How to get the correct value of precipitation?

[hgecol]

I calculated hourly toal precipitaiotn based on following eqs:

Code: Select all

ACCUMULATED TOTAL PRECIPITATION: RAIN = RAINC + RAINNC
Hourly TOTAL PRECIPITATION: RAIN = RAINC (t) + RAINNC (t) -  RAINC (t-1) - RAINNC (t-1)

Yesterday, I have run WRF 3.8 with CEP GDAS Final Analysis (ds083.3, 0.25 degree, 6-hourly). I got negative value of hourly total precipitation. I also found a new item of RAINSH in the output file.

Could you help me to get correct value of precipitaion, please.