diff --git a/configs/common/packages.yaml b/configs/common/packages.yaml
index 9bae2c5c1..d2eeb1edd 100644
--- a/configs/common/packages.yaml
+++ b/configs/common/packages.yaml
@@ -30,6 +30,9 @@ packages:
     - any_of: ['@2.3.0 ~openmp']
       when: '%intel@2021:'
       message: '2.3.0 is the last version to use C++17, use with Intel Classic'
+    - any_of: ['@2.3.0 ~openmp']
+      when: '%gcc@:10'
+      message: 2.3.0 is the last version to use C++17, use with GCC 10 and earlier
     - any_of: ['@2.3.0 ~openmp']
       when: '%apple-clang@:14'
       message: '2.3.0 is the last version to use C++17, use with Apple Clang 14 and earlier'
diff --git a/configs/sites/tier1/atlantis/packages.yaml b/configs/sites/tier1/atlantis/packages.yaml
index 6f587b3b6..51a597116 100644
--- a/configs/sites/tier1/atlantis/packages.yaml
+++ b/configs/sites/tier1/atlantis/packages.yaml
@@ -25,10 +25,6 @@ packages:
     externals:
     - spec: binutils@2.30.117
       prefix: /usr
-  bison:
-    externals:
-    - spec: bison@3.0.4
-      prefix: /usr
   coreutils:
     externals:
     - spec: coreutils@8.30
diff --git a/configs/sites/tier1/narwhal/compilers.gcc-direct.tmp b/configs/sites/tier1/narwhal/compilers.gcc-direct.tmp
new file mode 100644
index 000000000..d6a4bb95d
--- /dev/null
+++ b/configs/sites/tier1/narwhal/compilers.gcc-direct.tmp
@@ -0,0 +1,22 @@
+compilers::
+  - compiler:
+      spec: gcc@10.3.0
+      paths:
+        # For cylc-dev, can't use Cray wrappers (https://github.com/spack/spack/issues/48515)
+        cc: /opt/cray/pe/gcc/10.3.0/snos/bin/gcc
+        cxx: /opt/cray/pe/gcc/10.3.0/snos/bin/g++
+        f77: /opt/cray/pe/gcc/10.3.0/snos/bin/gfortran
+        fc: /opt/cray/pe/gcc/10.3.0/snos/bin/gfortran
+      flags: {}
+      operating_system: sles15
+      modules:
+      - PrgEnv-gnu/8.4.0
+      - gcc/10.3.0
+      - cray-libsci/23.05.1.4
+      - libfabric/1.12.1.2.2.1
+      environment:
+        prepend_path:
+          LD_LIBRARY_PATH: '/opt/cray/libfabric/1.12.1.2.2.1/lib64:/opt/cray/pe/libsci/23.05.1.4/GNU/10.3/x86_64/lib'
+        set:
+          CRAYPE_LINK_TYPE: 'dynamic'
+      extra_rpaths: []
diff --git a/spack b/spack
index ffeffba28..0ee54ff84 160000
--- a/spack
+++ b/spack
@@ -1 +1 @@
-Subproject commit ffeffba282acd873a288efb9dbb8e964f128c7e4
+Subproject commit 0ee54ff840d4a4bf78ca1e102681bb48a4e53f33
diff --git a/util/nrl/batch_install.sh b/util/nrl/batch_install.sh
new file mode 100755
index 000000000..6695f2018
--- /dev/null
+++ b/util/nrl/batch_install.sh
@@ -0,0 +1,404 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Developer switch: create buildcaches instead of deploying environments ["true"|"false"]
+# The default "false" means to deploy environments using existing buildcaches (installer mode)
+SPACK_STACK_BATCH_CREATE_BUILDCACHE="false"
+#SPACK_STACK_BATCH_CREATE_BUILDCACHE="true"
+
+# A value of SPACK_STACK_BATCH_CREATE_BUILDCACHE == "true" enters developer mode. In this
+# mode, one must choose between reusing existing buildcaches or rebuilding from scratch.
