diff --git a/modulefiles/gsi_acorn.intel.lua b/modulefiles/gsi_acorn.intel.lua
new file mode 100644
index 000000000..03928be82
--- /dev/null
+++ b/modulefiles/gsi_acorn.intel.lua
@@ -0,0 +1,54 @@
+help([[
+]])
+
+local PrgEnv_intel_ver=os.getenv("PrgEnv_intel_ver") or "8.1.0"
+local intel_ver=os.getenv("intel_ver") or "19.1.3.304"
+local craype_ver=os.getenv("craype_ver") or "2.7.8"
+local cray_mpich_ver=os.getenv("cray_mpich_ver") or "8.1.7"
+local cmake_ver= os.getenv("cmake_ver") or "3.20.2"
+local python_ver=os.getenv("python_ver") or "3.8.6"
+local prod_util_ver=os.getenv("prod_util_ver") or "2.0.10"
+
+local netcdf_ver=os.getenv("netcdf_ver") or "4.7.4"
+local bufr_ver=os.getenv("bufr_ver") or "11.7.0"
+local bacio_ver=os.getenv("bacio_ver") or "2.4.1"
+local w3emc_ver=os.getenv("w3emc_ver") or "2.9.2"
+local sp_ver=os.getenv("sp_ver") or "2.3.3"
+local ip_ver=os.getenv("ip_ver") or "3.3.3"
+local sigio_ver=os.getenv("sigio_ver") or "2.3.2"
+local sfcio_ver=os.getenv("sfcio_ver") or "1.4.1"
+local nemsio_ver=os.getenv("nemsio_ver") or "2.5.4"
+local wrf_io_ver=os.getenv("wrf_io_ver") or "1.2.0"
+local ncio_ver=os.getenv("ncio_ver") or "1.1.2"
+local crtm_ver=os.getenv("crtm_ver") or "2.4.0.1"
+local ncdiag_ver=os.getenv("ncdiag_ver") or "1.1.1"
+
+load(pathJoin("PrgEnv-intel", PrgEnv_intel_ver))
+load(pathJoin("intel", intel_ver))
+load(pathJoin("craype", craype_ver))
+load(pathJoin("cray-mpich", cray_mpich_ver))
+load(pathJoin("cmake", cmake_ver))
+load(pathJoin("python", python_ver))
+
+load(pathJoin("prod_util", prod_util_ver))
+
+load(pathJoin("netcdf", netcdf_ver))
+load(pathJoin("bufr", bufr_ver))
+load(pathJoin("bacio", bacio_ver))
+load(pathJoin("w3emc", w3emc_ver))
+load(pathJoin("sp", sp_ver))
+load(pathJoin("ip", ip_ver))
+load(pathJoin("sigio", sigio_ver))
+load(pathJoin("sfcio", sfcio_ver))
+load(pathJoin("nemsio", nemsio_ver))
+load(pathJoin("wrf_io", wrf_io_ver))
+load(pathJoin("ncio", ncio_ver))
+load(pathJoin("ncdiag",ncdiag_ver))
+
+-- Lastly, load CRTM from the EMC location
+append_path("MODULEPATH", "/lfs/h1/emc/nceplibs/noscrub/hpc-stack/libs/hpc-stack/modulefiles/compiler/intel/19.1.3.304")
+load(pathJoin("crtm", crtm_ver))
+
+pushenv("GSI_BINARY_SOURCE_DIR", "/lfs/h2/emc/global/noscrub/emc.global/FIX/fix/gsi/20240208")
+
+whatis("Description: GSI environment on WCOSS2 Acorn")
diff --git a/regression/regression_driver.sh b/regression/regression_driver.sh
index 805a9dd1f..6667d483f 100755
--- a/regression/regression_driver.sh
+++ b/regression/regression_driver.sh
@@ -45,7 +45,7 @@ for jn in `seq ${RSTART} ${REND}`; do
    fi
    rm -f ${job[$jn]}.out
 
