The National Weather Service (NWS) has been tasked with the issuance of severe weather watches and warnings designed to protect life and property. To this end, the collection of timely and accurate surface weather data is vital. In addition to the protection of life and property, the Department of Commerces' National Oceanic and Atmospheric Administration (of which the NWS is a part) has been given the job of maintaining a database of climatic weather information. This too is used by the NWS in preparing medium and long range forecasts.


These two jobs have the Cooperative Observer Program, Co-Op Program in short, in common. The Co-Op Program is the backbone of the United States Climatological database. Co-Op observers frequently act as both as severe storm spotters, phoning in reports of hazardous weather in the winter and summer.

What is the job of a Co-Op observer?

Being a NWS Co-Operative observer can be a demanding job. To provide accurate and complete weather data, observations are required seven days a week 365 days a year. This does not mean that someone has to be monitoring the "weather" all the time; instruments are provided to monitor temperature and precipitation. Yet someone should be available to record the daily maximum and minimum temperature, the precipitation, and snowfall. This generally is done around 7am.


This information is recorded on a form which is mailed monthly to the local NWS office for quality assurance before forwarding to the National Climatic Data Center (NCDC) in Asheville, North Carolina.
There is also a secondary level of cooperative observer, the unofficial coop. No less important that the official coop sites, unofficial coop observers provide valuable information on precipitation to the NWS. The only real difference between official and unofficial coops is the unofficial coops data are not archived on a national level. Unofficial coops typically receive just a plastic 4 inch rain gage.

What equipment do I use?

All equipment (such as a rain gage) and supplies (forms, envelopes, etc) are provided by the National Weather Service. To learn more about the equipment, click here!

Depending on the level of service expected, equipment can vary from a simple 4 inch non recording plastic or 8 inch metal rain gage, to a full coop station with electronic thermometer and recording precipitation gage. The placement and type of Cooperative Weather Observers is determined by the NCDC as requested by the NWS Representative (NWSREP). Generally cooperative stations are evenly spaced in relatively flat terrain (more than 30 miles apart) but may be closer together in hilly terrain or under special circumstances. Most common are the "C" order station which support meteorological programs rather than climatological programs. Typically these are observers have a non recording rain gage. "A" and "B" order stations are for longer term climatological and hydrologic operations and have less contact with a NWSREP.

The NWSREP will deliver, set up, and maintain the necessary equipment. Typically, a station consists of a set of Maximum/Minimum thermometers or a Max/Min Temperature System (MMTS) and a rain gage. There are two basic types of rain gages - recording and non-recording. Non-recording rain gages consist of a metal tube approximately 8 inches in diameter and 3 feet tall with a removable funnel and inner plastic or metal measuring tube. Precipitation is measured by placing a calibrated stick into the tube, seeing where the water marks the stick and recording the data.

A recording rain gage has either a drum which holds a paper chart or a drive mechanism which punches holes in a strip chart to record precipitation. At the end of each month, the charts are forwarded to the local NWS office for QA then forwarding to NCDC.

What happens with the information I collect daily?

Data can be transmitted to the local NWS office by using a PC based system called PC-ROSA, or sending on a web page. This near real-time data is used to support the day-to-day operations of the NWS in its forecast and warning decisions.



What kind of training is involved?

Training consists of on site, hands on instruction with the designated Coop Observer and their backup. This usually is done the same day as the equipment is installed and takes about one hour. If necessary, additional training may be provided upon request. Basic equipment maintenance is discussed and the Coop observer is provided with a name ("point of contact") and a number should additional questions or problems arise.
A reference binder is also provided. If you have additional questions, please email us at w-lot.coop@noaa.gov.






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