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(RESOLVED) How to set namelist dates for forecast simulation

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M

minh281182

New member
I am really new with WPS/WRF.
I want to do a prediction. I download the GRIB2 data at: https://rda.ucar.edu/datasets/ds084.1/
If I have data for 2018 Sep 09 and 10, then I want to run the prediction for 2018 Sep 11 and 12. Then I put in "namelist.wps":

...
start_date = '2018-09-11_00:00:00',
end_date = '2018-09-13_00:00:00',
interval_seconds = 21600
...

After run, the ungrib.exe and metgrib.exe, I got those file likes:
...
FILE:2018-09-11_00
FILE:2018-09-11_06
FILE:2018-09-11_12
FILE:2018-09-11_18
FILE:2018-09-12_00
FILE:2018-09-12_06
FILE:2018-09-12_12
FILE:2018-09-12_18
FILE:2018-09-13_00
...
met_em.d01.2018-09-11_00:00:00.nc
met_em.d01.2018-09-11_06:00:00.nc
met_em.d01.2018-09-11_12:00:00.nc
met_em.d01.2018-09-11_18:00:00.nc
met_em.d01.2018-09-12_00:00:00.nc
met_em.d01.2018-09-12_06:00:00.nc
met_em.d01.2018-09-12_12:00:00.nc
met_em.d01.2018-09-12_18:00:00.nc
met_em.d01.2018-09-13_00:00:00.nc
...
Then I will take metgrib file to WRF module for prediction processing.

I want to confirm if my understanding is correct or not?
Thank you very much!
 
Dear minh281182,

Your namelist.wps configuration is correct. However, you will need data from 2018 Sep 11 00:00 to 2018 Sep 13 00:00 .
WRF is a regional model, and in each time step it needs boundary conditions from a general circulation model (i.e. GFS).

Regards.
 
Thanks nacosta for your reply!
But I cannot catch up one point: If I have already had the data from 2018 Sep 11 00:00 to 2018 Sep 13 00:00 (Global GFS data), why do I need to run to predict for 2018 Sep 11 00:00 to 2018 Sep 13 00:00.

I have data of 2018 Sep 11 00:00 to 2018 Sep 13 00:00 ===> mean I know the weather of 2018 Sep 11 00:00 to 2018 Sep 13 00:00
I want to predict the weather for the future day liked from Sep 14, 15, 16...

Could you please enlighten me on this? Might be I am lost the way.
Thank you very much in advance!
 
What you have is the GFS forecast. Since WRF can run in high resolution with detailed description of surface features, one expects that WRF can yield more mesoscale details and somehow improve the regional forecast.

Ming Chen
 
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