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This service queries the archive of Storm Prediction Center (SPC) Mesoscale Convective Discussions (MCD) for a given lat/lon point.
Changelog
- 2026-03-10: Prevent NaN values in the response.
- 2025-03-12: Added new Most Probable Intensity tags for MCDs
- 2024-07-09: Add csv and excel output formats
Example Requests
Return MCDs issued for Ames, IA in JSON, then CSV, then Excel format.
https://mesonet.agron.iastate.edu/json/spcmcd.py?lat=42.0&lon=-95.0
https://mesonet.agron.iastate.edu/json/spcmcd.py?lat=42.0&lon=-95.0&fmt=csv
https://mesonet.agron.iastate.edu/json/spcmcd.py?lat=42.0&lon=-95.0&fmt=excel
CGI Arguments
The following table lists the CGI arguments that are accepted by this service. A HTTP GET request is required. Fields of type Multi-Params or CSV value can accept either a comma separated list or multiple parameter and value combinations. For example, ?foo=1&foo=2 is equivalent to ?foo=1,2.
| Field | Type | Description |
|---|---|---|
| callback | string or null | Legacy JSON-P style callback. It is likely best to not depend on this usage. The IEM website has a permissive CORS. |
| fmt | string | The format to return, either json, excel, or csv |
| lat | number | Latitude (decimal degrees) of point of interest |
| lon | number | Longitude (decimal degrees) of point of interest |