83rd Annual

Monday, 10 February 2003
Practical Applications of Roadway Weather Information Systems in Pennsylvania
Paul G. Knight, Penn State Univ., University Park, PA; and B. B. Ayers, R. H. Grumm, and D. J. Ondrejik
Poster PDF (39.6 kB)
The Pennsylvania State Climate Office and the National Weather Service in State College have acquired the data from the Pennsylvania Department of Transportation's (PENNDOT) network of Roadway Weather Information System (RWIS) sensors for over 20 months. Initial efforts focused on data retrieval and quality control issues. More recent work has focused on applications, both meteorological and climatological, to make better use of these valuable data.

For quality control purposes, each RWIS site was assigned a nearby Federal Aviation Administration (FAA) observing site as a check station. Data from individual RWIS sites were compared to the assigned FAA site to ensure the quality of the temperature, dew point, and wind sensors. Once the relative quality of these RWIS observations were established, these data were plotted for a more rigorous inspection of their worth. Stations, which were unrepresentative, were flagged and the observations were adjusted based on their nearest neighbor’s values. The database has enabled tracking of stations that report most often and which stations have the highest quality data. This has facilitated the development of a database for longer-term climatic study.

The data were used to create enhanced meteorological products. These products include a mesonet which joined FAA reports, Department of Environmental Protection observations and the RWIS data for web-based access. Another product was the incorporation of RWIS and DEP reports into AWIPS at the National Weather Service office in State College. These data form the basis for an integrated mesonet used in short-term forecasting in Pennsylvania. During several winter storms in 2001-2002 and recent severe weather events, these data have proven useful in identifying significant mesoscale features. During the winter events, these observations were useful in differentiating areas of snow occurring along the ridges and pockets of freezing rain.

The web-based data displays continue to evolve, allowing users to see evidence of microclimates in the state. In addition to the real-time displays, as the database expands, it will provide valuable information about winds, radiational cooling, and other climatic impacts due to the complex terrain across Pennsylvania.

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