PGH/MET/M1 - PWD spikes and missing data prior to revised install

The PWD was not installed efficiently, leading to occasional spikes and a period of 
missing data from 7/6 - 7/12 until revised installation took place and the programming was 
updated.

Use available PWD data with caution.

• Present weather detector ID(pwd_id)
• 1 hour present weather code(pwd_pw_code_1_hr)
• 1 minute average water intensity(pwd_avg_H2O_int_1_min)
• PWD alarm(pwd_err_code)
• Cumulative snow(pwd_cumul_snow)
• Average 1 min visibility(pwd_avg_vis_1_min)
• Cumulative water(pwd_cumul_water)
• Average 10 min visibility(pwd_avg_vis_10_min)
• 15 min present weather code(pwd_pw_code_15_min)
• PWD instantaneous present weather code(pwd_pw_code_inst)