Install the Meso-NH model in a nutshell

1. Download the tar.gz archive from the official website (http://mesonh.aero.obs-mip.fr/mesonh54/Download)

wget http://mesonh.aero.obs-mip.fr/mesonh/dir_open/dir_MESONH/MNH-V5-4-3.tar.gz

2. Copy the archive file in the $HOME directory

cp MNH-V5-4-3.tar.gz $HOME/

3. update the GCC suite (this step is needed only if GCC version is less than 6.X)

scl enable devtoolset-6 bash

4. untar the model archive file

cd $HOME/

tar -zxf MNH-V5-4-3.tar.gz

5. export environmental variables

export ARCH=LXgfortran

export VER_MPI=MPIAUTO

export OPTLEVEL=O2

that is

# Use "gfortran" compiler on LX=Linux Platform
# Use MPI with compiler wrapper 'mpif90', for computer having this wrapper installed

# Compile in O2, 4 times faster then DEBUG, but less error checks

6. fix the bug in routine latlon_to_xy.f90 (if needed)

vim $HOME/MNH-V5-4-3/src/MNH/latlon_to_xy.f90
and add the following line :
USE MODE_POS, ONLY: POSNAM
after this line

USE MODE_MODELN_HANDLER,   ONLY: GOTO_MODEL

7. cd src directory and run configure

cd $HOME/MNH-V5-4-3/src/

./configure

8. load the profile_mesonh file

. ../conf/profile_mesonh_etcetcetc_, with the above options it should be

. ../conf/profile_mesonh-LXgfortran-R8I4-MNH-V5-4-3-MPIAUTO-O2

9. make and install

make -j 8 && make installmaster

For future use, add the profile_mesonh_etc file in the ~/.bashrc file, i.e.

ln -svf $HOME/MNH-V5-4-3/conf/profile_mesonh-LXgfortran-R8I4-MNH-V5-4-3-MPIAUTO-O2 $HOME/MNH-V5-4-3/conf/profile_mesonh

and then add the line

.  $HOME/MNH-V5-4-3/conf/profile_mesonh

in the $HOME/.bashrc file

Also follow the link https://kvadlamudi85.medium.com/a-complete-guide-to-the-random-forest-algorithm-9f396294e2bb which provides similar instructions on how to install the Meso-NH model on a Ubuntu 18.04