-   /bin/sh $ush/$sub_cmd -q $queue -j ${job[$jn]} -t ${topts[$jn]} -p ${popts[$jn]} -r ${ropts[$jn]} $scripts/${regtest}.sh
+   /bin/sh $ush/$sub_cmd -m ${machine} -q $queue -j ${job[$jn]} -t ${topts[$jn]} -p ${popts[$jn]} -r ${ropts[$jn]} $scripts/${regtest}.sh
 
    if [ $debug == ".true." ]; then break; fi
    $scripts/regression_wait.sh ${job[$jn]} ${rcname} $check_resource
diff --git a/regression/regression_param.sh b/regression/regression_param.sh
index 209762569..34d5964d8 100755
--- a/regression/regression_param.sh
+++ b/regression/regression_param.sh
@@ -4,8 +4,8 @@ regtest=$1
 
 case $machine in
 
-	Hera)
-	   sub_cmd="sub_hera"
+    Hera)
+           sub_cmd="sub_hera"
            memnode=96
            numcore=40
     ;;
@@ -19,23 +19,28 @@ case $machine in
            memnode=512
            numcore=40
     ;;
-	Jet)
-	   sub_cmd="sub_jet"
+    Jet)
+           sub_cmd="sub_jet"
            memnode=96
            numcore=40
     ;;
-	Gaea)
-	   sub_cmd="sub_gaea"
+    Gaea)
+           sub_cmd="sub_gaea"
            memnode=251
            numcore=128
     ;;
-	wcoss2)
-	   sub_cmd="sub_wcoss2"
+    wcoss2)
+           sub_cmd="sub_wcoss2"
            memnode=512
            numcore=128
     ;;
-	Discover)
-	   sub_cmd="sub_discover"
+    acorn)
+           sub_cmd="sub_acorn"
+           memnode=512
+           numcore=128
+    ;;
+    Discover)
+       sub_cmd="sub_discover"
     ;;
     *) # EXIT out for unresolved machine
         echo "unknown $machine"
@@ -71,7 +76,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:10:00" ; popts[1]="12/8/" ; ropts[1]="/1"
            topts[2]="0:10:00" ; popts[2]="12/10/" ; ropts[2]="/2"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:10:00" ; popts[1]="12/8/" ; ropts[1]="/1"
            topts[2]="0:10:00" ; popts[2]="12/10/" ; ropts[2]="/2"
         fi
@@ -101,7 +106,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/"  ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="128/2/"  ; ropts[2]="/1"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/" ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="128/2/" ; ropts[2]="/1"
         fi
@@ -131,7 +136,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/"  ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="128/2/"  ; ropts[2]="/1"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/" ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="128/2/" ; ropts[2]="/1"
         fi
@@ -160,7 +165,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/"  ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="128/2/"  ; ropts[2]="/1"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/" ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="128/2/" ; ropts[2]="/1"
         fi
@@ -190,7 +195,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:15:00" ; popts[1]="28/1/"  ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="28/2/"  ; ropts[2]="/1"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:15:00" ; popts[1]="64/1/" ; ropts[1]="/1"
            topts[2]="0:15:00" ; popts[2]="64/2/" ; ropts[2]="/1"
         fi
@@ -220,7 +225,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:30:00" ; popts[1]="14/8/"  ; ropts[1]="/1"
            topts[2]="0:30:00" ; popts[2]="14/14/"  ; ropts[2]="/1"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:30:00" ; popts[1]="14/8/" ; ropts[1]="/1"
            topts[2]="0:30:00" ; popts[2]="14/14/" ; ropts[2]="/2"
         fi
@@ -250,7 +255,7 @@ case $regtest in
         elif [[ "$machine" = "Gaea" ]]; then
            topts[1]="0:10:00" ; popts[1]="16/2/" ; ropts[1]="/1"
            topts[2]="0:10:00" ; popts[2]="16/4/" ; ropts[2]="/2"
-        elif [[ "$machine" = "wcoss2" ]]; then
+        elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
            topts[1]="0:10:00" ; popts[1]="16/2/" ; ropts[1]="/1"
            topts[2]="0:10:00" ; popts[2]="16/4/" ; ropts[2]="/2"
         fi
@@ -316,7 +321,7 @@ elif [[ "$machine" = "Gaea" ]]; then
    export MPI_BUFS_PER_HOST=256
    export MPI_GROUP_MAX=256
    export APRUN="srun --export=ALL -n \$ntasks"
-elif [[ "$machine" = "wcoss2" ]]; then
+elif [[ "$machine" = "wcoss2" || "$machine" = "acorn" ]]; then
    export OMP_PLACES=cores
    export OMP_STACKSIZE=2G
    export FORT_BUFFERED=true
diff --git a/regression/regression_var.sh b/regression/regression_var.sh
index 4a2bc8587..d4e7d99aa 100755
--- a/regression/regression_var.sh
+++ b/regression/regression_var.sh
@@ -47,8 +47,12 @@ elif [[ -d /work ]]; then # Orion or Hercules
   else
     export machine="Orion"
   fi
-elif [[ -d /lfs/h2 ]]; then # wcoss2
-  export machine="wcoss2"
+elif [[ -d /lfs/h2 ]]; then # wcoss2 or acorn
+  if [[ $(hostname -f) =~ "alogin" ]]; then
+    export machine="acorn"
+  else
+    export machine="wcoss2"
+  fi
 fi
 echo "Running Regression Tests on '$machine'";
 
