diff --git a/coastal/calib/schism_calib.cfg b/coastal/calib/schism_calib.cfg
deleted file mode 100755
index 2bc61e4b..00000000
--- a/coastal/calib/schism_calib.cfg
+++ /dev/null
@@ -1,8 +0,0 @@
-export STARTPDY=20230611
-export STARTCYC=00
-export FCST_LENGTH_HRS=3.0
-export HOT_START_FILE=''
-export USE_TPXO="NO"
-export COASTAL_DOMAIN=pacific
-export METEO_SOURCE=NWM_RETRO
-export COASTAL_WORK_DIR=/efs/schism_use_case/sfincs_config_test/schism_2023-06-11T00-00-00Z
diff --git a/coastal/calib/sing_run.bash b/coastal/calib/sing_run.bash
index 27c7d5dc..b78d1c07 100755
--- a/coastal/calib/sing_run.bash
+++ b/coastal/calib/sing_run.bash
@@ -1,19 +1,53 @@
 #!/usr/bin/env bash
-#SBATCH --job-name=sing_mpi  #job name
-#SBATCH -N 2                     #number of nodes to use
-#SBATCH --partition=compute      #the patition
-#SBATCH --ntasks-per-node=18     #numebr of cores per node
+#SBATCH --job-name=sing_mpi      # job name
+#SBATCH -N 2                     # number of nodes to use
+#SBATCH --partition=c5n-18xlarge # the partition
+#SBATCH --ntasks-per-node=18     # number of cores per node
 #SBATCH --exclusive
 
-export NODES=2          #this must match the number of nodes defined above by slurm
-export NCORES=18        #this must match the number of cores per node defined above by slurm
+export NODES=2    # this must match the number of nodes defined above by slurm
+export NCORES=18  # this must match the number of cores per node defined above by slurm
 export NPROCS=$((NODES*NCORES))
 
-set -x
+set -euox pipefail
 
-#load the configuration file
+# load the configuration file
 . ./schism_calib.cfg
 
+# Check string variables
+for var in STARTPDY STARTCYC COASTAL_DOMAIN METEO_SOURCE COASTAL_WORK_DIR RAW_DOWNLOAD_DIR; do
+    if [[ -z "${!var}" ]]; then
+        echo "ERROR: $var is not defined in config file"
+        exit 1
+    fi
+done
+
+# Check numeric variables
+for var in FCST_LENGTH_HRS; do
+    if [[ -z "${!var}" ]] || ! [[ "${!var}" =~ ^[0-9]+$ ]]; then
+        echo "ERROR: $var must be a positive integer"
+        exit 1
+    fi
+done
+
+# Check YES/NO variables
+if [[ "${USE_TPXO}" != "YES" ]] && [[ "${USE_TPXO}" != "NO" ]]; then
+    echo "ERROR: USE_TPXO must be YES or NO"
+    exit 1
+fi
+
+# Check that HOT_START_FILE is defined (but allow empty string)
+if [[ ! -v HOT_START_FILE ]]; then
+    echo "ERROR: HOT_START_FILE must be defined (can be empty string '')"
+    exit 1
+fi
+
+# Optional: Validate HOT_START_FILE exists if provided
+if [[ -n "${HOT_START_FILE}" ]] && [[ ! -f "${HOT_START_FILE}" ]]; then
+    echo "ERROR: HOT_START_FILE specified but file does not exist: ${HOT_START_FILE}"
+    exit 1
+fi
+
 export NGWPC_COASTAL_PARM_DIR=/ngen-test/coastal/ngwpc-coastal
 
 export NGEN_APP_DIR=/ngen-app
@@ -50,42 +84,44 @@ export FI_OFI_RXM_SAR_LIMIT=3145728
 export FI_MR_CACHE_MAX_COUNT=0
 export FI_EFA_RECVWIN_SIZE=65536
 
-# User specific aliases and functions
+export NFS_MOUNT=/ngen-test
+
 # >>> conda initialize >>>
 # !! Contents within this block are managed by 'conda init' !!
-__conda_setup="$('/opt/conda/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
+__conda_setup="$($NFS_MOUNT/ngen-app/conda/bin/conda 'shell.bash' 'hook' 2> /dev/null)"
 if [ $? -eq 0 ]; then
     eval "$__conda_setup"
 else
-    if [ -f "/opt/conda/etc/profile.d/conda.sh" ]; then
-        . "/opt/conda/etc/profile.d/conda.sh"
+    if [ -f "$NFS_MOUNT/ngen-app/conda/etc/profile.d/conda.sh" ]; then
+        . "$NFS_MOUNT/ngen-app/conda/etc/profile.d/conda.sh"
     else
-        export PATH="/opt/conda/bin:$PATH"
+        export PATH="$NFS_MOUNT/ngen-app/conda/bin:$PATH"
     fi
 fi
 unset __conda_setup
 # <<< conda initialize <<<
-#
 
