diff --git a/ush/forecast_det.sh b/ush/forecast_det.sh
index 1337413030..257f0e13ff 100755
--- a/ush/forecast_det.sh
+++ b/ush/forecast_det.sh
@@ -39,7 +39,7 @@ FV3_GFS_det(){
 
   #-------------------------------------------------------
   # determine if restart IC exists to continue from a previous forecast
-  RERUN="NO"
+  RERUN=${RERUN:-"NO"}
   filecount=$(find "${RSTDIR_ATM:-/dev/null}" -type f | wc -l)
   if [[ ( ${CDUMP} = "gfs" || ( ${RUN} = "gefs" && ${CDATE_RST} = "" )) && ${rst_invt1} -gt 0 && ${FHMAX} -gt ${rst_invt1} && ${filecount} -gt 10 ]]; then
     reverse=$(echo "${restart_interval[@]} " | tac -s ' ')