@@ -63,7 +67,7 @@ case $machine in
     export check_resource="no"
     export accnt="ufs-ard"
   ;;
-  wcoss2)
+  wcoss2 | acorn)
       export local_or_default="${local_or_default:-/lfs/h2/emc/da/noscrub/$LOGNAME}"
       if [ -d $local_or_default ]; then
           export noscrub="$local_or_default/noscrub"
diff --git a/ush/detect_machine.sh b/ush/detect_machine.sh
index 0beb937f7..e06775dbb 100755
--- a/ush/detect_machine.sh
+++ b/ush/detect_machine.sh
@@ -14,8 +14,8 @@
 # First detect w/ hostname
 case $(hostname -f) in
 
-  adecflow0[12].acorn.wcoss2.ncep.noaa.gov)  MACHINE_ID=acorn ;; ### acorn
-  alogin0[12].acorn.wcoss2.ncep.noaa.gov)    MACHINE_ID=acorn ;; ### acorn
+  adecflow0[1-3].acorn.wcoss2.ncep.noaa.gov)  MACHINE_ID=acorn ;; ### acorn
+  alogin0[1-3].acorn.wcoss2.ncep.noaa.gov)    MACHINE_ID=acorn ;; ### acorn
   clogin0[1-9].cactus.wcoss2.ncep.noaa.gov)  MACHINE_ID=wcoss2 ;; ### cactus01-9
   clogin10.cactus.wcoss2.ncep.noaa.gov)      MACHINE_ID=wcoss2 ;; ### cactus10
   dlogin0[1-9].dogwood.wcoss2.ncep.noaa.gov) MACHINE_ID=wcoss2 ;; ### dogwood01-9
diff --git a/ush/module-setup.sh b/ush/module-setup.sh
index 299e13aa4..1f7a4462e 100755
--- a/ush/module-setup.sh
+++ b/ush/module-setup.sh
@@ -36,8 +36,8 @@ elif [[ $MACHINE_ID = s4* ]] ; then
     fi
     module purge
 
-elif [[ $MACHINE_ID = wcoss2 ]]; then
-    # We are on WCOSS2
+elif [[ $MACHINE_ID = wcoss2 || $MACHINE_ID = acorn ]]; then
+    # We are on WCOSS2 (cactus, dogwood, or acorn)
     module reset
 
 elif [[ $MACHINE_ID = stampede* ]] ; then
diff --git a/ush/sub_acorn b/ush/sub_acorn
new file mode 120000
index 000000000..c2df78493
--- /dev/null
+++ b/ush/sub_acorn
@@ -0,0 +1 @@
+sub_wcoss2
\ No newline at end of file
diff --git a/ush/sub_wcoss2 b/ush/sub_wcoss2
index cd21e932f..e0b4a03cc 100755
--- a/ush/sub_wcoss2
+++ b/ush/sub_wcoss2
@@ -1,6 +1,6 @@
 #!/bin/sh --login
 set -x
-echo "starting sub_wcoss2"
+echo "starting sub_${machine}"  # wcoss2 or acorn
 usage="\
 Usage:  $0 [options] executable [args]
       where the options are:
@@ -125,7 +125,7 @@ echo "" >> $cfile
 
 echo "module reset"                         >> $cfile
 echo "module use $modulefiles"              >> $cfile
-echo "module load gsi_wcoss2.intel"               >> $cfile
+echo "module load gsi_${machine}.intel"     >> $cfile
 echo "module load envvar/1.0"               >> $cfile
 echo "module load cray-pals/1.2.2"          >> $cfile
 echo "module -t list 2>&1 | while read line;do module show $line 2>&1 | sed -n -e '2p';done | sort" >> $cfile
@@ -167,5 +167,5 @@ if [[ -w $SUBLOG ]];then
 fi
 ##rm $cfile $ofile
 ##[[ $MKDATA = YES ]] && rmdir $DATA
-echo "ending sub_wcoss2"
+echo "ending sub_${machine}"
 exit $rc