-export NFS_MOUNT=/efs
-export PATH=/opt/conda/bin:${PATH}
+export PATH=$NFS_MOUNT/ngen-app/conda/bin:${PATH}
 export CONDA_ENVS_PATH=$NFS_MOUNT/ngen-app/conda/envs
 export CONDA_ENV_NAME=ngen_forcing_coastal
 export PATH=${CONDA_ENVS_PATH}/${CONDA_ENV_NAME}/bin:${PATH}
 
 SIF_PATH=/ngencerf-app/singularity/ngen-coastal.sif
+if [[ ! -f $SIF_PATH ]]; then
+   echo "ERROR: Singularity image file not found at $SIF_PATH"
+   exit 1
+fi
 
 conda activate ${CONDA_ENVS_PATH}/$CONDA_ENV_NAME
 
-export LD_LIBRARY_PATH=/opt/conda/lib:${CONDA_ENVS_PATH}/lib:$LD_LIBRARY_PATH
-
+export LD_LIBRARY_PATH=$NFS_MOUNT/ngen-app/conda/lib:${CONDA_ENVS_PATH}/lib:${LD_LIBRARY_PATH:-}
 #
-# location of the NWM retrospective or archieved forcing files
+# location of the NWM retrospective or archived forcing files
 # note that the time span of the files must cover the whole simulation period
 #export NWM_FORCING_DIR=/efs/schism_use_case/hi_nwm_ana_forcing_20240913/
 export NWM_FORCING_DIR=$RAW_DOWNLOAD_DIR/meteo/${METEO_SOURCE,,} #to lower case
 #
-# location of the NWM retrospective or archieved streamflow files
+# location of the NWM retrospective or archived streamflow files
 # note that the time span of the files must cover the whole simulation period
 if [[ ${METEO_SOURCE} == "NWM_RETRO" ]]; then
    export NWM_CHROUT_DIR=$RAW_DOWNLOAD_DIR/streamflow/nwm_retro
@@ -96,9 +132,6 @@ else
    exit 1
 fi
 
-export MPICOMMAND2="mpiexec -n ${NPROCS} "
-export MPICOMMAND3="mpiexec -n 4 "
-
 declare -A coastal_domain_to_inland_domain=( \
 	   [prvi]="domain_puertorico" \
 	   [hawaii]="domain_hawaii" \
@@ -117,6 +150,12 @@ declare -A coastal_domain_to_geo_grid=( \
 	   [atlgulf]="geo_em_CONUS.nc" \
 	   [pacific]="geo_em_CONUS.nc" )
 
+# Validate COASTAL_DOMAIN is a recognized domain
+if [[ -z "${coastal_domain_to_inland_domain[$COASTAL_DOMAIN]+x}" ]]; then
+    echo "ERROR: Unknown COASTAL_DOMAIN: $COASTAL_DOMAIN (valid: ${!coastal_domain_to_inland_domain[*]})"
+    exit 1
+fi
+
 export SCHISM_ESMFMESH=${PARMnwm}/coastal/${COASTAL_DOMAIN}/hgrid.nc
 export GEOGRID_FILE=${PARMnwm}/${coastal_domain_to_inland_domain[$COASTAL_DOMAIN]}/${coastal_domain_to_geo_grid[$COASTAL_DOMAIN]}
 
@@ -132,6 +171,16 @@ export BINDINGS="$NFS_MOUNT,$CONDA_ENVS_PATH,$NGWPC_COASTAL_PARM_DIR,/usr/bin/bc
 
 work_dir=${NGEN_APP_DIR}/ngen-forcing/coastal/calib
 
+MPICOMMAND="mpiexec -n ${NPROCS}"
+
+run_in_container() {
+    singularity exec -B "$BINDINGS" --pwd "${work_dir}" "$SIF_PATH" "$@"
+}
+
+run_in_container_mpi() {
+    ${MPICOMMAND} singularity exec -B "$BINDINGS" --pwd "${work_dir}" "$SIF_PATH" "$@"
+}
+
 start_itime=$(date -u -d "${STARTPDY} ${STARTCYC}" +"%s")
 end_itime=$(( $start_itime + $FCST_LENGTH_HRS * 3600 + 3600 ))
 export start_dt=$(date -u -d "@${start_itime}" +"%Y-%m-%dT%H-%M-%SZ")
@@ -142,27 +191,6 @@ if [[ $USE_TPXO == "YES" ]]; then
     export COASTAL_SOURCE=''
 fi
 
