NSA/MET/C1 - CMH communication failure

CMH lost communication with datalogger. All values from CMH were -6999 during this time 
resulting in the CMHRH flatlining at 100%. Communications was intermittent during entire 
time period.

Use 2m t/rh data

• CMH relative humidity, calculated(cmh_rh)
• CMH saturation vapor pressure, calculated(cmh_sat_vapor_pressure)
• CMH vapor pressure, calculated(cmh_vapor_pressure)
• CMH temperature(cmh_temp)
• CMH dew point(cmh_dew_point)