Network Description

The Pennsylvania Mesonet utilizes previously existing hourly reporting weather stations operated by various State and Federal agencies. Currently the following agencies and their respective networks provide data to the Pennsylvania State Climate Office to allow for a higher density of observations and level of quality assurance than each network by itself.

National Weather ServiceASOS, AWOS and BUOY Networks
Pennsylvania Department of TransportationRWIS Network
Pennsylvania Department of Environmental ProtectionCOPAMS Network
United States Forest ServiceRAWS Network
Citizens Weather Observing ProgramCWOP Network

ASOS (Automated Surface Observing System)

ASOS data includes hourly air temperature, dewpoint, precipitation, wind speed, wind direction, cloud cover, visibility and present weather. The most recent data can also be received every minute through a modem. The National Weather Service, Federal Aviation Administration and Department of Defense operate the 967 stations across the United States which includes the 24 in Pennsylvania.

AWOS (Automated Weather Observing System)

Operated by the Federal Aviation Administration, Aviation Divisions of State Departments of Transportation, and other state agencies, these 22 Pennsylvania stations output 20 minute observations of air temperature, dewpoint, precipitation, wind speed, wind direction, cloud cover, visibility, altimeter setting and present weather. 16 of the 22 stations only have data available through a dial-up modem, while all of these stations keep their observations for up to 3 weeks.

RWIS (Roadway Weather Information System)

The Pennsylvania Department of Transportation currently operates approximately 80 RWIS sites across the Commonwealth that report temperature, wind data, relative humidity, dew point, visibility, precipitation data and specific roadway conditions. The RWIS system reports data to the control center through a dial-up modem, although the data is received after an average time of only thirty minutes. The data is then interpreted by the DOT to make crucial decisions about pavement treatment. For further information on the PennDOT RWIS sites visit PennDOT's RWIS Homepage.

COPAMS (Commonwealth of Pennsylvania Air Monitoring System)

COPAMS sites are a bit different than the RWIS sites, in that COPAMS measure both the concentration of air pollutants and weather information. With 44 locations across the Commonwealth, the COPAMS stations also use a dial-up modem to link the data collection to the control center. Currently, data is being received approximately an hour and a half from the time the observation was taken. The Pennsylvania Department of Environmental Protection Bureau of Air Quality operates these stations. For further information on the COPAMS sites, visit Pennsylvania DEP's COPAMS Homepage.

RAWS (Remote Automated Weather Station Network)

The United States Forest Service supervises the 726 stations across the United States that are located in heavily forested areas. There is only 1 of these stations in Pennsylvania (located in the Northwestern part of the state) that produces hourly values of air temperature, dewpoint, precipitation, wind speed, wind direction, relative humidity, fuel temperature and fuel moisture.

CWOP (Citizens Weather Observing Program)

The Citizen Weather Observer Program (CWOP) began with ham radio operators broadcasting their weather data, and now consists of the weather observations of over 6500 private citizens worldwide. Data collection and quality control is handled by the NOAA MADIS system, and current data is available for free over the internet. Data reports can be as frequent as every five minutes, and include temperature, wind, relative humidity, and pressure observations. For further information, visit the CWOP homepage.

For further information about these networks, please visit the Pennsylvania Hydrometeorological Network site.