diff --git a/.github/workflows/cygwin-compile.yml b/.github/workflows/cygwin-compile.yml
new file mode 100644
index 0000000000..ed10f2b199
--- /dev/null
+++ b/.github/workflows/cygwin-compile.yml
@@ -0,0 +1,81 @@
+name: Check Cygwin Compile
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+
+    runs-on: windows-latest
+    env:
+      SHELLOPTS: igncr:pipefail
+      CYGWIN_NOWINPATH: 1
+      CHERE_INVOKING: 1
+      NETCDF: /usr
+      NETCDF4: 1
+      WRFIO_NCD_NO_LARGE_FILE_SUPPORT: 0
+      WRF_CHEM: ${{ matrix.chemistry }}
+      FLEX_LIB_DIR: /usr/lib
+      YACC: "/usr/bin/yacc -d"
+      WRF_HYDRO: ${{ matrix.hydrology }}
+
+    strategy:
+      max-parallel: 4
+      matrix:
+        parallelization: [3, 1, 2]
+        nesting: [0, 1]
+        chemistry: [0, 1]
+        hydrology: [0, 1]
+        exclude:
+          - hydrology: 1
+            parallelization: 1
+          - hydrology: 1
+            parallelization: 2
+
+    steps:
+    - name: Line-ending normalization
+      run: git config --global core.autocrlf input
+
+    - uses: actions/checkout@v4
+
+    - uses: cygwin/cygwin-install-action@v4
+      with:
+        packages: >-
+          gcc-core gcc-fortran
+          libnetcdf-fortran-devel libnetcdf-devel libhdf5-devel zlib-devel
+          ${{ matrix.parallelization >= 3 && 'openmpi libopenmpi-devel libhwloc-devel libevent-devel' || '' }}
+          libjasper-devel
+          perl perl_base tcsh m4 make sed
+          gawk tar gzip coreutils which file grep
+          libtirpc-devel
+          ${{ matrix.chemistry && 'flex bison' || '' }}
+
+    - name: configure
+      shell: 'C:\cygwin\bin\bash.exe -o igncr -eo pipefail {0}'
+      # Options:
+      # 1 serial 2 smpar 3 dmpar 4 dm+sm
+      # Nesting? 0 none 1 basic 2 preset move 3 vortex-following
+      run: |
+        ${{ matrix.hydrology == 1 && 'source hydro/template/setEnvar.sh' || '' }}
+        echo ${{ matrix.parallelization }}$'\n'${{ matrix.nesting }} | /bin/dash ./configure arw
+        if [ -f tools/nc4_test.log ] ; then cat tools/nc4_test.log; fi
+        test -f configure.wrf
+        ${{ matrix.hydrology == 1 && 'if [ ! -f hydro/Makefile.comm ] ; then cd hydro && /bin/bash -ex ./configure gfort && cd ..; fi' || '' }}
+        pwd
+        ls hydro
+        ${{ matrix.hydrology == 1 && 'test -f hydro/Makefile.comm' || '' }}
+
+    - name: Compile
+      shell: 'C:\cygwin\bin\bash.exe -o igncr -eo pipefail {0}'
+      run: |
+        ${{ matrix.hydrology == 1 && 'source hydro/template/setEnvar.sh' || '' }}
+        ./compile em_real
+        ls main/*.exe
+        ls test/em_real/real.exe
diff --git a/arch/configure.defaults b/arch/configure.defaults
index 36ca1b6e00..810c26624f 100644
--- a/arch/configure.defaults
+++ b/arch/configure.defaults
@@ -1994,7 +1994,7 @@ FCDEBUG         =       # -g $(FCNOOPT) # -ggdb -fbacktrace
 FORMAT_FIXED    =       -ffixed-form
 FORMAT_FREE     =       -ffree-form -ffree-line-length-none
 FCSUFFIX        =       
-FCCOMPAT        =       
+FCCOMPAT        =       -fallow-argument-mismatch -fallow-invalid-boz
 BYTESWAPIO      =       -fconvert=big-endian -frecord-marker=4
 FCBASEOPTS_NO_G =       -w $(FORMAT_FREE) $(BYTESWAPIO) $(FCCOMPAT)
 FCBASEOPTS      =       $(FCBASEOPTS_NO_G) $(FCDEBUG)
diff --git a/hydro/configure b/hydro/configure
index ce896c95fe..7e8b85719e 100755
--- a/hydro/configure
+++ b/hydro/configure
@@ -96,6 +96,9 @@ if [[ "$theArgument" == "2" ]] || [[ "$theArgument" == "gfort" ]]; then
     cp arc/macros.mpp.gfort macros 
     cp arc/Makefile.mpp Makefile.comm
     echo "Configured: gfort"
+    pwd
+    ls -lh Makefile.comm
+    file Makefile.comm
 fi
 
 if [[ "$theArgument" == "3" ]] || [[ "$theArgument" == "ifort" ]]; then
@@ -178,6 +181,7 @@ if [[ -e macros.tmp ]]; then
     rm -f macros.tmp
     mv macros.a macros
 fi
+test -f Makefile.comm
 
 ## success
 exit 0