Real-time objective analysis of surface data at the Meteorological Development Laboratory

As part of the Localized Aviation MOS Program (LAMP), the Meteorological Development Laboratory (MDL) is analyzing surface data reports on an hourly basis. The Bergthorssen-Cressman-Doos-Glahn (BCDG) analysis program being used for gridding MOS forecasts has been tailored to analyze quasi-continuous surface observations. Observations are obtained from the National Centers for Environmental Prediction in real time and are additionally quality controlled at MDL. The number of locations that can report is on the order of 20,000 over the contiguous United States, although only about half that number report on any given hour. MDL is making the analyses to judge the accuracy of the gridded MOS and LAMP forecasts as well as to provide gridded LAMP nowcasting. The analyses will be put into the National Digital Guidance Database (NDGD), the grid being the same as that used in the National Digital Forecast Database (NDFD). While only a few variables are currently being analyzed, the product suite will grow.

In this presentation, we describe the intensive effort needed to assure the metadata are correct for each location. Because the BCDG analysis differentiates between land and water (i.e., ocean and major lakes), it is essential that each reporting location be tagged as either land, ocean, or inland water, and for stations near the ocean or major lakes, a judgment is many times needed in addition to using high resolution Geographic Information System (GIS) capabilities. One of the features added to the analysis package is the ability to use a report from the previous hour if the site did not report at the analysis hour, and in so doing to account for possible diurnal changes from the previous hour's reports. The analysis method will be reviewed and examples of the analyses of temperature and dewpoint shown.