diff --git a/.github/workflows/GCC.yml b/.github/workflows/GCC.yml
index 4f1b7a894..0da81e763 100644
--- a/.github/workflows/GCC.yml
+++ b/.github/workflows/GCC.yml
@@ -15,33 +15,34 @@ on:
     - develop
 
 jobs:
-  GCC:
+  build_spack:
     runs-on: ubuntu-latest
 
     strategy:
       matrix:
-        cmake_opts: ["-D32BIT=ON", "-D32BIT=OFF"]
-        gcc_ver: ["11"]
-        mpi: ["mpich"]
+        gcc_ver: ["12"]
+        mpi: ["mpich", "openmpi"]
 
     steps:
 
-    - name: install-doxygen
-      run: |
-        sudo apt-get install doxygen graphviz
-        
     - name: checkout-fv3atm
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         path: ${{ github.workspace }}/fv3atm
         submodules: recursive
 
+    - name: install-cmake
+      run: | 
+        cd ${{ github.workspace }}
+        curl -f -s -S -R -L https://github.com/Kitware/CMake/releases/download/v3.29.2/cmake-3.29.2-Linux-x86_64.tar.gz | tar -zx
+        echo "${{ github.workspace }}/cmake-3.29.2-linux-x86_64/bin" >> $GITHUB_PATH
+
     - name: cache-spack
       id: cache-spack
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ github.workspace }}/spack-develop
-        key: spack-${{ hashFiles('fv3atm/ci/spack.yaml') }}-gcc${{ matrix.gcc_ver }}-2-${{ matrix.cmake_opts }}-${{ matrix.mpich }}
+        key: spack-${{ hashFiles('fv3atm/ci/spack.yaml') }}-gcc${{ matrix.gcc_ver }}-${{ matrix.mpi }}
 
     # Building dependencies takes 40+ min
     - name: spack-install
@@ -58,6 +59,42 @@ jobs:
         spack config add "packages:mpi:require:'${{ matrix.mpi }}'"
         spack concretize |& tee ${SPACK_ENV}/log.concretize
         spack install -j2 --fail-fast
+        spack clean --all
+
+  build_fv3atm:
+    needs: build_spack
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        cmake_opts: ["-D32BIT=ON", "-D32BIT=OFF"]
+        gcc_ver: ["12"]
+        mpi: ["mpich", "openmpi"]
+
+    steps:
+
+    - name: install-doxygen
+      run: |
+        sudo apt-get install doxygen graphviz
+
+    - name: install-cmake
+      run: | 
+        cd ${{ github.workspace }}
+        curl -f -s -S -R -L https://github.com/Kitware/CMake/releases/download/v3.29.2/cmake-3.29.2-Linux-x86_64.tar.gz | tar -zx
+        echo "${{ github.workspace }}/cmake-3.29.2-linux-x86_64/bin" >> $GITHUB_PATH
+
+    - name: checkout-fv3atm
+      uses: actions/checkout@v4
+      with:
+        path: ${{ github.workspace }}/fv3atm
+        submodules: recursive
+
+    - name: cache-spack
+      id: cache-spack
+      uses: actions/cache/restore@v4
+      with:
+        path: ${{ github.workspace }}/spack-develop
+        key: spack-${{ hashFiles('fv3atm/ci/spack.yaml') }}-gcc${{ matrix.gcc_ver }}-${{ matrix.mpi }}
 
     - name: build-fv3atm
       run: |
@@ -70,20 +107,24 @@ jobs:
         mkdir ${GITHUB_WORKSPACE}/build
         sed -i 's/doc /upp_doc /' upp/docs/CMakeLists.txt
         cd ${GITHUB_WORKSPACE}/build
+        export CC=mpicc
+        export CXX=mpicxx
+        export FC=mpif90
+        cat /home/runner/work/fv3atm/fv3atm/spack-develop/opt/spack/linux-ubuntu22.04-zen2/gcc-12.3.0/fms-2023.04-*/lib/cmake/fms/fms-config.cmake
         cmake ${GITHUB_WORKSPACE}/fv3atm -DBUILD_TESTING=ON ${{ matrix.cmake_opts }} -DENABLE_DOCS=ON
         make -j2
         ls -l /home/runner/work/fv3atm/fv3atm/fv3atm/io
 
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
-        name: docs
+        name: docs-gcc${{ matrix.gcc_ver }}-${{ matrix.mpi }}-${{ matrix.cmake_opts }}
         path: |
           build/docs/html
-          
+
     - name: debug-artifacts
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       if: ${{ failure() }}
       with:
-        name: ccpp_prebuild_logs
+        name: ccpp_prebuild_logs-gcc${{ matrix.gcc_ver }}-${{ matrix.mpi }}-${{ matrix.cmake_opts }}
         path: ${{ github.workspace }}/build/ccpp/ccpp_prebuild.*
 
diff --git a/upp b/upp
index 945cb2cef..5faac752d 160000
--- a/upp
+++ b/upp
@@ -1 +1 @@
-Subproject commit 945cb2cef5e8bd5949afd4f0fc35c4fb6e95a1bf
+Subproject commit 5faac752d9550d3570705358fa1eb3f5ac78a786