+# This variable is meaningless in installer mode (SPACK_STACK_BATCH_CREATE_BUILDCACHE== "false")
+SPACK_STACK_BATCH_REUSE_EXISTING_BUILDCACHE="true"
+#SPACK_STACK_BATCH_REUSE_EXISTING_BUILDCACHE="false"
+
+# Remove domain name suffices and digits to determine hostname
+SPACK_STACK_BATCH_HOST=$(echo ${HOSTNAME} | cut -d "." -f 1)
+SPACK_STACK_BATCH_HOST=${SPACK_STACK_BATCH_HOST//[0-9]/}
+
+case ${SPACK_STACK_BATCH_HOST} in
+  atlantis)
+    SPACK_STACK_BATCH_COMPILERS=("oneapi@2024.2.1" "intel@2021.6.0" "gcc@11.2.0")
+    SPACK_STACK_BATCH_TEMPLATES=("neptune-dev" "unified-dev" "cylc-dev")
+    SPACK_STACK_MODULE_CHOICE="lmod"
+    ;;
+  narwhal)
+    SPACK_STACK_BATCH_COMPILERS=("oneapi@2024.2.0" "intel@2021.10.0" "gcc@10.3.0")
+    SPACK_STACK_BATCH_TEMPLATES=("neptune-dev" "unified-dev" "cylc-dev")
+    SPACK_STACK_MODULE_CHOICE="tcl"
+    ;;
+  nautilus)
+    SPACK_STACK_BATCH_COMPILERS=("oneapi@2024.2.1" "intel@2021.5.0" "gcc@11.2.1")
+    SPACK_STACK_BATCH_TEMPLATES=("neptune-dev" "unified-dev" "cylc-dev")
+    SPACK_STACK_MODULE_CHOICE="tcl"
+    ;;
+  # DH*
+  blackpearl)
+    SPACK_STACK_BATCH_COMPILERS=("oneapi@2024.2.1" "gcc@13.3.0" "aocc@4.2.0")
+    SPACK_STACK_BATCH_TEMPLATES=("neptune-dev" "unified-dev" "cylc-dev")
+    SPACK_STACK_MODULE_CHOICE="tcl"
+    ;;
+  bounty)
+    SPACK_STACK_BATCH_COMPILERS=("oneapi@2025.0.0" "gcc@13.3.1" "aocc@5.0.0" "clang@19.1.4")
+    SPACK_STACK_BATCH_TEMPLATES=("neptune-dev" "unified-dev" "cylc-dev")
+    SPACK_STACK_MODULE_CHOICE="tcl"
+    ;;
+  # *DH
+  *)
+    echo "ERROR, host ${SPACK_STACK_BATCH_HOST} not configured"
+    exit 1
+    ;;
+esac
+
+##################################################################################################
+
+echo "\n"
+echo "Welcome to NRL SPACK-STACK BATCH INSTALL"
+echo
+
+if [[ ! -e "setup.sh" || ! -e ".spackstack" ]]; then
+  echo "ERROR, this script must be executed from the top-level spack-stack directory"
+  exit 1
+fi
+
+host=${SPACK_STACK_BATCH_HOST}
+module_choice=${SPACK_STACK_MODULE_CHOICE}
+
+# For Cray systems, capture the default=current environment (loaded modules)
+# so that it can be restored between building stacks for different compilers
+case ${host} in
+  narwhal)
+    module_snapshot=${PWD}/spack-stack.default-modules
+    module snapshot -f ${module_snapshot}
+    ;;
+esac
+
+# Create buildcaches or install environment?
+case ${SPACK_STACK_BATCH_CREATE_BUILDCACHE} in
+  "true")
+    case ${SPACK_STACK_BATCH_REUSE_EXISTING_BUILDCACHE} in
+      "false")
+        echo "Developer mode: create buildcaches, and ignore existing buildcaches"
+        create_buildcache="true-ignore"
+        ;;
+      "true")
+        echo "Developer mode: create buildcaches, but reuse existing buildcaches"
+        create_buildcache="true-reuse"
+        ;;
+      *)
+      echo "ERROR, invalid value for SPACK_STACK_BATCH_REUSE_EXISTING_BUILDCACHE"
+      exit 1
+      ;;
+    esac
+    ;;
+  "false")
+    echo "Installer mode: deploy environments using existing buildcaches"
+    create_buildcache="false"
+    ;;
+  *)
+    echo "ERROR, invalid value for SPACK_STACK_BATCH_CREATE_BUILDCACHE"
+    exit 1
+    ;;
+esac
+
+# Loop through all compilers and templates for this host
+for compiler in "${SPACK_STACK_BATCH_COMPILERS[@]}"; do
+
+  compiler_name=$(echo ${compiler} | cut -d "@" -f 1)
+  compiler_version=$(echo ${compiler} | cut -d "@" -f 2)
+
+  for template in "${SPACK_STACK_BATCH_TEMPLATES[@]}"; do
+
+    echo
+    #############################################################
+    # Add excluded combinations of compilers and templates here #
+    #############################################################
+    # cylc-dev only with gcc
+    if [[ "${template}" == "cylc-dev" && ! "${compiler_name}" == "gcc" ]]; then
+      echo "Skipping template ${template} with compiler ${compiler}"
+      continue
+    # unified-env not with intel
+    elif [[ "${template}" == "unified-dev" &&  "${compiler_name}" == "intel" ]]; then
+      echo "Skipping template ${template} with compiler ${compiler}"
+      continue
+    # With clang, only neptune-dev
+    elif [[ "${compiler_name}" == "clang" && ! "${template}" == "neptune-dev" ]]; then
+      echo "Skipping template ${template} with compiler ${compiler}"
+      continue
+    # With aocc, only neptune-dev
+    elif [[ "${compiler_name}" == "aocc" && ! "${template}" == "neptune-dev" ]]; then
+      echo "Skipping template ${template} with compiler ${compiler}"
+      continue
+    fi
+    echo "Processing template ${template} with compiler ${compiler}"
+    #############################################################
+
+    # Build environment name. Prefices are defined here
+    case ${template} in
+      unified-dev)
+        env_name_prefix="ue"
+        ;;
+      neptune-dev)
+        env_name_prefix="ne"
+        ;;
+      cylc-dev)
+        env_name_prefix="ce"
+        ;;
+      *)
+        echo "ERROR, template ${template} not configured"
+        exit 1
+        ;;
+    esac
+    env_name=${env_name_prefix}-${compiler_name}-${compiler_version}
+    [[ "${create_buildcache}" == "true"* ]] && env_name=${env_name}-buildcache
+    env_dir=${PWD}/envs/${env_name}
+
+    # Bail out if the environment already exists
+    if [[ -d ${env_dir} ]]; then
+      echo "ERROR, environment ${env_dir} already exists"
+      exit 1
+    fi
+
+    # Reset environment
+    echo "Resetting environment ..."