-#singularity exec -B $BINDINGS --pwd ${work_dir} $SIF_PATH \
-#	/bin/bash -c \
-# 	 '__conda_setup="$('/opt/conda/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"; \
-#         if [ $? -eq 0 ]; then \
-#                eval "$__conda_setup"; \
-#         else \
-#                if [ -f "/opt/conda/etc/profile.d/conda.sh" ]; then \
-#                     . "/opt/conda/etc/profile.d/conda.sh" ; \
-#                else \
-#                      export PATH="/opt/conda/bin:$PATH" ;\
-#                fi;                                              \
-#          fi;                                               \
-#         conda run -n $CONDA_ENV_NAME python \
-#	../forcing_downloader/main.py \
-#	"$COASTAL_WORK_DIR" \
-#	"${coastal_domain_to_nwm_domain[$COASTAL_DOMAIN]}"
-#	"$start_dt" \
-#	"$end_dt" \
-#	"$METEO_SOURCE" "nwm" "$COASTAL_SOURCE"'
-
-#
 # location of the archived STOFS file if STOFS data is
 # going to be used for the boundary nodes
 export STOFS_FILE=''
@@ -170,8 +198,7 @@ if [[ $USE_TPXO == "NO" ]]; then
   export STOFS_FILE=$(ls -1 $RAW_DOWNLOAD_DIR/coastal/stofs/* | head -n 1)
 fi
 
-singularity exec -B $BINDINGS --pwd ${work_dir} $SIF_PATH \
-	 ./run_sing_coastal_workflow_pre_forcing_coastal.bash
+run_in_container ./run_sing_coastal_workflow_pre_forcing_coastal.bash
 
 export LENGTH_HRS=$FCST_LENGTH_HRS
 export FORCING_BEGIN_DATE=${STARTPDY}${STARTCYC}00
@@ -186,72 +213,43 @@ export COASTAL_FORCING_OUTPUT_DIR=$DATAexec/coastal_forcing_output
 export FECPP_JOB_INDEX=0
 export FECPP_JOB_COUNT=1
 
-${MPICOMMAND3} singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
+run_in_container_mpi \
 	 $CONDA_ENVS_PATH/$CONDA_ENV_NAME/bin/python \
          $USHnwm/wrf_hydro_workflow_dev/forcings/WrfHydroFECPP/workflow_driver.py
 
-singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_post_forcing_coastal.bash
+run_in_container ./run_sing_coastal_workflow_post_forcing_coastal.bash
 
-singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_update_params.bash
+run_in_container ./run_sing_coastal_workflow_update_params.bash
 
 if [[ $USE_TPXO == "YES" ]]; then
-   singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_make_tpxo_ocean.bash
+   run_in_container ./run_sing_coastal_workflow_make_tpxo_ocean.bash
 else
    export CYCLE_DATE=$STARTPDY
    export CYCLE_TIME=${STARTCYC}00
-   export LENGTH_HRS=$(singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_pre_make_stofs_ocean.bash)
+   export LENGTH_HRS=$(run_in_container ./run_sing_coastal_workflow_pre_make_stofs_ocean.bash)
 
    export ESTOFS_INPUT_FILE=$STOFS_FILE
    export SCHISM_OUTPUT_FILE=$DATAexec/elev2D.th.nc
    export OPEN_BNDS_HGRID_FILE=$DATAexec/open_bnds_hgrid.nc
 
-   ${MPICOMMAND3} singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
+   run_in_container_mpi \
 	 $CONDA_ENVS_PATH/$CONDA_ENV_NAME/bin/python \
          $USHnwm/wrf_hydro_workflow_dev/coastal/regrid_estofs.py $ESTOFS_INPUT_FILE $OPEN_BNDS_HGRID_FILE $SCHISM_OUTPUT_FILE
 
-   singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_post_make_stofs_ocean.bash
+   run_in_container ./run_sing_coastal_workflow_post_make_stofs_ocean.bash
 
 fi
 
-singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_pre_schism.bash
-
-
-export PATH=/opt/amazon/openmpi/bin:/opt/amazon/efa/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin
+run_in_container ./run_sing_coastal_workflow_pre_schism.bash
 
-export LD_LIBRARY_PATH=/opt/amazon/openmpi/lib:/opt/amazon/openmpi/lib64
+# We want to use the Open MPI installed in the NFS_MOUNT instead of Conda's Open MPI
+# for running SCHISM
+export PATH=$NFS_MOUNT/openmpi/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin
+export LD_LIBRARY_PATH=$NFS_MOUNT/openmpi/lib
 export OMPI_ALLOW_RUN_AS_ROOT=1
 export OMPI_ALLOW_RUN_AS_ROOT_CONFIRM=1
 
-${MPICOMMAND2} singularity exec -B $BINDINGS --pwd $COASTAL_WORK_DIR \
-         $SIF_PATH \
+${MPICOMMAND} singularity exec -B "$BINDINGS" --pwd "$COASTAL_WORK_DIR" "$SIF_PATH" \
 	/bin/bash -c "/ngen-app/nwm.v3.0.6/exec/pschism_wcoss2_NO_PARMETIS_TVD-VL.openmpi $NSCRIBES"
 
-
-singularity exec -B $BINDINGS \
-	  --pwd ${work_dir} \
-         $SIF_PATH \
-	 ./run_sing_coastal_workflow_post_schism.bash
-
-
+run_in_container ./run_sing_coastal_workflow_post_schism.bash