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Severe Weather Data Inventory


The Severe Weather Data Inventory (SWDI) is an integrated database of severe weather records for the United States. The records in SWDI come from a variety of sources in the NCDC archive. SWDI provides the ability to search through all of these data to find records covering a particular time period and geographic region, and to download the results of your search in a variety of formats. The formats currently supported are Shapefile (for GIS), KMZ (for Google Earth), CSV (comma-separated), and XML.

Data Access

Map Search using location(s) of interest and allows for search of event type.

Bulk Download of the SWDI database is available as comma-separated text format (CSV) files for each dataset and are available for download from HTTP or FTP.

Web Services - automate queries or integrate into your own application.

Current Data Layers Descriptions

- Filtered Storm Cells (Max Reflectivity >= 45 dBZ) from NEXRAD (Level-III Storm Structure Product)
- All Storm Cells from NEXRAD (Level-III Storm Structure Product)
- Filtered Hail Signatures (Max Size > 0 and Probability = 100%) from NEXRAD (Level-III Hail Product)
- All Hail Signatures from NEXRAD (Level-III Hail Product)
- Mesocyclone Signatures from NEXRAD (Level-III Meso Product)
- Digital Mesocyclone Detection Algorithm from NEXRAD (Level-III MDA Product)
- Tornado Signatures from NEXRAD (Level-III TVS Product)
- Preliminary Local Storm Reports from the NOAA National Weather Service
- Lightning Strikes from Vaisala NLDN


SWDI provides a uniform way to access data from a variety of sources, but it does not provide any additional quality control beyond the processing taking place during data archival. The data sources in SWDI will not provide complete severe weather coverage of a geographic region nor period, due to a number of factors (e.g., reports for a location or time period not provided to NOAA). The absence of SWDI data for a particular location and time is not an indication that no severe weather occurred at that time and location. Furthermore, much of the automatically derived data in SWDI is from radar data and represents probable conditions for an event, rather than a confirmed occurrence.