+    case ${host} in
+      atlantis)
+        umask 0022
+        module purge
+        ;;
+      narwhal)
+        # Check if snapshot to restore default environment exists, then restore
+        if [[ ! -e ${module_snapshot} ]]; then
+          echo "ERROR, ${module_snapshot} not found for resetting environment"
+          exit 1
+        fi
+        # Unloading modules on Narwhal always throws an error:
+        # environment: line 0: unalias: mpirun: not found
+        set +e
+        echo "Please ignore warning 'environment: line 0: unalias: mpirun: not found' ..."
+        module purge
+        module restore -f ${module_snapshot}
+        set -e
+        umask 0022
+        set +e
+        case ${compiler} in
+          oneapi@2024.2.0)
+            module purge
+            module load PrgEnv-intel/8.4.0
+            module unload intel
+            module load intel/2024.2
+            module unload cray-mpich
+            module unload craype-network-ofi
+            module load libfabric/1.12.1.2.2.1
+            module unload cray-libsci
+            module load cray-libsci/23.05.1.4
+            ;;
+          intel@2021.10.0)
+            module purge
+            module load PrgEnv-intel/8.4.0
+            module unload intel
+            module load intel-classic/2023.2.0
+            module unload cray-mpich
+            module unload craype-network-ofi
+            module load libfabric/1.12.1.2.2.1
+            module unload cray-libsci
+            module load cray-libsci/23.05.1.4
+            ;;
+          gcc@10.3.0)
+            module purge
+            module load PrgEnv-gnu/8.4.0
+            module unload gcc
+            module load gcc/10.3.0
+            module unload cray-mpich
+            module unload craype-network-ofi
+            module load libfabric/1.12.1.2.2.1
+            module unload cray-libsci
+            module load cray-libsci/23.05.1.4
+            ;;
+          *)
+            echo "ERROR, compiler ${compiler} not configured for resetting environment"
+            exit 1
+            ;;
+        esac
+        set -e
+    ;;
+      nautilus)
+        umask 0022
+        module purge
+        ;;
+      # DH*
+      blackpearl)
+        ulimit -s unlimited
+        ;;
+      bounty)
+        ulimit -s unlimited
+        ;;
+      # *DH
+      *)
+        echo "ERROR, host ${host} not configured for resetting environment"
+        exit 1
+        ;;
+    esac
+    
+    # Info prints
+    ulimit -a
+    module li
+
+    source setup.sh
+    spack clean -a
+
+    spack stack create env --name=${env_name} \
+                           --site=${host} \
+                           --compiler=${compiler_name} \
+                           --template=${template} \
+                           2>&1 | tee log.create.${env_name}.001
+    spack env activate -p ${env_dir}
+
+    # Workaround for building cylc environment on Narwhal: We need to use GNU
+    # compilers without the Cray wrappers. Until we can come up with a smarter
+    # solution, use this.
