ENDYEAR=${DATE_LAST_CYCL:0:4}
 ENDMONTH=${DATE_LAST_CYCL:4:2}
 ENDDAY=${DATE_LAST_CYCL:6:2}
 ENDHOUR="23"
+FIRST_BLENDED_CYCLE="18"  # usually second partial cycle
+FIRST_BLENDED_CYCLE_DATE=${STARTYEAR}${STARTMONTH}${STARTDAY}${FIRST_BLENDED_CYCLE}
 
 PREEXISTING_DIR_METHOD="upgrade" # "rename"
 INITIAL_CYCLEDEF="${DATE_FIRST_CYCL}0600 ${DATE_LAST_CYCL}2300 12:00:00"