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Post processing WRF output for single time step with out namelist.input


New member
Hi, I have a WRF model output, that has only one time step; I don't even have namelist.input. Is it possible to do ARWPost? If it is possible, can you please explain it to me?
ARWpost can process wrfout files no matter how many time steps are included. So the answer is yes.
This document describes how to use ARWpost: WRF Post-processing — WRF Users Guide documentation

However, note that ARWpost is no longer developed and we only provide limited support to this package. We recommend you to switch to NCL and Python to process wrfout files.
thank you for your response
this is my namelist.ARWpost,

start_date = '2020-11-26_00:00:00',
end_date = '2020-11-26_01:00:00',
interval_seconds = 3600
tacc = 0,
debug_level = 0,
i given only datetime part, remaining parts are correct,
when i am running this, i am getting this error

ARWpost v3.1
At line 93 of file gridinfo_module.f (unit = 10, file = 'namelist.ARWpost')
Fortran runtime error: Cannot match namelist object name io_form_input

Error termination. Backtrace:
#0 0x7f981a9012ed in ???
#1 0x7f981a901ed5 in ???
#2 0x7f981a90269d in ???
#3 0x7f981aa7372a in ???
#4 0x7f981aa7c56f in ???
#5 0x7f981aa7c828 in ???
#6 0x56476f55a8b0 in ???
#7 0x56476f55b58f in ???
#8 0x7f981a178c86 in ???
#9 0x56476f559fc9 in ???
#10 0xffffffffffffffff in ???

after that i checked commenting some options in datetime part, like below

start_date = '2020-11-26_00:00:00',
!end_date = '2020-11-26_00:00:00',
!interval_seconds = 3600
!tacc = 0,
!debug_level = 0,
after runnig my namelist.ARWpost, i am getting like below message,

ARWpost v3.1

FOUND the following input files:

GETH_IDTS: Month of ODATE = 0
Screwy ODATE: 0000-00-00_00:00:00
STOP odate_1

can you please help me to solve my problem?
Last edited:
please issue the command:

ncdump -v Times wrfout_d02_2020-11-26_00

What value do you get for Times? This is the time you should specify in your namelist.ARWpost
thank you for your reply, When i am trying to check my wrfout file by using
ncdump -h wrfout_d02_2020-11-26_00
ncdump -v Times wrfout_d02_2020-11-26_00
i am getting error like
ncdump: wrfout_d02_2020-11-26_00: NetCDF: Unknown file format.

It is showing that it is not a NetCDF file but a WRF output only. Have you ever faced this kind of problem? If yes, can you please help me?
How did you set "io_form_history" in namelist.input?
If io_form_history = 2, then the output should be netCDF format data.
Thank you for taking the time to reply.
I realized that since my file is in HDF format, it is not possible to post-process it using ARWPost. Do we have any tools to post-process the wrfout?
NCL can be used to process HDF data. Please see the website here for more information:

Python is another robust tool.

Hope this is helpful for you.
Hello Ming, when i am post processing the wrout in ncl, i am getting the below error. i haven't changed any thing in WRFUserARW.ncl library. can you please help me to solve this
fatal:["Execute.c":8637]:Execute: Error occurred at or near line 145 in file $NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl

fatal:["Execute.c":8637]:Execute: Error occurred at or near line 3290 in file $NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl

fatal:["Execute.c":8635]:Execute: Error occurred at or near line 25