+    if [[ ${host} == "narwhal" && ${template} == "cylc-dev" ]]; then
+      echo "Applying workaround for ${template} on ${host}"
+      cp -av configs/sites/tier1/narwhal/compilers.gcc-direct.tmp ${env_dir}/site/compilers.yaml
+    fi
+
+    # Check that the site has mirrors configured for local source and binary caches,
+    # and extract the local path on disk. Need to strip leading "file://" from path
+    result=$(spack mirror list | grep local-source) || \
+        (echo "ERROR, no local source cache configured" && exit 1)
+    source_mirror_path=$(echo ${result} | cut -d " " -f 3)
+    source_mirror_path=${source_mirror_path:7}
+    echo "Spack source mirror path: ${source_mirror_path}"
+    result=$(spack mirror list | grep local-binary) || \
+        (echo "ERROR, no local binary cache configured" && exit 1)
+    binary_mirror_path=$(echo ${result} | cut -d " " -f 3)
+    binary_mirror_path=${binary_mirror_path:7}
+    echo "Spack binary mirror path: ${binary_mirror_path}"
+
+    if [[ "${create_buildcache}" == "true"* ]]; then
+      spack config add config:install_tree:padded_length:200
+    fi
+
+    # Concretize environment, and check that spack.lock is created
+    spack concretize --force --fresh 2>&1 | tee log.concretize.${env_name}.001
+    if [[ ! -e ${env_dir}/spack.lock ]]; then
+      echo "ERROR during concretization of environment ${env_name}, spack.lock not found"
+      exit 1
+    fi
+
+    # Check for duplicate packages
+    ./util/show_duplicate_packages.py -i crtm -i esmf -d log.concretize.${env_name}.001
+
+    # In developer mode, update local source cache
+    if [[ "${create_buildcache}" == "true"* ]]; then
+      echo "Updating local source cache ..."
+      spack mirror create -a -d ${source_mirror_path}
+    fi
+
+    # Update the buildcache index if it already contains packages
+    if [[ -e ${binary_mirror_path}/build_cache ]]; then
+      spack buildcache update-index local-binary
+    fi
+
+    # Install the environment with the correct flags
+    case ${create_buildcache} in
+      "false")
+        buildcache_install_flags="--no-check-signature"
+        ;;
+      "true-reuse")
+        buildcache_install_flags="--no-check-signature"
+        ;;
+      "true-ignore")
+        buildcache_install_flags="--no-cache"
+        ;;
+      *)
+        echo "ERROR, unkown create_buildcache value ${create_buildcache} for setting install flags"
+        exit 1
+        ;;
+    esac
+    spack install --verbose ${buildcache_install_flags} 2>&1 | tee log.install.${env_name}.001
+
+    # Run another spack install without redirects to catch build errors
+    spack install
+
+    # In developer mode, update local binary cache
+    if [[ "${create_buildcache}" == "true"* ]]; then
+      spack buildcache push -u ${binary_mirror_path}
+      spack buildcache update-index local-binary
+    fi
+
+    # In installer mode, create environment modules
+    if [[ "${create_buildcache}" == "false" ]]; then
+      spack module ${module_choice} refresh --yes --upstream-modules 2>&1 | tee log.modules.${env_name}.001
+      spack stack setup-meta-modules 2>&1 | tee log.setup-meta-modules.${env_name}.001
+    fi
+    
+    # In installer mode, run post-install scripts if applicable
+    if [[ "${create_buildcache}" == "false" ]]; then
+      # On Narwhal, fix bad links to libsci
+      case ${host} in
+        atlantis)
+          ;;
+        narwhal)
+          ./util/narwhal/fix_libsci.sh 2>&1 | tee log.fix_libsci.${env_name}.001
+          ;;
+        nautilus)
+          ;;
+        # DH*
+        blackpearl)
+          ;;
+        bounty)
+          ;;
+        # *DH
+        *)
+          echo "ERROR, post-install scripts not configured for ${host}"
+          exit 1
+          ;;
+      esac
+    fi
+
+    # Clean up
+    spack clean -a
+    spack env deactivate
+
+  done
+
+done
+
+# Remove any module snapshots
+rm -vf ${module_snapshot}
+
+# Note. Add in the xargs stuff
+# Repair permissions for environments
+case ${host} in
+  atlantis)
+    find ./ -type d -print0 | xargs --null chmod a+rx
+    find ./ -type f -executable -print0 | xargs --null chmod a+rx
+    find ./ -type f -print0 | xargs --null chmod a+r
+    ;;
+  narwhal)
+    nice -n 19 lfs find ./ -type d -print0 | xargs --null chmod a+rx
+    nice -n 19 find ./ -type f -executable -print0 | xargs --null chmod a+rx
+    nice -n 19 lfs find ./ -type f -print0 | xargs --null chmod a+r
+    ;;
+  nautilus)
+    nice -n 19 lfs find ./ -type d -print0 | xargs --null chmod a+rx
+    nice -n 19 find ./ -type f -executable -print0 | xargs --null chmod a+rx
+    nice -n 19 lfs find ./ -type f -print0 | xargs --null chmod a+r
+    ;;
+  # DH*
+  blackpearl)
+    ;;
+  bounty)
+    ;;
+  # *DH
+  *)
+    echo "ERROR, xargs-chmod command not configured for ${host}"
+    exit 1
+    ;;
+esac
+
+echo "NRL SPACK-STACK BATCH INSTALL SUCCESSFUL"
+
+exit 0